Given South Africa’s foot-and-mouth disease (FMD) epidemic, the resultant widespread grave concerns, fears and uncertainty are contributing to the spread of information, some of it reportedly generated by artificial intelligence (AI), that may well be incorrect and possibly even dangerous. This also pertains to the hot topic of “tiger heart” syndrome.
By Lloyd Phillips, senior journalist at African Farming and Landbouweekblad
Various animal health experts that African Farming spoke to recently have confirmed without reservation that the foot-and-mouth disease (FMD) virus can indeed cause the symptoms of what is generically termed “tiger heart” syndrome. These experts caution, however, that “tiger heart” syndrome can also be caused by a range of other factors.
“Tiger heart” syndrome refers to the striped lesions that can, during a post-mortem examination, be observed on the surface of the heart of an animal that was previously or recently afflicted by one or more factors that caused myocarditis (inflammation of the heart muscle) and/or myocardial necrosis (death of heart muscle cells).
Drs Dave Midgley, Peter Evans, Shaun Morris and Mark Chimes are all highly regarded and knowledgeable veterinarians in South Africa’s livestock industry.
Speaking separately to African Farming, they agree that there are increasing numbers of livestock, especially among suckling animals, that are dying from myocarditis and/or myocardial necrosis after becoming infected with FMD. Necropsies of these animals often show the striped heart lesions that fall under the term “tiger heart” syndrome.
Also read: FMD | ‘Tiger heart’ syndrome causing sudden calf deaths
‘The Virus May Have Changed’
Midgley is chief executive officer of the Ruminant Veterinary Association of South Africa (RuVASA). He says “tiger heart” syndrome, as a direct result of infection with FMD, has long been scientifically documented in other parts of the world. However, this syndrome’s occurrence among animals infected with this disease in South Africa has only been observed since late last year.
“It seems the virus here may have changed. It is doing things that it has never done before. Calves are now dying in large numbers, with some farms reporting mortalities of up to 52%. It was previously unheard of for pregnant cows to abort because of infection with the foot-and-mouth virus, but it has started happening.
“I have heard reports of free-roaming wildlife in KwaZulu-Natal whose hooves are so badly affected by foot-and-mouth infection that farmworkers are able to catch these animals by hand. We are also getting reports of livestock that are at least 10km away from the nearest confirmed outbreak of foot-and-mouth disease that suddenly also start showing symptoms of infection.”
Chimes is the veterinary adviser and programme manager for animal health and welfare at Milk South Africa. He confirms that when herds become infected with FMD, there are usually large numbers of young animals that die and that then show symptoms of “tiger heart” syndrome.
“These animals pick up infection in the mother’s womb. Most of the deaths occur within the first week after birth and within approximately three weeks the deaths seem to ease off.
“It is quite a dramatic disease. The young animals appear 100% healthy. But if they are chased, handled or stressed, they literally drop dead from a heart attack. Others, though, may show signs of heart failure such as shortness of breath and/or fluid on the lungs.”
Also read: Minister Steenhuisen establishes Industry Coordination Council to combat FMD
‘Use Vets as the First Line of Attack’
The veterinarians agree, though, that if “tiger heart” syndrome is observed in herds that have no history of FMD or are in an area with no known cases of this disease, other causes of the syndrome should be investigated.
These other possible causes include, but are not limited to, infections by Clostridium sp. bacteria, deficiencies of vitamin E and selenium, heavy burdens of internal parasites and toxins in feed.
The veterinarians also agree that livestock farmers should ideally consult their local veterinarian to conduct post-mortems of animals that have died inexplicably, so that an informed and accurate diagnosis is achieved, and that can then be used to guide an appropriate response. This is particularly relevant for determining the accurate cause of “tiger heart” syndrome.
Midgley adds: “Veterinarians have all the correct equipment and biosecurity protocols for doing post-mortems. I’ve seen farmers doing post-mortems with their bare hands. Pathogens can get under their nails and on their clothes. If these farmers go to a meeting or shake hands with other farmers, these pathogens can possibly transfer to the other farmers. When the other farmers go back to their farms, they can potentially introduce the pathogens into their own herds and flocks.
“Veterinarians have trained and worked hard to earn the immense knowledge, skills and advice they have. Farmers must use them as the first line of attack.”
Also read: FMD | First 1,5 million Turkish vaccine doses due to arrive in six weeks
