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Trypa-NO! contributes to the elimination of <i>gambiense</i> human African trypanosomiasis by combining tsetse control with “screen, diagnose and treat” using innovative tools and strategies

PLoS Neglected Tropical Diseases News - 12 November 2020 - 10:00pm

by Joseph Mathu Ndung’u, Alain Boulangé, Albert Picado, Albert Mugenyi, Allan Mortensen, Andrew Hope, Brahim Guihini Mollo, Bruno Bucheton, Charles Wamboga, Charles Waiswa, Dramane Kaba, Enock Matovu, Fabrice Courtin, Gala Garrod, Geoffrey Gimonneau, Georgina V. Bingham, Hassane Mahamat Hassane, Inaki Tirados, Isabel Saldanha, Jacques Kabore, Jean-Baptiste Rayaisse, Jean-Mathieu Bart, Jessica Lingley, Johan Esterhuizen, Joshua Longbottom, Justin Pulford, Lingue Kouakou, Lassina Sanogo, Lucas Cunningham, Mamadou Camara, Mathurin Koffi, Michelle Stanton, Mike Lehane, Moise Saa Kagbadouno, Oumou Camara, Paul Bessell, Peka Mallaye, Philippe Solano, Richard Selby, Sophie Dunkley, Steve Torr, Sylvain Biéler, Veerle Lejon, Vincent Jamonneau, Wilfried Yoni, Zachary Katz

The risk of adverse clinical outcomes following treatment of Plasmodium vivax malaria with and without primaquine in Papua, Indonesia

PLoS Neglected Tropical Diseases News - 11 November 2020 - 10:00pm

by Kamala Thriemer, Jeanne-Rini Poespoprodjo, Enny Kenangalem, Nicholas M. Douglas, Paulus Sugiarto, Nicholas M. Anstey, Julie Anne Simpson, Ric N. Price

The widespread use of primaquine (PQ) radical cure for P. vivax, is constrained by concerns over its safety. We used routinely collected patient data to compare the overall morbidity and mortality in patients treated with and without PQ without prior testing of Glucose-6-Phosphate-Dehydrogenase (G6PD) deficiency in Papua, Indonesia, where there is a low prevalence of G6PD deficiency. Records were collated from patients older than 1 year, with P. vivax infection, who were treated with an artemisinin combination therapy (ACT). The risks of re-presentation, hospitalization, major fall in haemoglobin and death within 30 days were quantified and compared between patients treated with and without PQ using a Cox regression model. In total 26,216 patients with P. vivax malaria presented to the hospital with malaria during the study period. Overall 27.56% (95% Confidence Interval (95%CI): 26.96–28.16) of 21,344 patients treated with PQ re-presented with any illness within 30 days and 1.69% (1.51–1.88) required admission to hospital. The corresponding risks were higher in the 4,872 patients not treated with PQ; Adjusted Hazard Ratio (AHR) = 0.84 (0.79–0.91; p<0.001) and 0.54 (0.41–0.70; p<0.001) respectively. By day 30, 14.15% (12.45–16.05) of patients who had received PQ had a fall in haemoglobin (Hb) below 7g/dl compared to 20.43% (16.67–24.89) of patients treated without PQ; AHR = 0.66 (0.45–0.97; p = 0.033). A total of 75 (0.3%) patients died within 30 days of treatment with a mortality risk of 0.27% (0.21–0.35) in patients treated with PQ, compared to 0.38% (0.24–0.60) without PQ; AHR = 0.79 (0.43–1.45; p = 0.448). In Papua, Indonesia routine administration of PQ radical cure without prior G6PD testing, was associated with lower risk of all cause hospitalization and other serious adverse clinical outcomes. In areas where G6PD testing is not available or cannot be delivered reliably, the risks of drug induced haemolysis should be balanced against the potential benefits of reducing recurrent P. vivax malaria and its associated morbidity and mortality.

