Brucellosis: a study of five calves from reactor dams

Area of Science:

• Veterinary Medicine
• Bacteriology
• Animal Health

Background:

• Brucella abortus is a significant pathogen causing brucellosis in cattle.
• Reactor cows pose a risk for disease transmission to calves.
• Early life infection and shedding can occur even with negative serological results.

Purpose of the Study:

• To investigate the potential for Brucella abortus shedding in calves born to infected dams.
• To evaluate the efficacy of serological tests in detecting infection in young calves.
• To determine the viability of Brucella abortus in isolated calves.

Main Methods:

• Five calves from Brucella abortus reactor cows were isolated and monitored.
• Serological examinations (Rose-Bengal, serum agglutination, complement fixation) were conducted for six months.
• Post-mortem cultural and biological examinations were performed.

Main Results:

• One calf, serologically negative for eight weeks, yielded a culture of Brucella abortus biotype 1.
• The same Brucella abortus serotype was isolated from the calf's dam at parturition.
• This indicates persistent shedding and potential for transmission.

Conclusions:

• Calves from infected dams can shed Brucella abortus despite prolonged serological negativity.
• Serological tests may not reliably detect infection in all infected calves.
• Further investigation into transmission dynamics and diagnostic limitations is warranted.