Molecular surveillance based on anaplasmosis in domestic small ruminants: First report on zoonotic Anaplasma capra and phylogenetic insights from Faisalabad, Pakistan

Anaplasma is an intracellular alphaproteobacteria that infects diverse blood cell types in animal hosts including small ruminants. Epidemiological and risk factors information on zoonotic anaplasmosis with respect to anaplasmosis in sheep and goats are scarce. Therefore, the objective of the current study was to estimate the prevalence, risk factors of anaplasmosis and phylogenetic investigation of A. capra in sheep and goats from Faisalabad district, Pakistan. Briefly, 384 blood samples were randomly collected from sheep and goats of Faisalabad district, Pakistan, during January to May 2022. The samples were processed for the detection of Anaplasma targeting 16S rRNA gene using PCR. The data regarding disease determinants were collected using a predesigned questionnaire. Out of 384 samples, 131 samples were found positive for Anaplasma spp. with a prevalence rate of 34.11%. The results indicated a significantly higher prevalence of anaplasmosis in goats (41.88%) compared to sheep (22.00%). In addition, the chi square indicated that housing type, tick infestation, gender, tick control practices, age, mix farming, and hygiene were significantly associated with the occurrence of disease. The analysis of multivariate logistic regression expressed gender as the significant risk factor (p = 0.0001, OR = 1.757, CI = 1.305-2.366). The acquired sequences revealed four novel isolates of A. capra (Genbank accession numbers ON834323, ON838209, ON838210, and ON838211). The phylogenetic analysis of the 16S rRNA gene of A. capra revealed three distinct clusters with 99-100% homology with other isolates from different countries. Our isolates showed higher similarity with isolates from China (KM206273, KP314237, MT799937), Pakistan (ON238129, ON238130, ON238131), Angola (MT898988), India (MZ558066), Iran (MW692362), and Turkey (MT632469) isolated from human, sheep, ticks, goats, cattle, Gaddi goat, Persian Onager (Equus hemionus onager), and Turkish goats, respectively. In conclusion, A. capra is endemic in Punjab, Pakistan, there is a need to conduct large scale surveillance studies to assess the status of this pathogen at human-animal interface as well as to develop effective preventive and control strategies to reduce the economic losses associated with anaplasmosis in small ruminants.