Prevalence and haemato-biochemical profile of Anaplasma marginale infection in dairy animals of Punjab (India)

Objective: To do the systematic comparison of prevalence of anaplasmosis by PCR and Giemsa stained thin blood smear (GSTBS) based parasitological assays in dairy cattle of Punjab, which has not been reported yet. To analyse the haematobiochemical alterations in infected animals to arrive at the conclusion regarding the pathogenicity induced by Anaplasma marginale (A. marginale) in latent and patent infection. Methods: Study was conducted on 320 animals (236 cows, 62 calves and 22 buffaloes) of Punjab, India. PCR on genome of A. marginale was performed by targeting msp1 beta gene using specific primers BAP-2/AL34S, amplifies products of size 407 bp. Questionnaires based data on the characteristics of the infected animals and management strategies of the farm were collected and correlated. Results: Higher prevalence and more significant association was observed in the PCR based molecular diagnosis (P=0.00012) as compared to that in GSTBS (P=0.028 8) based diagnosis with various regions under study. With respect to the regions, highest prevalence was recorded in Ferozepur by PCR based diagnosis, while that in Jalandhar by GSTBS examination. Similar marked significant association of the PCR based diagnosis with the age of the animals under study (P=0.00013) was observed elucidating no inverse age resistance to A. marginale in cow calves. Haematobiochemical profile of infected animals revealed marked anemia, liver dysfunction and increase globulin concentrate indicating rise in immunoglobulin level to counteract infection. Conclusions: PCR is far more sensitive in detecting the disease even in latent infection which may act as nidus for spread of anaplasmosis to susceptible animals in endemic areas. Severity of anaemia and liver dysfunction were comparable both in patent as well as latent infection indicating pathogenicity of both.