Detection and epidemiology of Taenia solium in Northern Peru

Taenia solium Taen/asis is prevalent in humans in developing countries, and an imported disease in developed countries. It may cause severe or fatal illness when humans ingest eggs and develop larval cysts in the central nervous system (neurocysticercosis). This project has two parts: the development of a laboratory diagnostic method to accurately detect Taenia solium carriers at the species-level, and the use of a Geographic Information System (CIS) as a tool to study transmission dynamics between human and pig hosts. A capture enzyme-linked immunosorbent assay (ELISA) test that detects taeniid antigens (coproantigens) in human faeces was developed and standardised to use antibodies against somatic and secretory -excretory antigens produced by the tapeworm, achieving Taen/asis detection sensitivity values of 96% and up to 100% specificity for Taenia solium. This simple and reliable ELISA is potentially very useful as a screening method for human T. solium Taen/asis. Porcine serosurveys (for T solium antibodies) and total culling (for pig cyst counts) were performed within the framework of a large intervention programme being applied in endemic villages in northern Peru. Necropsy data for the entire porcine population was obtained, the whole carcass being examined for T. solium cysts. The number and characteristics of the cysts were recorded. All data, along with geographic location of the tapeworm carriers and pigs, were entered in a GIS model developed using ArcGis 10. The results for porcine cysticercosis and human Taen/asis were plotted on maps and spatial relations among human and pig hosts were established. Correlation between the hosts' locations was analyzed using binary logistic regressions performed in SPSS 11.0. The model showed a visual spatial relationship between the locations of hosts. An approximate influence area for Taenia solium was established at 300 meters around human tapeworm carrier household locations, and confirmed by logistic regression (p< 0.005). Pigs living inside this area may be a source of new tapeworms. Using this model, focused control measures can be established in high risk areas, targeting treatment or elimination of possible sources of infection