Impact of a 3-year mass drug administration pilot project for taeniasis control in Madagascar

Taenia solium is endemic in Madagascar and presents a significant burden on the population and the health system. The parasite cycles through humans who host the adult tapeworm, and pigs that host the larval stages. Accidental infection of humans may occur with the larval stages which encyst in the nervous central system causing neurocysticercosis, a major cause of seizure disorders and a public health problem. One of the interventions to facilitate the control of the disease is mass drug administration (MDA) of the human population with taeniacide. Here we describe a pilot project conducted in Antanifotsy district of Madagascar from 2015 to 2017 where three annual rounds of MDA (praziquantel, 10mg/Kg) were undertaken in 52 villages. Changes in the prevalence of taeniasis were assessed before, during and after the treatments. A total of 221,308 treatments were given to all eligible people above 5 years of age representing a 95% coverage of the targeted population. No major adverse effects were notified related to the implementation of the MDA. The prevalence of taeniasis was measured using Kato-Katz and copro-antigen techniques. Analyses undertaken combining the results of the Kato-Katz with copro-antigen, or using the Kato-Katz results alone, showed that there was a significant reduction in taeniasis 4 months after the last MDA, but 12 months later (16 months after the last MDA) the taeniasis prevalence had returned to its original levels. Results of the pilot project emphasize the need of a multi-sectorial One-Health approach for the sustained control of T. solium

Kankanet : an artificial neural network-based object detection smartphone application and mobile microscope as a point-of-care diagnostic aid for soil-transmitted helminthiases

Endemic areas for soil-transmitted helminthiases often lack the tools and trained personnel necessary for point-of-care diagnosis. This study pilots the use of smartphone microscopy and an artificial neural network-based object detection application named Kankanet to address those two needs.; A smartphone was equipped with a USB Video Class (UVC) microscope attachment and Kankanet, which was trained to recognize eggs of Ascaris lumbricoides, Trichuris trichiura, and hookworm using a dataset of 2,078 images. It was evaluated for interpretive accuracy based on 185 new images. Fecal samples were processed using Kato-Katz (KK), spontaneous sedimentation technique in tube (SSTT), and Merthiolate-Iodine-Formaldehyde (MIF) techniques. UVC imaging and ANN interpretation of these slides was compared to parasitologist interpretation of standard microscopy.Relative to a gold standard defined as any positive result from parasitologist reading of KK, SSTT, and MIF preparations through standard microscopy, parasitologists reading UVC imaging of SSTT achieved a comparable sensitivity (82.9%) and specificity (97.1%) in A. lumbricoides to standard KK interpretation (97.0% sensitivity, 96.0% specificity). The UVC could not accurately image T. trichiura or hookworm. Though Kankanet interpretation was not quite as sensitive as parasitologist interpretation, it still achieved high sensitivity for A. lumbricoides and hookworm (69.6% and 71.4%, respectively). Kankanet showed high sensitivity for T. trichiura in microscope images (100.0%), but low in UVC images (50.0%).; The UVC achieved comparable sensitivity to standard microscopy with only A. lumbricoides. With further improvement of image resolution and magnification, UVC shows promise as a point-of-care imaging tool. In addition to smartphone microscopy, ANN-based object detection can be developed as a diagnostic aid. Though trained with a limited dataset, Kankanet accurately interprets both standard microscope and low-quality UVC images. Kankanet may achieve sensitivity comparable to parasitologists with continued expansion of the image database and improvement of machine learning technology

High prevalence of intestinal parasite infestations among stunted and control children aged 2 to 5 years old in two neighborhoods of Antananarivo, Madagascar

International audienceBackgroundThis study aimed to compare the prevalence of intestinal parasite infestations (IPIs) in stunted children, compared to control children, in Ankasina and Andranomanalina Isotry (two disadvantaged neighborhoods of Antananarivo, Madagascar), to characterize associated risk factors and to compare IPI detection by real-time PCR and standard microscopy techniques.Methodology/Principal findingsFecal samples were collected from a total of 410 children (171 stunted and 239 control) aged 2–5 years. A single stool sample per subject was examined by simple merthiolate-iodine-formaldehyde (MIF), Kato-Katz smear and real-time PCR techniques. A total of 96.3% of the children were infested with at least one intestinal parasite. The most prevalent parasites were Giardia intestinalis (79.5%), Ascaris lumbricoides (68.3%) and Trichuris trichiura (68.0%). For all parasites studied, real-time PCR showed higher detection rates compared to microscopy ( G . intestinalis [77.6% (n = 318) versus 20.9% (n = 86)], Entamoeba histolytica [15.8% (n = 65) versus 1.9% (n = 8)] and A . lumbricoides [64.1% (n = 263) versus 50.7% (n = 208)]). Among the different variables assessed in the study, age of 4 to 5 years (AOR = 4.61; 95% CI, (1.35–15.77)) and primary and secondary educational level of the mother (AOR = 12.59; 95% CI, (2.76–57.47); AOR = 9.17; 95% CI, (2.12–39.71), respectively) were significantly associated with IPIs. Children drinking untreated water was associated with infestation with G . intestinalis (AOR = 1.85; 95% CI, (1.1–3.09)) and E . histolytica (AOR = 1.9; 95% CI, (1.07–3.38)). E . histolytica was also associated with moderately stunted children (AOR = 0.37; 95% CI, 0.2–0.71). Similarly, children aged between 4 and 5 years (AOR = 3.2; 95% CI (2.04–5.01)) and living on noncemented soil types (AOR = 1.85; 95% CI, (1.18–2.09)) were associated with T . trichiura infestation.Conclusions/SignificanceThe prevalence of IPIs is substantial in the studied areas in both stunted and control children, despite the large-scale drug administration of antiparasitic drugs in the country. This high prevalence of IPIs warrants further investigation. Improved health education, environmental sanitation and quality of water sources should be provided

