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Population-based coverage survey results following the mass drug administration of azithromycin for the treatment of trachoma in Amhara, Ethiopia

PLoS Neglected Tropical Diseases News - 16 February 2018 - 10:00pm

by Tigist Astale, Eshetu Sata, Mulat Zerihun, Andrew W. Nute, Aisha E. P. Stewart, Demelash Gessesse, Gedefaw Ayenew, Berhanu Melak, Melsew Chanyalew, Zerihun Tadesse, E. Kelly Callahan, Scott D. Nash

Background

Trachoma is the leading infectious cause of blindness worldwide. In communities where the district level prevalence of trachomatous inflammation-follicular among children ages 1–9 years is ≥5%, WHO recommends annual mass drug administration (MDA) of antibiotics with the aim of at least 80% coverage. Population-based post-MDA coverage surveys are essential to understand the effectiveness of MDA programs, yet published reports from trachoma programs are rare.

Methods

In the Amhara region of Ethiopia, a population-based MDA coverage survey was conducted 3 weeks following the 2016 MDA to estimate the zonal prevalence of self-reported drug coverage in all 10 administrative zones. Survey households were selected using a multi-stage cluster random sampling design and all individuals in selected households were presented with a drug sample and asked about taking the drug during the campaign. Zonal estimates were weighted and confidence intervals were calculated using survey procedures. Self-reported drug coverage was then compared with regional reported administrative coverage.

Results

Region-wide, 24,248 individuals were enumerated, of which, 20,942 (86.4%) individuals were present. The regional self-reported antibiotic coverage was 76.8% (95%Confidence Interval (CI):69.3–82.9%) in the population overall and 77.4% (95%CI = 65.7–85.9%) among children ages 1–9 years old. Zonal coverage ranged from 67.8% to 90.2%. Five out of 10 zones achieved a coverage >80%. In all zones, the reported administrative coverage was greater than 90% and was considerably higher than self-reported MDA coverage. Main reasons reported for MDA campaign non-attendance included being physically unable to get to MDA site (22.5%), traveling (20.6%), and not knowing about the campaign (21.0%). MDA refusal was low (2.8%) in this population.

Conclusions

Although self-reported MDA coverage in Amhara was greater than 80% in some zones, programmatic improvements are warranted throughout Amhara to achieve higher coverage. These results will be used to enhance community mobilization and improve training for MDA distributors and supervisors to improve coverage in future MDAs.

Dengue knowledge, attitudes and practices and their impact on community-based vector control in rural Cambodia

PLoS Neglected Tropical Diseases News - 16 February 2018 - 10:00pm

by Emmanuelle Kumaran, Dyna Doum, Vanney Keo, Ly Sokha, BunLeng Sam, Vibol Chan, Neal Alexander, John Bradley, Marco Liverani, Didot Budi Prasetyo, Agus Rachmat, Sergio Lopes, Jeffrey Hii, Leang Rithea, Muhammad Shafique, John Hustedt

Background

Globally there are an estimated 390 million dengue infections per year, of which 96 million are clinically apparent. In Cambodia, estimates suggest as many as 185,850 cases annually. The World Health Organization global strategy for dengue prevention aims to reduce mortality rates by 50% and morbidity by 25% by 2020. The adoption of integrated vector management approach using community-based methods tailored to the local context is one of the recommended strategies to achieve these objectives. Understanding local knowledge, attitudes and practices is therefore essential to designing suitable strategies to fit each local context.

Methods and findings

A Knowledge, Attitudes and Practices survey in 600 randomly chosen households was administered in 30 villages in Kampong Cham which is one of the most populated provinces of Cambodia. KAP surveys were administered to a sub-sample of households where an entomology survey was conducted (1200 households), during which Aedes larval/pupae and adult female Aedes mosquito densities were recorded. Participants had high levels of knowledge regarding the transmission of dengue, Aedes breeding, and biting prevention methods; the majority of participants believed they were at risk and that dengue transmission is preventable. However, self-reported vector control practices did not match observed practices recorded in our surveys. No correlation was found between knowledge and observed practices either.

Conclusion

An education campaign regarding dengue prevention in this setting with high knowledge levels is unlikely to have any significant effect on practices unless it is incorporated in a more comprehensive strategy for behavioural change, such a COMBI method, which includes behavioural models as well as communication and marketing theory and practice.

Trial registration

ISRCTN85307778.

Detection of <i>Bartonella spp</i>. in fleas by MALDI-TOF MS

PLoS Neglected Tropical Diseases News - 16 February 2018 - 10:00pm

by Basma El Hamzaoui, Maureen Laroche, Lionel Almeras, Jean Michel Bérenger, Didier Raoult, Philippe Parola

Background

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has recently emerged in the field of entomology as a promising method for the identification of arthropods and the detection of associated pathogens.

