Host-pathogen interactions, diagnostics, and control measures for brucellosis in ruminants-A review

Ruminants are usually endemic to brucellosis, a disease caused by B. abortus, B. melitensis, B. suis and B. ovis. Brucella can affect animals of any age, regardless of sex, and is typically linked to substantial morbidity, spontaneous abortion both in ruminants (last trimester), and humans. Brucella species form a closely related monophyletic cluster with DNA-to-DNA hybridization values that are close to 100%. The Ochrobactrum genus members are the nearby phylogenetic ancestors of Brucella, which share over 97% identity with the Brucella consensus sequence of the 16S rRNA gene. Lipopolysaccharide (LPS), Type IV secretion system (T4SS), Urease, Cytochrome oxidase and BvrR/BvrS system are important virulence factors which help bacteria to invade and cause infection in a host. Stamp’s modified Ziehl-Neelsen (ZN) staining, immunohistochemistry, serological tests, and bacterial culture (gold standard) are the important tests for screening and diagnosis of brucellosis. Test and slaughter policies are not feasible to control brucellosis in developing nation such as India because cows are often used as a symbol of zeal and pride. Therefore, to reduce the burden of brucellosis in ruminants, attention must be focused on proper screening and segregation, vaccination, better cleanliness and hygiene, better management, increased farmer awareness, and more robust cows, in addition to the disease reporting system, such as diagnostic options and surveillance in farm animals.

• Brucella species can invade and persist in both phagocytic and non-phagocytic host cells.

• LPS, T4SS, Urease, Cytochrome oxidase and BvrR/BvrS system are important virulence factors.

• Test and slaughter, test and segregation, vaccination, increasing farmer awareness about the disease are important measures to control brucellosis.