Comparison of microscopic and molecular methods in the diagnosis of Anaplasma marginale and determination of related risk factors in cattle in Semnan province

This study aimed to determine the molecular prevalence of Anaplasma marginale among cattle of Semnan province. A total of 208 blood samples were randomly collected via the ear vein and jugular vein from healthy cattle for microscopy and molecular examination, respectively. The extracted DNA from blood cells was amplified by a pair of primer, which amplify an approximately 866bp DNA fragment from the region of the msp4 gene of  A. marginale and 45.2% of cattle blood samples were identified positive for A. marginale. Chi-square tests were used to compare molecular prevalence values relative to climate, altitude, longitude, latitude, season, farm-type, hygiene of the farm, vectors, farm density, age, sex, and milk yield. The significant major risk factors of A. marginale in cattle were identified as latitude, farm-type, vectors, age, and milk yield by the multivariable logistic regression analysis (P< 0.05). The examination of 50 microscopic fields showed 31.9% sensitivity and 54.4% specificity compared to molecular examination. The Kappa coefficient between molecular and microscopy (50 fields) techniques indicated a slight level of agreement (Kappa= 0.13). This study is the first molecular detection of A. marginale from cattle in Semnan province, Iran. Further researches are needed to determine the vectors, vector-host interactions, and genotypic variants that may affect the presence and distribution of Anaplasma species in Semnan province.