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Assessing Progress in Reducing the At-Risk Population after 13 Years of the Global Programme to Eliminate Lymphatic Filariasis

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Pamela J. Hooper, Brian K. Chu, Alexei Mikhailov, Eric A. Ottesen, Mark Bradley

Background

In 1997, the World Health Assembly adopted Resolution 50.29, committing to the elimination of lymphatic filariasis (LF) as a public health problem, subsequently targeted for 2020. The initial estimates were that 1.2 billion people were at-risk for LF infection globally. Now, 13 years after the Global Programme to Eliminate Lymphatic Filariasis (GPELF) began implementing mass drug administration (MDA) against LF in 2000—during which over 4.4 billion treatments have been distributed in 56 endemic countries—it is most appropriate to estimate the impact that the MDA has had on reducing the population at risk of LF.

Methodology/Principal Findings

To assess GPELF progress in reducing the population at-risk for LF, we developed a model based on defining reductions in risk of infection among cohorts of treated populations following each round of MDA. The model estimates that the number of people currently at risk of infection decreased by 46% to 789 million through 2012.

Conclusions/Significance

Important progress has been made in the global efforts to eliminate LF, but significant scale-up is required over the next 8 years to reach the 2020 elimination goal.

Standardizing Visual Control Devices for Tsetse Flies: East African Species Glossina fuscipes fuscipes and Glossina tachinoides

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Francis Oloo, Andrea Sciarretta, Mohamed M. Mohamed-Ahmed, Thomas Kröber, Andrew McMullin, Steve Mihok, Patrick M. Guerin

Background

Riverine species of tsetse are responsible for most human African trypanosomiasis (HAT) transmission and are also important vectors of animal trypanosomiasis. This study concerns the development of visual control devices for two such species, Glossina fuscipes fuscipes and Glossina tachinoides, at the eastern limits of their continental range. The goal was to determine the most long-lasting, practical and cost-effective visually attractive device that induces the strongest landing responses in these species for use as insecticide-impregnated tools in vector population suppression.

Methods and Findings

Field trials were conducted in different seasons on G. f. fuscipes in Kenya, Ethiopia and the Sudan and on G. tachinoides in Ethiopia to measure the performance of traps and 2D targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used to enumerate flies at these remote locations to compare trapping efficiencies. The findings show that targets made from black and blue fabrics (either phthalogen or turquoise) covered with adhesive film render them equal to or more efficient than traps at capturing G. f. fuscipes and G. tachinoides. Biconical trap efficiency varied between 25% and 33% for the two species. Smaller 0.25 m×0.25 m phthalogen blue-black targets proved more efficient than the regular 1 m2 target for both species, by over six times for Glossina f. fuscipes and two times for G. tachinoides based on catches per m2. Overall, targets with a higher edge/surface area ratio were more efficient at capturing flies.

Conclusions/Significance

Taking into account practical considerations and fly preferences for edges and colours, we propose a 0.5×0.75 m blue-black target as a simple cost-effective device for management of G. f. fuscipes and G. tachinoides, impregnated with insecticide for control and covered with adhesive film for population sampling.

The Plasmodium vivax Merozoite Surface Protein 3β Sequence Reveals Contrasting Parasite Populations in Southern and Northwestern Thailand

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Chaturong Putaporntip, Jun Miao, Napaporn Kuamsab, Jetsumon Sattabongkot, Jeeraphat Sirichaisinthop, Somchai Jongwutiwes, Liwang Cui

Background

Malaria control efforts have a significant impact on the epidemiology and parasite population dynamics. In countries aiming for malaria elimination, malaria transmission may be restricted to limited transmission hot spots, where parasite populations may be isolated from each other and experience different selection forces. Here we aim to examine the Plasmodium vivax population divergence in geographically isolated transmission zones in Thailand.

Methodology

We employed the P. vivax merozoite surface protein 3β (PvMSP3β) as a molecular marker for characterizing P. vivax populations based on the extensive diversity of this gene in Southeast Asian parasite populations. To examine two parasite populations with different transmission levels in Thailand, we obtained 45 P. vivax isolates from Tak Province, northwestern Thailand, where the annual parasite incidence (API) was more than 2%, and 28 isolates from Yala and Narathiwat Provinces, southern Thailand, where the API was less than 0.02%. We sequenced the PvMSP3β gene and examined its genetic diversity and molecular evolution between the parasite populations.