Methodology/Principal findings

An experimental model of Ctenocephalides felis (cat fleas) infected with Bartonella quintana and Bartonella henselae was developed to evaluate the efficacy of MALDI-TOF MS in distinguishing infected from uninfected fleas, and its ability to distinguish fleas infected with Bartonella quintana from fleas infected with Bartonella henselae. For B. quintana, two groups of fleas received three successive blood meals, infected or not. A total of 140 fleas (100 exposed fleas and 40 control fleas) were engorged on human blood, infected or uninfected with B. quintana. Regarding the second pathogen, two groups of fleas (200 exposed fleas and 40 control fleas) were fed in the same manner with human blood, infected or not with Bartonella henselae. Fleas were dissected longitudinally; one-half was used for assessment of B. quintana and B. henselae infectious status by real-time PCR, and the second half was subjected to MALDI-TOF MS analysis. Comparison of MS spectra from infected fleas and uninfected fleas revealed distinct MS profiles. Blind queries against our MALDI-TOF MS arthropod database, upgraded with reference spectra from B. quintana and B. henselae and infected but also non-infected fleas, provided the correct classification for 100% of the different categories of specimens tested on the first model of flea infection with Bartonella quintana. As for Bartonella henselae, 81% of exposed positive fleas, 96% of exposed negative fleas and 100% of control fleas were correctly identified on the second model of flea infection.MALDI-TOF MS successfully differentiated Bartonella spp.-infected and uninfected fleas and was also able to correctly differentiate fleas infected with Bartonella quintana and fleas infected with Bartonella henselae. MALDI-TOF MS correctly identified flea species as well as their infectious status, consistent with the results of real-time PCR.

Conclusions/Significance

MALDI-TOF is a promising tool for identification of the infection status of fleas infected with Bartonella spp., which allows new possibilities for fast and accurate diagnosis in medical entomology and vector surveillance.

West Nile and St. Louis encephalitis viral genetic determinants of avian host competence

PLoS Neglected Tropical Diseases News - 15 February 2018 - 10:00pm

by Payal D. Maharaj, Angela M. Bosco-Lauth, Stanley A. Langevin, Michael Anishchenko, Richard A. Bowen, William K. Reisen, Aaron C. Brault

West Nile virus (WNV) and St. Louis encephalitis (SLEV) virus are enzootically maintained in North America in cycles involving the same mosquito vectors and similar avian hosts. However, these viruses exhibit dissimilar viremia and virulence phenotypes in birds: WNV is associated with high magnitude viremias that can result in mortality in certain species such as American crows (AMCRs, Corvus brachyrhynchos) whereas SLEV infection yields lower viremias that have not been associated with avian mortality. Cross-neutralization of these viruses in avian sera has been proposed to explain the reduced circulation of SLEV since the introduction of WNV in North America; however, in 2015, both viruses were the etiologic agents of concurrent human encephalitis outbreaks in Arizona, indicating the need to re-evaluate host factors and cross-neutralization responses as factors potentially affecting viral co-circulation. Reciprocal chimeric WNV and SLEV viruses were constructed by interchanging the pre-membrane (prM)-envelope (E) genes, and viruses subsequently generated were utilized herein for the inoculation of three different avian species: house sparrows (HOSPs; Passer domesticus), house finches (Haemorhous mexicanus) and AMCRs. Cross-protective immunity between parental and chimeric viruses were also assessed in HOSPs. Results indicated that the prM-E genes did not modulate avian replication or virulence differences between WNV and SLEV in any of the three avian species. However, WNV-prME proteins did dictate cross-protective immunity between these antigenically heterologous viruses. Our data provides further evidence of the important role that the WNV / SLEV viral non-structural genetic elements play in viral replication, avian host competence and virulence.

Prevalence of trachoma in school children in the Marajó Archipelago, Brazilian Amazon, and the impact of the introduction of educational and preventive measures on the disease over eight years

PLoS Neglected Tropical Diseases News - 15 February 2018 - 10:00pm

by Joana Favacho, Antonio José Ledo Alves da Cunha, Samara Tatielle Monteiro Gomes, Felipe Bonfim Freitas, Maria Alice Freitas Queiroz, Antonio Carlos Rosário Vallinoto, Ricardo Ishak, Marluísa de Oliveira Guimarães Ishak

Trachoma is the leading infectious cause of blindness in the world and is associated with precarious living conditions in developing countries. The aim of the present study was to evaluate the prevalence of trachoma in three municipalities of the Marajó Archipelago, located in the state of Pará, Brazil. In 2008, 2,054 schoolchildren from the public primary school system of the urban area of the region and their communicants were clinically examined; in 2016, 1,502 schoolchildren were examined. The positive cases seen during the clinical evaluation were confirmed by direct immunofluorescence (DIF) laboratory tests. The presence of antibodies against the genus Chlamydia was evaluated by indirect immunofluorescence (IIF), and the serotypes were determined by microimmunofluorescence (MIF). In 2008, the prevalence of trachoma among schoolchildren was 3.4% (69 cases) and it was more frequent in children between six and nine years of age and in females; among the communicants, a prevalence of 16.5% was observed. In 2016, three cases of trachoma were diagnosed (prevalence of 0.2%), found only in the municipality of Soure. The results of the present study showed that in 2008, trachoma had a low prevalence (3.4%) among schoolchildren in the urban area of Marajó Archipelago; eight years after the first evaluation and the introduction of control and prevention measures (SAFE strategy), there was a drastic reduction in the number of cases (0.2%), demonstrating the need for constant monitoring and effective measures for the elimination of trachoma.

