Relationship between the Prevalence of Ectoparasites and Associated Risk Factors in Free-Range Pigs in Kenya

A cross-sectional study was undertaken to determine the prevalence of ectoparasites and possible risk factors in free-range pigs from 135 farms of Busia District, Kenya. Three hundred and six pigs were examined for presence of external parasites using standard parasitological methods. Data on management practices including housing and history of acaricide spraying were also collected. The ectoparasites found in the pigs were Haematopinus suis (96.1%), Sarcoptes scabiei (63.7%), and ticks (29.7%). The tick species included Rhipicephalus appendiculatus (70%), Boophilus decoloratus (31%), and Amblyomma variegatum (12%). The occurrence of the infestations was associated with age, being highest in sows (S. scabiei) and finishers (ticks and H. suis). Male pigs had highest prevalences of H. suis and ticks, while female pigs had highest prevalence of S. scabiei. The prevalence of the parasitic infestations was significantly ( ) associated with their origin being either lower (H. suis and S. scabiei) or higher (ticks) in pigs originating from divisions with high rainfall. Housed pigs had significantly ( ) lower prevalence of H. suis and ticks than those from households without pig housing. It is concluded that the free-range pigs have high prevalence of ectoparasites, and effective control strategies focussing on improved animal husbandry and acaricide use should be implemented. 1. Introduction The main ectoparasites of pigs are Sarcoptes scabiei var. suis and Haematopinus suis. Sarcoptic mange, caused by Sarcoptes scabiei var. suis, is of major economic importance in pig farming as it significantly reduces production efficiency, and costs of acaricides used in its control are enormous and run into billions of dollars worldwide [1]. Although occurrence of sarcoptic mange is not widely studied in Kenya and African countries, the few studies undertaken so far have shown that the disease is a serious constraint to production of pigs kept under intensive indoor systems [2, 3]. However, little is known regarding the prevalence of sarcoptic mange in free-range pigs. Hog louse (Haematopinus suis) is also a common ectoparasite of pigs all over the world [4–6]. The parasite infests pigs of any age or body condition, although pigs kept outdoors and those in poor body condition are more susceptible [5]. The blood sucking activity of the hog louse results in irritation and discomfort of the pigs and may lead to extensive hair loss and wounds, reduced performance, and increased susceptibility to other diseases [4, 6]. The hog louse has also been implicated in the