Principal Findings

Of 58 isolates containing single PvMSP3β alleles, 31 sequence types were identified. The overall haplotype diversity was 0.77±0.06 and nucleotide diversity 0.0877±0.0054. The northwestern vivax malaria population exhibited extensive haplotype diversity (HD) of PvMSP3β (HD = 1.0). In contrast, the southern parasite population displayed a single PvMSP3β allele (HD = 0), suggesting a clonal population expansion. This result revealed that the extent of allelic diversity in P. vivax populations in Thailand varies among endemic areas.

Conclusion

Malaria parasite populations in a given region may vary significantly in genetic diversity, which may be the result of control and influenced by the magnitude of malaria transmission intensity. This is an issue that should be taken into account for the implementation of P. vivax control measures such as drug policy and vaccine development.

Dengue and Chikungunya Fever among Viral Diseases in Outpatient Febrile Children in Kilosa District Hospital, Tanzania

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Beatrice Chipwaza, Joseph P. Mugasa, Majige Selemani, Mbaraka Amuri, Fausta Mosha, Steve D. Ngatunga, Paul S. Gwakisa

Introduction

Viral etiologies of fever, including dengue, Chikungunya, influenza, rota and adeno viruses, cause major disease burden in tropical and subtropical countries. The lack of diagnostic facilities in developing countries leads to failure to estimate the true burden of such illnesses, and generally the diseases are underreported. These diseases may have similar symptoms with other causes of acute febrile illnesses including malaria and hence clinical diagnosis without laboratory tests can be difficult. This study aimed to identify viral etiologies as a cause of fever in children and their co-infections with malaria.

Methods

A cross sectional study was conducted for 6 months at Kilosa district hospital, Tanzania. The participants were febrile children aged 2–13 years presented at the outpatient department. Diagnostic tests such as IgM and IgG ELISA, and PCR were used.

Results

A total of 364 patients were enrolled, of these 83(22.8%) had malaria parasites, 76 (20.9%) had presumptive acute dengue infection and among those, 29(38.2%) were confirmed cases. Dengue was more likely to occur in children ≥ 5 years than in <5 years (OR 2.28, 95% CI: 1.35–3.86). Presumptive acute Chikungunya infection was identified in 17(4.7%) of patients. We observed no presenting symptoms that distinguished patients with Chikungunya infection from those with dengue infection or malaria. Co-infections between malaria and Chikungunya, malaria and dengue fever as well as Chikungunya and dengue were detected. Most patients with Chikungunya and dengue infections were treated with antibacterials. Furthermore, our results revealed that 5(5.2%) of patients had influenza virus while 5(12.8%) had rotavirus and 2(5.1%) had adenovirus.

Conclusion

Our results suggest that even though viral diseases are a major public health concern, they are not given due recognition as a cause of fever in febrile patients. Emphasis on laboratory diagnostic tests for proper diagnosis and management of febrile patients is recommended.

Global Metabolomic Profiling of Acute Myocarditis Caused by Trypanosoma cruzi Infection

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Núria Gironès, Sofía Carbajosa, Néstor A. Guerrero, Cristina Poveda, Carlos Chillón-Marinas, Manuel Fresno

Chagas disease is caused by Trypanosoma cruzi infection, being cardiomyopathy the more frequent manifestation. New chemotherapeutic drugs are needed but there are no good biomarkers for monitoring treatment efficacy. There is growing evidence linking immune response and metabolism in inflammatory processes and specifically in Chagas disease. Thus, some metabolites are able to enhance and/or inhibit the immune response. Metabolite levels found in the host during an ongoing infection could provide valuable information on the pathogenesis and/or identify deregulated metabolic pathway that can be potential candidates for treatment and being potential specific biomarkers of the disease. To gain more insight into those aspects in Chagas disease, we performed an unprecedented metabolomic analysis in heart and plasma of mice infected with T. cruzi. Many metabolic pathways were profoundly affected by T. cruzi infection, such as glucose uptake, sorbitol pathway, fatty acid and phospholipid synthesis that were increased in heart tissue but decreased in plasma. Tricarboxylic acid cycle was decreased in heart tissue and plasma whereas reactive oxygen species production and uric acid formation were also deeply increased in infected hearts suggesting a stressful condition in the heart. While specific metabolites allantoin, kynurenine and p-cresol sulfate, resulting from nucleotide, tryptophan and phenylalanine/tyrosine metabolism, respectively, were increased in heart tissue and also in plasma. These results provide new valuable information on the pathogenesis of acute Chagas disease, unravel several new metabolic pathways susceptible of clinical management and identify metabolites useful as potential specific biomarkers for monitoring treatment and clinical severity in patients.

