A young farmer from Ofcalaco in Limpopo’s Lowveld had his entire cattle herd culled following an outbreak of corridor disease among his cattle after they came into contact with “disease-free” buffalo on a game farm.
By Jasper Raats, senior journalist at African Farming and Landbouweekblad
Dr Gerrit Scheepers of the Phalaborwa Animal Hospital diagnosed the disease and, thanks to good cooperation with the young cattle farmer, the landowner and members of the provincial and national animal health departments, was able to do take the right action at the right time to contain the disease before it could spread to other cattle in the area.
However, questions remain about how the disease broke out on this farm with its small herd of “disease-free” buffalo. “There has been no corridor disease among cattle here for more than 20 years,” says Scheepers.
According to Drs Pamela and Peter Oberem’s Guide to Animal Diseases in South Africa – Game, the parasitic organism Theileria parva originated in buffalo populations in East Africa.
Because buffalo and the parasite have co-evolved over a very long period of time, they are well adapted to each other and the parasite no longer has any effect on buffalo health. The African buffalo (Syncerus caffer) remains a lifelong asymptomatic carrier of T. parva.
However, in cattle it is fatal, with severe economic consequences where there are outbreaks. The brown-eared tick (Rhipecephalus appendiculatus) becomes infected with T. parva when it parasitises on infected buffalo and then transfers the infection to disease-free buffalo or cattle. The cattle then get corridor disease.
In South Africa it is a notifiable as well as a controlled disease, which is controlled through strict protocols.
Protocols For Corridor Disease
These are the very protocols that the veterinarians and farmers of Phalaborwa applied without hesitation when they realised what they were dealing with.
When corridor disease is diagnosed in cattle, a state veterinarian must quarantine the herd immediately.
According to the Oberems’ manual, two fences, 5m apart, should ensure that there is no direct contact between the infected herd and other cattle or disease-free buffalo.
The cattle must be slaughtered and after the last animal has been slaughtered and/or all the buffalo have been removed from the farm or shot, no more cattle or buffalo may be kept on that farm for at least two years.
“We immediately corralled the cattle that had not yet died and began dipping over a period of two weeks to ensure that all brown-eared ticks in their various life stages on the cattle were killed,” says Scheepers.
On Friday 11 July, the cattle were taken to an approved abattoir in a sealed truck, in accordance with a Red Cross permit, to be slaughtered.
Because the parasite is endemic in most of South Africa’s national parks and adjacent reserves, infected buffalo may be moved between or into these areas under certain circumstances.
The two-year period only starts after the last cattle or buffalo has been removed from the land. Because the parasite is not transmitted to the eggs of the brown-eared tick, the cycle is broken after two years and the land can be used for cattle and disease-free buffalo once more. In the meantime, farming with other game species may be allowed.
Dr Dave Midgley of the Ruminant Veterinary Association of South Africa (RuVASA) praised Scheepers and the state veterinarians of the Lowveld, as well as the cattle farmer and landowner for their successful cooperation and prompt action.
“This unprecedented outbreak has shown what can be done when veterinarians work together. We have systems in place and know how to combat diseases,” Midgley says. “We are veterinarians; that’s what we do.”
Tracking Down The Origin
Scheepers says the biggest challenge now lies in determining where and how a herd of disease-free buffalo became infected with T. parva.
Corridor disease owes its name to the area where it was first observed among cattle – in the border area between the Hluhluwe and uMfolozi nature reserves in KwaZulu-Natal.
After an incubation period of two weeks once an infected tick has bitten a bovine animal, the following symptoms are usually observed:
- Loss of appetite, with the body condition deteriorating rapidly.
- Fever (higher than 40°C).
- Enlargement of the superficial lymph nodes.
- Severe pulmonary oedema, with laboured breathing and foaming that later appears at the nose.
Most cases are fatal, with death occurring approximately three days to two weeks after the onset of fever. About 80% of cattle that contract the disease die.
Cattle cannot transmit corridor disease to one another.
Corridor disease vs East Coast fever
Corridor disease, also known as buffalo-associated Theileria parva, is a tick-borne illness affecting cattle, primarily in areas bordering game reserves where infected African buffalo reside. It stems from buffalo-derived parasites, unlike East Coast fever, which is caused by cattle-derived T. parva.
Find Out More
For more information about corridor disease, call Scheepers on 082 920 9934 or send an email to phbdierekliniek@gmail.com. Dr Dave Midgley can be reached on 082 493 3424 or dave.midgley@vodamail.co.za.
