Seroprevalence of Anaplasma spp. among sheep and goats in Charsadda District, Pakistan

Abstract

Anaplasmosis is a widespread tick-borne rickettsial disease responsible for fever, weakness, dyspnea, and progressive anemia in small ruminants, including sheep, goats, deer, and antelope. Anaplasma spp., the causative agent of anaplasmosis, are mainly transmitted via infected ticks to susceptible hosts during blood feeding. These pathogens are particularly devastating to sheep and goat herds in Pakistan, resulting in significant economic losses. However, limited information are available on the epidemiology of Anaplasma spp. among small ruminants in some parts of Pakistan. A commercially available competitive enzyme-linked immunosorbent assay (cELISA) was used to investigate the seroprevalence of Anaplasma antibodies in small ruminants from the three tehsils of the Charsadda District in Pakistan. A total of 600 blood samples (300 sheep and 300 goat) were collected from small farms as well as a standard survey from farmers at each location describing specific aspects related to their livestock management practices. A multivariable logistic regression model was used to assess the relationship between Anaplasma sero-positivity and associated risk factors. The overall seroprevalence of Anaplasma antibodies was higher in goats (25%) than in sheep (19%). A significantly higher infection rate in animals was observed in the Charsadda tehsil compared to the two other tehsils (Shabqadar and Tangi). Age, adopted grazing system, and administrative division were also significant factors for infection (P ≤ 0.5) in animals from all three tehsils studied. Anaplasma spp. infection is a serious health problem in small ruminants in Pakistan and this is the first study focused on quantifying seroprevalence in sheep and goats in the Charsadda District. Further studies are needed to enhance the understanding of factors related to the disease, which can help design new methods for anaplasmosis control in livestock.