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Changes over Time in IgE Sensitization to Allergens of the Fish Parasite <i>Anisakis</i> spp.

PLoS Neglected Tropical Diseases News - 22 July 2016 - 9:00pm

by Noelia Carballeda-Sangiao, Ana I. Rodríguez-Mahillo, Mercedes Careche, Alfonso Navas, Ignacio Moneo, Miguel González-Muñoz

Background

Sensitization to Anisakis spp. can produce allergic reactions after eating raw or undercooked parasitized fish. Specific IgE is detected long after the onset of symptoms, but the changes in specific IgE levels over a long follow-up period are unknown; furthermore, the influence of Anisakis spp. allergen exposure through consumption of fishery products is also unknown.

Objective

To analyse the changes in IgE sensitization to Anisakis spp. allergens over several years of follow-up and the influence of the consumption of fishery products in IgE sensitization.

Methods

Total IgE, Anisakis spp.-specific IgE, anti-Ani s 1 and anti-Ani s 4 IgE were repeatedly measured over a median follow-up duration of 49 months in 17 sensitized patients.

Results

Anisakis spp.-specific IgE was detected in 16/17 patients throughout the follow-up period. The comparison between baseline and last visit measurements showed significant decreases in both total IgE and specific IgE. The specific IgE values had an exponential or polynomial decay trend in 13/17 patients. In 4/17 patients, an increase in specific IgE level with the introduction of fish to the diet was observed. Three patients reported symptoms after eating aquaculture or previously frozen fish, and in two of those patients, symptom presentation was coincident with an increase in specific IgE level.

Conclusions

IgE sensitization to Anisakis spp. allergens lasts for many years since specific IgE was detectable in some patients after more than 8 years from the allergic episode. Specific IgE monitoring showed that specific IgE titres increase in some allergic patients and that allergen contamination of fishery products can account for the observed increase in Anisakis spp.-specific IgE level.

Clinical Relevance

Following sensitization to Anisakis spp. allergens, the absence of additional exposure to those allergens does not result in the loss of IgE sensitization. Exposure to Anisakis spp. allergens in fishery products can increase the specific IgE level in some sensitized patients.

Evidence for Suppression of Onchocerciasis Transmission in Bioko Island, Equatorial Guinea

PLoS Neglected Tropical Diseases News - 22 July 2016 - 9:00pm

by Laura Moya, Zaida Herrador, Thuy Huong Ta-Tang, Jose Miguel Rubio, Maria Jesús Perteguer, Ana Hernandez-González, Belén García, Rufino Nguema, Justino Nguema, Policarpo Ncogo, Teresa Garate, Agustín Benito, Anacleto Sima, Pilar Aparicio

Onchocerciasis or "river blindness" is a chronic parasitic neglected tropical disease which is endemic both in mainland and insular Equatorial Guinea. We aim to estimate the current epidemiological situation of onchocerciasis in Bioko Island after vector elimination in 2005 and more than sixteen years of Community Directed Treatment with Ivermectin (CDTI) by using molecular and serological approaches for onchocerciasis diagnosis. A community-based cross-sectional study was carried out in Bioko Island from mid-January to mid-February 2014. A total of 544 study participants were recruited. A complete dermatological examination was performed and three skin snips were performed in every participant for parasitological and molecular assessments. Blood spots were also taken for determination of Ov16 IgG4 antibodies trough an “in-house” ELISA assay. Overall, we found 15 out of 522 individuals suffering any onchocerciasis specific cutaneous lesions and 16 out of 528 (3.0%) with onchocercal nodules in the skin. Nodules were significantly associated with age, being more common in subjects older than 10 years than in younger people (3.9% vs. 0%, p = 0.029). Regarding the onchocerciasis laboratory assessment, no positive parasitological test for microfilaria detection was found in the skin snips. The calculated seroprevalence through IgG4 serology was 7.9%. No children less than 10 years old were found to be positive for this test. Only one case was positive for Onchocerca volvulus (O. volvulus) after skin PCR. The present study points out that the on-going mass ivermectin treatment has been effective in reducing the prevalence of onchocerciasis and corroborates the interruption of transmission in Bioko Island. To our knowledge, this is the first time that accurate information through molecular and serological techniques is generated to estimate the onchocerciasis prevalence in this zone. Sustained support from the national program and appropriate communication and health education strategies to reinforce participation in CDTI activities are essential to ensure progress towards onchocerciasis elimination in the country.