Spatiotemporal Transmission Dynamics of Hemorrhagic Fever with Renal Syndrome in China, 2005–2012

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Wen-Yi Zhang, Li-Ya Wang, Yun-Xi Liu, Wen-Wu Yin, Wen-Biao Hu, Ricardo J. Soares. Magalhaes, Fan Ding, Hai-Long Sun, Hang Zhou, Shen-Long Li, Ubydul Haque, Shi-Lu Tong, Gregory E. Glass, Peng Bi, Archie C. A. Clements, Qi-Yong Liu, Cheng-Yi Li

Background

Hemorrhagic fever with renal syndrome (HFRS) is a rodent-borne disease caused by many serotypes of hantaviruses. In China, HFRS has been recognized as a severe public health problem with 90% of the total reported cases in the world. This study describes the spatiotemporal dynamics of HFRS cases in China and identifies the regions, time, and populations at highest risk, which could help the planning and implementation of key preventative measures.

Methods

Data on all reported HFRS cases at the county level from January 2005 to December 2012 were collected from Chinese Center for Disease Control and Prevention. Geographic Information System-based spatiotemporal analyses including Local Indicators of Spatial Association and Kulldorff's space-time scan statistic were performed to detect local high-risk space-time clusters of HFRS in China. In addition, cases from high-risk and low-risk counties were compared to identify significant demographic differences.

Results

A total of 100,868 cases were reported during 2005–2012 in mainland China. There were significant variations in the spatiotemporal dynamics of HFRS. HFRS cases occurred most frequently in June, November, and December. There was a significant positive spatial autocorrelation of HFRS incidence during the study periods, with Moran's I values ranging from 0.46 to 0.56 (P<0.05). Several distinct HFRS cluster areas were identified, mainly concentrated in northeastern, central, and eastern of China. Compared with cases from low-risk areas, a higher proportion of cases were younger, non-farmer, and floating residents in high-risk counties.

Conclusions

This study identified significant space-time clusters of HFRS in China during 2005–2012 indicating that preventative strategies for HFRS should be particularly focused on the northeastern, central, and eastern of China to achieve the most cost-effective outcomes.

Effect of the Brazilian Conditional Cash Transfer and Primary Health Care Programs on the New Case Detection Rate of Leprosy

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Joilda Silva Nery, Susan Martins Pereira, Davide Rasella, Maria Lúcia Fernandes Penna, Rosana Aquino, Laura Cunha Rodrigues, Mauricio Lima Barreto, Gerson Oliveira Penna

Background

Social determinants can affect the transmission of leprosy and its progression to disease. Not much is known about the effectiveness of welfare and primary health care policies on the reduction of leprosy occurrence. The aim of this study is to evaluate the impact of the Brazilian cash transfer (Bolsa Família Program-BFP) and primary health care (Family Health Program-FHP) programs on new case detection rate of leprosy.

Methodology/Principal Findings

We conducted the study with a mixed ecological design, a combination of an ecological multiple-group and time-trend design in the period 2004–2011 with the Brazilian municipalities as unit of analysis. The main independent variables were the BFP and FHP coverage at the municipal level and the outcome was new case detection rate of leprosy. Leprosy new cases, BFP and FHP coverage, population and other relevant socio-demographic covariates were obtained from national databases. We used fixed-effects negative binomial models for panel data adjusted for relevant socio-demographic covariates. A total of 1,358 municipalities were included in the analysis. In the studied period, while the municipal coverage of BFP and FHP increased, the new case detection rate of leprosy decreased. Leprosy new case detection rate was significantly reduced in municipalities with consolidated BFP coverage (Risk Ratio 0.79; 95% CI  = 0.74–0.83) and significantly increased in municipalities with FHP coverage in the medium (72–95%) (Risk Ratio 1.05; 95% CI  = 1.02–1.09) and higher coverage tertiles (>95%) (Risk Ratio 1.12; 95% CI  = 1.08–1.17).

