PLOS Neglected Tropical Diseases: New ArticlesPLOShttps://journals.plos.org/plosntds/webmaster@plos.orghttps://journals.plos.org/plosntds/feed/atomAll PLOS articles are Open Access.https://journals.plos.org/plosntds/resource/img/favicon.icohttps://journals.plos.org/plosntds/resource/img/favicon.ico2024-03-28T14:53:22ZSpecies-specific responses during Seoul orthohantavirus infection in human and rat lung microvascular endothelial cellsDanny NoackMirjam C. G. N. van den HoutCarmen W. E. EmbregtsWilfred F. J. van IJckenMarion P. G. KoopmansBarry Rockx10.1371/journal.pntd.00120742024-03-27T14:00:00Z2024-03-27T14:00:00Z<p>by Danny Noack, Mirjam C. G. N. van den Hout, Carmen W. E. Embregts, Wilfred F. J. van IJcken, Marion P. G. Koopmans, Barry Rockx</p>
Seoul orthohantavirus (SEOV) is a rat-borne zoonotic virus that is transmitted via inhalation of aerosolized infectious excreta, and can cause hemorrhagic fever with renal syndrome (HFRS) in humans worldwide. In rats, SEOV predominantly exists as a persistent infection in the absence of overt clinical signs. Lack of disease in rats is attributed to downregulation of pro-inflammatory and upregulation of regulatory host responses. As lung microvascular endothelial cells (LMECs) represent a primary target of infection in both human and rats, infections in these cells provide a unique opportunity to study the central role of LMECs in the dichotomy between pathogenicity in both species. In this study, host responses to SEOV infection in primary human and rat LMECs were directly compared on a transcriptional level. As infection of rat LMECs was more efficient than human LMECs, the majority of anti-viral defense responses were observed earlier in rat LMECs. Most prominently, SEOV-induced processes in both species included responses to cytokine stimulus, negative regulation of innate immune responses, responses to type I and II interferons, regulation of pattern recognition receptor signaling and MHC-I signaling. However, over time, in the rat LMECs, responses shifted from an anti-viral state towards a more immunotolerant state displayed by a PD-L1, B2M-, JAK2-focused interaction network aiding in negative regulation of cytotoxic CD8-positive T cell activation. This suggests a novel mechanism by which species-specific orthohantavirus-induced endothelium and T cell crosstalk may play a crucial role in the development of acute disease in humans and persistence in rodents.Urinary proteomics reveals biological processes related to acute kidney injury in <i>Bothrops atrox</i> envenomingsLisele Maria Brasileiro-MartinsSofia Angiole CavalcanteThaís Pinto NascimentoAlexandre Vilhena Silva-NetoMarlon Dias Mariano SantosAmanda C. Camillo-AndradeJuliana de Saldanha da Gama FischerCaroline Coelho FerreiraLucas Barbosa OliveiraMarco Aurelio SartimAllyson Guimarães CostaManuela B. PuccaFan Hui WenAna Maria Moura-da-SilvaJacqueline SachettPaulo Costa CarvalhoPriscila Ferreira de AquinoWuelton M. Monteiro10.1371/journal.pntd.00120722024-03-27T14:00:00Z2024-03-27T14:00:00Z<p>by Lisele Maria Brasileiro-Martins, Sofia Angiole Cavalcante, Thaís Pinto Nascimento, Alexandre Vilhena Silva-Neto, Marlon Dias Mariano Santos, Amanda C. Camillo-Andrade, Juliana de Saldanha da Gama Fischer, Caroline Coelho Ferreira, Lucas Barbosa Oliveira, Marco Aurelio Sartim, Allyson Guimarães Costa, Manuela B. Pucca, Fan Hui Wen, Ana Maria Moura-da-Silva, Jacqueline Sachett, Paulo Costa Carvalho, Priscila Ferreira de Aquino, Wuelton M. Monteiro</p>
Acute kidney injury (AKI) is a critical systemic complication caused by <i>Bothrops</i> envenoming, a neglected health problem in the Brazilian Amazon. Understanding the underlying mechanisms leading to AKI is crucial for effectively mitigating the burden of this complication. This study aimed to characterize the urinary protein profile of <i>Bothrops atrox</i> snakebite victims who developed AKI. We analyzed three groups of samples collected on admission: healthy subjects (controls, n = 10), snakebite victims who developed AKI (AKI, n = 10), and those who did not evolve to AKI (No-AKI, n = 10). Using liquid-chromatography tandem mass spectrometry, we identified and quantified (label-free) 1190 proteins. A panel of 65 proteins was identified exclusively in the urine of snakebite victims, with 32 exclusives to the AKI condition. Proteins more abundant or exclusive in AKI’s urine were associated with acute phase response, endopeptidase inhibition, complement cascade, and inflammation. Notable proteins include serotransferrin, SERPINA-1, alpha-1B-glycoprotein, and NHL repeat-containing protein 3. Furthermore, evaluating previously reported biomarkers candidates for AKI and renal injury, we found retinol-binding protein, beta-2-microglobulin, cystatin-C, and hepcidin to be significant in cases of AKI induced by <i>Bothrops</i> envenoming. This work sheds light on physiological disturbances caused by <i>Bothrops</i> envenoming, highlighting potential biological processes contributing to AKI. Such insights may aid in better understanding and managing this life-threatening complication.Endothelial and inflammatory pathophysiology in dengue shock: New insights from a prospective cohort study in VietnamAngela McBrideHuynh Thi Le DuyenNguyen Lam VuongPhan Vinh ThoLuong Thi Hue TaiNguyen Thanh PhongNguyen Thanh NgocLam Minh YenPhung Tran Huy NhatTran Thuy ViMartin J. LlewelynLouise ThwaitesNguyen Van HaoSophie Yacoub10.1371/journal.pntd.00120712024-03-27T14:00:00Z2024-03-27T14:00:00Z<p>by Angela McBride, Huynh Thi Le Duyen, Nguyen Lam Vuong, Phan Vinh Tho, Luong Thi Hue Tai, Nguyen Thanh Phong, Nguyen Thanh Ngoc, Lam Minh Yen, Phung Tran Huy Nhat, Tran Thuy Vi, Martin J. Llewelyn, Louise Thwaites, Nguyen Van Hao, Sophie Yacoub</p>
Dengue shock (DS) is the most severe complication of dengue infection; endothelial hyperpermeability leads to profound plasma leakage, hypovolaemia and extravascular fluid accumulation. At present, the only treatment is supportive with intravenous fluid, but targeted endothelial stabilising therapies and host immune modulators are needed. With the aim of prioritising potential therapeutics, we conducted a prospective observational study of adults (≥16 years) with DS in Vietnam from 2019–2022, comparing the pathophysiology underlying circulatory failure with patients with septic shock (SS), and investigating the association of biomarkers with clinical severity (SOFA score, ICU admission, mortality) and pulmonary vascular leak (daily lung ultrasound for interstitial and pleural fluid). Plasma was collected at enrolment, 48 hours later and hospital discharge. We measured biomarkers of inflammation (IL-6, ferritin), endothelial activation (Ang-1, Ang-2, sTie-2, VCAM-1) and endothelial glycocalyx breakdown (hyaluronan, heparan sulfate, endocan, syndecan-1). We enrolled 135 patients with DS (median age 26, median SOFA score 7, 34 required ICU admission, 5 deaths), together with 37 patients with SS and 25 healthy controls. Within the DS group, IL-6 and ferritin were associated with admission SOFA score (IL-6: βeta0.70, p<0.001 & ferritin: βeta0.45, p<0.001), ICU admission (IL-6: OR 2.6, p<0.001 & ferritin: OR 1.55, p<0.001) and mortality (IL-6: OR 4.49, p = 0.005 & ferritin: OR 13.8, p = 0.02); both biomarkers discriminated survivors and non-survivors at 48 hours and all patients who died from DS had pre-mortem ferritin ≥100,000ng/ml. IL-6 most strongly correlated with severity of pulmonary vascular leakage (R = 0.41, p<0.001). Ang-2 correlated with pulmonary vascular leak (R = 0.33, p<0.001) and associated with SOFA score (β 0.81, p<0.001) and mortality (OR 8.06, p = 0.002). Ang-1 was associated with ICU admission (OR 1.6, p = 0.005) and mortality (OR 3.62, p = 0.006). All 4 glycocalyx biomarkers were positively associated with SOFA score, but only syndecan-1 was associated with ICU admission (OR 2.02, p<0.001) and mortality (OR 6.51, p<0.001). This study highlights the central role of hyperinflammation in determining outcomes from DS; the data suggest that anti-IL-1 and anti-IL-6 immune modulators and Tie2 agonists may be considered as candidates for therapeutic trials in severe dengue.Small Intestine Bacterial Overgrowth is associated with increased <i>Campylobacter</i> and epithelial injury in duodenal biopsies of Bangladeshi childrenShah Mohammad FahimJeffrey R. DonowitzEkaterina SmirnovaNing-Juin JanSubhasish DasMustafa MahfuzS. M. Abdul GaffarWilliam A. Petri JrChelsea MarieTahmeed Ahmed10.1371/journal.pntd.00120232024-03-27T14:00:00Z2024-03-27T14:00:00Z<p>by Shah Mohammad Fahim, Jeffrey R. Donowitz, Ekaterina Smirnova, Ning-Juin Jan, Subhasish Das, Mustafa Mahfuz, S. M. Abdul Gaffar, William A. Petri Jr, Chelsea Marie, Tahmeed Ahmed</p>