Comparison of three data mining models for prediction of advanced schistosomiasis prognosis in the Hubei province

PLoS Neglected Tropical Diseases News - 15 February 2018 - 10:00pm

by Guo Li, Xiaorong Zhou, Jianbing Liu, Yuanqi Chen, Hengtao Zhang, Yanyan Chen, Jianhua Liu, Hongbo Jiang, Junjing Yang, Shaofa Nie

Background

In order to better assist medical professionals, this study aimed to develop and compare the performance of three models—a multivariate logistic regression (LR) model, an artificial neural network (ANN) model, and a decision tree (DT) model—to predict the prognosis of patients with advanced schistosomiasis residing in the Hubei province.

Methodology/Principal findings

Schistosomiasis surveillance data were collected from a previous study based on a Hubei population sample including 4136 advanced schistosomiasis cases. The predictive models use LR, ANN, and DT methods. From each of the three groups, 70% of the cases (2896 cases) were used as training data for the predictive models. The remaining 30% of the cases (1240 cases) were used as validation groups for performance comparisons between the three models. Prediction performance was evaluated using area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy. Univariate analysis indicated that 16 risk factors were significantly associated with a patient’s outcome of prognosis. In the training group, the mean AUC was 0.8276 for LR, 0.9267 for ANN, and 0.8229 for DT. In the validation group, the mean AUC was 0.8349 for LR, 0.8318 for ANN, and 0.8148 for DT. The three models yielded similar results in terms of accuracy, sensitivity, and specificity.

Conclusions/Significance

Predictive models for advanced schistosomiasis prognosis, respectively using LR, ANN and DT models were proved to be effective approaches based on our dataset. The ANN model outperformed the LR and DT models in terms of AUC.

Imported endemic mycoses in Spain: Evolution of hospitalized cases, clinical characteristics and correlation with migratory movements, 1997-2014

PLoS Neglected Tropical Diseases News - 15 February 2018 - 10:00pm

by Daniel Molina-Morant, Adrián Sánchez-Montalvá, Fernando Salvador, Augusto Sao-Avilés, Israel Molina

Endemic mycoses are systemic fungal infections. Histoplasmosis is endemic in all temperate areas of the world; coccidioidomycosis and paracoccidioidomycosis are only present in the American continent. These pathogens are not present in Spain, but in the last years there has been an increase of reported cases due to migration and temporary movements. We obtained from the Spanish hospitals records clinical and demographic data of all hospitalized cases between 1997 and 2014. There were 286 cases of histoplasmosis, 94 of Coccidioidomycosis and 25 of paracoccidioidomycosis. Overall, histoplasmosis was strongly related to HIV infection, as well as with greater morbidity and mortality. For the other mycoses, we did not find any immunosuppressive condition in most of the cases. Although we were not able to obtain data about clinical presentation of all the cases, the most frequently found was pulmonary involvement. We also found a temporal correlation between the Spanish population born in endemic countries and the number of hospitalized cases along this period. This study reflects the importance of imported diseases in non-endemic countries due to migratory movements.

<i>Mycobacterium tuberculosis</i> complex genotypes circulating in Nigeria based on spoligotyping obtained from Ziehl-Neelsen stained slides extracted DNA

PLoS Neglected Tropical Diseases News - 15 February 2018 - 10:00pm

by Barbara Molina-Moya, Michel K. Gomgnimbou, Lizania Spinasse, Joshua Obasanya, Olanrewaju Oladimeji, Russell Dacombe, Thomas Edwards, Xavier-Olessa Daragon, Lovett Lawson, Saddiq T. Abdurrahman, Luis E. Cuevas, Jose Dominguez, Christophe Sola

Methods

All State TB control programmes in Nigeria were requested to submit 25–50 smear-positive Ziehl-Neelsen (ZN) stained slides for screening during 2013–2014. DNA was extracted from 929 slides for spoligotyping and drug-resistance analysis using microbead-based flow-cytometry suspension arrays.

Results

Spoligotyping results were obtained for 549 (59.1%) of 929 samples. Lineage 4 Cameroon sublineage (L4.6.2) represented half of the patterns, Mycobacterium africanum (L5 and L6) represented one fifth of the patterns, and all other lineages, including other L4 sublineages, represented one third of the patterns. Sublineage L4.6.2 was mostly identified in the north of the country whereas L5 was mostly observed in the south and L6 was scattered. The spatial distribution of genotypes had genetic geographic gradients. We did not obtain results enabling the detection of drug-resistance mutations.