Conclusions

At the same time the Family Health Program had been effective in increasing the new case detection rate of leprosy in Brazil, the Bolsa Família Program was associated with a reduction of the new case detection rate of leprosy that we propose reflects a reduction in leprosy incidence.

The Colposcopic Atlas of Schistosomiasis in the Lower Female Genital Tract Based on Studies in Malawi, Zimbabwe, Madagascar and South Africa

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Hanne M. Norseth, Patricia D. Ndhlovu, Elisabeth Kleppa, Bodo S. Randrianasolo, Peter M. Jourdan, Borghild Roald, Sigve D. Holmen, Svein G. Gundersen, Jayanthilall Bagratee, Mathias Onsrud, Eyrun F. Kjetland

Background

Schistosoma (S.) haematobium is a neglected tropical disease which may affect any part of the genital tract in women. Female genital schistosomiasis (FGS) may cause abnormal vaginal discharge, contact bleeding, genital tumours, ectopic pregnancies and increased susceptibility to HIV. Symptoms may mimic those typical of sexually transmitted infections (STIs) and women with genital schistosomiasis may be incorrectly diagnosed. An expert consensus meeting suggested that the following findings by visual inspection should serve as proxy indicators for the diagnosis of schistosomiasis of the lower genital tract in women from S. haematobium endemic areas: sandy patches appearing as (1) single or clustered grains or (2) sandy patches appearing as homogenous, yellow areas, or (3) rubbery papules. In this atlas we aim to provide an overview of the genital mucosal manifestations of schistosomiasis in women.

Methodology/Principal findings

Photocolposcopic images were captured from women, between 1994 and 2012 in four different study sites endemic for S. haematobium in Malawi, Zimbabwe, South Africa and Madagascar. Images and specimens were sampled from sexually active women between 15 and 49 years of age. Colposcopic images of other diseases are included for differential diagnostic purposes.

Significance

This is the first atlas to present the clinical manifestations of schistosomiasis in the lower female genital tract. It will be freely available for online use, downloadable as a presentation and for print. It could be used for training purposes, further research, and in clinical practice.

PKDL and Other Dermal Lesions in HIV Co-infected Patients with Leishmaniasis: Review of Clinical Presentation in Relation to Immune Responses

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Eduard E. Zijlstra

Background

Co-infection of leishmaniasis and HIV is increasingly reported. The clinical presentation of leishmaniasis is determined by the host immune response to the parasite; as a consequence, this presentation will be influenced by HIV-induced immunosuppression. As leishmaniasis commonly affects the skin, increasing immunosuppression changes the clinical presentation, such as in post-kala-azar dermal leishmaniasis (PKDL) and cutaneous leishmaniasis (CL); dermal lesions are also commonly reported in visceral leishmaniasis (VL) and HIV co-infection.

Methods

We reviewed the literature with regard to dermal manifestations in leishmaniasis and HIV co-infection, in three clinical syndromes, according to the primary presentation: PKDL, VL, or CL.

Results

A wide variety of descriptions of dermal leishmaniasis in HIV co-infection has been reported. Lesions are commonly described as florid, symmetrical, non-ulcerating, nodular lesions with atypical distribution and numerous parasites. Pre-existing, unrelated dermal lesions may become parasitized. Parasites lose their tropism and no longer exclusively cause VL or CL. PKDL in HIV co-infected patients is more common and more severe and is not restricted to Leishmania donovani. In VL, dermal lesions occur in up to 18% of patients and may present as (severe) localized cutaneous leishmaniasis, disseminated cutaneous leishmaniasis (DL) or diffuse cutaneous leishmaniasis (DCL); there may be an overlap with para-kala-azar dermal leishmaniasis. In CL, dissemination in the skin may occur resembling DL or DCL; subsequent spread to the viscera may follow. Mucosal lesions are commonly found in VL or CL and HIV co-infection. Classical mucocutaneous leishmaniasis is more severe. Immune reconstitution disease (IRD) is uncommon in HIV co-infected patients with leishmaniasis on antiretroviral treatment (ART).

