Epidemiological Study of Brucellosis in a dairy herd of Chattogram

Abstract

Brucellosis is a highly transmissible zoonosis caused by bacteria of the genus Brucella that affects humans and animals.It is a serious public health and animal health problem causing reproductive complications in dairy animals; hence control measures to prevent its spread are of great importance. This study aimed to confirm probable causes of abortion with subsequent characterization of Brucella isolates, from a dairy herd in Chattogram district of Bangladesh. This study was conducted on a dairy herd of 137 cattle in which two abortions were experienced within days. Samples comprising of aborted fetal tissues, uterine fluid, placental cotyledon and whole blood were collected and processed to know cause of abortions. Serum samples (n=137) were tested by Rose Bengal Plate Test (RBPT) and I-ELISA (Indirect Enzyme Linked Immune Sorbent Assay). Isolation and identification were performed following standard bacteriological and molecular techniques. A total of 91 (66.42%, 95% CI: 58.15- 73.80) and 101 (73.72%, 95% CI: 65.75- 80.40) samples were tested positive by RBPT and I-ELISA, respectively. Both the aborted samples were positive inculture characteristics along with RBPT and I-ELISA tests followed by B. abortus confirmation through AMOS-PCR assay. Partial genome sequencing of two PCR positive samples and subsequent phylogenetic analysis depicts close similarity with the isolates from India, Pakistan and China. The culling of brucellosis-positive cattle is the key to control and prevent brucellosis in herds. The findings clearly highlighted the importance of brucellosis screening for optimizing both the herd health and public health. Key words: Br