Conclusion/Significance

We present the first national snapshot of the M. tuberculosis spoligotypes circulating in Nigeria based on ZN slides. Spoligotyping data can be obtained in a rapid and high-throughput manner with DNA extracted from ZN-stained slides, which may potentially improve our understanding of the genetic epidemiology of TB.

Joint ancestry and association test indicate two distinct pathogenic pathways involved in classical dengue fever and dengue shock syndrome

PLoS Neglected Tropical Diseases News - 15 February 2018 - 10:00pm

by Marisa Oliveira, Worachart Lert-itthiporn, Bruno Cavadas, Verónica Fernandes, Ampaiwan Chuansumrit, Orlando Anunciação, Isabelle Casademont, Fanny Koeth, Marina Penova, Kanchana Tangnararatchakit, Chiea Chuen Khor, Richard Paul, Prida Malasit, Fumihiko Matsuda, Etienne Simon-Lorière, Prapat Suriyaphol, Luisa Pereira, Anavaj Sakuntabhai

Ethnic diversity has been long considered as one of the factors explaining why the severe forms of dengue are more prevalent in Southeast Asia than anywhere else. Here we take advantage of the admixed profile of Southeast Asians to perform coupled association-admixture analyses in Thai cohorts. For dengue shock syndrome (DSS), the significant haplotypes are located in genes coding for phospholipase C members (PLCB4 added to previously reported PLCE1), related to inflammation of blood vessels. For dengue fever (DF), we found evidence of significant association with CHST10, AHRR, PPP2R5E and GRIP1 genes, which participate in the xenobiotic metabolism signaling pathway. We conducted functional analyses for PPP2R5E, revealing by immunofluorescence imaging that the coded protein co-localizes with both DENV1 and DENV2 NS5 proteins. Interestingly, only DENV2-NS5 migrated to the nucleus, and a deletion of the predicted top-linking motif in NS5 abolished the nuclear transfer. These observations support the existence of differences between serotypes in their cellular dynamics, which may contribute to differential infection outcome risk. The contribution of the identified genes to the genetic risk render Southeast and Northeast Asian populations more susceptible to both phenotypes, while African populations are best protected against DSS and intermediately protected against DF, and Europeans the best protected against DF but the most susceptible against DSS.

Multiplex serology for impact evaluation of bed net distribution on burden of lymphatic filariasis and four species of human malaria in northern Mozambique

PLoS Neglected Tropical Diseases News - 14 February 2018 - 10:00pm

by Mateusz M. Plucinski, Baltazar Candrinho, Geraldo Chambe, João Muchanga, Olinda Muguande, Graça Matsinhe, Guidion Mathe, Eric Rogier, Timothy Doyle, Rose Zulliger, James Colborn, Abu Saifodine, Patrick Lammie, Jeffrey W. Priest

Background

Universal coverage with long-lasting insecticidal nets (LLINs) is a primary control strategy against Plasmodium falciparum malaria. However, its impact on the three other main species of human malaria and lymphatic filariasis (LF), which share the same vectors in many co-endemic areas, is not as well characterized. The recent development of multiplex antibody detection provides the opportunity for simultaneous evaluation of the impact of control measures on the burden of multiple diseases.

Methodology/Principal findings

Two cross-sectional household surveys at baseline and one year after a LLIN distribution campaign were implemented in Mecubúri and Nacala-a-Velha Districts in Nampula Province, Mozambique. Both districts were known to be endemic for LF; both received mass drug administration (MDA) with antifilarial drugs during the evaluation period. Access to and use of LLINs was recorded, and household members were tested with P. falciparum rapid diagnostic tests (RDTs). Dried blood spots were collected and analyzed for presence of antibodies to three P. falciparum antigens, P. vivax MSP-119, P. ovale MSP-119, P. malariae MSP-119, and three LF antigens. Seroconversion rates were calculated and the association between LLIN use and post-campaign seropositivity was estimated using multivariate regression. The campaign covered 68% (95% CI: 58–77) of the population in Nacala-a-Velha and 46% (37–56) in Mecubúri. There was no statistically significant change in P. falciparum RDT positivity between the two surveys. Population seropositivity at baseline ranged from 31–81% for the P. falciparum antigens, 3–4% for P. vivax MSP-119, 41–43% for P. ovale MSP-119, 46–56% for P. malariae MSP-119, and 37–76% for the LF antigens. The seroconversion rate to the LF Bm33 antigen decreased significantly in both districts. The seroconversion rate to P. malariae MSP-119 and the LF Wb123 and Bm14 antigens each decreased significantly in one of the two districts. Community LLIN use was associated with a decreased risk of P. falciparum RDT positivity, P. falciparum CSP and LSA-1 seropositivity, and P. malariae MSP-119 seropositivity, but not LF antigen seropositivity.