Small intestine bacterial overgrowth (SIBO) has been associated with enteric inflammation, linear growth stunting, and neurodevelopmental delays in children from low-income countries. Little is known about the histologic changes or epithelial adherent microbiota associated with SIBO. We sought to describe these relationships in a cohort of impoverished Bangladeshi children. Undernourished 12-18-month-old children underwent both glucose hydrogen breath testing for SIBO and duodenoscopy with biopsy. Biopsy samples were subject to both histological scoring and 16s rRNA sequencing. 118 children were enrolled with 16s sequencing data available on 53. Of 11 histological features, we found that SIBO was associated with one, enterocyte injury in the second part of the duodenum (<i>R</i> = 0.21, p = 0.02). SIBO was also associated with a significant increase in <i>Campylobacter</i> by 16s rRNA analysis (Log 2-fold change of 4.43; adjusted p = 1.9 x 10<sup>−6</sup>). These findings support the growing body of literature showing an association between SIBO and enteric inflammation and enterocyte injury and further delineate the subgroup of children with environmental enteric dysfunction who have SIBO. Further, they show a novel association between SIBO and <i>Campylobacter</i>. Mechanistic work is needed to understand the relationship between SIBO, enterocyte injury, and <i>Campylobacter</i>.Reinfection of farm dogs following praziquantel treatment in an endemic region of cystic echinococcosis in southeastern IranMehdi BorhaniMohammad Ali MohammadiMahbod EntezamiMohammad Reza BaneshiSaeid NasibiJoaquin M. PradaMajid Fasihi Harandi10.1371/journal.pntd.00119392024-03-27T14:00:00Z2024-03-27T14:00:00Z<p>by Mehdi Borhani, Mohammad Ali Mohammadi, Mahbod Entezami, Mohammad Reza Baneshi, Saeid Nasibi, Joaquin M. Prada, Majid Fasihi Harandi</p>
Cystic Echinococcosis (CE) as a prevalent tapeworm infection of human and herbivorous animals worldwide, is caused by accidental ingestion of <i>Echinococcus granulosus</i> eggs excreted from infected dogs. CE is endemic in the Middle East and North Africa, and is considered as an important parasitic zoonosis in Iran. It is transmitted between dogs as the primary definitive host and different livestock species as the intermediate hosts. One of the most important measures for CE control is dog deworming with praziquantel. Due to the frequent reinfection of dogs, intensive deworming campaigns are critical for breaking CE transmission. Dog reinfection rate could be used as an indicator of the intensity of local CE transmission in endemic areas. However, our knowledge on the extent of reinfection in the endemic regions is poor. The purpose of the present study was to determine <i>E</i>. <i>granulosus</i> reinfection rate after praziquantel administration in a population of owned dogs in Kerman, Iran. A cohort of 150 owned dogs was recruited, with stool samples collected before praziquantel administration as a single oral dose of 5 mg/kg. The re-samplings of the owned dogs were performed at 2, 5 and 12 months following initial praziquantel administration. Stool samples were examined microscopically using Willis flotation method. Genomic DNA was extracted, and <i>E</i>. <i>granulosus sensu lato</i>-specific primers were used to PCR-amplify a 133-bp fragment of a repeat unit of the parasite genome. Survival analysis was performed using Kaplan-Meier method to calculate cumulative survival rates, which is used here to capture reinfection dynamics, and monthly incidence of infection, capturing also the spatial distribution of disease risk. Results of survival analysis showed 8, 12 and 17% total reinfection rates in 2, 5 and 12 months following initial praziquantel administration, respectively, indicating that 92, 88 and 83% of the dogs had no detectable infection in that same time periods. The monthly incidence of reinfection in total owned dog population was estimated at 1.5% (95% CI 1.0–2.1). The results showed that the prevalence of echinococcosis in owned dogs, using copro-PCR assay was 42.6%. However, using conventional microscopy, 8% of fecal samples were positive for taeniid eggs. Our results suggest that regular treatment of the dog population with praziquantel every 60 days is ideal, however the frequency of dog dosing faces major logistics and cost challenges, threatening the sustainability of control programs. Understanding the nature and extent of dog reinfection in the endemic areas is essential for successful implementation of control programs and understanding patterns of CE transmission.Predictors for participation in mass-treatment and female genital schistosomiasis re-investigation, and the effect of praziquantel treatment in South African adolescentsTakalani Girly NemungadiElisabeth KleppaHashini Nilushika Galappaththi-ArachchigePavitra PillaySvein Gunnar GundersenBirgitte Jyding VennervaldPatricia Doris NdhlovuMyra TaylorSaloshni NaidooEyrun Floerecke Kjetland10.1371/journal.pntd.00117982024-03-27T14:00:00Z2024-03-27T14:00:00Z<p>by Takalani Girly Nemungadi, Elisabeth Kleppa, Hashini Nilushika Galappaththi-Arachchige, Pavitra Pillay, Svein Gunnar Gundersen, Birgitte Jyding Vennervald, Patricia Doris Ndhlovu, Myra Taylor, Saloshni Naidoo, Eyrun Floerecke Kjetland</p>
Objective <p>Female Genital Schistosomiasis (FGS) causes intravaginal lesions and symptoms that could be mistaken for sexually transmitted diseases or cancer. In adults, FGS lesions [grainy sandy patches (GSP), homogenous yellow patches (HYP), abnormal blood vessels and rubbery papules] are refractory to treatment. The effect of treatment has never been explored in young women; it is unclear if gynaecological investigation will be possible in this young age group (16–23 years). We explored the predictors for accepting anti-schistosomal treatment and/or gynaecological reinvestigation in young women, and the effects of anti-schistosomal mass-treatment (praziquantel) on the clinical manifestations of FGS at an adolescent age.</p> Method <p>The study was conducted between 2011 and 2013 in randomly selected, rural, high schools in Ilembe, uThungulu and Ugu Districts, KwaZulu-Natal Province, East Coast of South Africa. At baseline, gynaecological investigations were conducted in female learners in grades 8 to 12, aged 16–23 years (n = 2293). Mass-treatment was offered in the low-transmission season between May and August (a few in September, n = 48), in accordance with WHO recommendations. Reinvestigation was offered after a median of 9 months (range 5–14 months). Univariate, multivariable and logistic regression analysis were used to measure the association between variables.</p> Results <p>Prevalence: Of the 2293 learners who came for baseline gynaecological investigations, 1045 (46%) had FGS lesions and/or schistosomiasis, 209/1045 (20%) had GSP; 208/1045 (20%) HYP; 772/1045 (74%) had abnormal blood vessels; and 404/1045 (39%) were urine positive.Overall participation rate for mass treatment and gynaecological investigation: Only 26% (587/2293) learners participated in the mass treatment and 17% (401/2293) participated in the follow up gynaecological reinvestigations.Loss to follow-up among those with FGS: More than 70% of learners with FGS lesions at baseline were lost to follow-up for gynaecological investigations: 156/209 (75%) GSP; 154/208 (74%) HYP; 539/722 (75%) abnormal blood vessels; 238/404 (59%) urine positive. The grade 12 pupil had left school and did not participate in the reinvestigations (n = 375; 16%).Follow-up findings: Amongst those with lesions who came for both treatment and reinvestigation, 12/19 still had GSP, 8/28 had HYP, and 54/90 had abnormal blood vessels. Only 3/55 remained positive for <i>S</i>. <i>haematobium</i> ova.Factors influencing treatment and follow-up gynaecological investigation: HIV, current water contact, water contact as a toddler and urinary schistosomiasis influenced participation in mass treatment. Grainy sandy patches, abnormal blood vessels, HYP, previous pregnancy, current water contact, water contact as a toddler and father present in the family were strongly associated with coming back for follow-up gynaecological investigation.Challenges in sample size for follow-up analysis of the effect of treatment: The low mass treatment uptake and loss to follow up among those who had baseline FGS reduced the chances of a larger sample size at follow up investigation. However, multivariable analysis showed that treatment had effect on the abnormal blood vessels (adjusted odds ratio = 2.1, 95% CI 1.1–3.9 and p 0.018).</p> Conclusion <p>Compliance to treatment and gynaecological reinvestigation was very low. There is need to embark on large scale awareness and advocacy in schools and communities before implementing mass-treatment and investigation studies. Despite challenges in sample size and significant loss to follow-up, limiting the ability to fully understand the treatment’s effect, multivariable analysis demonstrated a significant treatment effect on abnormal blood vessels.</p>Landscape of toxin-neutralizing therapeutics for snakebite envenoming (2015–2022): Setting the stage for an R&D agendaJuliette BorriJosé María GutiérrezCecilie KnudsenAbdulrazaq G. HabibMaya GoldsteinAndrew Tuttle10.1371/journal.pntd.00120522024-03-26T14:00:00Z2024-03-26T14:00:00Z<p>by Juliette Borri, José María Gutiérrez, Cecilie Knudsen, Abdulrazaq G. Habib, Maya Goldstein, Andrew Tuttle</p>
