Seasonal variation and persistence of tungiasis infestation in dogs in an endemic community, Bahia State (Brazil): longitudinal study

Tungiasis is a zoonosis neglected by authorities, health professionals, and affected populations. Domestic, synanthropic, and sylvatic animals serve as reservoirs for human infestation, and dogs are usually considered a main reservoir in endemic communities. To describe the seasonal variation and the persistence of tungiasis in dogs, we performed quarterly surveys during a period of 2years in a tourist village in the municipality of Ilheus, Bahia State, known to be endemic for tungiasis. Prevalence in dogs ranged from 62.1% (43/66) in August 2013 to 82.2% (37/45) in November 2014, with no significant difference (p=0.06). The prevalence of infestation remained high, regardless of rainfall patterns. Of the 31 dogs inspected at all surveys, period prevalence was 94% (29/31; 95% CI 79.3-98.2%) and persistence of infestation indicator [PII] was high (median PII=6 surveys, q1=5, q3=7). Dogs <1year of age had a higher mean prevalence of 84.5%, as compared with 69.3% in the older dogs. No significant difference was found between the risk of infestation and age or sex (p=0.61). Our data indicate that canine tungiasis persisted in the area during all periods of the year. The seasonal variation described in human studies from other endemic areas was not observed, most probably due to different rainfall patterns throughout the year. The study has important implications for the planning of integrated control measures in both humans and animal reservoirs, considering a One Health approach.