Biliary Microbiota, Gallstone Disease and Infection with <i>Opisthorchis felineus</i>

PLoS Neglected Tropical Diseases News - 22 July 2016 - 9:00pm

by Irina V. Saltykova, Vjacheslav A. Petrov, Maria D. Logacheva, Polina G. Ivanova, Nikolay V. Merzlikin, Alexey E. Sazonov, Ludmila M. Ogorodova, Paul J. Brindley

Background

There is increasing interest in the microbiome of the hepatobiliary system. This study investigated the influence of infection with the fish-borne liver fluke, Opisthorchis felineus on the biliary microbiome of residents of the Tomsk region of western Siberia.

Methodology/Principal Findings

Samples of bile were provided by 56 study participants, half of who were infected with O. felineus, and all of who were diagnosed with gallstone disease. The microbiota of the bile was investigated using high throughput, Illumina-based sequencing targeting the prokaryotic 16S rRNA gene. About 2,797, discrete phylotypes of prokaryotes were detected. At the level of phylum, bile from participants with opisthorchiasis showed greater numbers of Synergistetes, Spirochaetes, Planctomycetes, TM7 and Verrucomicrobia. Numbers of > 20 phylotypes differed in bile of the O. felineus-infected compared to non-infected participants, including presence of species of the genera Mycoplana, Cellulosimicrobium, Microlunatus and Phycicoccus, and the Archaeans genus, Halogeometricum, and increased numbers of Selenomonas, Bacteroides, Rothia, Leptotrichia, Lactobacillus, Treponema and Klebsiella.

Conclusions/Significance

Overall, infection with the liver fluke O. felineus modified the biliary microbiome, increasing abundance of bacterial and archaeal phylotypes.

Global Assessment of Schistosomiasis Control Over the Past Century Shows Targeting the Snail Intermediate Host Works Best

PLoS Neglected Tropical Diseases News - 21 July 2016 - 9:00pm

by Susanne H. Sokolow, Chelsea L. Wood, Isabel J. Jones, Scott J. Swartz, Melina Lopez, Michael H. Hsieh, Kevin D. Lafferty, Armand M. Kuris, Chloe Rickards, Giulio A. De Leo

Background

Despite control efforts, human schistosomiasis remains prevalent throughout Africa, Asia, and South America. The global schistosomiasis burden has changed little since the new anthelmintic drug, praziquantel, promised widespread control.

Methodology

We evaluated large-scale schistosomiasis control attempts over the past century and across the globe by identifying factors that predict control program success: snail control (e.g., molluscicides or biological control), mass drug administrations (MDA) with praziquantel, or a combined strategy using both. For data, we compiled historical information on control tactics and their quantitative outcomes for all 83 countries and territories in which: (i) schistosomiasis was allegedly endemic during the 20th century, and (ii) schistosomiasis remains endemic, or (iii) schistosomiasis has been "eliminated," or is "no longer endemic," or transmission has been interrupted.

Principal Findings

Widespread snail control reduced prevalence by 92 ± 5% (N = 19) vs. 37 ± 7% (N = 29) for programs using little or no snail control. In addition, ecological, economic, and political factors contributed to schistosomiasis elimination. For instance, snail control was most common and widespread in wealthier countries and when control began earlier in the 20th century.

Conclusions/Significance

Snail control has been the most effective way to reduce schistosomiasis prevalence. Despite evidence that snail control leads to long-term disease reduction and elimination, most current schistosomiasis control efforts emphasize MDA using praziquantel over snail control. Combining drug-based control programs with affordable snail control seems the best strategy for eliminating schistosomiasis.