Conclusions/Significance

The study area noted significant declines in LF seropositivity, but these were not associated with LLIN use. The MDA could have masked any impact of the LLINs on population LF seropositivity. The LLIN campaign did not reach adequately high coverage to decrease P. falciparum RDT positivity, the most common measure of P. falciparum burden. However, the significant decreases in the seroconversion rate to the P. malariae antigen, coupled with an association between community LLIN use and individual-level decreases in seropositivity to P. falciparum and P. malariae antigens show evidence of impact of the LLIN campaign and highlight the utility of using multiantigenic serological approaches for measuring intervention impact.

Sensitive and less invasive confirmatory diagnosis of visceral leishmaniasis in Sudan using loop-mediated isothermal amplification (LAMP)

PLoS Neglected Tropical Diseases News - 14 February 2018 - 10:00pm

by Maowia Mukhtar, Sababil S. Ali, Salah A. Boshara, Audrey Albertini, Séverine Monnerat, Paul Bessell, Yasuyoshi Mori, Yutaka Kubota, Joseph M. Ndung’u, Israel Cruz

Background

Confirmatory diagnosis of visceral leishmaniasis (VL), as well as diagnosis of relapses and test of cure, usually requires examination by microscopy of samples collected by invasive means, such as splenic, bone marrow or lymph node aspirates. This causes discomfort to patients, with risks of bleeding and iatrogenic infections, and requires technical expertise. Molecular tests have great potential for diagnosis of VL using peripheral blood, but require well-equipped facilities and trained personnel. More user-friendly, and field-amenable options are therefore needed. One method that could meet these requirements is loop-mediated isothermal amplification (LAMP) using the Loopamp Leishmania Detection Kit, which comes as dried down reagents that can be stored at room temperature, and allows simple visualization of results.

Methodology/Principal findings

The Loopamp Leishmania Detection Kit (Eiken Chemical Co., Japan), was evaluated in the diagnosis of VL in Sudan. A total of 198 VL suspects were tested by microscopy of lymph node aspirates (the reference test), direct agglutination test-DAT (in house production) and rK28 antigen-based rapid diagnostic test (OnSite Leishmania rK39-Plus, CTK Biotech, USA). LAMP was performed on peripheral blood (whole blood and buffy coat) previously processed by: i) a direct boil and spin method, and ii) the QIAamp DNA Mini Kit (QIAgen). Ninety seven of the VL suspects were confirmed as cases by microscopy of lymph node aspirates. The sensitivity and specificity for each of the tests were: rK28 RDT 98.81% and 100%; DAT 88.10% and 78.22%; LAMP-boil and spin 97.65% and 99.01%; LAMP-QIAgen 100% and 99.01%.

Conclusions/Significance

Due to its simplicity and high sensitivity, rK28 RDT can be used first in the diagnostic algorithm for primary VL diagnosis, the excellent performance of LAMP using peripheral blood indicates that it can be also included in the algorithm for diagnosis of VL as a simple test when parasitological confirmatory diagnosis is required in settings that are lower than the reference laboratory, avoiding the need for invasive lymph node aspiration.

Promising approach to reducing Malaria transmission by ivermectin: Sporontocidal effect against <i>Plasmodium vivax</i> in the South American vectors <i>Anopheles aquasalis</i> and <i>Anopheles darlingi</i>

PLoS Neglected Tropical Diseases News - 14 February 2018 - 10:00pm

by Yudi T. Pinilla, Stefanie C. P. Lopes, Vanderson S. Sampaio, Francys S. Andrade, Gisely C. Melo, Alessandra S. Orfanó, Nágila F. C. Secundino, Maria G. V. B. Guerra, Marcus V. G. Lacerda, Kevin C. Kobylinski, Karin S. Escobedo-Vargas, Victor M. López-Sifuentes, Craig A. Stoops, G. Christian Baldeviano, Joel Tarning, Gissella M. Vasquez, Paulo F. P. Pimenta, Wuelton M. Monteiro

Background

The mosquito resistance to the insecticides threatens malaria control efforts, potentially becoming a major public health issue. Alternative methods like ivermectin (IVM) administration to humans has been suggested as a possible vector control to reduce Plasmodium transmission. Anopheles aquasalis and Anopheles darlingi are competent vectors for Plasmodium vivax, and they have been responsible for various malaria outbreaks in the coast of Brazil and the Amazon Region of South America.

Methods

To determine the IVM susceptibility against P. vivax in An. aquasalis and An. darlingi, ivermectin were mixed in P. vivax infected blood: (1) Powdered IVM at four concentrations (0, 5, 10, 20 or 40 ng/mL). (2) Plasma (0 hours, 4 hours, 1 day, 5, 10 and 14 days) was collected from healthy volunteers after to administer a single oral dose of IVM (200 μg/kg) (3) Mosquitoes infected with P. vivax and after 4 days was provided with IVM plasma collected 4 hours post-treatment (4) P. vivax-infected patients were treated with various combinations of IVM, chloroquine, and primaquine and plasma or whole blood was collected at 4 hours. Seven days after the infective blood meal, mosquitoes were dissected to evaluate oocyst presence. Additionally, the ex vivo effects of IVM against asexual blood-stage P. vivax was evaluated.

