Risk Factors to Human Tick Infestations in Sri Lanka

Abstract

Ticks are ectoparasites of major public health concern. Humans and animals are affected directly by tick bites and indirectly by disease transmission. A study was carried out to determine socio-ecological risk factors of human tick infestations in five selected districts, namely, Anuradhapura, Kandy, Kurunegala, Nuwara Eliya and Ratnapura. A total of 40 villages (8 per district) and 400 households (10 per village) were sampled randomly. Data was collected by interviewing household members using a questionnaire. The prevalence of tick infestation was highest in Kandy (65.4%) followed by Anuradhapura (58.3%) and lowest in Nuwara Eliya (23.7%). Tick infestations were significantly high in those who were engaged in outdoor activities (𝜒 2 =146.180, p<0.001). Among those 41.6% had been interacted with the forest in gathering firewood. Among the different professions, housewives (35.4%) and farmers (33.8%) experienced a high percentage of tick bites. Except in Ratnapura district, tick attacks were also significantly dependant on the presence of wildlife around the homeland (𝜒 2 =42.313, p<0.001). Tick infestation did not depend on the gender (𝜒 2 =0.355, p=0.551) or on the presence of pets and livestock at home (𝜒 2 =0.548, p=0.459) but in Kandy district, both factors posed a risk. Outdoor activities and the presence of wild animals around the house were identified as the major risk factors of human tick infestation.