Multiple Mycetoma Lung Secondaries from Knee Eumycetoma: An Unusual Complication

PLoS Neglected Tropical Diseases News - 21 July 2016 - 9:00pm

by EL Samani Wadaa Mohamed, Nancy Seif EL Din, Ahmed Hassan Fahal

Rapid Enhanced MM3-COPRO ELISA for Detection of <i>Fasciola</i> Coproantigens

PLoS Neglected Tropical Diseases News - 20 July 2016 - 9:00pm

by Victoria Martínez-Sernández, Ricardo A. Orbegozo-Medina, Marta González-Warleta, Mercedes Mezo, Florencio M. Ubeira

ELISA-based methods of detecting Fasciola cathepsins in feces are powerful techniques for diagnosing infections by F. hepatica and F. gigantica. In the last decade, the in-house MM3-COPRO ELISA and its commercial version BIO K 201 (BIO X Diagnostics, Belgium) have been recognized as useful tools for detecting early infections by such trematodes and for monitoring the efficacy of anthelmintic treatments in human and animal species, as they provide some advantages over classic fecal egg counts. However, the sensitivity of MM3-COPRO ELISA can sometimes be compromised by the high variability in the concentration of cathepsins in fecal samples throughout the biological cycle of Fasciola (mainly in cattle) and by differences in the between-batch performance of peroxidase-labeled anti-mouse IgG polyclonal antibodies. To prevent such problems, we investigated whether the incorporation of a commercial streptavidin-polymerized horseradish peroxidase conjugate, in order to reveal bound biotinylated monoclonal antibody MM3, can improve the sensitivity of the MM3-COPRO ELISA. We observed that inclusion of this reagent shifted the previous detection limit of the assay from 0.6 ng/mL to 150 pg/mL and that the modified test is able to identify infection in cows harboring only one fluke. Moreover, we demonstrated that maximal OD values can be achieved with short incubations (30 min each step) at RT with shaking, rather than standard incubations, which significantly accelerates the diagnostic procedure. Finally, we did not find a significant correlation between coproantigen concentration and parasite burden in cattle, which may be due to the low parasite burden (1–10 adult flukes) of the animals used in the present study. As the usefulness of the classic MM3-COPRO test for detecting animal and human infections has already been demonstrated, it is expected that the improvements reported in this study will add new insights into the diagnosis and control of fasciolosis.

Cultural Understanding of Wounds, Buruli Ulcers and Their Management at the Obom Sub-district of the Ga South Municipality of the Greater Accra Region of Ghana

PLoS Neglected Tropical Diseases News - 20 July 2016 - 9:00pm

by Eric Koka, Dorothy Yeboah-Manu, Daniel Okyere, Philip Baba Adongo, Collins K. Ahorlu

Background

This study was conducted with the aim to understand some of the cultural belief systems in the management of wounds and patients practices that could contaminate wounds at the Obom sub-district of the Ga South Municipality of Ghana.

Methods

This was an ethnographic study using in-depth interviews, Focus Group Discussions and participant observation techniques for data collection. Observations were done on Buruli ulcer patients to document how they integrate local and modern wound management practices in the day-to-day handling of their wounds. Content analysis was done after the data were subjected to thematic coding and representative narratives selected for presentation.

Results

It was usually believed that wounds were caused by charms or spirits and, therefore, required the attention of a native healer. In instances where some patients’ wounds were dressed in the hospital by clinicians whose condition/age/sex contradict the belief of the patient, the affected often redress the wounds later at home. Some of the materials often used for such wound dressing include urine and concoctions made of charcoal and gunpowder with the belief of driving out evil spirits from the wounds.

Conclusion

Clinicians must therefore be aware of these cultural beliefs and take them into consideration when managing Buruli ulcer wounds to prevent redressing at home after clinical treatment. This may go a long way to reduce secondary infections that have been observed in Buruli ulcer wounds.

Heterogeneity in District-Level Transmission of Ebola Virus Disease during the 2013-2015 Epidemic in West Africa

PLoS Neglected Tropical Diseases News - 19 July 2016 - 9:00pm

by Fabienne Krauer, Sandro Gsteiger, Nicola Low, Christian H. Hansen, Christian L. Althaus

