Taenia solium is the most common parasitic infection of the central nervous system and a leading cause of acquired epilepsy in low and middle income countries. Endemic transmission occurs primarily in rural areas where pigs are allowed to roam and consume human feces, thus risking contamination with T. solium eggs and subsequent infection with larval cysts (cysticercosis). Identification and treatment of adult tapeworm carriers (taeniasis) who shed eggs into the environment is therefore critical to control strategy. In our previous NIH R21 award we demonstrated that targeted screening for taeniasis in household clusters surrounding infected pigs (ring-screening) identifies tapeworm carriers for treatment and significantly reduces community transmission of the parasite. This strategy involves identifying heavily-infected pigs through tongue examination followed by thorough investigation for the source tapeworm among residents in neighboring households. Our long-term goals are 1) to develop effective, affordable and sustainable strategies for T. solium control in endemic areas, and 2) to increase population-based research capacity for neurologic disorders in rural Peru.
The first aim of this R01 proposal is to refine ring-screening strategy so that it can be implemented in control programs. We propose a community trial with five parallel study arms to evaluate the long-term efficacy, cost- effectiveness and acceptability of ring-screening for control of T. solium compared against mass treatment. Additional methods for evaluation include use of portable ultrasound and rapid-diagnostic serologic assays to identify heavily-infected pigs in the field, and presumptive treatment within rings (ring-treatment) as a potential alternative to ring-screening. We will enroll communities totaling approximately 10,000 residents and 6,000 pigs in studies which range from 2 to 4 years in duration.
Our second aim i s to increase the local capacity for planning, developing and operating neuroepidemiologic studies in rural northern Peru. We will train two PhD candidates in advanced quantitative methods at Johns Hopkins University Bloomberg School of Public Health, as well as 4 Masters level candidates in research-related disciplines at Universidad Cayetano Peruana Heredia in Lima over the 5-year award period. The results of our combined research and training programs will provide tools, methods and capacitation necessary to enable scale-up of the most promising control strategies we identify.
Cysticercosis is an emerging public health problem in much of the developing world where it is a leading cause of preventable epilepsy. This proposal refines ring-screening for intestinal tapeworm carriers as a potentially effective, affordable and sustainable control strategy.
|Vilchez Barreto, Percy M; Gamboa, Ricardo; Santivañez, Saul et al. (2017) Prevalence, Age Profile, and Associated Risk Factors for Hymenolepis nana Infection in a Large Population-Based Study in Northern Peru. Am J Trop Med Hyg 97:583-586|
|Flecker, Robert H; Pray, Ian W; Santiva?ez, Saul J et al. (2017) Assessing Ultrasonography as a Diagnostic Tool for Porcine Cysticercosis. PLoS Negl Trop Dis 11:e0005282|
|Garvey, Brian T; Moyano, Luz M; Ayvar, Viterbo et al. (2017) Neurocysticercosis among People Living Nearby Pigs Heavily Infected with Cysticercosis in Rural Endemic Peru. Am J Trop Med Hyg :|
|Pray, Ian W; Ayvar, Viterbo; Gamboa, Ricardo et al. (2017) Spatial relationship between Taenia solium tapeworm carriers and necropsy cyst burden in pigs. PLoS Negl Trop Dis 11:e0005536|
|Muro, Claudio; Gomez-Puerta, Luis A; Flecker, Robert H et al. (2017) Porcine Cysticercosis: Possible Cross-Reactivity of Taenia hydatigena to GP50 Antigen in the Enzyme-Linked Immunoelectrotransfer Blot Assay. Am J Trop Med Hyg 97:1830-1832|
|Pray, Ian W; Swanson, Dallas J; Ayvar, Viterbo et al. (2016) GPS Tracking of Free-Ranging Pigs to Evaluate Ring Strategies for the Control of Cysticercosis/Taeniasis in Peru. PLoS Negl Trop Dis 10:e0004591|