Background <p>Progress in snakebite envenoming (SBE) therapeutics has suffered from a critical lack of data on the research and development (R&D) landscape. A database characterising this information would be a powerful tool for coordinating and accelerating SBE R&D. To address this need, we aimed to identify and categorise all active investigational candidates in development for SBE and all available or marketed products.</p> Methodology/Principal findings <p>In this landscape study, publicly available data and literature were reviewed to canvas the state of the SBE therapeutics market and research pipeline by identifying, characterising, and validating all investigational drug and biologic candidates with direct action on snake venom toxins, and all products available or marketed from 2015 to 2022. We identified 127 marketed products and 196 candidates in the pipeline, describing a very homogenous market of similar but geographically bespoke products and a diverse but immature pipeline, as most investigational candidates are at an early stage of development, with only eight candidates in clinical development.</p> Conclusions/Significance <p>Further investment and research is needed to address the shortfalls in products already on the market and to accelerate R&D for new therapeutics. This should be accompanied by efforts to converge on shared priorities and reshape the current SBE R&D ecosystem to ensure translation of innovation and access.</p><i>In vitro</i> immunoreactivity and <i>in vivo</i> neutralization of <i>Trimeresurus gracilis</i> venom with antivenoms targeting four pit viper speciesPo-Chun ChuangJia-Wei ChenYuen-Ying ChanTsz-Chun TseYu-Wei ChiangTein-Shun Tsai10.1371/journal.pntd.00120702024-03-25T14:00:00Z2024-03-25T14:00:00Z<p>by Po-Chun Chuang, Jia-Wei Chen, Yuen-Ying Chan, Tsz-Chun Tse, Yu-Wei Chiang, Tein-Shun Tsai</p>
Snakebite envenomation is a significant global health issue that requires specific antivenom treatments. In Taiwan, available antivenoms target a variety of snakes, but none specifically target <i>Trimeresurus gracilis</i>, an endemic and protected species found in the high mountain areas of Taiwan. This study evaluated the effectiveness of existing antivenoms against <i>T</i>. <i>gracilis</i> venom, focusing on a bivalent antivenom developed for <i>Trimeresurus stejnegeri</i> and <i>Protobothrops mucrosquamatu</i>s (TsPmAV), as well as monovalent antivenoms for <i>Deinagkistrodon acutus</i> (DaAV) and <i>Gloydius brevicaudus</i> (GbAV). Our research involved <i>in vivo</i> toxicity testing in mice and <i>in vitro</i> immunobinding experiments using (chaotropic) enzyme-linked immunosorbent assays, comparing venoms from four pit viper species (<i>T</i>. <i>gracilis</i>, <i>T</i>. <i>stejnegeri</i>, <i>P</i>. <i>mucrosquamatus</i>, and <i>D</i>. <i>acutus</i>) with three types of antivenoms. These findings indicate that TsPmAV partially neutralized <i>T</i>. <i>gracilis</i> venom, marginally surpassing the efficacy of DaAV. <i>In vitro</i> tests revealed that GbAV displayed higher binding capacities toward <i>T</i>. <i>gracilis</i> venom than TsPmAV or DaAV. Comparisons of electrophoretic profiles also reveal that <i>T</i>. <i>gracilis</i> venom has fewer snake venom C-type lectin like proteins than <i>D</i>. <i>acutus</i>, and has more P-I snake venom metalloproteases or fewer phospholipase A<sub>2</sub> than <i>G</i>. <i>brevicaudus</i>, <i>T</i>. <i>stejnegeri</i>, or <i>P</i>. <i>mucrosquamatus</i>. This study highlights the need for antivenoms that specifically target <i>T</i>. <i>gracilis</i>, as current treatments using TsPmAV show limited effectiveness in neutralizing local effects in patients. These findings provide crucial insights into clinical treatment protocols and contribute to the understanding of the evolutionary adaptation of snake venom, aiding in the development of more effective antivenoms for human health.The national distribution of lymphatic filariasis cases in Malawi using patient mapping and geostatistical modellingCarrie BarrettJohn ChiphwanyaSquare MkwandaDorothy E. MatipulaPaul NdhlovuLimbikani ChapondaJoseph D. TurnerEmanuele GiorgiHannah BettsSarah MartindaleMark J. TaylorJonathan M. ReadLouise A. Kelly-Hope10.1371/journal.pntd.00120562024-03-25T14:00:00Z2024-03-25T14:00:00Z<p>by Carrie Barrett, John Chiphwanya, Square Mkwanda, Dorothy E. Matipula, Paul Ndhlovu, Limbikani Chaponda, Joseph D. Turner, Emanuele Giorgi, Hannah Betts, Sarah Martindale, Mark J. Taylor, Jonathan M. Read, Louise A. Kelly-Hope</p>
Background <p>In 2020 the World Health Organization (WHO) declared that Malawi had successfully eliminated lymphatic filariasis (LF) as a public health problem. Understanding clinical case distributions at a national and sub-national level is important, so essential care packages can be provided to individuals living with LF symptoms. This study aimed to develop a national database and map of LF clinical case numbers across Malawi using geostatistical modelling approaches, programme-identified clinical cases, antigenaemia prevalence and climate information.</p> Methodology <p>LF clinical cases identified through programme house-to-house surveys across 90 sub-district administrative boundaries (Traditional Authority (TA)) and antigenaemia prevalence from 57 sampled villages in Malawi were used in a two-step geostatistical modelling process to predict LF clinical cases across all TAs of the country. First, we modelled antigenaemia prevalence in relation to climate covariates to predict nationwide antigenaemia prevalence. Second, we modelled clinical cases for unmapped TAs based on our antigenaemia prevalence spatial estimates.</p> Principle findings <p>The models estimated 20,938 (95% CrI 18,091 to 24,071) clinical cases in unmapped TAs (70.3%) in addition to the 8,856 (29.7%), programme-identified cases in mapped TAs. In total, the overall national number of LF clinical cases was estimated to be 29,794 (95% CrI 26,957 to 32,927). The antigenaemia prevalence and clinical case mapping and modelling found the highest burden of disease in Chikwawa and Nsanje districts in the Southern Region and Karonga district in the Northern Region of the country.</p> Conclusions <p>The models presented in this study have facilitated the development of the first national LF clinical case database and map in Malawi, the first endemic country in sub-Saharan Africa. It highlights the value of using existing LF antigenaemia prevalence and clinical case data together with modelling approaches to produce estimates that may be used for the WHO dossier requirements, to help target limited resources and implement long-term health strategies.</p>Phenotypic screening reveals a highly selective phthalimide-based compound with antileishmanial activityFarnaz ZahedifardMeenakshi BansalNeha SharmaSumit KumarSiqi ShenPriyamvada SinghBrijesh RathiMartin Zoltner10.1371/journal.pntd.00120502024-03-25T14:00:00Z2024-03-25T14:00:00Z<p>by Farnaz Zahedifard, Meenakshi Bansal, Neha Sharma, Sumit Kumar, Siqi Shen, Priyamvada Singh, Brijesh Rathi, Martin Zoltner</p>
Pharmacophores such as hydroxyethylamine (HEA) and phthalimide (PHT) have been identified as potential synthons for the development of compounds against various parasitic infections. In order to further advance our progress, we conducted an experiment utilising a collection of PHT and HEA derivatives through phenotypic screening against a diverse set of protist parasites. This approach led to the identification of a number of compounds that exhibited significant effects on the survival of <i>Entamoeba histolytica</i>, <i>Trypanosoma brucei</i>, and multiple life-cycle stages of <i>Leishmania spp</i>. The <i>Leishmania</i> hits were pursued due to the pressing necessity to expand our repertoire of reliable, cost-effective, and efficient medications for the treatment of leishmaniases. Antileishmanials must possess the essential capability to efficiently penetrate the host cells and their compartments in the disease context, to effectively eliminate the intracellular parasite. Hence, we performed a study to assess the effectiveness of eradicating <i>L</i>. <i>infantum</i> intracellular amastigotes in a model of macrophage infection. Among eleven <i>L</i>. <i>infantum</i> growth inhibitors with low-micromolar potency, PHT-39, which carries a trifluoromethyl substitution, demonstrated the highest efficacy in the intramacrophage assay, with an EC50 of 1.2 +/- 3.2 μM. Cytotoxicity testing of PHT-39 in HepG2 cells indicated a promising selectivity of over 90-fold. A chemogenomic profiling approach was conducted using an orthology-based method to elucidate the mode of action of PHT-39. This genome-wide RNA interference library of <i>T</i>. <i>brucei</i> identified sensitivity determinants for PHT-39, which included a P-type ATPase that is crucial for the uptake of miltefosine and amphotericin, strongly indicating a shared route for cellular entry. Notwithstanding the favourable properties and demonstrated efficacy in the <i>Plasmodium berghei</i> infection model, PHT-39 was unable to eradicate <i>L</i>. <i>major</i> infection in a murine infection model of cutaneous leishmaniasis. Currently, PHT-39 is undergoing derivatization to optimize its pharmacological characteristics.Chitosan nanoparticles improve the effectivity of miltefosine against <i>Acanthamoeba</i>Alireza LatifiFariba EsmaeiliMehdi MohebaliSetayesh Yasami-KhiabaniMostafa RezaeianMohammad SoleimaniElham KazemiradAmir Amani10.1371/journal.pntd.00119762024-03-25T14:00:00Z2024-03-25T14:00:00Z<p>by Alireza Latifi, Fariba Esmaeili, Mehdi Mohebali, Setayesh Yasami-Khiabani, Mostafa Rezaeian, Mohammad Soleimani, Elham Kazemirad, Amir Amani</p>