The Ebola virus disease (EVD) epidemic in West Africa in 2013–2015 spread heterogeneously across the three hardest-hit countries Guinea, Liberia and Sierra Leone and the estimation of national transmission of EVD provides little information about local dynamics. To investigate district-level transmissibility of EVD, we applied a statistical modelling approach to estimate the basic reproduction number (R0) for each affected district and each country using weekly incident case numbers. We estimated growth rates during the early exponential phase of the outbreak using exponential regression of the case counts on the first eight weeks since onset. To take into account the heterogeneity between and within countries, we fitted a mixed effects model and calculated R0 based on the predicted individual growth rates and the reported serial interval distribution. At district level, R0 ranged from 0.36 (Dubréka) to 1.72 (Beyla) in Guinea, from 0.53 (Maryland) to 3.37 (Margibi) in Liberia and from 1.14 (Koinadugu) to 2.73 (Western Rural) in Sierra Leone. At national level, we estimated an R0 of 0.97 (95% CI 0.77–1.18) for Guinea, 1.26 (95% CI 0.98–1.55) for Liberia and 1.66 (95% CI 1.32–2.00) for Sierra Leone. Socio-demographic variables related to urbanisation such as high population density and high wealth index were found positively associated with R0 suggesting that the consequences of fast urban growth in West Africa may have contributed to the increased spread of EVD.

Th-1, Th-2 Cytokines Profile among <i>Madurella mycetomatis</i> Eumycetoma Patients

PLoS Neglected Tropical Diseases News - 19 July 2016 - 9:00pm

by Amre Nasr, Amir Abushouk, Anhar Hamza, Emmanuel Siddig, Ahmed H. Fahal

Eumycetoma is a progressive and destructive chronic granulomatous subcutaneous inflammatory disease caused by certain fungi, the most common being Madurella mycetomatis. The host defence mechanisms against fungi usually range from an early non-specific immune response to activation and induction of specific adaptive immune responses by the production of Th-1 and Th-2 cytokines. The aim of this study is to determine the levels of Th-1 and Th-2 cytokines in patients infected with Madurella mycetomatis, and the association between their levels and disease prognosis. This is a descriptive cross-sectional study conducted at the Mycetoma Research Centre, University of Khartoum, Sudan, where 70 patients with confirmed M. mycetomatis eumycetoma were enrolled; 35 with, and 35 without surgical excision. 70 healthy individuals from mycetoma endemic areas were selected as controls. The levels of serum cytokines were determined by cytometric bead array technique. Significantly higher levels of the Th-1 cytokines (IFN-γ, TNF-α, IL-1β and IL-2) were recorded in patients treated with surgical excision, compared to those treated without surgical excision. In contrast, the Th-2 cytokines (IL-4, IL-5, IL-6 and IL-10) were significantly lower in patients treated with surgical excision compared to those treated without surgical excision. In conclusion, the results of this study suggest that cell-mediated immunity can have a role to play in the pathogenesis of eumycetoma.

Spatiotemporal Co-existence of Two <i>Mycobacterium ulcerans</i> Clonal Complexes in the Offin River Valley of Ghana

PLoS Neglected Tropical Diseases News - 19 July 2016 - 9:00pm

by Araceli Lamelas, Kobina Assan Ampah, Samuel Aboagye, Sarah Kerber, Emelia Danso, Adwoa Asante-Poku, Prince Asare, Julian Parkhill, Simon R. Harris, Gerd Pluschke, Dorothy Yeboah-Manu, Katharina Röltgen

In recent years, comparative genome sequence analysis of African Mycobacterium ulcerans strains isolated from Buruli ulcer (BU) lesion specimen has revealed a very limited genetic diversity of closely related isolates and a striking association between genotype and geographical origin of the patients. Here, we compared whole genome sequences of five M. ulcerans strains isolated in 2004 or 2013 from BU lesions of four residents of the Offin river valley with 48 strains isolated between 2002 and 2005 from BU lesions of individuals residing in the Densu river valley of Ghana. While all M. ulcerans isolates from the Densu river valley belonged to the same clonal complex, members of two distinct clonal complexes were found in the Offin river valley over space and time. The Offin strains were closely related to genotypes from either the Densu region or from the Asante Akim North district of Ghana. These results point towards an occasional involvement of a mobile reservoir in the transmission of M. ulcerans, enabling the spread of bacteria across different regions.

Preparing towards Preventing and Containing an Ebola Virus Disease Outbreak: What Socio-cultural Practices May Affect Containment Efforts in Ghana?