Conclusion

With increasing immunosuppression, the clinical syndromes of CL, VL, and PKDL become more severe and may overlap. These syndromes may be best described as VL with disseminated cutaneous lesions (before, during, or after VL) and disseminated cutaneous leishmaniasis with or without visceralization.

Differential Dermal Expression of CCL17 and CCL18 in Tuberculoid and Lepromatous Leprosy

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by William R. Berrington, Chhatra B. Kunwar, Kapil Neupane, Susan J. F. van den Eeden, James C. Vary, Glenna J. Peterson, Richard D. Wells, Annemieke Geluk, Deanna A. Hagge, Thomas R. Hawn

Background

Leprosy is characterized by polar clinical, histologic and immunological presentations. Previous immunologic studies of leprosy polarity were limited by the repertoire of cytokines known at the time.

Methodology

We used a candidate gene approach to measure mRNA levels in skin biopsies from leprosy lesions. mRNA from 24 chemokines and cytokines, and 6 immune cell type markers were measured from 85 Nepalese leprosy subjects. Selected findings were confirmed with immunohistochemistry.

Principal Results

Expression of three soluble mediators (CCL18, CCL17 and IL-10) and one macrophage cell type marker (CD14) was significantly elevated in lepromatous (CCL18, IL-10 and CD14) or tuberculoid (CCL17) lesions. Higher CCL18 protein expression by immunohistochemistry and a trend in increased serum CCL18 in lepromatous lesions was observed. No cytokines were associated with erythema nodosum leprosum or Type I reversal reaction following multiple comparison correction. Hierarchical clustering suggested that CCL18 was correlated with cell markers CD209 and CD14, while neither CCL17 nor CCL18 were highly correlated with classical TH1 and TH2 cytokines.

Conclusions

Our findings suggest that CCL17 and CCL18 dermal expression is associated with leprosy polarity.

Retrospective Study of the Epidemiology and Clinical Manifestations of Cryptococcus gattii Infections in Colombia from 1997–2011

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Jairo Lizarazo, Patricia Escandón, Clara Inés Agudelo, Carolina Firacative, Wieland Meyer, Elizabeth Castañeda

Background

Cryptococcosis due to Cryptococcus gattii is endemic in various parts of the world, affecting mostly immunocompetent patients. A national surveillance study of cryptococcosis, including demographical, clinical and microbiological data, has been ongoing since 1997 in Colombia, to provide insights into the epidemiology of this mycosis.

Methodology/Principal Findings

From 1,209 surveys analyzed between 1997–2011, 45 cases caused by C. gattii were reported (prevalence 3.7%; annual incidence 0.07 cases/million inhabitants/year). Norte de Santander had the highest incidence (0.81 cases/million/year), representing 33.3% of all cases. The male: female ratio was 3.3∶1. Mean age at diagnosis was 41±16 years. No specific risk factors were identified in 91.1% of patients. HIV infection was reported in 6.7% of patients, autoimmune disease and steroids use in 2.2%. Clinical features included headache (80.5%), nausea/vomiting (56.1%) and neurological derangements (48.8%). Chest radiographs were taken in 21 (46.7%) cases, with abnormal findings in 7 (33.3%). Cranial CT scans were obtained in 15 (33.3%) cases, with abnormalities detected in 10 (66.7%). Treatment was well documented in 30 cases, with most receiving amphotericin B. Direct sample examination was positive in 97.7% cases. Antigen detection was positive for all CSF specimens and for 75% of serum samples. C. gattii was recovered from CSF (93.3%) and respiratory specimens (6.6%). Serotype was determined in 42 isolates; 36 isolates were serotype B (85.7%), while 6 were C (14.3%). The breakdowns of molecular types were VGII (55.6%), VGIII (31.1%) and VGI (13.3%). Among 44 strains, 16 MLST sequence types (ST) were identified, 11 of them newly reported.

Conclusions/Significance

The results of this passive surveillance study demonstrate that cryptococcosis caused by C. gattii has a low prevalence in Colombia, with the exception of Norte de Santander. The predominance of molecular type VGII is of concern considering its association with high virulence and the potential to evolve into outbreaks.