Background <p><i>Acanthamoeba</i> keratitis (AK) is a corneal sight-threatening infection caused by the free-living amoebae of the genus <i>Acanthamoeba</i>. Early and appropriate treatment significantly impacts visual outcomes. Mucoadhesive polymers such as chitosan are a potential strategy to prolong the residence time and bioavailability of the encapsulated drugs in the cornea. Regarding the recent administration of miltefosine (MF) for treating resistant AK, in the present study, we synthesized miltefosine-loaded chitosan nanoparticles (MF-CS-NPs) and evaluated them against <i>Acanthamoeba</i>.</p> Methodology/Principal findings <p>Chitosan nanoparticles (CNPs) were prepared using the ionic gelation method with negatively charged tripolyphosphate (TPP). The zeta-potential (ZP) and the particle size of MF-CS-NPs were 21.8±3.2 mV and 46.61±18.16 nm, respectively. The release profile of MF-CS-NPs indicated linearity with sustained drug release. The cytotoxicity of MF-CS-NPs on the <i>Vero</i> cell line was 2.67 and 1.64 times lower than free MF at 24 and 48 hours. This formulation exhibited no hemolytic activity <i>in vitro</i> and ocular irritation in rabbit eyes. The IC<sub>50</sub> of MF-CS-NPs showed a significant reduction by 2.06 and 1.69-fold in trophozoites at 24 and 48 hours compared to free MF. Also, the MF-CS-NPs IC<sub>50</sub> in the cysts form was slightly decreased by 1.26 and 1.21-fold at 24 and 48 hours compared to free MF.</p> Conclusions <p>The MF-CS-NPs were more effective against the trophozoites and cysts than free MF. The nano-chitosan formulation was more effective on trophozoites than the cysts form. MF-CS-NPs reduced toxicity and improved the amoebicidal effect of MF. Nano-chitosan could be an ideal carrier that decreases the cytotoxicity of miltefosine. Further analysis in animal settings is needed to evaluate this nano-formulation for clinical ocular drug delivery.</p>Extensive variation and strain-specificity in dengue virus susceptibility among African <i>Aedes aegypti</i> populationsStéphanie DaboAnnabelle Henrion-LacritickAlicia LecuyerDavy JiolleChristophe PaupyDiego AyalaSilvânia da Veiga LealAthanase BadoloAnubis Vega-RúaMassamba SyllaJewelna AkorliSampson OtooJoel LutomiahRosemary SangJohn-Paul MutebiMaria-Carla SalehNoah H. RoseCarolyn S. McBrideLouis Lambrechts10.1371/journal.pntd.00118622024-03-25T14:00:00Z2024-03-25T14:00:00Z<p>by Stéphanie Dabo, Annabelle Henrion-Lacritick, Alicia Lecuyer, Davy Jiolle, Christophe Paupy, Diego Ayala, Silvânia da Veiga Leal, Athanase Badolo, Anubis Vega-Rúa, Massamba Sylla, Jewelna Akorli, Sampson Otoo, Joel Lutomiah, Rosemary Sang, John-Paul Mutebi, Maria-Carla Saleh, Noah H. Rose, Carolyn S. McBride, Louis Lambrechts</p>
African populations of the mosquito <i>Aedes aegypti</i> are usually considered less susceptible to infection by human-pathogenic flaviviruses than globally invasive populations found outside Africa. Although this contrast has been well documented for Zika virus (ZIKV), it is unclear to what extent it is true for dengue virus (DENV), the most prevalent flavivirus of humans. Addressing this question is complicated by substantial genetic diversity among DENV strains, most notably in the form of four genetic types (DENV1 to DENV4), that can lead to genetically specific interactions with mosquito populations. Here, we carried out a survey of DENV susceptibility using a panel of seven field-derived <i>Ae</i>. <i>aegypti</i> colonies from across the African range of the species and a colony from Guadeloupe, French West Indies as non-African reference. We found considerable variation in the ability of African <i>Ae</i>. <i>aegypti</i> populations to acquire and replicate a panel of six DENV strains spanning the four DENV types. Although African <i>Ae</i>. <i>aegypti</i> populations were generally less susceptible than the reference non-African population from Guadeloupe, in several instances some African populations were equally or more susceptible than the Guadeloupe population. Moreover, the relative level of susceptibility between African mosquito populations depended on the DENV strain, indicating genetically specific interactions. We conclude that unlike ZIKV susceptibility, there is no clear-cut dichotomy in DENV susceptibility between African and non-African <i>Ae</i>. <i>aegypti</i>. DENV susceptibility of African <i>Ae</i>. <i>aegypti</i> populations is highly heterogeneous and largely governed by the specific pairing of mosquito population and DENV strain.Egg excretion patterns of soil-transmitted helminth infections in humans following albendazole-ivermectin and albendazole treatmentSophie WelschePierre H. H. SchneebergerJan HattendorfSomphou SayasoneEveline HürlimannJennifer Keiser10.1371/journal.pntd.00120732024-03-22T14:00:00Z2024-03-22T14:00:00Z<p>by Sophie Welsche, Pierre H. H. Schneeberger, Jan Hattendorf, Somphou Sayasone, Eveline Hürlimann, Jennifer Keiser</p>
Background <p>Control efforts of soil-transmitted helminthiases rely primarily on large scale administration with anthelminthic drugs. The assessment of drug efficacies and understanding of drug behavior is pivotal to the evaluation of treatment successes, both in preventive chemotherapy programs as well as in research of novel treatment options. The current WHO guidelines recommend an interval of 14–21 days between the treatment and follow-up, yet no in-depth analysis of egg excretion patterns of <i>Trichuris trichiura</i> after treatment has been conducted to date.</p> Methods <p>Within the framework of a multi-country trial to assess the efficacy and safety of ivermectin-albendazole combination therapy vs albendazole monotherapy against <i>T</i>. <i>trichiura</i> infections, we conducted a study collecting daily stool samples over the period of 28 days post-treatment in 87 participants in Pak Khan, Lao PDR. Egg counts were derived by duplicate Kato-Katz on-site for <i>T</i>. <i>trichiura</i>, hookworm and <i>Ascaris lumbricoides</i> and stool sample aliquots were subsequently analyzed by qPCR for the detection of <i>T</i>. <i>trichiura</i> infections. Sensitivity and specificity was calculated for each day separately using data derived by Kato-Katz to determine the optimal timepoint at which to assess drug efficacy.</p> Results <p>Egg excretion patterns varied across treatment arms. For <i>T</i>. <i>trichiura</i>, only the ivermectin-albendazole treatment led to a considerable reduction in mean egg counts, whereas both treatments reduced hookworm egg counts and <i>A</i>. <i>lumbricoides</i> were cleared in all participants after day 7. For <i>T</i>. <i>trichiura</i>, we found sensitivity to be highest at days 18 and 22 when using egg counts as outcome and days 19 and 24 when using qPCR. Specificity was high (>0.9) from day 14 onwards. For hookworm, the highest sensitivity and specificity rates were found at days 17 and 25, respectively.</p> Conclusions <p>Based on our study the ideal time period to assess drug efficacy for soil-transmitted helminth infections would be between day 18 and 24. The current WHO recommendation of 14 to 21 days is likely to yield acceptable outcome measures for soil-transmitted helminth infections.</p> Trial registration <p>NCT03527732.</p>Assessing vulnerability for future Zika virus outbreaks using seroprevalence data and environmental suitability mapsYannik RoellLaura PezziAnyela Lozano-ParraDaniel OlsonJane MessinaTalia QuandelacyJan Felix DrexlerOliver BradyMorteza KarimzadehThomas Jaenisch10.1371/journal.pntd.00120172024-03-22T14:00:00Z2024-03-22T14:00:00Z<p>by Yannik Roell, Laura Pezzi, Anyela Lozano-Parra, Daniel Olson, Jane Messina, Talia Quandelacy, Jan Felix Drexler, Oliver Brady, Morteza Karimzadeh, Thomas Jaenisch</p>
