Taenia solium taeniosis and cysticercosis literature in Tanzania provides research evidence justification for control: A scoping review

Abstract

Research evidence to guide policy and research agenda for Taenia solium taeniosis and cysticercosis (TSTC) in Sub-Saharan Africa is lacking. A scoping review of all TSTC studies undertaken in Tanzania and published up to November 2018 was conducted. The literature were searched from PUBMED, Tanzania Veterinary Journal, Tanzania Journal of Health Research and Google, and extracted to provide evidence on disease burden and potential for control. Fifty (50) articles met the inclusion criteria and were reviewed. Prevalence of taeniosis of 2.3% - 5.2% was estimated based on copro-antigen ELISA while human cysticercosis of >16% was estimated based on serum antigen ELISA (Ag-ELISA) or IgG Western Blot. Neurocysticercosis contributed significantly to epilepsy in adults. Farm prevalence of porcine cysticercosis were 6.0% - 17.4% (lingual examination), 1.5% - 33.3% (Ag-ELISA) and incidence rates of 25/100 pig-years (lingual examination) and 69/100 pig-years (Ag-ELISA). Slaughter-slab prevalence were 0% - 18.2% (routine meat inspection). Lacking latrines, watering pigs with river or pond waters and feeding pigs with potato peels were associated with high porcine cysticercosis prevalence. Washing hands by dipping method instead of running water increased the risk of human cysticercosis. For the year 2012 the number of DALYs/1000 person-years for NCC-associated epilepsy was 0.7 (95% UI, 0.2–1.6), around 5 million USD (95% UI, 797,535– 16,933,477) were spent due to NCC-associated epilepsy and nearly 3 million USD (95% UI, 1,095,960–5,366,038) were potentially lost due to porcine cysticercosis. Three rounds of annual treatment of school-age children with praziquantel significantly reduced prevalence of taeniosis and porcine cysticercosis. A health education intervention reduced porcine cysticercosis incidence by approximately 43% with no improvement in pig confinement or use of latrines. A single dose of oxfendazole 30 mg/kg body weight eliminated T. solium cysticerci in pig musculature but not in the brain. High prevalence of T. solium infections in humans and pigs have been reported in Tanzania while the parasite accounts for a considerable proportion of epilepsy in humans that could be prevented. A one-health approach is mandatory to elimination of TSTC. There is potential for integrating control of TSTC with schistosomiasis control.

Key words: Taeniosis, Cysticercosis, Slaughter-slab, Epilepsy, Public health