PLoS Neglected Tropical Diseases News - 18 July 2016 - 9:00pm

by Philip Baba Adongo, Philip Teg-Nefaah Tabong, Emmanuel Asampong, Joana Ansong, Magda Robalo, Richard M. Adanu

Background

Ebola Virus Disease (EVD) is a condition with high fatality. Though the disease is deadly, taking precautions to reduce contact with infected people and their secretions can prevent cross- infection. In the 2014 EVD outbreak, socio-cultural factors were identified to be responsible for the spread of the disease in the three most affected countries in West Africa. In this light, we undertook this study to identify socio-cultural factors that may influence the prevention and containment of EVD in Ghana and ways to address such practices.

Methods

We conducted a descriptive qualitative study in five regions in Ghana. Twenty-five focus group discussions (5 in each region) with community members (4 in each region) and nurses (1 in each region) were conducted. In addition, forty (40) in-depth interviews were conducted with various stakeholders and opinion leaders; eight in each region. All interviews were recorded using a digital voice recorder and transcribed. With the aid of Nvivo 10 for windows, we analyzed the data using framework analysis.

Results

We found that socio-cultural practices, such as care of the body of dead and burial practices, widowhood rites and anointing children with water used to rinse the dead, were common. These practices require individuals coming into direct contact with either the dead or items used to take care of the dead. Social norms also require frequent handshakes in all social gatherings such as funeral, and religious congregations. We also found that self-medication (using herbs and orthodox medications) was a common practice. People use both biomedical and non-orthodox health outlets either simultaneously or in sequence in times of ill-health.

Conclusion

The study concludes that high risk socio-cultural practices were common among Ghanaians and generally perceived as indispensable. These high risk practices may hinder containment efforts in the event of an outbreak. Community leaders should be engaged in any social mobilization to modify these practices as part of preparation efforts.

Effect of Spatial Repellent Exposure on Dengue Vector Attraction to Oviposition Sites

PLoS Neglected Tropical Diseases News - 18 July 2016 - 9:00pm

by Diane B. Choi, John P. Grieco, Charles S. Apperson, Coby Schal, Loganathan Ponnusamy, Dawn M. Wesson, Nicole L. Achee

Background

Aedes aegypti is a primary vector of dengue virus (DENV), the causative agent of dengue fever, an arthropod-borne disease of global importance. Although a vaccine has been recommended for prevention, current dengue prevention strategies rely on vector control. Recently, volatile pyrethroids—spatial repellents—have received interest as a novel delivery system for adult Ae. aegypti control. Understanding the full range of behavioral effects spatial repellents elicit in mosquito species will be critical to understanding the overall impact these products have on vector populations and will guide expectations of efficacy against DENV transmission.

Methodology/Principal Findings

The current study quantified changes in attraction of gravid Ae. aegypti to experimental oviposition sites following exposure to the spatial repellent transfluthrin. Responses were measured with two-choice olfaction bioassays using ‘sticky-screens’ covering cups to prevent contact with the oviposition substrate. Two cups contained a bacterial attractant composed of four species of bacteria in calcium alginate beads in water and two cups contained only deionized water. Results from 40 replicates (n = 780 females total per treatment) indicated an estimated difference in attraction of 9.35% ± 0.18 (p ≤ 0.003), implying that the transfluthrin-exposed mosquitoes were more attracted to the experimental oviposition sites than the non-exposed mosquitoes.

Conclusions/Significance

Findings from this study will further characterize the role of spatial repellents to modify Ae. aegypti behavior related to dengue prevention specifically, and encourage innovation in vector control product development more broadly.

Rapid and Sensitive Multiplex Detection of <i>Burkholderia pseudomallei</i>-Specific Antibodies in Melioidosis Patients Based on a Protein Microarray Approach

PLoS Neglected Tropical Diseases News - 18 July 2016 - 9:00pm

by Christian Kohler, Susanna J. Dunachie, Elke Müller, Anne Kohler, Kemajittra Jenjaroen, Prapit Teparrukkul, Vico Baier, Ralf Ehricht, Ivo Steinmetz

Background

The environmental bacterium Burkholderia pseudomallei causes the infectious disease melioidosis with a high case-fatality rate in tropical and subtropical regions. Direct pathogen detection can be difficult, and therefore an indirect serological test which might aid early diagnosis is desirable. However, current tests for antibodies against B. pseudomallei, including the reference indirect haemagglutination assay (IHA), lack sensitivity, specificity and standardization. Consequently, serological tests currently do not play a role in the diagnosis of melioidosis in endemic areas. Recently, a number of promising diagnostic antigens have been identified, but a standardized, easy-to-perform clinical laboratory test for sensitive multiplex detection of antibodies against B. pseudomallei is still lacking.

