Contents lists available at ScienceDirect Small Ruminant Research journal homepage: www.elsevier.com/locate/smallrumres Seroprevalence of Anaplasma spp. among sheep and goats in Charsadda District, Pakistan Adil Khan a, ⁎ , Nasreen a , Robert D. Mitchell III b , Sadaf Niaz a , Sultan Ayaz c , Irfan Khattak c , Huma Naeem d , Adalberto A. Pérez de León b , Muhammad Arfan Zaman e a Department of Zoology, Abdul Wali Khan University, Mardan, Pakistan b USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Kerrville, TX, 78028, USA c College of Veterinary and Animal Husbandry, Abdul Wali Khan University, Mardan, Pakistan d Department of Parasitology, University of Veterinary and Animal Sciences, Lahore, Pakistan e Department of Pathobiology, College of Veterinary and Animal Sciences, Jhang, SubCampus, University of Veterinary and Animal Science, Lahore, Pakistan ARTICLEINFO Keywords: Anaplasma spp. Anaplasmosis Small ruminants Seroprevalence ELISA Pakistan ABSTRACT Anaplasmosis is a widespread tick-borne rickettsial disease responsible for fever, weakness, dyspnea, and pro- gressive 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 signifcant economic losses. However, limited information are available on the epidemiology of Anaplasma spp. among small rumi- nants 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 specifc 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 signifcantly 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 signifcant factors for infection (P ≤ 0.5) in an- imals from all three tehsils studied. Anaplasma spp. infection is a serious health problem in small ruminants in Pakistan and this is the frst 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. 1. Introduction Anaplasma spp. (Rickettsiales: Anaplasmatacea) are obligate in- tracellular bacteria that can cause anaplasmosis in several animal spe- cies including small ruminants The bacteria are tick-borne all over the world and transmitted via the bite and subsequent blood feeding of hard tick species from the genera Ixodes, Dermacentor, Rhipicephalus, and Amblyomma into a susceptible mammalian host (da Silva et al., 2018; Rymaszewska and Grenda, 2008; Seo et al., 2018). Anaplasma spp. reside in the salivary gland and midgut cells of ticks until they bloodfeed, at which point the bacteria are transferred to a mammalian host where they enter and replicate within cells typically of hemato- poietic origin. Once inside a host the bacteria actively dysregulate (up- or down-regulate) or completely inhibit host immune factors to facil- itate their survival and proliferation until they are passed to another tick vector feeding on an infected host (Rikihisa, 2011). Anaplasmosis is mainly endemic to tropical and subtropical regions including much of Africa and Australia, but it is also frequently documented in temperate areas of the world like the United States and Europe (Demessie and Derso, 2015; Yasini et al., 2012). However, the pattern of disease dis- tribution varies constantly due to global change driving tick popula- tions into new environments (Jonsson et al., 2008; Dantas-Torres, 2015). In Pakistan, several studies characterized Anaplasma distribution among cattle or water bufalo (Atif et al., 2013; Hussain et al., 2017; Jabbar et al., 2015; Turi et al., 2018). However, information are lacking https://doi.org/10.1016/j.smallrumres.2019.05.008 Received 5 April 2019; Received in revised form 14 May 2019; Accepted 14 May 2019 ⁎ Corresponding author. E-mail address: zoologyawkum@gmail.com (A. Khan). Small Ruminant Research 176 (2019) 5–10 Available online 15 May 2019 0921-4488/ © 2019 Published by Elsevier B.V. T