Van Greunen Boerdery, a dairy farm in George in the Western Cape, has already lost close to 400 calves due to the cryptosporidiosis disease, says the farm manager, Inga Butshingi.
Butshingi says the disease remains their biggest challenge on the dairy farm. What makes matters worse, is that a vaccine for the disease caused by the protozoan parasite Cryptosporidium parvum has not yet been developed.
It continues to be a concern for beef and dairy farmers worldwide. The clinical signs of the disease is a watery and profuse diarrhoea mainly in calves under three-weeks-old, causing dehydration, depression and in some cases death.
Watch out for these symptoms
The parasite lives in soil, food and in the bodies of all animals. It can also be found on surfaces that have been contaminated with faeces. Furthermore, both animals and humans can become infected should the parasite end up in food or water, and it can also be passed on from some cattle to their calves through feeding.
If the disease is not treated it can decimate herds of animals, but people do not normally succumb to it unless it’s quite a severe infection, says Dr Munyaradzi Christopher Marufu, a senior lecturer in veterinary parasitology at the University of Pretoria. Infected animals and humans can also experience symptoms of dehydration, weight loss, stomach cramps or pain, fever, nausea, and vomiting.
According to Marufu, Cryptosporidium parvum takes advantage of a weakened immune system. “Normally those organisms are inside the guts or the intestines of normal healthy animals and when the immune system is down it takes advantage and it colonises the intestines casing the disease,” he says.
He explains that the parasite normally affects young animals or neonatal animals with underdeveloped immune systems.
“They could get infected from the time that they are born until they are about three weeks of age. