The impact of multiple infections and community knowledge on engagement with a historical deworming programme: hookworm and Ascaris in Jamaica, 1913-1936.

Introduction: Community engagement with public health efforts often depends on existing knowledge of a health issue.

Methods: Here, qualitative analysis of archival material from the Jamaica Hookworm Commission (1919-1936) and quantitative analysis of prevalence data are used to assess knowledge of and ecological interactions between different helminths during a historical hookworm eradication campaign.

Results: Archival sources demonstrate that Jamaicans were familiar with Ascaris lumbricoides. Surveys revealed a high prevalence of hookworm (62% of individuals infected), Ascaris (30%) and Trichuris trichiura (32%) in communities targeted for hookworm control. Community prevalence of Trichuris was positively associated with the prevalence of Ascaris and hookworm. Many individuals were infected with more than one parasite. At an individual level, data from hospital patients and soldiers showed significant associations between all three parasites. The co-occurrence of hookworm and Ascaris, alongside folk treatment of Ascaris with the same plant used by the Hookworm Commission (Chenopodium ambrisoides) to treat hookworm, made biomedical claims about hookworm credible and biomedical treatment more acceptable. Expulsions of Ascaris following treatment also provided dramatic proof of the effectiveness of treatment, further facilitating engagement.

Discussion/conclusion: Knowledge of Ascaris and other helminths directly shaped engagement with hookworm treatment, demonstrating how folk medical knowledge, grounded in the biology of the worms, aided a biomedical public health program.