CA induces mid- to late-term abortion storms in cows. Rates can range from 30% to 80%, leading to significant economic losses.
According to the National Institute of Communicable Diseases, CA is under-reported and underdiagnosed in developing countries including South Africa, where it’s endemic, occurring in all provinces.
Vaccination of heifers between four and eight months is mandatory, and provides protection against CA through live vaccines S19 and RB51.
Transmission of CA within a herd is usually oral and through the ingestion or licking of membranes, aborted foetuses and infected milk. Animal to human transmission can be via contact with infected cattle secretions, foetal membranes, carcasses and injuries incurred while inoculating animals with live vaccines.
The disease in humans is known as Malta fever and is characterised by weakness, sweating, headaches, anaemia and joint and muscle pain.
As a member of the World Animal Health Organisation, SA is obliged to report outbreaks and events of listed diseases within 24 hours.