Circulating microtranscriptome profiles reveal distinct expression of microRNAs in severe leptospirosis

PLoS Neglected Tropical Diseases News - 11 November 2020 - 10:00pm

by Umaporn Limothai, Janejira Dinhuzen, Titipon Payongsri, Sasipha Tachaboon, Pisit Tangkijvanich, Natthaya Chuaypen, Nattachai Srisawat

Biomarkers to predict the severity of leptospirosis are still lacking. This study aimed to identify and validate microRNAs in patients with severe leptospirosis, that could potentially be used as biomarkers for predicting an unfavorable outcome. Serum samples were collected from participants with definite diagnosis of leptospirosis. The participants were divided into two groups, non-severe and severe leptospirosis, as defined by the Specific Organ Sequential Organ Failure (SOFA) Score of more than two in any organ. Microtranscriptome analysis was performed using the NanoString miRNA Expression Assay. The expression level of candidate miRNAs was then validated by quantitative RT-PCR. Based on the NanoString, the microtranscriptome profile of the severe group was significantly different from that of the non-severe group. Upregulation of miR155-5p, miR362-3p, miR502-5p, miR601, miR1323, and miR630 in the severe group were identified, and further investigated. A total of 119 participants were enrolled in the validation cohort. Serum miR155-5p and miR630 levels were significantly higher in the severe group compared to the non-severe group. The combined use of miR155-5p or miR-630 with serum bicarbonate levels had an AUC of 0.79 (95%CI; 0.69–0.89, p<0.001) in identifying the severity of the disease. This data provides the first evidence that the microtranscriptome profiles of patients with severe leptospirosis were different from the non-severe group. Serum miR155-5p and miR630 levels might be novel biomarkers for identifying severe leptospirosis.

Comparing machine learning with case-control models to identify confirmed dengue cases

PLoS Neglected Tropical Diseases News - 10 November 2020 - 10:00pm

by Tzong-Shiann Ho, Ting-Chia Weng, Jung-Der Wang, Hsieh-Cheng Han, Hao-Chien Cheng, Chun-Chieh Yang, Chih-Hen Yu, Yen-Jung Liu, Chien Hsiang Hu, Chun-Yu Huang, Ming-Hong Chen, Chwan-Chuen King, Yen-Jen Oyang, Ching-Chuan Liu

In recent decades, the global incidence of dengue has increased. Affected countries have responded with more effective surveillance strategies to detect outbreaks early, monitor the trends, and implement prevention and control measures. We have applied newly developed machine learning approaches to identify laboratory-confirmed dengue cases from 4,894 emergency department patients with dengue-like illness (DLI) who received laboratory tests. Among them, 60.11% (2942 cases) were confirmed to have dengue. Using just four input variables [age, body temperature, white blood cells counts (WBCs) and platelets], not only the state-of-the-art deep neural network (DNN) prediction models but also the conventional decision tree (DT) and logistic regression (LR) models delivered performances with receiver operating characteristic (ROC) curves areas under curves (AUCs) of the ranging from 83.75% to 85.87% [for DT, DNN and LR: 84.60% ± 0.03%, 85.87% ± 0.54%, 83.75% ± 0.17%, respectively]. Subgroup analyses found all the models were very sensitive particularly in the pre-epidemic period. Pre-peak sensitivities (<35 weeks) were 92.6%, 92.9%, and 93.1% in DT, DNN, and LR respectively. Adjusted odds ratios examined with LR for low WBCs [≤ 3.2 (x103/μL)], fever (≥38°C), low platelet counts [< 100 (x103/μL)], and elderly (≥ 65 years) were 5.17 [95% confidence interval (CI): 3.96–6.76], 3.17 [95%CI: 2.74–3.66], 3.10 [95%CI: 2.44–3.94], and 1.77 [95%CI: 1.50–2.10], respectively. Our prediction models can readily be used in resource-poor countries where viral/serologic tests are inconvenient and can also be applied for real-time syndromic surveillance to monitor trends of dengue cases and even be integrated with mosquito/environment surveillance for early warning and immediate prevention/control measures. In other words, a local community hospital/clinic with an instrument of complete blood counts (including platelets) can provide a sentinel screening during outbreaks. In conclusion, the machine learning approach can facilitate medical and public health efforts to minimize the health threat of dengue epidemics. However, laboratory confirmation remains the primary goal of surveillance and outbreak investigation.