Results

IVM significantly reduced the prevalence of An. aquasalis that developed oocysts in 10 to 40 ng/mL pIVM concentrations and plasma 4 hours, 1 day and 5 days. In An. darlingi to 4 hours and 1 day. The An. aquasalis mortality was expressively increased in pIVM (40ng/mL) and plasma 4 hours, 1, 5 10 and 14 days post-intake drug and in An. darlingi only to 4 hours and 1 day. The double fed meal with mIVM by the mosquitoes has a considerable impact on the proportion of infected mosquitoes for 7 days post-feeding. The oocyst infection prevalence and intensity were notably reduced when mosquitoes ingested blood from P. vivax patients that ingested IVM+CQ, PQ+CQ and IVM+PQ+CQ. P. vivax asexual development was considerably inhibited by mIVM at four-fold dilutions.

Conclusion

In conclusion, whole blood spiked with IVM reduced the infection rate of P. vivax in An. aquasalis and An. darlingi, and increased the mortality of mosquitoes. Plasma from healthy volunteers after IVM administration affect asexual P. vivax development. These findings support that ivermectin may be used to decrease P. vivax transmission.

Prevalence of trachoma in the Kayes region of Mali eight years after stopping mass drug administration

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Lamine Traoré, Benoit Dembele, Modibo Keita, Steven Reid, Mahamadou Dembéle, Bréhima Mariko, Famolo Coulibaly, Whitney Goldman, Dramane Traoré, Daouda Coulibaly, Boubacar Guindo, Joe Amon, Marily Knieriemen, Yaobi Zhang

Background

In 2009, three years after stopping mass treatment with azithromycin, a trachoma impact survey in four health districts in the Kayes region of Mali found a prevalence of trachomatous inflammation—follicular (TF) among children aged 1 to 9 years of >5% and a trachomatous trichiasis (TT) prevalence within the general population (≥1-year-old) of <1%. As a result, the government’s national trachoma program expanded trichiasis surgery and related activities required to achieve trachoma elimination.

Methodology/Principal findings

In 2015, to assess progress towards elimination, a follow-up impact survey was conducted in the Kayes, Kéniéba, Nioro and Yélimané health districts. The survey used district level two-stage cluster random sampling methodology with 20 clusters of 30 households in each evaluation unit. Subjects were eligible for examination if they were ≥1 year. TF and TT cases were identified and confirmed by experienced ophthalmologists. In total 14,159 people were enumerated and 11,620 (82%) were examined. TF prevalence (95% confidence interval (CI)) was 0.5% (0.3–1%) in Kayes, 0.8% (0.4–1.7%) in Kéniéba, 0.2% (0–0.9%) in Nioro and 0.3% (0.1–1%) in Yélimané. TT prevalence (95% CI) was 0.04% (0–0.25%) in Kayes, 0.29% (0.11–0.6%) in Kéniéba, 0.04% (0–0.25%) in Nioro and 0.07% (0–0.27%) in Yélimané.

Conclusions/Significance

Eight years after stopping MDA and intensifying trichiasis surgery outreach campaigns, all four districts reached the TF elimination threshold of <5% and three of four districts reached the TT elimination threshold of <0.1%.

Submicroscopic placental infection by non-<i>falciparum Plasmodium</i> spp.

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Justin Y. A. Doritchamou, Richard A. Akuffo, Azizath Moussiliou, Adrian J. F. Luty, Achille Massougbodji, Philippe Deloron, Nicaise G. Tuikue Ndam

Background

Among the Plasmodium species that infect humans, adverse effects of P. falciparum and P. vivax have been extensively studied and reported with respect to poor outcomes particularly in first time mothers and in women living in areas with unstable malaria transmission. Although, other non-falciparum malaria infections during pregnancy have sometimes been reported, little is known about the dynamics of these infections during pregnancy.

Methods and findings

Using a quantitative PCR approach, blood samples collected from Beninese pregnant women during the first antenatal visit (ANV) and at delivery including placental blood were screened for Plasmodium spp. Risk factors associated with Plasmodium spp. infection during pregnancy were assessed as well as the relationships with pregnancy outcomes.P. falciparum was the most prevalent Plasmodium species detected during pregnancy, irrespective either of parity, of age or of season during which the infection occurred. Although no P. vivax infections were detected in this cohort, P. malariae (9.2%) and P. ovale (5.8%) infections were observed in samples collected during the first ANV. These non-falciparum infections were also detected in maternal peripheral blood (1.3% for P. malariae and 1.2% for P. ovale) at delivery. Importantly, higher prevalence of P. malariae (5.5%) was observed in placental than peripheral blood while that of P. ovale was similar (1.8% in placental blood). Among the non-falciparum infected pregnant women with paired peripheral and placental samples, P. malariae infections in the placental blood was significantly higher than in the peripheral blood, suggesting a possible affinity of P. malariae for the placenta. However, no assoctiation of non-falciparum infections and the pregnancy outcomes was observed

Conclusions

Overall this study provided insights into the molecular epidemiology of Plasmodium spp. infection during pregnancy, indicating the lack association of non-falciparum infections with adverse pregnancy outcomes.