Diethylcarbamazine Increases Activation of Voltage-Activated Potassium (SLO-1) Currents in Ascaris suum and Potentiates Effects of Emodepside

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Samuel K. Buxton, Alan P. Robertson, Richard J. Martin

Diethylcarbamazine is a drug that is used for the treatment of filariasis in humans and animals; it also has effects on intestinal nematodes, but its mechanism of action remains unclear. Emodepside is a resistance-busting anthelmintic approved for treating intestinal parasitic nematodes in animals. The novel mode of action and resistance-breaking properties of emodepside has led to its use against intestinal nematodes of animals, and as a candidate drug for treating filarial parasites. We have previously demonstrated effects of emodepside on SLO-1 K+-like currents in Ascaris suum. Here, we demonstrate that diethylcarbamazine, which has been proposed to work through host mediated effects, has direct effects on a nematode parasite, Ascaris suum. It increases activation of SLO-1 K+ currents and potentiates effects of emodepside. Our results suggest consideration of the combination of emodepside and diethylcarbamazine for therapy, which is predicted to be synergistic. The mode of action of diethylcarbamazine may involve effects on parasite signaling pathways (including nitric oxide) as well as effects mediated by host inflammatory mediators.

Risk Factors for Buruli Ulcer in Ghana—A Case Control Study in the Suhum-Kraboa-Coaltar and Akuapem South Districts of the Eastern Region

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Ernest Kenu, Kofi Mensah Nyarko, Linda Seefeld, Vincent Ganu, Michael Käser, Margaret Lartey, Benedict Nii Laryea Calys-Tagoe, Kwodwo Koram, Richard Adanu, Oliver Razum, Edwin Afari, Fred N. Binka

Background

Buruli ulcer (BU) is a skin disease caused by Mycobacterium ulcerans. Its exact mode of transmission is not known. Previous studies have identified demographic, socio-economic, health and hygiene as well as environment related risk factors. We investigated whether the same factors pertain in Suhum-Kraboa-Coaltar (SKC) and Akuapem South (AS) Districts in Ghana which previously were not endemic for BU.

Methods

We conducted a case control study. A case of BU was defined as any person aged 2 years or more who resided in study area (SKC or AS District) diagnosed according to the WHO clinical case definition for BU and matched with age- (+/−5 years), gender-, and community controls. A structured questionnaire on host, demographic, environmental, and behavioural factors was administered to participants.

Results

A total of 113 cases and 113 community controls were interviewed. Multivariate conditional logistic regression analysis identified presence of wetland in the neighborhood (OR = 3.9, 95% CI = 1.9–8.2), insect bites in water/mud (OR = 5.7, 95% CI = 2.5–13.1), use of adhesive when injured (OR = 2.7, 95% CI = 1.1–6.8), and washing in the Densu river (OR = 2.3, 95% CI = 1.1–4.96) as risk factors associated with BU. Rubbing an injured area with alcohol (OR = 0.21, 95% CI = 0.008–0.57) and wearing long sleeves for farming (OR = 0.29, 95% CI = 0.14–0.62) showed protection against BU.

Conclusion

This study identified the presence of wetland, insect bites in water, use of adhesive when injured, and washing in the river as risk factors for BU; and covering limbs during farming as well as use of alcohol after insect bites as protective factors against BU in Ghana. Until paths of transmission are unraveled, control strategies in BU endemic areas should focus on these known risk factors.

Clinical Efficacy and Tolerability of Praziquantel for Intestinal and Urinary Schistosomiasis—A Meta-analysis of Comparative and Non-comparative Clinical Trials

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Julien Zwang, Piero L. Olliaro

Background

Extensive use of praziquantel for treatment and control of schistosomiasis requires a comprehensive understanding of efficacy and safety of various doses for different Schistosoma species.