Modeling the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on skin, currency, and clothing

PLoS Neglected Tropical Diseases News - 9 November 2020 - 10:00pm

by David E. Harbourt, Andrew D. Haddow, Ashley E. Piper, Holly Bloomfield, Brian J. Kearney, David Fetterer, Kathleen Gibson, Timothy Minogue

A new coronavirus (SARS-CoV-2) emerged in the winter of 2019 in Wuhan, China, and rapidly spread around the world. The extent and efficiency of SARS-CoV-2 pandemic is far greater than previous coronaviruses that emerged in the 21st Century. Here, we modeled stability of SARS-CoV-2 on skin, paper currency, and clothing to determine if these surfaces may factor in the fomite transmission dynamics of SARS-CoV-2. Skin, currency, and clothing samples were exposed to SARS-CoV-2 under laboratory conditions and incubated at three different temperatures (4°C± 2°C, 22°C± 2°C, and 37°C ± 2°C). We evaluated stability at 0 hours (h), 4 h, 8 h, 24 h, 72 h, 96 h, 7 days, and 14 days post-exposure. SARS-CoV-2 was stable on skin through the duration of the experiment at 4°C (14 days). Virus remained stable on skin for at least 96 h at 22°C and for at least 8h at 37°C. There were minimal differences between the tested currency samples. The virus remained stable on the $1 U.S.A. Bank Note for at least 96 h at 4°C while we did not detect viable virus on the $20 U.S.A. Bank Note samples beyond 72 h. The virus remained stable on both Bank Notes for at least 8 h at 22°C and 4 h at 37°C. Clothing samples were similar in stability to the currency. Viable virus remained for at least 96 h at 4°C and at least 4 h at 22°C. We did not detect viable virus on clothing samples at 37°C after initial exposure. This study confirms the inverse relationship between virus stability and temperature. Furthermore, virus stability on skin demonstrates the need for continued hand hygiene practices to minimize fomite transmission both in the general population as well as in workplaces where close contact is common.

Challenges in the care of patients with Chagas disease in the Brazilian public health system: A qualitative study with primary health care doctors

PLoS Neglected Tropical Diseases News - 9 November 2020 - 10:00pm

by Renata Fiúza Damasceno, Ester Cerdeira Sabino, Ariela Mota Ferreira, Antonio Luiz Pinho Ribeiro, Hugo Fonseca Moreira, Thalita Emily Cezário Prates, Cristina Andrade Sampaio, Desirée Sant´Ana Haikal

Background

Care to patients with Chagas disease (CD) is still a challenge for health systems in endemic and non-endemic countries. In the Brazilian public health system, the expansion of Primary Health Care (PHC) services to remote and disadvantaged areas has facilitated the access of patients with CD to medical care, however this is in a context where care gaps remain, with insufficient public funding and inadequate distribution of services. Considering the need for studies on care to patients with CD in different settings, this study explored the challenges of family doctors to provide care to patients with CD in an endemic region in Brazil with high coverage of public PHC services.

Methods and findings

This is a qualitative study. A focus group with 15 family doctors was conducted in a municipality participating in a multicenter cohort that monitors almost two thousand patients with CD in an endemic region in Brazil. The data were analyzed using a thematic content analysis technique. The family doctors pointed out the following challenges for care to patients with CD: unsatisfactory medical training (academic education not suitable for the clinical management of the disease, and lack of training on CD in PHC); uncertainties regarding antiparasitic treatment in the chronic phase of the disease; difficulty in patients’ access to specialized care when necessary, especially to the cardiologist; and trivialization of the disease by patients as a barrier to seeking care.

Conclusion

The access of CD patients to adequate medical care, even in regions with high coverage of public PHC services, still represents an important challenge for health systems. The results of this study may contribute to the development of strategies to improve the clinical management of CD in PHC.