Usefulness of environmental DNA for detecting Schistosoma mansoni occurrence sites in Madagascar

Objectives: Schistosomiasis is an important disease in Madagascar, and several studies on the disease have focused on the occurrence of the parasite in humans. However, the range of the pathogen in the environment and its impact on human infection is difficult to predict. An environmental DNA (eDNA) detection system for Schistosoma mansoni was developed to improve schistosomiasis eco-epidemiology studies. Methods: Primers and probes were designed and tested in experimental biotopes. The field study was conducted in Maevatanana District of Madagascar. Seven water sources with human use were sampled, with a total of 21 water samples collected. Snails were collected, and patients were examined by ultrasound to determine the occurrence of schistosomiasis in the study area. Results: One water source with active transmission was identified through the detection of S. mansoni eDNA in the water and the intermediate host Biomphalaria pfeifferi collected from the same water source. People with clinical schistosomiasis were found in the area, reinforcing the findings. Conclusions: The application of eDNA in eco-epidemiology enables the determination of hot spots and safe spots in endemic areas, constituting an alternative ecological tool for follow-up and monitoring of control programs for schistosomiasis, and contributing information on water safety for improving the standard of living of the people in endemic areas. Keywords: Eco-epidemiology, EcoHealth, One Health, Environment, Schistosomiasis, Africa, Madagascar, eDN

Prevalence and factors associated with human Taenia solium taeniosis and cysticercosis in twelve remote villages of Ranomafana rainforest, Madagascar

International audienceBackgroundInfections with the tapeworm Taenia solium (taeniosis and cysticercosis) are Neglected Tropical Diseases (NTD) highly endemic in Madagascar. These infections are however underdiagnosed, underreported and their burden at the community level remains unknown especially in rural remote settings. This study aims at assessing the prevalence of T. solium infections and associated risk factors in twelve remote villages surrounding Ranomafana National Park (RNP), Ifanadiana District, Madagascar.MethodologyA community based cross-sectional survey was conducted in June 2016. Stool and serum samples were collected from participants. Tapeworm carriers were identified by stool examination. Taenia species and T. solium genotypes were characterised by PCR and sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Detection of specific anti-cysticercal antibodies (IgG) or circulating cysticercal antigens was performed by ELISA or EITB/Western blot assays.Principal findingsOf the 459 participants with paired stool and blood samples included ten participants from seven distinct villages harbored Taenia spp. eggs in their stools samples DNA sequencing of the cox1 gene revealed a majority of T. solium Asian genotype (9/10) carriage. The overall seroprevalences of anti-cysticercal IgGs detected by ELISA and EITB were quite similar (27.5% and 29.8% respectively). A prevalence rate of 12.4% of circulating cysticercal antigens was observed reflecting cysticercosis with viable cysts. Open defecation (Odds Ratio, OR = 1.5, 95% CI: 1.0–2.3) and promiscuity with households of more than 4 people (OR = 1.9, 95% CI: 1.1–3.1) seem to be the main risk factors associated with anticysticercal antibodies detection. Being over 15 years of age would be a risk factor associated with an active cysticercosis (OR = 1.6, 95% CI: 1.0–2.7). Females (OR = 0.5, 95% CI: 0.3–0.9) and use of river as house water source (OR = 0.3, 95% CI: 0.1–1.5) were less likely to have cysticercosis with viable cysts.Conclusions/SignificanceThis study indicates a high exposure of the investigated population to T. solium infections with a high prevalence of cysticercosis with viable cysts. These data can be useful to strengthen public health interventions in these remote settings

Impact of a 3-year mass drug administration pilot project for taeniasis control in Madagascar

Taenia solium is endemic in Madagascar and presents a significant burden on the population and the health system. The parasite cycles through humans who host the adult tapeworm, and pigs that host the larval stages. Accidental infection of humans may occur with the larval stages which encyst in the nervous central system causing neurocysticercosis, a major cause of seizure disorders and a public health problem. One of the interventions to facilitate the control of the disease is mass drug administration (MDA) of the human population with taeniacide. Here we describe a pilot project conducted in Antanifotsy district of Madagascar from 2015 to 2017 where three annual rounds of MDA (praziquantel, 10mg/Kg) were undertaken in 52 villages. Changes in the prevalence of taeniasis were assessed before, during and after the treatments. A total of 221,308 treatments were given to all eligible people above 5 years of age representing a 95% coverage of the targeted population. No major adverse effects were notified related to the implementation of the MDA. The prevalence of taeniasis was measured using Kato-Katz and copro-antigen techniques. Analyses undertaken combining the results of the Kato-Katz with copro-antigen, or using the Kato- Katz results alone, showed that there was a significant reduction in taeniasis 4 months after the last MDA, but 12 months later (16 months after the last MDA) the taeniasis prevalence had returned to its original levels. Results of the pilot project emphasize the need of a multisectorial One-Health approach for the sustained control of T. solium