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

BACKGROUND: Infections 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. METHODOLOGY: A 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 FINDINGS: Of 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/SIGNIFICANCE: This 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.

Hyperendemicity of cysticercosis in Madagascar: Novel insights from school children population-based antigen prevalence study.

OBJECTIVE: Taenia solium (Ts) cysticercosis is a neglected zoonotic disease particularly prevalent in Madagascar. Few data are available for children, current data mainly rely on antibody prevalence. We sought to determine the Ts-antigen seroprevalence-determining active cysticercosis-amongst school children from various cities in Madagascar (excluding the capital) and evaluated associated risk factors. METHODS: In seven cities in Madagascar, the presence of cysticercosis in school children (n = 1751) was investigated in 2007 using the B158/B60 antigen (Ag)-ELISA. RESULTS: The overall prevalence based on Ag detection was 27.7% [95%CI: 10-37%]. Risk factors associated with Ag positivity were age, biotope, altitude and annual average rainfall. CONCLUSION: These results highlight the high prevalence of active cysticercosis in Madagascar among school children in an urban setting. This high prevalence as well as the risk factors unraveled point to the emergency to implement appropriate Public Health measure son a national scale.

Evaluation of the performance of 5 commercialized enzyme immunoassays for the detection of Taenia solium antibodies and for the diagnosis of neurocysticercosis.

This study aimed to evaluate 5 enzyme immunoassays for detecting human antibodies against Taenia solium in human serum and for the diagnosis of neurocysticercosis (NCC): DRG™, RIDASCREEN™, NOVATECH™, CYPRESS™, and IVD™. A collection of 114 reference serum samples were used. All sera were tested both by ELISA and by an immunoblot method (enzyme-linked immunoelectrotransfer blot [EITB]). When compared with EITB, the Ridascreen™ test had the best positive concordance rate (85.1-91.2%) and the NovaLisa test™ showed the optimal negative concordance rate (93.7-95.6%). All tests had a sensitivity under 72% and a specificity above 60%. The best sensitivity was obtained using Ridascreen™ test (71.4%). An optimal specificity was achieved by the NovaLisa test™. T. solium-positive sera all cross-reacted with E. granulosus positive samples. In the commercial assays evaluated here, the most appropriate ELISA test for screening may be the Ridascreen™ assay. Antibody detection seems to be not appropriate for NCC diagnosis because of its overall lack of sensitivity.

Comparison of ELISA and PCR assays for the diagnosis of porcine cysticercosis.

Cysticercosis is a zoonotic disease due to Taenia solium, which involves porcines as intermediate host. It is endemic in Madagascar, however minimal data has been reported concerning porcine cysticercosis prevalence. Lack of ante-mortem diagnostic tools renders the evaluation of its prevalence difficult. Tongue palpation is specific but has poor sensitivity. Serological tests detecting antigens or antibodies are sensitive to human cysticercosis and apt for diagnosis but are not yet considered as a gold standard in porcine ante-mortem examination. PCR are widely used to detect pathogens but also poorly evaluated in regards to the diagnosis of cysticercosis. We compare the performance of PCR and ELISA assays on 67 pig serums: 22 from cysticercosis positive pigs (meat inspection) and 45 from cysticercosis negative animals (originating from a non-endemic country or grown in industrial and well isolated pigsties). Among the negative samples 19 were collected from pigs with trichinellosis and 4 from pigs with toxoplasmosis. Results indicate that ELISA assay showed high sensitivity and good specificity while the PCR assays showed high specificity but a low sensitivity.