Methods and Principal Findings

In this study, we developed and validated a protein microarray which can be used in a standard 96-well format. Our array contains 20 recombinant and purified B. pseudomallei proteins, previously identified as serodiagnostic candidates in melioidosis. In total, we analyzed 196 sera and plasmas from melioidosis patients from northeast Thailand and 210 negative controls from melioidosis-endemic and non-endemic regions. Our protein array clearly discriminated between sera from melioidosis patients and controls with a specificity of 97%. Importantly, the array showed a higher sensitivity than did the IHA in melioidosis patients upon admission (cut-off IHA titer ≥1:160: IHA 57.3%, protein array: 86.7%; p = 0.0001). Testing of sera from single patients at 0, 12 and 52 weeks post-admission revealed that protein antigens induce either a short- or long-term antibody response.

Conclusions

Our protein array provides a standardized, rapid, easy-to-perform test for the detection of B. pseudomallei-specific antibody patterns. Thus, this system has the potential to improve the serodiagnosis of melioidosis in clinical settings. Moreover, our high-throughput assay might be useful for the detection of anti-B. pseudomallei antibodies in epidemiological studies. Further studies are needed to elucidate the clinical and diagnostic significance of the different antibody kinetics observed during melioidosis.

Distribution and Dispersal of <i>Phlebotomus papatasi</i> (Diptera: Psychodidae) in a Zoonotic Cutaneous Leishmaniasis Focus, the Northern Negev, Israel

PLoS Neglected Tropical Diseases News - 18 July 2016 - 9:00pm

by Laor Orshan, Shirly Elbaz, Yossi Ben-Ari, Fouad Akad, Ohad Afik, Ira Ben-Avi, Debora Dias, Dan Ish-Shalom, Liora Studentsky, Irina Zonstein

Background

Zoonotic cutaneous leishmaniasis has long been endemic in Israel. In recent years reported incidence of cutaneous leishmaniasis increased and endemic transmission is being observed in a growing number of communities in regions previously considered free of the disease. Here we report the results of an intensive sand fly study carried out in a new endemic focus of Leishmania major. The main objective was to establish a method and to generate a data set to determine the exposure risk, sand fly populations' dynamics and evaluate the efficacy of an attempt to create "cordon sanitaire" devoid of active jird burrows around the residential area.

Methodology/Principal Findings

Sand flies were trapped in three fixed reference sites and an additional 52 varying sites. To mark sand flies in the field, sugar solutions containing different food dyes were sprayed on vegetation in five sites. The catch was counted, identified, Leishmania DNA was detected in pooled female samples and the presence of marked specimens was noted. Phlebotomus papatasi, the vector of L. major in the region was the sole Phlebotomus species in the catch. Leishmania major DNA was detected in ~10% of the pooled samples and the highest risk of transmission was in September. Only a few specimens were collected in the residential area while sand fly numbers often exceeded 1,000 per catch in the agricultural fields. The maximal travel distance recorded was 1.91km for females and 1.51km for males. The calculated mean distance traveled (MDT) was 0.75km.

Conclusions

The overall results indicate the presence of dense and mobile sand fly populations in the study area. There seem to be numerous scattered sand fly microsites suitable for development and resting in the agricultural fields. Sand flies apparently moved in all directions, and reached the residential area from the surrounding agricultural fields. The travel distance noted in the current work, supported previous findings that P. papatasi like P. ariasi, can have a relatively long flight range and does not always stay near breeding sites. Following the results, the width of the "cordon sanitaire" in which actions against the reservoir rodents were planned, was extended into the depth of the agricultural fields.