Correction: Indirect Immunofluorescence Assay for the Simultaneous Detection of Antibodies against Clinically Important Old and New World Hantaviruses

PLoS Neglected Tropical Diseases News - 9 November 2020 - 10:00pm

by Sabine Lederer, Erik Lattwein, Merle Hanke, Karen Sonnenberg, Winfried Stoecker, Åke Lundkvist, Antti Vaheri, Olli Vapalahti, Paul K. S. Chan, Heinz Feldmann, Daryl Dick, Jonas Schmidt-Chanasit, Paula Padula, Pablo A. Vial, Raluca Panculescu-Gatej, Cornelia Ceianu, Paul Heyman, Tatjana Avšič-Županc, Matthias Niedrig

COVID-19 unfolding filariasis: The first case of SARS-CoV-2 and <i>Wuchereria bancrofti</i> coinfection

PLoS Neglected Tropical Diseases News - 9 November 2020 - 10:00pm

by Mouhand F. H. Mohamed, Sara F. Mohamed, Zohaib Yousaf, Samah Kohla, Faraj Howady, Yahia Imam

With the evolution of the Coronavirus Disease 2019 (COVID-19) pandemic, the number of patients brought to medical attention has increased. This has led to the unmasking of many coexisting occult infections and comorbidities such as tuberculosis, dengue, human immunodeficiency viral infection, diabetes, and hypertension. We report the first case of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, unveiling the diagnosis of asymptomatic filariasis. A 37-year-old gentleman presented with shortness of breath, fever, and cough. He was found to have COVID-19 pneumonia. During his stay, microfilaria of Wuchereria bancrofti was detected incidentally on a blood smear exam. Consequently, the patient received appropriate treatment for both conditions. In order not to miss relevant concomitant diagnoses, it is prudent to keep a broad differential diagnosis when faced with SARS-CoV-2–infected patients; this is especially true when atypical symptoms are present or in areas endemic with other infections.

Estimating the basic reproduction number for the 2015 bubonic plague outbreak in Nyimba district of Eastern Zambia

PLoS Neglected Tropical Diseases News - 9 November 2020 - 10:00pm

by Joseph Sichone, Martin C. Simuunza, Bernard M. Hang’ombe, Mervis Kikonko

Background

Plague is a re-emerging flea-borne infectious disease of global importance and in recent years, Zambia has periodically experienced increased incidence of outbreaks of this disease. However, there are currently no studies in the country that provide a quantitative assessment of the ability of the disease to spread during these outbreaks. This limits our understanding of the epidemiology of the disease especially for planning and implementing quantifiable and cost-effective control measures. To fill this gap, the basic reproduction number, R0, for bubonic plague was estimated in this study, using data from the 2015 Nyimba district outbreak, in the Eastern province of Zambia. R0 is the average number of secondary infections arising from a single infectious individual during their infectious period in an entirely susceptible population.

Methodology/Principal findings

Secondary epidemic data for the most recent 2015 Nyimba district bubonic plague outbreak in Zambia was analyzed. R0 was estimated as a function of the average epidemic doubling time based on the initial exponential growth rate of the outbreak and the average infectious period for bubonic plague. R0 was estimated to range between 1.5599 [95% CI: 1.382–1.7378] and 1.9332 [95% CI: 1.6366–2.2297], with average of 1.7465 [95% CI: 1.5093–1.9838]. Further, an SIR deterministic mathematical model was derived for this infection and this estimated R0 to be between 1.4 to 1.5, which was within the range estimated above.

Conclusions/Significance

This estimated R0 for bubonic plague is an indication that each bubonic plague case can typically give rise to almost two new cases during these outbreaks. This R0 estimate can now be used to quantitatively analyze and plan measurable interventions against future plague outbreaks in Zambia.

