Serological and molecular survey of Anaplasma spp. in Egyptian cattle reveals high A. marginale infection prevalence

Document Type : Full paper (Original article)

Author

Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt

10.22099/ijvr.2021.40587.5879

Abstract

Background: Bovine anaplasmosis is an infectious disease with worldwide distribution. It is spread by various routes mainly through tick bites. Aims: To investigate bovine related Anaplasma spp. in cattle from three northern governorates by serological and molecular assays, and to evaluate the associated risk factors. Methods: During 2020, a total of 650 blood samples were collected from asymptomatic cattle in the governorates of Kafr El-Sheikh (n=240), Menofia (n=230), and Al-Gharbia (n=180). Sera samples were examined using the Anaplasma Antibody Test Kit, cELISA v2. Then, blood genomic DNA of seropositive samples were examined by PCRs specific to A. marginale, A. centrale and A. bovis, and selected positive samples were subjected to nucleotide sequencing. Risk factors (i.e. geographical area, breed, type of production, sex, age, herd size, season, husbandry system, tick infestation, and application of acaricides) were evaluated by logistic regression approach. Results: In total, 130 cattle (20%, 95% CI 17.1–23.3) scored seropositive for Anaplasma species. Major risk factors associated with seropositivity were being crossbreed, dairy cattle, aged more than 5 years, summer season, herd size of below 300, pasture grazing, tick infestation, and not being subjected to regular treatment with acaricides. By using species-specific PCR only A. marginale was detected. Nucleotide sequencing showed the occurrence of two different msp4 genotypes. Conclusion: This study proves the high prevalence of A. marginale in cattle of Kafr El-Sheikh, Al-Gharbia and Menofia. However, the connection between Anaplasma species and their tick vectors in Egypt remains unknown and merits further investigation. Since these infections are spread primarily through ixodid tick bites, effective ectoparasite control strategies, regular examination of cattle and successful chemoprophylaxis are recommended.

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