The 2015–17 Zika virus (ZIKV) epidemic in the Americas subsided faster than expected and evolving population immunity was postulated to be the main reason. Herd immunization is suggested to occur around 60–70% seroprevalence, depending on demographic density and climate suitability. However, herd immunity was only documented for a few cities in South America, meaning a substantial portion of the population might still be vulnerable to a future Zika virus outbreak. The aim of our study was to determine the vulnerability of populations to ZIKV by comparing the environmental suitability of ZIKV transmission to the observed seroprevalence, based on published studies. Using a systematic search, we collected seroprevalence and geospatial data for 119 unique locations from 37 studies. Extracting the environmental suitability at each location and converting to a hypothetical expected seroprevalence, we were able to determine the discrepancy between observed and expected. This discrepancy is an indicator of vulnerability and divided into three categories: high risk, low risk, and very low risk. The vulnerability was used to evaluate the level of risk that each location still has for a ZIKV outbreak to occur. Of the 119 unique locations, 69 locations (58%) fell within the high risk category, 47 locations (39%) fell within the low risk category, and 3 locations (3%) fell within the very low risk category. The considerable heterogeneity between environmental suitability and seroprevalence potentially leaves a large population vulnerable to future infection. Vulnerability seems to be especially pronounced at the fringes of the environmental suitability for ZIKV (e.g. Sao Paulo, Brazil). The discrepancies between observed and expected seroprevalence raise the question: “why did the ZIKV epidemic stop with large populations unaffected?”. This lack of understanding also highlights that future ZIKV outbreaks currently cannot be predicted with confidence.Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective studyLuís-Jorge AmaralStephen Raimon JadaAimee Kemayou NdjanfaJane Y. CarterGasim Abd-ElfaragSamuel OkaroMakoy Yibi LogoraYak Yak BolThomson LakwoJoseph N Siewe FodjoRobert Colebunders10.1371/journal.pntd.00120592024-03-21T14:00:00Z2024-03-21T14:00:00Z<p>by Luís-Jorge Amaral, Stephen Raimon Jada, Aimee Kemayou Ndjanfa, Jane Y. Carter, Gasim Abd-Elfarag, Samuel Okaro, Makoy Yibi Logora, Yak Yak Bol, Thomson Lakwo, Joseph N Siewe Fodjo, Robert Colebunders</p>
Objectives <p>The potential impact of cumulative community-directed treatment with ivermectin (CDTI) on epilepsy epidemiology in Mvolo County, South Sudan, an onchocerciasis-endemic area with high epilepsy prevalence, was investigated. Annual CDTI was introduced in 2002 in Mvolo, with interruptions in 2016 and 2020.</p> Methods <p>Comprehensive house-to-house surveys in Mvolo (June 2020 and 2022) identified cases of epilepsy, including probable nodding syndrome (pNS). Community workers screened households in selected sites for suspected epilepsy, and medical doctors confirmed the diagnosis and determined the year of seizure onset. The incidence of epilepsy, including pNS, was analysed using 95% confidence intervals (CIs). Data on ivermectin intake and onchocerciasis-associated manifestations (itching and blindness) were collected.</p> Results <p>The surveys covered 15,755 (2020) and 15,092 (2022) individuals, identifying 809 (5.2%, 95% CI: 4.8–5.5%) and 672 (4.5%, 95% CI: 4.1–4.8%) epilepsy cases, respectively. Each survey reported that a third of the surveyed population experienced skin itching, and 3% were blind. Epilepsy incidence per 100,000 person-years gradually declined, from 326.5 (95% CI: 266.8–399.1) in 2013–2015 to 96.6 (95% CI: 65.5–141.7) in 2019–2021. Similarly, pNS incidence per 100,000 person-years decreased from 151.7 (95% CI: 112.7–203.4) to 27.0 (95% CI: 12.5–55.5). Coverage of CDTI was suboptimal, reaching only 64.0% of participants in 2019 and falling to 24.1% in 2021 following an interruption in 2020 due to COVID-19 restrictions. Additionally, while 99.4% of cases had active epilepsy in 2022, less than a quarter of these had access to antiseizure medication.</p> Conclusions <p>The observed decrease in epilepsy incidence despite suboptimal CDTI coverage highlights the potential impact of onchocerciasis control efforts and underscores the need to strengthen these efforts in Mvolo County and across South Sudan. As a proactive measure, Mvolo and neighbouring counties are transitioning to biannual CDTI. Furthermore, the substantial epilepsy treatment gap in Mvolo should be addressed.</p>Harnessing <i>Schistosoma</i>-associated metabolite changes in the human host to identify biomarkers of infection and morbidity: Where are we and what should we do next?Mireille KameniFungai MusaigwaLeonel Meyo KamguiaSeverin Donald KamdemGladice MbanyaPoppy H. L. LambertonJustin Komguep Nono10.1371/journal.pntd.00120092024-03-21T14:00:00Z2024-03-21T14:00:00Z<p>by Mireille Kameni, Fungai Musaigwa, Leonel Meyo Kamguia, Severin Donald Kamdem, Gladice Mbanya, Poppy H. L. Lamberton, Justin Komguep Nono</p>
Schistosomiasis is the second most widespread parasitic disease affecting humans. A key component of today’s infection control measures is the diagnosis and monitoring of infection, informing individual- and community-level treatment. However, newly acquired infections and/or low parasite burden are still difficult to diagnose reliably. Furthermore, even though the pathological consequence of schistosome egg sequestration in host tissues is well described, the evidence linking egg burden to morbidity is increasingly challenged, making it inadequate for pathology monitoring. In the last decades, omics-based instruments and methods have been developed, adjusted, and applied in parasitic research. In particular, the profiling of the most reliable determinants of phenotypes, metabolites by metabolomics, emerged as a powerful boost in the understanding of basic interactions within the human host during infection. As such, the fine detection of host metabolites produced upon exposure to parasites such as <i>Schistosoma</i> spp. and the ensuing progression of the disease are believed to enable the identification of <i>Schistosoma</i> spp. potential biomarkers of infection and associated pathology. However, attempts to provide such a comprehensive understanding of the alterations of the human metabolome during schistosomiasis are rare, limited in their design when performed, and mostly inconclusive. In this review, we aimed to briefly summarize the most robust advances in knowledge on the changes in host metabolic profile during <i>Schistosoma</i> infections and provide recommendations for approaches to optimize the identification of metabolomic signatures of human schistosomiasis.Amidst spreading infectious diseases and climate change, US FDA should renew its focus on neglected tropical diseasesMitchell Berger10.1371/journal.pntd.00120052024-03-21T14:00:00Z2024-03-21T14:00:00Z<p>by Mitchell Berger</p>Epidemiological, clinical, and geographical characterization of Leprosy in the County of Santarém-Pará: Insights for effective control and targeted interventionEdson Jandrey Cota QueirozIngrid Nunes da RochaLívia de Aguiar ValentimThiago Junio Costa QuaresmaZilmar Augusto de Souza FilhoSheyla Mara Silva de OliveiraFranciane de Paula FernandesCaroline Gomes MacedoTatiane Costa QuaresmaWaldiney Pires Moraes10.1371/journal.pntd.00120632024-03-20T14:00:00Z2024-03-20T14:00:00Z<p>by Edson Jandrey Cota Queiroz, Ingrid Nunes da Rocha, Lívia de Aguiar Valentim, Thiago Junio Costa Quaresma, Zilmar Augusto de Souza Filho, Sheyla Mara Silva de Oliveira, Franciane de Paula Fernandes, Caroline Gomes Macedo, Tatiane Costa Quaresma, Waldiney Pires Moraes</p>
Leprosy is an infectious disease characterized by slow and chronic evolution, caused by <i>Mycobacterium leprae</i> and or <i>Mycobacterium lepromatosis</i>, an intracellular alcohol-acid-resistant (BAAR) bacillus. The objective of this study was to provide an epidemiological, clinical, and geographic characterization of leprosy in the city of Santarém-Pará during the period 2011–2020. A cross-sectional, descriptive, and quantitative approach was used, employing maps and tables to illustrate clinical and epidemiological variables, including: sex, age, race, area of residence, operational classification, clinical form, number of skin lesions, number of affected nerves, and health units. During the analyzed period, 581 cases of leprosy were diagnosed, resulting in the following cumulative incidence rates: male (60%); age over 15 years (94%); urban area (73%); multibacillary (74%); borderline form (46%); skin lesions greater than 5 (34%); and no nerves affected (68%). In the urban perimeter, a higher cumulative incidence of cases was observed in the central area with 133 cases. However, the health unit reporting the largest number of cases belonged to the southern area, specifically the Basic Health Unit of Nova República, with 48 cases. This study highlights the need to characterize the nuances of leprosy and its variability within the urban environment, according to different areas. Further research is essential to inform the implementation of public policies aimed at addressing the population with the highest vulnerability index, thereby reducing leprosy rates in Santarém.The role of point-of-care ultrasound in the assessment of schistosomiasis-induced liver fibrosis: A systematic scoping reviewEloise S. OckendenSandrena Ruth FrischerHuike ChengJ. Alison NobleGoylette F. Chami10.1371/journal.pntd.00120332024-03-20T14:00:00Z2024-03-20T14:00:00Z<p>by Eloise S. Ockenden, Sandrena Ruth Frischer, Huike Cheng, J. Alison Noble, Goylette F. Chami</p>