Correction: Mortality among blood donors seropositive and seronegative for Chagas disease (1996–2000) in São Paulo, Brazil: A death certificate linkage study

PLoS Neglected Tropical Diseases News - 6 November 2020 - 10:00pm

by Ligia Capuani, Ana Luiza Bierrenbach, Airlane Pereira Alencar, Alfredo Mendrone Jr., João Eduardo Ferreira, Brian Custer, Antonio Luiz P. Ribeiro, Ester Cerdeira Sabino

Evaluation of the diagnostic accuracy of lateral flow devices as a tool to diagnose rabies in post-mortem animals

PLoS Neglected Tropical Diseases News - 5 November 2020 - 10:00pm

by Kazunori Kimitsuki, Nobuo Saito, Kentaro Yamada, Chun-Ho Park, Satoshi Inoue, Motoi Suzuki, Mariko Saito-Obata, Yasuhiko Kamiya, Daria L. Manalo, Catalino S. Demetria, Milagros R. Mananggit, Beatriz P. Quiambao, Akira Nishizono

Implementation of lateral flow devices (LFDs) for rabies antigen detection is expected to improve surveillance through the efficient detection of rabid animals in resource-limited settings; however, the use of LFDs for diagnosis remains controversial because some commercially available kits show low sensitivity. Therefore, we compared the diagnostic efficacy of three LFDs (ADTEC, Bionote, and Elabscience kits) paralleled with the direct fluorescent antibody test (dFAT) using fresh samples and investigated the diagnostic accuracies. To do so, we evaluated rabies-suspected samples submitted to the Regional Animal Disease Diagnostic Laboratory III, Philippines. Furthermore, we conducted real-time RT-PCR and sequencing to measure the accuracy of field laboratory diagnosis. The total number of animals submitted during this study period was 184 cases, including negative control samples. Of these, 53.9% (84 cases) were positive in the dFAT. Dogs were the most common rabies-suspected animal (n = 135). The sensitivities of the ADTEC and Bionote kits were 0.88 (74 cases) and 0.95 (80 cases), respectively. The specificity of both kits was 1.00 (100 cases). Furthermore, the sensitivity and specificity of the ADTEC kit after directly homogenizing the samples in assay buffer without dilution in phosphate-buffered saline (ADTEC kit DM) were 0.94 (79 cases) and 1.00 (100 cases), respectively. By contrast, there were no positive results using the Elabscience kit among all dFAT-positive samples. The sensitivity and specificity of LFDs make these tests highly feasible if properly used. Therefore, LFD tests can be used to strengthen the surveillance of rabies-infected animals in endemic and resource-limited settings.

The NTD Supply Chain Forum—Strengthening the backbone of NTD programs

PLoS Neglected Tropical Diseases News - 5 November 2020 - 10:00pm

by Ashley A. Souza, Cassandra Holloway, Tijana Williams

Global programs targeting 5 preventive chemotherapy neglected tropical diseases (PC-NTDs) have scaled up rapidly in recent decades due, in large part, to the generous drug donations from 6 pharmaceutical companies—Eisai; Johnson & Johnson (J&J); GlaxoSmithKline (GSK); Merck & Co., Inc., Kenilworth, New Jersey, United States of America (MSD); Merck KgaA; and Pfizer. Today, the scale of the PC-NTD drug donation programs is staggering. Nearly 15 billion tablets have been manufactured, packaged, shipped, and distributed in order to reach the people in need. The supply chains established to support such massive operations are enormously complex. Here, we describe a unique public–private partnership that was formed to bring together supply chain expertise to overcome the critical challenges associated with such large-scale production and delivery of donated pharmaceutical products.

<i>Strongyloides stercoralis</i> disseminated infection in an HIV-infected adult

PLoS Neglected Tropical Diseases News - 5 November 2020 - 10:00pm

by Ambroise Le Pogam, Julien Lopinto, Adrien Pecriaux, Muriel Fartoukh, Juliette Guitard, Guillaume Voiriot

In this visual case of Strongyloides stercoralis disseminated infection with Enterobacteriaceae-related invasive infection, we demonstrated the in-host S. stercoralis circulation with DNA found in different fluids and specimens, but also in cerebrospinal fluid (CSF), supporting the role of migrant larvae in the Enterobacteriaceae-related invasive and central nervous system infection.