Methodology/Principal Findings

A systematic review and meta-analysis of comparative and non-comparative trials of praziquantel at any dose for any Schistosoma species assessed within two months post-treatment. Of 273 studies identified, 55 were eligible (19,499 subjects treated with praziquantel, control treatment or placebo). Most studied were in school-aged children (64%), S. mansoni (58%), and the 40 mg/kg dose (56%); 68% of subjects were in Africa. Efficacy was assessed as cure rate (CR, n = 17,017) and egg reduction rate (ERR, n = 13,007); safety as adverse events (AE) incidence. The WHO-recommended dose of praziquantel 40 mg/kg achieved CRs of 94.7% (95%CI 92.2–98.0) for S. japonicum, 77.1% (68.4–85.1) for S. haematobium, 76.7% (95%CI 71.9–81.2) for S. mansoni, and 63.5% (95%CI 48.2–77.0) for mixed S. haematobium/S. mansoni infections. Using a random-effect meta-analysis regression model, a dose-effect for CR was found up to 40 mg/kg for S. mansoni and 30 mg/kg for S. haematobium. The mean ERR was 95% for S. japonicum, 94.1% for S. haematobium, and 86.3% for S. mansoni. No significant relationship between dose and ERR was detected. Tolerability was assessed in 40 studies (12,435 subjects). On average, 56.9% (95%CI 47.4–67.9) of the subjects receiving praziquantel 40 mg/kg experienced an AE. The incidence of AEs ranged from 2.3% for urticaria to 31.1% for abdominal pain.

Conclusions/Significance

The large number of subjects allows generalizable conclusions despite the inherent limitations of aggregated-data meta-analyses. The choice of praziquantel dose of 40 mg/kg is justified as a reasonable compromise for all species and ages, although in a proportion of sites efficacy may be lower than expected and age effects could not be fully explored.

Pathophysiologic and Transcriptomic Analyses of Viscerotropic Yellow Fever in a Rhesus Macaque Model

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Flora Engelmann, Laurence Josset, Thomas Girke, Byung Park, Alex Barron, Jesse Dewane, Erika Hammarlund, Anne Lewis, Michael K. Axthelm, Mark K. Slifka, Ilhem Messaoudi

Infection with yellow fever virus (YFV), an explosively replicating flavivirus, results in viral hemorrhagic disease characterized by cardiovascular shock and multi-organ failure. Unvaccinated populations experience 20 to 50% fatality. Few studies have examined the pathophysiological changes that occur in humans during YFV infection due to the sporadic nature and remote locations of outbreaks. Rhesus macaques are highly susceptible to YFV infection, providing a robust animal model to investigate host-pathogen interactions. In this study, we characterized disease progression as well as alterations in immune system homeostasis, cytokine production and gene expression in rhesus macaques infected with the virulent YFV strain DakH1279 (YFV-DakH1279). Following infection, YFV-DakH1279 replicated to high titers resulting in viscerotropic disease with ∼72% mortality. Data presented in this manuscript demonstrate for the first time that lethal YFV infection results in profound lymphopenia that precedes the hallmark changes in liver enzymes and that although tissue damage was noted in liver, kidneys, and lymphoid tissues, viral antigen was only detected in the liver. These observations suggest that additional tissue damage could be due to indirect effects of viral replication. Indeed, circulating levels of several cytokines peaked shortly before euthanasia. Our study also includes the first description of YFV-DakH1279-induced changes in gene expression within peripheral blood mononuclear cells 3 days post-infection prior to any clinical signs. These data show that infection with wild type YFV-DakH1279 or live-attenuated vaccine strain YFV-17D, resulted in 765 and 46 differentially expressed genes (DEGs), respectively. DEGs detected after YFV-17D infection were mostly associated with innate immunity, whereas YFV-DakH1279 infection resulted in dysregulation of genes associated with the development of immune response, ion metabolism, and apoptosis. Therefore, WT-YFV infection is associated with significant changes in gene expression that are detectable before the onset of clinical symptoms and may influence disease progression and outcome of infection.

CD8+ T cells Are Preferentially Activated during Primary Low Dose Leishmania major Infection but Are Completely Dispensable during Secondary Anti-Leishmania Immunity

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Ifeoma B. Okwor, Ping Jia, Zhirong Mou, Chukwunonso Onyilagha, Jude E. Uzonna

