Anti-parasite treatment of humans and pigs may eliminate endemic Taenia solium

1. Broad anti-parasite treatment of humans and pigs living in Taenia solium (TS) endemic regions of Peru along with vaccination of pigs was effective in reducing prevalence of the parasite among pigs.

2. Pigs in many villages participating in the program were TS free 1 year after the intervention.

Evidence Rating: 2 (Good)

Study Rundown: A leading cause of late-onset seizes occurring in low-income countries around he world is TS infection. TS is a tapeworm that produces infectious larval cysts in pig tissue after a pig consumes tapeworm containing material (commonly human feces), and when pork is consumed by humans the larvae can mature in the brain. International agencies have determined effective interruption of pig-human transmission of TS can eradicate the tapeworm in endemic areas.

 This study evaluated the potential for regional eradication of TS in endemic areas of rural Peru. The main outcome of this study was assessing pigs to evaluate whether they harbored the parasite. The study was carried out in 3 phases. Phase 1 looked to determine what interventions would be most effective and feasible. Phase 2 involved protocol modifications of the two most successful strategies in Phase 1 and treating more humans and pigs. Phase 3 was designed based on the results of phase 2 and included mass treatment of humans and pigs, and vaccination of pigs. Prevalence of TS in pigs was greatly reduced following vaccination of pigs and treatment of pigs and humans. At a 1-year follow-up TS was more prevalent than immediately following phase 2, though far below baseline prevalence, suggesting continued intervention is needed for TS control.

Click to read the study, published today in NEJM

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In-Depth [prospective cohort]: This study was composed of 3 phases which each lasted for 12 months. Phase 1 (10 753 humans, 17 102 pigs) investigated the type of interventions that would be most effective among strategies of mass pig and human treatment with anti-parasite agents (niclosamide for humans, oxfendazole for pigs). Phase 2 (10 380 humans, 13 488 pigs) involved modified protocols of the two most successful strategies in Phase 1. A Phase 3 (81 170 humans, 55 638 pigs) involved mass anti-parasite treatment of humans and pigs, and vaccination of pigs, as this was determined to be the best eradication strategy based on phase 2 outcomes. Outcomes were measured immediately after interventions as well as 1 year later. At baseline 34.7-50.2% (depending on villages studied) of pigs were seropositive for TS. Immediately after the program 0.9% of sampled pigs had infectious cysts, while 1 year later 2.3% of sampled pigs had infectious cysts. Prevalence of sampled pigs with infectious cysts after phase 3 was 0.9% (3/342), and the 3 pigs with infectious cysts were concluded to have not been treated/vaccinated during the program. Most people (84.7%) living in the studied villages were treated with the anti-parasite agent, and no severe adverse reactions to the treatment were reported.

Image: PD

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