Rickettsial Disease in the Peruvian Amazon Basin

PLoS Neglected Tropical Diseases News - 14 July 2016 - 9:00pm

by Claudine Kocher, Amy C. Morrison, Mariana Leguia, Steev Loyola, Roger M. Castillo, Hugo A. Galvez, Helvio Astete, Carmen Flores-Mendoza, Julia S. Ampuero, Daniel G. Bausch, Eric S. Halsey, Manuel Cespedes, Karine Zevallos, Ju Jiang, Allen L. Richards

Using a large, passive, clinic-based surveillance program in Iquitos, Peru, we characterized the prevalence of rickettsial infections among undifferentiated febrile cases and obtained evidence of pathogen transmission in potential domestic reservoir contacts and their ectoparasites. Blood specimens from humans and animals were assayed for spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR) by ELISA and/or PCR; ectoparasites were screened by PCR. Logistic regression was used to determine associations between patient history, demographic characteristics of participants and symptoms, clinical findings and outcome of rickettsial infection. Of the 2,054 enrolled participants, almost 2% showed evidence of seroconversion or a 4-fold rise in antibody titers specific for rickettsiae between acute and convalescent blood samples. Of 190 fleas (Ctenocephalides felis) and 60 ticks (Rhipicephalus sanguineus) tested, 185 (97.4%) and 3 (5%), respectively, were positive for Rickettsia spp. Candidatus Rickettsia asemboensis was identified in 100% and 33% of the fleas and ticks tested, respectively. Collectively, our serologic data indicates that human pathogenic SFGR are present in the Peruvian Amazon and pose a significant risk of infection to individuals exposed to wild, domestic and peri-domestic animals and their ectoparasites.

<i>Allovahlkampfia spelaea</i> Causing Keratitis in Humans

PLoS Neglected Tropical Diseases News - 14 July 2016 - 9:00pm

by Mohammed Essa Marghany Tolba, Enas Abdelhameed Mahmoud Huseein, Haiam Mohamed Mahmoud Farrag, Hanan El Deek Mohamed, Seiki Kobayashi, Jun Suzuki, Tarek Ahmed Mohamed Ali, Sumio Sugano

Background

Free-living amoebae are present worldwide. They can survive in different environment causing human diseases in some instances. Acanthamoeba sp. is known for causing sight-threatening keratitis in humans. Free-living amoeba keratitis is more common in developing countries. Amoebae of family Vahlkampfiidae are rarely reported to cause such affections. A new genus, Allovahlkampfia spelaea was recently identified from caves with no data about pathogenicity in humans. We tried to identify the causative free-living amoeba in a case of keratitis in an Egyptian patient using morphological and molecular techniques.

Methods

Pathogenic amoebae were culture using monoxenic culture system. Identification through morphological features and 18S ribosomal RNA subunit DNA amplification and sequencing was done. Pathogenicity to laboratory rabbits and ability to produce keratitis were assessed experimentally.

Results

Allovahlkampfia spelaea was identified as a cause of human keratitis. Whole sequence of 18S ribosomal subunit DNA was sequenced and assembled. The Egyptian strain was closely related to SK1 strain isolated in Slovenia. The ability to induce keratitis was confirmed using animal model.

Conclusions

This the first time to report Allovahlkampfia spelaea as a human pathogen. Combining both molecular and morphological identification is critical to correctly diagnose amoebae causing keratitis in humans. Use of different pairs of primers and sequencing amplified DNA is needed to prevent misdiagnosis.

Strong-LAMP: A LAMP Assay for <i>Strongyloides</i> spp. Detection in Stool and Urine Samples. Towards the Diagnosis of Human Strongyloidiasis Starting from a Rodent Model

PLoS Neglected Tropical Diseases News - 14 July 2016 - 9:00pm

by Pedro Fernández-Soto, Alicia Sánchez-Hernández, Javier Gandasegui, Cristina Bajo Santos, Julio López-Abán, José María Saugar, Esperanza Rodríguez, Belén Vicente, Antonio Muro

Background

Strongyloides stercoralis, the chief causative agent of human strongyloidiasis, is a nematode globally distributed but mainly endemic in tropical and subtropical regions. Chronic infection is often clinically asymptomatic but it can result in severe hyperinfection syndrome or disseminated strongyloidiasis in immunocompromised patients. There is a great diversity of techniques used in diagnosing the disease, but definitive diagnosis is accomplished by parasitological examination of stool samples for morphological identification of parasite. Until now, no molecular method has been tested in urine samples as an alternative to stool samples for diagnosing strongyloidiasis. This study aimed to evaluate the use of a new molecular LAMP assay in a well-established Wistar rat experimental infection model using both stool and, for the first time, urine samples. The LAMP assay was also clinically evaluated in patients´ stool samples.