Preliminary evaluations of 3-dimensional human skin models for their ability to facilitate <i>in vitro</i> the long-term development of the debilitating obligatory human parasite <i>Onchocerca volvulus</i>

PLoS Neglected Tropical Diseases News - 5 November 2020 - 10:00pm

by Christoph Malkmus, Shabnam Jawahar, Nancy Tricoche, Sara Lustigman, Jan Hansmann

Onchocerciasis also known as river blindness is a neglected tropical disease and the world's second-leading infectious cause of blindness in humans; it is caused by Onchocerca volvulus. Current treatment with ivermectin targets microfilariae and transmission and does not kill the adult parasites, which reside within subcutaneous nodules. To support the development of macrofilaricidal drugs that target the adult worm to further support the elimination of onchocerciasis, an in-depth understanding of O. volvulus biology especially the factors that support the longevity of these worms in the human host (>10 years) is required. However, research is hampered by a lack of access to adult worms. O. volvulus is an obligatory human parasite and no small animal models that can propagate this parasite were successfully developed. The current optimized 2-dimensional (2-D) in vitro culturing method starting with O. volvulus infective larvae does not yet support the development of mature adult worms. To overcome these limitations, we have developed and applied 3-dimensional (3-D) culture systems with O. volvulus larvae that simulate the human in vivo niche using in vitro engineered skin and adipose tissue. Our proof of concept studies have shown that an optimized indirect co-culture of in vitro skin tissue supported a significant increase in growth of the fourth-stage larvae to the pre-adult stage with a median length of 816–831 μm as compared to 767 μm of 2-D cultured developed larvae. Notably, when larvae were co-cultured directly with adipose tissue models, a significant improvement for larval motility and thus fitness was observed; 95% compared to 26% in the 2-D system. These promising co-culture concepts are a first step to further optimize the culturing conditions and improve the long-term development of adult worms in vitro. Ultimately, it could provide the filarial research community with a valuable source of O. volvulus worms at various developmental stages, which may accelerate innovative unsolved biomedical inquiries into the parasite’s biology.

Development and evaluation of a rapid and simple diagnostic assay for COVID-19 based on loop-mediated isothermal amplification

PLoS Neglected Tropical Diseases News - 4 November 2020 - 10:00pm

by Rokusuke Yoshikawa, Haruka Abe, Yui Igasaki, Saeki Negishi, Hiroaki Goto, Jiro Yasuda

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly pathogenic novel coronavirus that has caused a worldwide outbreak. Here we describe a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay that uses a portable device for efficient detection of SARS-CoV-2. This RT-LAMP assay specifically detected SARS-CoV-2 without cross-reacting with the most closely related human coronavirus, SARS-CoV. Clinical evaluation of nasal swab samples from suspected SARS-CoV-2 pneumonia (COVID-19) patients showed that the assay could detect over 23.7 copies within 15 min with a 100% probability. Since the RT-LAMP assay can be performed with a portable battery-supported device, it is a rapid, simple, and sensitive diagnostic assay for COVID-19 that can be available at point-of-care. We also developed the RT-LAMP assay without the RNA extraction step–Direct RT-LAMP, which could detect more than 1.43 x 103 copies within 15 min with a 100% probability in clinical evaluation test. Although the Direct RT-LAMP assay was less sensitive than the standard RT-LAMP, the Direct RT-LAMP assay can be available as the rapid first screening of COVID-19 in poorly equipped areas, such as rural areas in developing countries.

Validation of verbal autopsy and nasopharyngeal swab collection for the investigation of deaths at home during the COVID-19 pandemics in Brazil

PLoS Neglected Tropical Diseases News - 4 November 2020 - 10:00pm

by Pedro Mansueto Melo de Souza, Gunter Gerson, Josebson Silva Dias, Deborah Nunes de Melo, Sarlene Gomes de Souza, Erasmo Miessa Ruiz, Fabio Rocha Fernandes Tavora, Luciano Pamplona de Góes Cavalcanti

Informing children citizens efficiently to better engage them in the fight against COVID-19 pandemic

