Towards the control of neurocysticercosis: challenges in rural and remote endemic regions
Résumé
Humans, pigs, and even dogs can develop cysticercosis or neurocysticercosis (NCC) through accidental ingestion of Taenia solium eggs released from tapeworm carriers. Humans become tapeworm carriers through eating uncooked or under-cooked pork contaminated with cysticerci. The T. solium life cycle is commonly found in areas where pigs are raised using traditional methods, veterinary meat inspection is insufficient, parasite transmission education is lacking, and sanitation is poor. Individuals with an adult tapeworm infection (taeniasis) may also develop cysticercosis/NCC via autoinfection. Since pigs are often allowed to roam freely in endemic areas, they frequently have access to the feces of a variety of species, including humans. Due to their scavenging behavior, pigs are often at risk of developing infections with numerous parasites, including several species of Taenia (e.g., T. solium, Taenia asiatica, Taenia hydatigena) and Echinococcus (e.g., Echinococcus canadensis and Echinococcus multilocularis). Serological methods have been developed to detect human NCC cases. These tests typically detect specific antibody responses using T. solium antigens or antigens from other parasite species which may be cross-reactive in NCC patients. An alternative is to detect circulating antigens using monoclonal antibodies to components of T. saginata, with the belief that T. solium shares certain epitopes with T. saginata. Unfortunately, since pigs can be infected with other Taenia species besides T. solium, these methods are not specific for the detection of T. solium infection in pigs. Therefore, serological screening of pigs should be followed by necropsy to confirm the infecting species. In this presentation, data from pigs in Indonesia, Thailand, and China will be presented and possible ways to overcome the problem of cross-reactivity in pigs will be discussed.