Estimation of the number of women of reproductive age in need of preventive chemotherapy for soil-transmitted helminth infections

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Denise Mupfasoni, Alexei Mikhailov, Pamela Mbabazi, Jonathan King, Theresa W. Gyorkos, Antonio Montresor

Background

Soil-transmitted helminth infections are among the most common infections in developing countries. Globally, as many as 2 billion people are considered to be at risk for soil-transmitted-helminth (STH) infections. Preschool children (PSAC), school-age children (SAC) and women of reproductive age (WRA) are at high risk of STH-attributable morbidity and preventive chemotherapy (PC) for STH is recommended by the World health Organization (WHO).

Methodology/Principal findings

Over the last five years, PC coverage in PSAC and SAC has gradually increased, while coverage in WRA has lagged. Estimating the numbers of WRA in each endemic country would inform scale-up in this group. A two-step process was used: 1) total numbers of girls and women between 15 and 49 years of age were obtained from the United Nations World Population Prospects 2015 database; and 2) the proportion in need of PC was obtained primarily from extrapolation from the WHO PC Databank. WRA were divided into four sub-groups reflecting different reproductive life stages, each having a potentially different interface with the health care system and, consequently, presenting different opportunities for intervention strategies.Worldwide, we estimated that 688 million WRA in 102 countries were in need of PC for STH in 2015. The South-East Asia (49%) and Africa regions (26%) had the highest numbers. Adolescent girls accounted for 16%, while pregnant and lactating women each represented 10%. Over 25 million pregnant women alone were estimated living in areas where the prevalence of hookworm and T. trichiura infection was ≥ 20%. Approximately 20% of at-risk WRA had received deworming with albendazole through the Global Programme to Eliminate Filariasis.

Conclusions/Significance

To close current gaps in coverage, numbers of WRA in need of PC for STH are essential for operational strategies to control STH infection.

Forecasting the spatial and seasonal dynamic of <i>Aedes albopictus</i> oviposition activity in Albania and Balkan countries

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Clément Tisseuil, Enkelejda Velo, Silvia Bino, Perparim Kadriaj, Kujtim Mersini, Ada Shukullari, Artan Simaku, Elton Rogozi, Beniamino Caputo, Els Ducheyne, Alessandra della Torre, Paul Reiter, Marius Gilbert

The increasing spread of the Asian tiger mosquito, Aedes albopictus, in Europe and US raises public health concern due to the species competence to transmit several exotic human arboviruses, among which dengue, chikungunya and Zika, and urges the development of suitable modeling approach to forecast the spatial and temporal distribution of the mosquito. Here we developed a dynamical species distribution modeling approach forecasting Ae. albopictus eggs abundance at high spatial (0.01 degree WGS84) and temporal (weekly) resolution over 10 Balkan countries, using temperature times series of Modis data products and altitude as input predictors. The model was satisfactorily calibrated and validated over Albania based observed eggs abundance data weekly monitored during three years. For a given week of the year, eggs abundance was mainly predicted by the number of eggs and the mean temperature recorded in the preceding weeks. That is, results are in agreement with the biological cycle of the mosquito, reflecting the effect temperature on eggs spawning, maturation and hatching. The model, seeded by initial egg values derived from a second model, was then used to forecast the spatial and temporal distribution of eggs abundance over the selected Balkan countries, weekly in 2011, 2012 and 2013. The present study is a baseline to develop an easy-handling forecasting model able to provide information useful for promoting active surveillance and possibly prevention of Ae. albopictus colonization in presently non-infested areas in the Balkans as well as in other temperate regions.

Microexon gene transcriptional profiles and evolution provide insights into blood processing by the <i>Schistosoma japonicum</i> esophagus

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Xiao-Hong Li, Ricardo DeMarco, Leandro X. Neves, Sally R. James, Katherine Newling, Peter D. Ashton, Jian-Ping Cao, R. Alan Wilson, William Castro-Borges

Background

Adult schistosomes have a well-developed alimentary tract comprising an oral sucker around the mouth, a short esophagus and a blind ending gut. The esophagus is not simply a muscular tube for conducting blood from the mouth to gut but is divided into compartments, surrounded by anterior and posterior glands, where processing of ingested blood is initiated. Self-cure of rhesus macaques from a Schistosoma japonicum infection appears to operate by blocking the secretory functions of these glands so that the worms cease feeding and slowly starve to death. Here we use subtractive RNASeq to characterise the genes encoding the principal secretory products of S. japonicum esophageal glands, preparatory to evaluating their relevance as targets of the self-cure process.