We previously showed that CD8+ T cells are required for optimal primary immunity to low dose Leishmania major infection. However, it is not known whether immunity induced by low dose infection is durable and whether CD8+ T cells contribute to secondary immunity following recovery from low dose infection. Here, we compared primary and secondary immunity to low and high dose L. major infections and assessed the influence of infectious dose on the quality and magnitude of secondary anti-Leishmania immunity. In addition, we investigated the contribution of CD8+ T cells in secondary anti-Leishmania immunity following recovery from low and high dose infections. We found that the early immune response to low and high dose infections were strikingly different: while low dose infection preferentially induced proliferation and effector cytokine production by CD8+ T cells, high dose infection predominantly induced proliferation and cytokine production by CD4+ T cells. This differential activation of CD4+ and CD8+ T cells by high and low dose infections respectively, was imprinted during in vitro and in vivo recall responses in healed mice. Both low and high dose-infected mice displayed strong infection-induced immunity and were protected against secondary L. major challenge. While depletion of CD4+ cells in mice that healed low and high dose infections abolished resistance to secondary challenge, depletion of CD8+ cells had no effect. Collectively, our results show that although CD8+ T cells are preferentially activated and may contribute to optimal primary anti-Leishmania immunity following low dose infection, they are completely dispensable during secondary immunity.

Serological Evidence of Henipavirus Exposure in Cattle, Goats and Pigs in Bangladesh

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Sukanta Chowdhury, Salah Uddin Khan, Gary Crameri, Jonathan H. Epstein, Christopher C. Broder, Ausraful Islam, Alison J. Peel, Jennifer Barr, Peter Daszak, Lin-Fa Wang, Stephen P. Luby

Background

Nipah virus (NiV) is an emerging disease that causes severe encephalitis and respiratory illness in humans. Pigs were identified as an intermediate host for NiV transmission in Malaysia. In Bangladesh, NiV has caused recognized human outbreaks since 2001 and three outbreak investigations identified an epidemiological association between close contact with sick or dead animals and human illness.

Methodology

We examined cattle and goats reared around Pteropus bat roosts in human NiV outbreak areas. We also tested pig sera collected under another study focused on Japanese encephalitis.

Principal Findings

We detected antibodies against NiV glycoprotein in 26 (6.5%) cattle, 17 (4.3%) goats and 138 (44.2%) pigs by a Luminex-based multiplexed microsphere assay; however, these antibodies did not neutralize NiV. Cattle and goats with NiVsG antibodies were more likely to have a history of feeding on fruits partially eaten by bats or birds (PR = 3.1, 95% CI 1.6–5.7) and drinking palmyra palm juice (PR = 3.9, 95% CI 1.5–10.2).

Conclusions

This difference in test results may be due to the exposure of animals to one or more novel viruses with antigenic similarity to NiV. Further research may identify a novel organism of public health importance.

An Integrated In Vitro Imaging Platform for Characterizing Filarial Parasite Behavior within a Multicellular Microenvironment

PLoS Neglected Tropical Diseases News - 20 November 2014 - 10:00pm

by Timothy Kassis, Henry M. Skelton, Iris M. Lu, Andrew R. Moorhead, J. Brandon Dixon

Lymphatic Filariasis, a Neglected Tropical Disease, is caused by thread-like parasitic worms, including B. malayi, which migrate to the human lymphatic system following transmission. The parasites reside in collecting lymphatic vessels and lymph nodes for years, often resulting in lymphedema, elephantiasis or hydrocele. The mechanisms driving worm migration and retention within the lymphatics are currently unknown. We have developed an integrated in vitro imaging platform capable of quantifying B. malayi migration and behavior in a multicellular microenvironment relevant to the initial site of worm injection by incorporating the worm in a Polydimethylsiloxane (PDMS) microchannel in the presence of human dermal lymphatic endothelial cells (LECs) and human dermal fibroblasts (HDFs). The platform utilizes a motorized controllable microscope with CO2 and temperature regulation to allow for worm tracking experiments with high resolution over large length and time scales. Using post-acquisition algorithms, we quantified four parameters: 1) speed, 2) thrashing intensity, 3) percentage of time spent in a given cell region and 4) persistence ratio. We demonstrated the utility of our system by quantifying these parameters for L3 B. malayi in the presence of LECs and HDFs. Speed and thrashing increased in the presence of both cell types and were altered within minutes upon exposure to the anthelmintic drug, tetramisole. The worms displayed no targeted migration towards either cell type for the time course of this study (3 hours). When cells were not present in the chamber, worm thrashing correlated directly with worm speed. However, this correlation was lost in the presence of cells. The described platform provides the ability to further study B. malayi migration and behavior.

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