Methodology/Principal Findings

Stool and urine samples were obtained daily during a 28-day period from rats infected subcutaneously with different infective third-stage larvae doses of S. venezuelensis. The dynamics of parasite infection was determined by daily counting the number of eggs per gram of feces from day 1 to 28 post-infection. A set of primers for LAMP assay based on a DNA partial sequence in the 18S rRNA gene from S. venezuelensis was designed. The set up LAMP assay (namely, Strong-LAMP) allowed the sensitive detection of S. venezuelensis DNA in both stool and urine samples obtained from each infection group of rats and was also effective in S. stercoralis DNA amplification in patients´ stool samples with previously confirmed strongyloidiasis by parasitological and real-time PCR tests.

Conclusions/Significance

Our Strong-LAMP assay is an useful molecular tool in research of a strongyloidiasis experimental infection model in both stool and urine samples. After further validation, the Strong-LAMP could also be potentially applied for effective diagnosis of strongyloidiasis in a clinical setting.

Pediatric Cutaneous Leishmaniasis in an Endemic Region in Turkey: A Retrospective Analysis of 8786 Cases during 1998-2014

PLoS Neglected Tropical Diseases News - 14 July 2016 - 9:00pm

by Mustafa Aksoy, Nebiye Doni, Hatice Uce Ozkul, Yavuz Yesilova, Nurittin Ardic, Abdullah Yesilova, Jennifer Ahn-Jarvis, Steve Oghumu, Cesar Terrazas, Abhay R. Satoskar

Background

Cutaneous leishmaniasis (CL) is a major public health concern in Turkey and Sanliurfa represents the most endemic city in Turkey. Although children are most commonly affected by CL, detailed studies of pediatric CL in Turkey are lacking.

Methodology/Principal Findings

In this report we retrospectively evaluated clinical and epidemiological data of 8786 pediatric CL cases, and how children respond to antimonial therapy. CL was observed most frequently in children between 6–10 years old. Interestingly this group showed shorter duration of disease and smaller lesions compared to 0–5 year and 11–15 year old groups. Females were more affected in all groups. Lesion localization and types varied among groups, with 0–5 year old presenting head/neck and mucosal lesions, and more often suffered from recidivans type, this could be associated to the longest duration of the disease in this group. Eleven-15 year old group showed fewer lesions in the head/neck but more generalized lesions. Evaluation of treatment response revealed that intra-lesional treatment was preferred over intramuscular treatment. However, 0–5 year old received intramuscular treatment more often than the other groups. Furthermore, the majority of 0–5 year old group which received intra-lesional treatment did not received subsequent intra-lesional cycles, as did children in the range of 6–15 years old.

Conclusions/Significance

We report an increase in pediatric CL patients within the last four years. Analysis of pediatric CL patients by age revealed significant differences in CL progression. The data suggest that children between 0–5 years old responded better than other groups to intralesional treatment, since they received more often a single cycle of IL treatment, although follow up observation is required since they were more prone to develop recidivans. Eleven-15 year old patients comprise the largest percentage of patients receiving two or three cycles of intralesional treatment, suggesting that this group did not respond efficiently to intralesional treatment and highlighting the need for more effective therapeutic strategies against CL.

Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar

PLoS Neglected Tropical Diseases News - 14 July 2016 - 9:00pm

by Marie-Marie Olive, Véronique Chevalier, Vladimir Grosbois, Annelise Tran, Soa-Fy Andriamandimby, Benoit Durand, Jean-Pierre Ravalohery, Seta Andriamamonjy, Fanjasoa Rakotomanana, Christophe Rogier, Jean-Michel Heraud

Background

Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008–2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts.

Methodology/Principal Findings

First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001). Areas with high cattle density were at risk (p<0.01; OR = 2.6). Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6). Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle.

Conclusions/Significance

Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution of vectorial or direct transmissions could be further assessed by mathematic modelling.

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