ASSESSMENT OF HAEMATO-BIOCHEMICAL AND THERAPEUTIC RESPONSES OF CHRONIC BRUCELLOSIS IN CROSSBRED DAIRY COWS IN BANGLADESH

Abstract

Background: Sero-molecular methods have been used for the study on the prevalence and economic impact of brucellosis in Bangladesh. The physio-pathological effects and therapeutic trials against brucellosis in animals or humans could not be traced in the available inland literature. Objectives: This study was conducted to determine the sero-prevalence and haemato-biochemical and therapeutic responses in Brucella-infected dairy crossbred cows. Materials and Methods: Sera samples of 552 cross-bred dairy cows of Military Dairy Farm, Jessore and smallholder dairy farms of Sirajgonj and Dhaka were initially screened for Brucella infection with Rapid kit test (RKT) and Rose Bengal test (RBT) and positive samples were tested further with ELISA and PCR for confirmatory diagnosis during the period from January 2018 to June 2019. Out of 11 all tests positive cows, of which four had history of abortion were selected for therapeutic trials with combined long acting oxytetracycline @ 25 mg/kg BW 16 doses at 72 hours intervals and streptomycin @ 25 mg / kg BW 10 doses at 24 hours interval injections. Blood samples of all the Brucella negative control and pre- and post-treatment stages of all the Brucella-infected cows were tested for haemato-biochemical changes and Brucella antibody responses by using ELISA and PCR. Results: Of the 552 sera screened for Brucella infection, of which 18 (3.26%) cows were found positive with the RKT, RBPT and ELISA, whereas only 11 (1.99%) samples showed positive with PCR. The haemato-biochemical values between Brucella-negative and positive cows and antibiotic pre-treated and post-treated values of Brucella-infected cows were compared and discussed. The antibody titer decreased with antibiotic treatment and increased on with-drawl of the antibiotic at 180 days which indicates that antibiotics only effective against bacteremic form not intracellular stage that caused to relapse. However, of the four treated cows, one became pregnant on artificial insemination with normal reproductive cycle which needs to explore its status in further research. Conclusions: The haemato-biochemical values in cows affected with sub-clinical brucellosis can determine the extent of harmful effects on the health of cows. Therapy with multiple antibiotics for long period, absence of effective vaccines and the most expensive quarantine and ‘test and slaughter’ methods, brucellosis remains as a challenge for its control and eradication in developing world. Human patients affected with brucellosis is treated with antibiotics with overall neglecting the animal reservoir of Brucella infection, therefore ‘One Health’ approach would be required to control this disease.