Background <p>Abdominal ultrasound imaging is an important method for hepatic schistosomiasis diagnosis and staging. Several ultrasound staging systems have been proposed, each attempting to standardise schistosomal periportal fibrosis (PPF) diagnosis. This review aims to establish the role of ultrasound in the diagnosis and staging of schistosomal PPF, and to map the evolution of ultrasound staging systems over time, focusing on internal validation and external reproducibility.</p> Methods <p>A systematic search was undertaken on 21<sup>st</sup> December 2022 considering the following databases: PubMed/MEDLINE (1946-present), Embase (1974-present), Global Health (1973-present), Global Index Medicus (1901-present), and Web of Science Core Collection–Science Citation Index Expanded (1900-present) and the Cochrane Central Register of Controlled Trials (1996-present). Case reports, systematic reviews and meta-analyses, and studies exclusively using transient or shear-wave elastography were excluded. Variables extracted included study design, study population, schistosomal PPF characteristics, and diagnostic methods. The PRISMA-ScR (2018) guidelines were followed to inform the structure of the scoping analysis.</p> Results <p>The initial search yielded 573 unique articles, of which 168 were removed after screening titles and abstracts, 43 were not retrieved due to full texts not being available online or through inter-library loans, and 170 were excluded during full text review. There were 192 remaining studies eligible for extraction. Of the extracted studies, 61.8% (76/123) of studies that reported study year were conducted after the year 2000. Over half of all extracted studies (59.4%; 114/192) were conducted in Brazil (26.0%; 50/192), China (18.8%; 36/192) or Egypt (14.6%; 28/192). For the species of schistosome considered, 77.6% (149/192) of studies considered <i>S</i>. <i>mansoni</i> and 21.4% (41/192) of studies considered <i>S</i>. <i>japonicum</i>. The ultrasound staging systems used took on three forms: measurement-based, feature-based and image pattern-based. The Niamey protocol, a measurement and image pattern-based system, was the most used among the staging systems (32.8%; 63/192), despite being the most recently proposed in 1996. The second most used was the Cairo protocol (20.8%; 40/192). Of the studies using the Niamey protocol, 77.8% (49/63) only used the image patterns element. Where ultrasound technology was specified, studies after 2000 were more likely to use convex transducers (43.4%; 33/76) than studies conducted before 2000 (32.7%; 16/49). Reporting on ultrasound-based hepatic diagnoses and their association with clinical severity was poor. Just over half of studies (56.2%; 108/192) reported the personnel acquiring the ultrasound images. A small number (9.4%; 18/192) of studies detailed their methods of image quality assurance, and 13.0% (25/192) referenced, discussed or quantified the inter- or intra-observer variation of the staging system that was used.</p> Conclusions <p>The exclusive use of the image patterns in many studies despite lack of specific acquisition guidance, the increasing number of studies over time that conduct ultrasound staging of schistosomal PPF, and the advances in ultrasound technology used since 2000 all indicate a need to consider an update to the Niamey protocol. The protocol update should simplify and prioritise what is to be assessed, advise on who is to conduct the ultrasound examination, and procedures for improved standardisation and external reproducibility.</p>Correction: <i>Entamoeba</i> lysyl-tRNA Synthetase Contains a Cytokine-Like Domain with Chemokine Activity towards Human Endothelial CellsManuel Castro de MouraFrancesc MiroJung Min HanSunghoon KimAntonio CeladaLluís Ribas de Pouplana10.1371/journal.pntd.00120472024-03-19T14:00:00Z2024-03-19T14:00:00Z<p>by Manuel Castro de Moura, Francesc Miro, Jung Min Han, Sunghoon Kim, Antonio Celada, Lluís Ribas de Pouplana</p>Expression of Concern: Molecular Characterization of Severin from <i>Clonorchis sinensis</i> Excretory/Secretory Products and Its Potential Anti-apoptotic Role in Hepatocarcinoma PLC CellsThe PLOS Neglected Tropical Diseases Editors10.1371/journal.pntd.00120432024-03-19T14:00:00Z2024-03-19T14:00:00Z<p>by The PLOS Neglected Tropical Diseases Editors </p>Sero-prevalence and risk factors associated with occurrence of anti-<i>Brucella</i> antibodies among slaughterhouse workers in UgandaJames Katamba BugezaKristina RoeselDenis Rwabiita MugiziLordrick AlinaitweVelma KivaliClovice KankyaIgnacio MoriyonElizabeth Anne Jessie Cook10.1371/journal.pntd.00120462024-03-18T14:00:00Z2024-03-18T14:00:00Z<p>by James Katamba Bugeza, Kristina Roesel, Denis Rwabiita Mugizi, Lordrick Alinaitwe, Velma Kivali, Clovice Kankya, Ignacio Moriyon, Elizabeth Anne Jessie Cook</p>
Introduction <p>Brucellosis is a febrile zoonosis occurring among high-risk groups such as livestock keepers and abattoir workers and is a public health priority in Uganda. The technical complexities of bacteriological and molecular methods make serological approaches the cornerstone of diagnosis of human brucellosis in resource limited settings. Therefore, proper application and interpretation of serological tests is central to achieve a correct diagnosis.</p> Materials and methods <p>We conducted a cross-sectional study to estimate the seroprevalence and factors associated with anti-<i>Brucella</i> antibodies among slaughterhouse workers processing ruminants and pigs in three regions of the country with serial testing using a combination of the Rose Bengal Test (RBT) and the BrucellaCapt test. An authorized clinician collected 543 blood samples from consenting abattoir workers as well as attribute medical and social demographic data. Univariable and multivariable logistic regression were used to determine factors associated with anti-<i>Brucella</i> sero-positivity.</p> Results and discussion <p>The sero-prevalence among ruminant slaughterhouse workers ranged from 7.3% (95% CI: 4.8–10.7) using BrucellaCapt to 9.0% (95% CI: 6.3–12.7) using RBT. Slaughterhouse workers from the Eastern regions (AOR = 9.84, 95%CI 2.27–69.2, p = 0.006) and those who graze animals for alternative income (AOR = 2.36, 95% CI: 1.91–6.63, p = 0.040) were at a higher risk of exposure to <i>Brucella</i>. Similarly, those who wore Personal Protective Equipment (AOR = 4.83, 95%CI:1.63–18.0, p = 0.009) and those who slaughter cattle (AOR = 2.12, 95%CI: 1.25–6.0, p = 0.006) were at a higher risk of exposure to <i>Brucella</i>. Those who slaughter small ruminants (AOR = 1.54, 95%CI: 1.32–4.01, p = 0.048) were also at a higher risk of exposure to <i>Brucella</i>.</p> Conclusions and recommendations <p>Our study demonstrates the combined practical application of the RBT and BrucellaCapt in the diagnosis of human brucellosis in endemic settings. Both pharmaceutical (e.g., routine testing and timely therapeutic intervention), and non-pharmaceutical (e.g., higher index of suspicion of brucellosis when investigating fevers of unknown origin and observation of strict abattoir hygiene) countermeasures should be considered for control of the disease in high-risk groups.</p>Cross-sectional serosurvey of <i>Leptospira</i> species among slaughter pigs, goats, and sheep in UgandaLordrick AlinaitweChristopher Joshua AturindaAshiraf LubegaVelma KivaliJames BugezaMartin WainainaMartin H. RichterJolly Justine HoonaKristina RoeselAnne Mayer-SchollElizabeth Anne Jessie CookClovice KankyaSalome Dürr10.1371/journal.pntd.00120552024-03-15T14:00:00Z2024-03-15T14:00:00Z<p>by Lordrick Alinaitwe, Christopher Joshua Aturinda, Ashiraf Lubega, Velma Kivali, James Bugeza, Martin Wainaina, Martin H. Richter, Jolly Justine Hoona, Kristina Roesel, Anne Mayer-Scholl, Elizabeth Anne Jessie Cook, Clovice Kankya, Salome Dürr</p>
Introduction <p><i>Leptospira</i> are a group of bacteria, including pathogenic types that cause leptospirosis. In Uganda, <i>Leptospira</i> exposure has been reported in humans, with domesticated animals being speculated as the source. However, comparable evidence of <i>Leptospira</i> prevalence and circulating serovars/serogroups in animals is only documented for cattle, and dogs. Our study determined <i>Leptospira</i> seroprevalence, associated risk factors and serogroups circulating among slaughtered pigs, goats, and sheep in Uganda.</p> Methods <p>During an 11-month cross-sectional survey in selected slaughter facilities in three regions of Uganda, we collected blood from 926 pigs, 347 goats, and 116 sheep. The age, sex, breed, and origin of each sampled animal were noted. The samples were tested for anti-<i>Leptospira</i> antibodies using the microscopic agglutination test, based on a panel of 12 serovars belonging to 12 serogroups.</p> Results <p><i>Leptospira</i> seroprevalence was 26.67% (247/926, 95%CI 23.92–29.61) among pigs, and 21.81% (101/463, 95%CI 18.29–25.80) in goats and sheep (small ruminants). <i>L</i>. <i>interrogans</i> Australis and <i>L</i>. <i>kirschneri</i> Grippotyphosa were the commonest serovars among pigs, as was <i>L</i>. <i>borgpetersenii</i> Tarassovi in small ruminants. Pigs sourced from the Eastern (Odds Ratio [OR] = 2.82, 95%CI 1.84–4.30) and Northern (OR = 3.56, 95%CI 2.52–5.02) regions were more likely to be seropositive, compared to those from the Central region. For small ruminants, being female (OR 2.74, 95% CI 1.69–4.57) and adult (OR 4.47, 95% CI 1.57–18.80) was significantly more associated with <i>Leptospira</i> seropositivity.Conclusion/significance: Detection of a moderate seroprevalence, and several <i>Leptospira</i> serogroups among pigs, sheep, and goats from all regions of Uganda, supports existing reports in cattle and dogs, and implies widespread <i>Leptospira</i> exposure in domestic animals in Uganda. These findings may inform future programs for the control of leptospirosis in livestock in Uganda.</p>Comparative evaluation of four rapid diagnostic tests that detect human <i>Trypanosoma cruzi-</i>specific antibodies to support diagnosis of Chagas Disease in urban population of ArgentinaRocío RiveroM. Soledad SantiniConstanza Lopez-AlbizuMarcelo RodriguezAdriana CalbosaDaniela OlivetoMónica EstevaMargarita BisioLaura C. Bohorquez10.1371/journal.pntd.00119972024-03-15T14:00:00Z2024-03-15T14:00:00Z<p>by Rocío Rivero, M. Soledad Santini, Constanza Lopez-Albizu, Marcelo Rodriguez, Adriana Calbosa, Daniela Oliveto, Mónica Esteva, Margarita Bisio, Laura C. Bohorquez</p>