Methodology/Principal findings

The heads and a small portion of the rear end of male and female S. japonicum worms were separately enriched by microdissection, for mRNA isolation and library construction. The sequence reads were then assembled de novo using Trinity and those genes enriched more than eightfold in the head preparation were subjected to detailed bioinformatics analysis. Of the 62 genes selected from the male heads, more than one third comprised MEGs encoding secreted or membrane-anchored proteins. Database searching using conserved motifs revealed that the MEG-4 and MEG-8/9 families had counterparts in the bird schistosome Trichobilharzia regenti, indicating an ancient association with blood processing. A second group of MEGs, including a MEG-26 family, encoded short peptides with amphipathic properties that most likely interact with ingested host cell membranes to destabilise them. A number of lysosomal hydrolases, two protease inhibitors, a secreted VAL and a putative natterin complete the line-up. There was surprisingly little difference between expression patterns in males and females despite the latter processing much more blood.

Significance/Conclusions

The mixture of approximately 40 proteins specifically secreted by the esophageal glands is responsible for initiating blood processing in the adult worm esophagus. They comprise the potential targets for the self-cure process in the rhesus macaque, and thus represent a completely new cohort of secreted proteins that can be investigated as vaccine candidates.

Vector-borne disease risk indexes in spatially structured populations

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Jorge Velázquez-Castro, Andrés Anzo-Hernández, Beatriz Bonilla-Capilla, Moisés Soto-Bajo, Andrés Fraguela-Collar

There are economic and physical limitations when applying prevention and control strategies for urban vector borne diseases. Consequently, there are increasing concerns and interest in designing efficient strategies and regulations that health agencies can follow in order to reduce the imminent impact of viruses like Dengue, Zika and Chikungunya. That includes fumigation, abatization, reducing the hatcheries, picking up trash, information campaigns. A basic question that arise when designing control strategies is about which and where these ones should focus. In other words, one would like to know whether preventing the contagion or decrease vector population, and in which area of the city, is more efficient. In this work, we propose risk indexes based on the idea of secondary cases from patch to patch. Thus, they take into account human mobility and indicate which patch has more chance to be a corridor for the spread of the disease and which is more vulnerable, i.e. more likely to have cases?. They can also indicate the neighborhood where hatchery control will reduce more the number of potential cases. In order to illustrate the usefulness of these indexes, we run a set of numerical simulations in a mathematical model that takes into account the urban mobility and the differences in population density among the areas of a city. If we label by i a particular neighborhood, the transmission risk index (TRi) measures the potential secondary cases caused by a host in that neighborhood. The vector transmission risk index (VTRi) measures the potential secondary cases caused by a vector. Finally, the vulnerability risk index (VRi) measures the potential secondary cases in the neighborhood. Transmission indexes can be used to give geographical priority to some neighborhoods when applying prevention and control measures. On the other hand, the vulnerability index can be useful to implement monitoring campaigns or public health investment.

Community knowledge, perceptions and attitudes regarding leprosy in rural Cameroon: The case of Ekondotiti and Mbonge health districts in the South-west Region

PLoS Neglected Tropical Diseases News - 12 February 2018 - 10:00pm

by Earnest Njih Tabah, Dickson Shey Nsagha, Anne-Cecile Zoung-Kanyi Bissek, Theophilus Ngeh Njamnshi, Irine Ngani-Nformi Njih, Gerd Pluschke, Alfred Kongnyu Njamnshi

Background

Although leprosy is one of the oldest diseases known to humanity, it remains largely misunderstood. Misconceptions about leprosy leads to stigma towards people with the disease. This study aimed at exploring the knowledge, perceptions and attitudes regarding leprosy in rural Cameroon.

Methods

We carried out a cross-sectional community survey of 233 respondents aged 15–75 years, free from leprosy, and living in two rural health districts of the South-west Region of Cameroon. A questionnaire designed to evaluate knowledge, perceptions and attitudes about leprosy was used. Binary logistic regression was used to determine independent predictors of negative attitudes.

Results

About 82% of respondents had heard about, and 64.4% knew someone with leprosy. Information on leprosy was mainly from community volunteers (40.6%), friends (38.0%), and the media (24%). Only 19.7% of respondents knew the cause of leprosy, and a considerable proportion linked it to a spell (25.3%), unclean blood (15.5%) and heredity (14.6%). About 72% knew that leprosy is curable and 86.3% would advise medical treatment. Attitudes towards leprosy patients were generally negative. Only 42% would shake hands, 32.6% would share the same plate, and 28.3% and 27% respectively, would allow their child to play or marry with a person with leprosy. Furthermore, only 33.9% approved of participation of leprosy patients, and 42.9% of their employment. Independent predictors of negative attitudes were: the belief that leprosy is a curse; is caused by a germ; and having seen a leprosy patient. The negative attitudes were dampened by: the beliefs that leprosy is a punishment, is hereditary and is due to poor personal hygiene.

Conclusion

An awareness intervention using community volunteers and the media, with information on the cause of leprosy, its clinical manifestations and curability, and sensitization messages correcting the misconceptions and beliefs regarding leprosy, could improve the community knowledge and attitudes towards leprosy. This would ultimately contribute to the reduction of leprosy burden in the community.

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