Diversity of small mammal ectoparasite species and factors that affect their abundance in Chimit Kola, northwestern Ethiopia

Small mammals host different ectoparasite species. Data on ectoparasites associated with small mammals are limited in Ethiopia. Species diversity and factors that influence the abundance and mean intensity of ectoparasites were investigated and identified using the available taxonomic keys. Chi-square test was used to test the association of ectoparasite among host species. Regression analyses were performed using the hurdle model for the abundance of ectoparasite groups. About 73% of small mammals were infested by ectoparasites with an average of 10 individual ectoparasites per host. A total of 11 species of ectoparasites (four ticks, three mites, two fleas, one chigger mite, and one louse) were identified. Fleas were the most prevalent ectoparasites occurring with a prevalence rate of 44.5% followed by mites (40.3%) and the least louse (2.3%). The prevalence of ectoparasite species was significantly associated with host species (p < 0.05). Nearly 50% of the small mammals in the mixed forest harboured fleas while 38% of the host in the bushland harboured ticks. Grasslands harboured about 56% and 38% of small mammals that hosted mites and chigger mites, respectively. Polyparasitism positively influenced the prevalence of most ectoparasite groups and the mean intensity of chigger mites and ticks (p < 0.05). Similarly, older hosts were more likely to be infested by mites, chigger mites, and ticks than younger ones (p < 0.05) but with similar intensity (p > 0.05). The prevalence of ticks was higher during the dry season but the mean intensity of fleas and chigger mites was high during the wet season (p < 0.05). The weight of host species was positively correlated with flea prevalence but negatively with mites and tick prevalence (p < 0.05). Factors such as polyparasitism, the age of the host, season, the weight of the host, and habitats significantly influenced the prevalence and intensity of some ectoparasites. Some species of fleas and ticks that occur in this study are also important vectors of some zoonotic diseases for many animal species including humans. Zoonotic disease control strategies should be implemented.