Background <p>Chagas disease (CD), caused by the parasite <i>Trypanosoma cruzi</i>, is the most important endemic anthropozoonosis in Argentina. Since 2010, the World Health Organization has highlighted the urgent need to validate diagnostic systems that allow rapid detection of <i>T</i>. <i>cruzi</i>, infection in primary healthcare centers. Serological rapid diagnostic tests (RDTs) for <i>T</i>. <i>cruzi</i>, infection could be used to improve case management, as RDTs do not require specialized laboratories or highly trained staff to use them. We aimed to generate unbiased performance data of RDTs in Argentina, to evaluate their usefulness for improving <i>T</i>. <i>cruzi</i>, diagnosis rates.</p> Methods and principal findings <p>This is a retrospective, laboratory-based, diagnostic evaluation study to estimate the clinical sensitivity/specificity of four commercially available RDTs for <i>T</i>. <i>cruzi</i>, using the Chagas disease diagnostic algorithm currently used in Argentina as the reference standard. In total, 400 serum samples were tested, 200 from individuals with chronic <i>T</i>. <i>cruzi</i> infection and 200 from individuals not infected with <i>T</i>. <i>cruzi</i>. All results were registered as the agreement of at least two operators who were blinded to the reference standard results. The sensitivity estimates ranged from 92.5–100% (95% confidence interval (CI) lower bound 87.9–98.2%); for specificity, the range was 76–96% (95% CI lower bound 69.5–92.3%). Most RDTs evaluated showed performances comparable with the reference standard method, showing almost perfect concordance (<i>Kappa</i> 0.76–0.92).</p> Conclusions <p>Our study demonstrates that, under controlled laboratory conditions, commercially available RDTs for CD have a performance comparable to the Argentinian diagnostic algorithm, which is based on laboratory-based serological tests. For the next stage of our work, the RDTs will be evaluated in real-world settings.</p>Analysis of diagnostic test outcomes in a large loiasis cohort from an endemic region: Serological tests are often false negative in hyper-microfilaremic infectionsLuzia VeletzkyKirsten Alexandra EberhardtJennifer HergethDaniel Robert StelzlRella Zoleko ManegoRuth KreuzmairGerrit BurgerJohannes MischlingerMatthew B. B. McCallGhyslain Mombo-NgomaAyôla Akim AdegnikaSelidji Todagbe AgnandjiPierre Blaise MatsieguiBertrand LellPeter KremsnerBenjamin MordmüllerDennis TappeMichael Ramharter10.1371/journal.pntd.00120542024-03-14T14:00:00Z2024-03-14T14:00:00Z<p>by Luzia Veletzky, Kirsten Alexandra Eberhardt, Jennifer Hergeth, Daniel Robert Stelzl, Rella Zoleko Manego, Ruth Kreuzmair, Gerrit Burger, Johannes Mischlinger, Matthew B. B. McCall, Ghyslain Mombo-Ngoma, Ayôla Akim Adegnika, Selidji Todagbe Agnandji, Pierre Blaise Matsiegui, Bertrand Lell, Peter Kremsner, Benjamin Mordmüller, Dennis Tappe, Michael Ramharter</p>
Background <p>The parasitic disease loiasis is associated with significant morbidity and mortality. Individuals with hyper-microfilaremia (greater than 20,000 microfilariae per mL of blood) may suffer from serious treatment-related or spontaneous adverse events. Diagnosing loiasis remains complex and primarily relies on direct parasite detection. In this study, we analyzed the performance of various diagnostic tests and the influence of parasitological and clinical factors on test outcomes in samples from individuals living in an endemic region.</p> Methods <p>Data and samples were collected from rural Gabon. Loiasis was defined as either detectable microfilaremia, or a positive history of eyeworm as assessed by the RAPLOA questionnaire. Diagnostic testing included a quantitative PCR (qPCR) for detection of <i>Loa loa</i> DNA in blood samples, an in-house crude <i>L</i>. <i>loa</i> antigen IgG ELISA, and a rapid test for antibodies against the Ll-SXP-1 antigen (RDT). Sensitivity and specificity were determined for each test and factors potentially influencing outcomes were evaluated in an exploratory analysis.</p> Results <p>ELISA, RDT and qPCR results were available for 99.8%, 78.5%, and 100% of the 1,232 participants, respectively. The ELISA and RDT had only modest diagnostic accuracy. qPCR was specific for <i>L</i>. <i>loa</i> microfilaremia and Cycle threshold values correlated with microfilarial density. Anti-<i>L</i>. <i>loa</i> IgG levels were highest in occult loiasis, and antibody levels correlated inversely with <i>L</i>. <i>loa</i> microfilarial density as did RDT line intensities. Only 84.6% and 16.7% of hyper-microfilaremic individuals tested positive by ELISA (11/13) and RDT (2/12), respectively.</p> Conclusion <p>None of the tests demonstrated high sensitivity and specificity for loiasis. Indirect diagnostic assays were characterized by low specificity. Additionally, hyper-microfilaremic individuals often tested negative by RDT and ELISA, indicating that these tests are not suitable for individual case management in endemic populations.</p>Absence of Anti-<i>Babesia microti</i> antibody in commercial intravenous immunoglobulin (IVIG)Julia KostkaAnu S. MaharjanSanjai KumarDouglas HackenyosPeter J. KrauseKevin Dieckhaus10.1371/journal.pntd.00120352024-03-14T14:00:00Z2024-03-14T14:00:00Z<p>by Julia Kostka, Anu S. Maharjan, Sanjai Kumar, Douglas Hackenyos, Peter J. Krause, Kevin Dieckhaus</p>
Background <p>Babesiosis is a worldwide emerging protozoan infection that is associated with a spectrum of disease severity from asymptomatic infection to severe organ damage and death. While effective treatment strategies are available, some immunocompromised patients experience severe acute and prolonged/relapsing illness due in part to an impaired host antibody response. Intravenous immunoglobulin (IVIG) has been used as an adjunctive therapy in some immunocompromised babesiosis patients, but its therapeutic effect is uncertain. We evaluated the presence of <i>Babesia microti</i> antibodies in commercial samples of IVIG.</p> Methods/principle findings <p>The presence of <i>B</i>. <i>microti</i> antibodies in commercial samples of IVIG were tested using an immunofluorescence assay. A subset of samples was then tested for <i>B</i>. <i>microti</i> antibodies using an enzyme linked immunosorbent assay.Out of 57 commercial IVIG samples tested using IFA, and 52 samples tested using ELISA, none were positive for <i>B</i>. <i>microti</i> antibodies.</p> Conclusions <p>Commercially available IVIG may not be of therapeutic benefit for babesiosis patients. Additional sampling of IVIG for B. microti antibody and a clinical trial of babesiosis patients given IVIG compared with controls would provide further insight into the use of IVIG for the treatment of babesiosis.</p>Successful introgression of <i>w</i>Mel <i>Wolbachia</i> into <i>Aedes aegypti</i> populations in Fiji, Vanuatu and KiribatiCameron P. SimmonsWesley DonaldLekon TagaviLen TarivondaTimothy QuaiRaynelyn TavoaTebikau NoranErirau ManikaotiLavinia KareauaTabomoa Tinte AbwaiDip ChandVineshwaran RamaVimal DeoKharishma Karti DeoAminiasi TavuiiWame ValentineRavi PrasadEremasi SeruLeikitah NaitukuAnaseini RatuMark HeskethNichola KennySarah C. BeebeAnjali A. GoundarAndrew McCawMolly BuntineBen GreenTibor FrossardJeremie R. L. GillesD. Albert JoubertGeoff WilsonLe Quyen DuongJean B BouvierDarren StanfordCarolyn ForderJohanna M. DuyvestynEtiene C. PacidônioHeather A. FloresNatalie WittmeierKate RetzkiPeter A. RyanJai A. DentonRuth SmithymanStephanie K. TanamasPeter KyrylosYi DongAnam KhalidLauren HodgsonKatherine L. AndersScott L. O’Neill10.1371/journal.pntd.00120222024-03-14T14:00:00Z2024-03-14T14:00:00Z<p>by Cameron P. Simmons, Wesley Donald, Lekon Tagavi, Len Tarivonda, Timothy Quai, Raynelyn Tavoa, Tebikau Noran, Erirau Manikaoti, Lavinia Kareaua, Tabomoa Tinte Abwai, Dip Chand, Vineshwaran Rama, Vimal Deo, Kharishma Karti Deo, Aminiasi Tavuii, Wame Valentine, Ravi Prasad, Eremasi Seru, Leikitah Naituku, Anaseini Ratu, Mark Hesketh, Nichola Kenny, Sarah C. Beebe, Anjali A. Goundar, Andrew McCaw, Molly Buntine, Ben Green, Tibor Frossard, Jeremie R. L. Gilles, D. Albert Joubert, Geoff Wilson, Le Quyen Duong, Jean B Bouvier, Darren Stanford, Carolyn Forder, Johanna M. Duyvestyn, Etiene C. Pacidônio, Heather A. Flores, Natalie Wittmeier, Kate Retzki, Peter A. Ryan, Jai A. Denton, Ruth Smithyman, Stephanie K. Tanamas, Peter Kyrylos, Yi Dong, Anam Khalid, Lauren Hodgson, Katherine L. Anders, Scott L. O’Neill</p>