PLoS Neglected Tropical Diseases News - 4 November 2020 - 10:00pm

by Jean-Eric Ghia, Sophie Gaulin, Laure Ghia, Laure Garancher, Claude Flamand

Since the beginning of the year, the world’s attention has rightly been focused on the spread of the Coronavirus Disease 2019 (COVID-19) pandemic and the implementation of drastic mitigation strategies to limit disease transmission. However, public health information campaigns tailored to children are very rare. Now more than ever, at a time when some governments are taking populations out of lockdown and youth are returning to schools, children around the world need to fully grasp the modes of transmission of the disease, the health risks, the scientific notions of the immune system, the value of barrier measures, and the progress of scientific research. In the context of the COVID-19 pandemic, comics can be very useful for communicating quickly and effectively abstract and important information to children who might be under the influence of a large amount of sometimes contradictory information. Conveying precise, reliable, and accessible information to children is key in a world overwhelmingly impacted by the outbreak. This should be the role and the responsibility of world health official leaders and governments in compliance with the United Nations Convention on the Rights of the Child. In partnership with mainstream medias, consortia of scientists, communication experts, and education specialists, it is urgent that world leaders engage children in this worldwide public health fight.

A voluntary use of insecticide treated nets can stop the vector transmission of Chagas disease

PLoS Neglected Tropical Diseases News - 3 November 2020 - 10:00pm

by Cheol Yong Han, Habeeb Issa, Jan Rychtář, Dewey Taylor, Nancy Umana

One of the stated goals of the London Declaration on Neglected Tropical Diseases is the interruption of domiciliary transmissions of Chagas disease in the region of the Americas. We used a game-theoretic approach to assess the voluntary use of insecticide treated nets (ITNs) in the prevention of the spread of infection through vector bites. Our results show that individuals behave rationally and weigh the risks of insect bites against the cost of the ITNs. The optimal voluntary use of ITNs results in predicted incidence rates that closely track the real incidence rates in Latin America. This means that ITNs are effective and could be used to control the spread of the disease by relying on individual decisions rather than centralized policies. Our model shows that to completely eradicate the vector transmission through the voluntary individual use of ITNs, the cost of ITNs should be as low as possible.

Development of an antigen detection assay for early point-of-care diagnosis of <i>Zaire ebolavirus</i>

PLoS Neglected Tropical Diseases News - 3 November 2020 - 10:00pm

by Haley L. DeMers, Shihua He, Sujata G. Pandit, Emily E. Hannah, Zirui Zhang, Feihu Yan, Heather R. Green, Denise F. Reyes, Derrick Hau, Megan E. McLarty, Louis Altamura, Cheryl Taylor-Howell, Marcellene A. Gates-Hollingsworth, Xiangguo Qiu, David P. AuCoin

The 2013–2016 Ebola virus (EBOV) outbreak in West Africa and the ongoing cases in the Democratic Republic of the Congo have spurred development of a number of medical countermeasures, including rapid Ebola diagnostic tests. The likelihood of transmission increases as the disease progresses due to increasing viral load and potential for contact with others. Early diagnosis of EBOV is essential for halting spread of the disease. Polymerase chain reaction assays are the gold standard for diagnosing Ebola virus disease (EVD), however, they rely on infrastructure and trained personnel that are not available in most resource-limited settings. Rapid diagnostic tests that are capable of detecting virus with reliable sensitivity need to be made available for use in austere environments where laboratory testing is not feasible. The goal of this study was to produce candidate lateral flow immunoassay (LFI) prototypes specific to the EBOV glycoprotein and viral matrix protein, both targets known to be present during EVD. The LFI platform utilizes antibody-based technology to capture and detect targets and is well suited to the needs of EVD diagnosis as it can be performed at the point-of-care, requires no cold chain, provides results in less than twenty minutes and is low cost. Monoclonal antibodies were isolated, characterized and evaluated in the LFI platform. Top performing LFI prototypes were selected, further optimized and confirmed for sensitivity with cultured live EBOV and clinical samples from infected non-human primates. Comparison with a commercially available EBOV rapid diagnostic test that received emergency use approval demonstrates that the glycoprotein-specific LFI developed as a part of this study has improved sensitivity. The outcome of this work presents a diagnostic prototype with the potential to enable earlier diagnosis of EVD in clinical settings and provide healthcare workers with a vital tool for reducing the spread of disease during an outbreak.

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