Identification and Genotyping of Anaplasma phagocytophylum Strains with Zoonotic Potential in Dogs from Mashhad Shelters, Khorasan-Razavi Province, Iran

 Anaplasmosis caused by Anaplasma spp. is an important arthropod-borne disease of various vertebrates with health concerns to humans. The present study aimed to investigate the detection and genotype of Anaplasma phagocytophilum using microscopic examination, real-time PCR technique, and phylogenetic analysis in dogs from Mashhad shelters, Khorasan-Razavi province.

 For this purpose, 250 blood specimens were collected during routine health checkups from dogs in different shelters in Mashhad, Iran, in 2020. First, smears were prepared from the blood specimens, stained with Giemsa, and examined under the light microscope for Anaplasma inclusions. Then, the genomic DNAs were extracted from buffy coats of blood specimens and screened by real-time PCR for the presence of Anaplasma infection by amplifying a 1400 bp sequence of 16S rRNA belonging to the Anaplasma genus. Finally, sequencing and BLAST analyses were carried out on the amplified fragments for the phylogenetic assessments in positive specimens.

A total of 9 dogs (3.60%), including 5 females (3.40%) and 4 males (3.88%) were found to be positive for Anaplasma infection in real-time PCR. Moreover, in blood smear observation, A. phagocytophilum morulae were detected in the neutrophils of 3 PCR positive animals.

This study provides important data regarding A. phagocytophilum in dogs and the degree of genetic homology/heterogeneities among these pathogen strains from dogs and humans in Iran and other countries. To our knowledge, this is the first molecular evidence on the infection of A. phagocytophilum in sheltered dogs of the region.