Pacific Island countries have experienced periodic dengue, chikungunya and Zika outbreaks for decades. The prevention and control of these mosquito-borne diseases rely heavily on control of <i>Aedes aegypti</i> mosquitoes, which in most settings are the primary vector. Introgression of the intracellular bacterium <i>Wolbachia pipientis</i> (<i>w</i>Mel strain) into <i>Ae</i>. <i>aegypti</i> populations reduces their vector competence and consequently lowers dengue incidence in the human population. Here we describe successful area-wide deployments of <i>w</i>Mel-infected <i>Ae</i>. <i>aegypti</i> in Suva, Lautoka, Nadi (Fiji), Port Vila (Vanuatu) and South Tarawa (Kiribati). With community support, weekly releases of <i>w</i>Mel-infected <i>Ae</i>. <i>aegypti</i> mosquitoes for between 2 to 5 months resulted in <i>w</i>Mel introgression in nearly all locations. Long term monitoring confirmed a high, self-sustaining prevalence of <i>w</i>Mel infecting mosquitoes in almost all deployment areas. Measurement of public health outcomes were disrupted by the Covid19 pandemic but are expected to emerge in the coming years.Cryptic circulation of chikungunya virus in São Jose do Rio Preto, Brazil, 2015–2019Nathalia ZiniMatheus Henrique Tavares ÁvilaNatalia Morbi CezarottiMaisa Carla Pereira ParraCecília Artico BanhoLivia SacchettoAndreia Francesli NegriEmerson AraújoCintia BittarBruno Henrique Gonçalves de Aguiar MilhinVictor Miranda HernandesKarina Rocha DutraLeonardo Agopian TrigoLeonardo Cecílio da RochaRafael Alves da SilvaGislaine Celestino Dutra da SilvaTamires Fernanda Pereira dos SantosBeatriz de Carvalho MarquesAndresa Lopes dos SantosMarcos Tayar AugustoNatalia Franco Bueno MistrãoMilene Rocha RibeiroTauyne Menegaldo PinheiroThayza Maria Izabel Lopes dos SantosClarita Maria Secco AvillaVictoria BernardiCaroline FreitasFlora de Andrade GandolfiHélio Correa Ferraz JúniorGabriela Camilotti PerimMirella Cezare GomesPedro Henrique Carrilho GarciaRodrigo Sborghi RochaTayna Manfrin GalvãoEliane Aparecida FávaroSamuel Noah ScamardiKaren Sanmartin RogovskiRenan Luiz PeixotoLuiza BenfattiLeonardo Teixeira CruzPaula Patricia de Freitas ChamaMânlio Tasso OliveiraAripuanã Sakurada Aranha WatanabeAna Carolina Bernardes TerzianAlice de Freitas VersianiMargareth Regina DiboFrancisco Chiaravalotti-NetoScott Cameron WeaverCassia Fernanda EstofoleteNikos VasilakisMauricio Lacerda Nogueira10.1371/journal.pntd.00120132024-03-14T14:00:00Z2024-03-14T14:00:00Z<p>by Nathalia Zini, Matheus Henrique Tavares Ávila, Natalia Morbi Cezarotti, Maisa Carla Pereira Parra, Cecília Artico Banho, Livia Sacchetto, Andreia Francesli Negri, Emerson Araújo, Cintia Bittar, Bruno Henrique Gonçalves de Aguiar Milhin, Victor Miranda Hernandes, Karina Rocha Dutra, Leonardo Agopian Trigo, Leonardo Cecílio da Rocha, Rafael Alves da Silva, Gislaine Celestino Dutra da Silva, Tamires Fernanda Pereira dos Santos, Beatriz de Carvalho Marques, Andresa Lopes dos Santos, Marcos Tayar Augusto, Natalia Franco Bueno Mistrão, Milene Rocha Ribeiro, Tauyne Menegaldo Pinheiro, Thayza Maria Izabel Lopes dos Santos, Clarita Maria Secco Avilla, Victoria Bernardi, Caroline Freitas, Flora de Andrade Gandolfi, Hélio Correa Ferraz Júnior, Gabriela Camilotti Perim, Mirella Cezare Gomes, Pedro Henrique Carrilho Garcia, Rodrigo Sborghi Rocha, Tayna Manfrin Galvão, Eliane Aparecida Fávaro, Samuel Noah Scamardi, Karen Sanmartin Rogovski, Renan Luiz Peixoto, Luiza Benfatti, Leonardo Teixeira Cruz, Paula Patricia de Freitas Chama, Mânlio Tasso Oliveira, Aripuanã Sakurada Aranha Watanabe, Ana Carolina Bernardes Terzian, Alice de Freitas Versiani, Margareth Regina Dibo, Francisco Chiaravalotti-Neto, Scott Cameron Weaver, Cassia Fernanda Estofolete, Nikos Vasilakis, Mauricio Lacerda Nogueira</p>
Background <p>Chikungunya virus (CHIKV) has spread across Brazil with varying incidence rates depending on the affected areas. Due to cocirculation of arboviruses and overlapping disease symptoms, CHIKV infection may be underdiagnosed. To understand the lack of CHIKV epidemics in São José do Rio Preto (SJdRP), São Paulo (SP), Brazil, we evaluated viral circulation by investigating anti-CHIKV IgG seroconversion in a prospective study of asymptomatic individuals and detecting anti-CHIKV IgM in individuals suspected of dengue infection, as well as CHIKV presence in <i>Aedes</i> mosquitoes. The opportunity to assess two different groups (symptomatic and asymptomatic) exposed at the same geographic region aimed to broaden the possibility of identifying the viral circulation, which had been previously considered absent.</p> Methodology/principal findings <p>Based on a prospective population study model and demographic characteristics (sex and age), we analyzed the anti-CHIKV IgG seroconversion rate in 341 subjects by ELISA over four years. The seroprevalence increased from 0.35% in the first year to 2.3% after 3 years of follow-up. Additionally, we investigated 497 samples from a blood panel collected from dengue-suspected individuals during the 2019 dengue outbreak in SJdRP. In total, 4.4% were positive for anti-CHIKV IgM, and 8.6% were positive for IgG. To exclude alphavirus cross-reactivity, we evaluated the presence of anti-Mayaro virus (MAYV) IgG by ELISA, and the positivity rate was 0.3% in the population study and 0.8% in the blood panel samples. In CHIKV and MAYV plaque reduction neutralization tests (PRNTs), the positivity rate for CHIKV-neutralizing antibodies in these ELISA-positive samples was 46.7%, while no MAYV-neutralizing antibodies were detected. Genomic sequencing and phylogenetic analysis revealed CHIKV genotype ECSA in São José do Rio Preto, SP. Finally, mosquitoes collected to complement human surveillance revealed CHIKV positivity of 2.76% of <i>A</i>. <i>aegypti</i> and 9.09% of <i>A</i>. <i>albopictus</i> (although it was far less abundant than <i>A</i>. <i>aegypti</i>) by RT–qPCR.</p> Conclusions/significance <p>Our data suggest cryptic CHIKV circulation in SJdRP detected by continual active surveillance. These low levels, but increasing, of viral circulation highlight the possibility of CHIKV outbreaks, as there is a large naïve population. Improved knowledge of the epidemiological situation might aid in outbreaks prevention.</p>Correction: Development of a Humanized Antibody with High Therapeutic Potential against Dengue Virus Type 2Pi-Chun LiMei-Ying LiaoPing-Chang ChengJian-Jong LiangI-Ju LiuChien-Yu ChiuYi-Ling LinGwong-Jen J. ChangHan-Chung Wu10.1371/journal.pntd.00120312024-03-13T14:00:00Z2024-03-13T14:00:00Z<p>by Pi-Chun Li, Mei-Ying Liao, Ping-Chang Cheng, Jian-Jong Liang, I-Ju Liu, Chien-Yu Chiu, Yi-Ling Lin, Gwong-Jen J. Chang, Han-Chung Wu</p>Prokaryotic and eukaryotic skin microbiota modifications triggered by <i>Leishmania</i> infection in localized Cutaneous LeishmaniasisJesús JaimesLuz Helena PatiñoGiovanny HerreraClaudia CruzJulie PérezCamilo A. Correa-CárdenasMarina MuñozJuan David Ramírez10.1371/journal.pntd.00120292024-03-13T14:00:00Z2024-03-13T14:00:00Z<p>by Jesús Jaimes, Luz Helena Patiño, Giovanny Herrera, Claudia Cruz, Julie Pérez, Camilo A. Correa-Cárdenas, Marina Muñoz, Juan David Ramírez</p>
Cutaneous Leishmaniasis (CL) is a tropical disease characterized by cutaneous ulcers, sometimes with satellite lesions and nodular lymphangitis. <i>Leishmania</i> parasites, transmitted by sandfly vectors, cause this widespread public health challenge affecting millions worldwide. CL’s complexity stems from diverse <i>Leishmania</i> species and intricate host interactions. Therefore, this study aims to shed light on the spatial-temporal distribution of <i>Leishmania</i> species and exploring the influence of skin microbiota on disease progression. We analyzed 40 samples from CL patients at three military bases across Colombia. Using Oxford Nanopore’s Heat Shock Protein 70 sequencing, we identified <i>Leishmania</i> species and profiled microbiota in CL lesions and corresponding healthy limbs. Illumina sequencing of <i>16S-rRNA</i> and <i>18S-rRNA</i> genes helped analyze prokaryotic and eukaryotic communities. Our research uncovered a spatial-temporal overlap between regions of high CL incidence and our sampling locations, indicating the coexistence of various <i>Leishmania</i> species. <i>L</i>. <i>naiffi</i> emerged as a noteworthy discovery. In addition, our study delved into the changes in skin microbiota associated with CL lesions sampled by scraping compared with healthy skin sampled by brushing of upper and lower limbs. We observed alterations in microbial diversity, both in prokaryotic and eukaryotic communities, within the lesioned areas, signifying the potential role of microbiota in CL pathogenesis. The significant increase in specific bacterial families, such as Staphylococcaceae and Streptococcaceae, within CL lesions indicates their contribution to local inflammation. In essence, our study contributes to the ongoing research into CL, highlighting the need for a multifaceted approach to decipher the intricate interactions between Leishmaniasis and the skin microbiota.