By Nico van Burick
Heavy rains at the beginning of the year in the northern parts of the summer rainfall region led to a sudden increase in insect-borne diseases such as lumpy skin disease, three-day stiff-sickness and blue tongue by the end of January.
These outbreaks were, however, less severe than in 2022 and 2023, according to the Veterinarian Network and the Ruminant Veterinary Association of South Africa (RuVASA). With the onset of autumn and cooler temperatures, the incidence of these diseases is expected to remain low.
The disease that now requires priority attention, says Dr Danie Odendaal, is Asiatic redwater, a tick-borne parasitic infection that is the leading cause of cattle deaths in South Africa. Dr Odendaal is the director of the Veterinarian Network, and he has taken over the reporting of animal disease outbreaks from Dr Faffa Malan, who retired in December.
To combat the spread of Asiatic redwater, the available vaccine stock will be reviewed, animals in different herds will be tested for immunity, and follow-up studies will be conducted with veterinarians to prevent the disease through vaccinations. More feedback will likely be provided in the Disease Distribution Report for February.
Dr Odendaal says one of the most important goals of the disease reports is to identify and combat priority diseases with the limited resources available.
Currently, 300 veterinarians from 175 veterinary practices across the country report animal diseases and participate in a WhatsApp group that provides real-time feedback and contributes to surveys so information can be gathered on specific diseases.
Dr Odendaal believes it as a unique system worldwide. “Its purpose is to identify a problem disease as quickly as possible so an action plan can be developed to prevent and treat it, either through a targeted approach or further research.
“An example was the feedback on the WhatsApp group that eye infections were an ongoing and persistent problem, which could have been caused by a high prevalence of disease-causing bacteria and viruses, or environmental conditions conducive to them.”
Another trend observed and validated by a survey on the WhatsApp group was a temporary increase in fly prevalence. Follow-up discussions with veterinarians confirmed that this surge was brief, occurring only in January due to high humidity following rains in the north and a few weeks of high temperatures.
Other trends observed
A survey also showed a low incidence of three-day stiff-sickness in January, though cases were expected to rise significantly in February. The same trend applied to lumpy skin disease, which remained uncommon in January but was anticipated to increase sharply in February.
Dr Odendaal says that January’s disease trends were influenced by rapid shifts in environmental conditions, such as rainfall, temperature fluctuations, wind, grazing quality, soil conditions and nutrition. These factors impacted animals in different ways depending on the presence of disease-causing organisms and other contributing elements.
In the first half of December, a heat wave swept across the summer rainfall region, bringing dry conditions and poor grazing. This occurred during the breeding season, negatively impacting reproduction.
Due to the warm yet exceptionally dry weather, disease issues remained minimal, as most insect-borne summer diseases rely on moisture. However, in the second half of December and particularly in January unusual rainfall occurred in the north (Gauteng, Limpopo, and the Northern Free State), the east (Mpumalanga and KwaZulu-Natal) and the west (North-West).
Maps illustrating the distribution and severity of animal diseases in South Africa are available on the Red Meat Industry Services (RMIS) website under “Statistics”. The Disease Distribution Report for January 2025, based on data supplied by veterinarians, can be accessed here.
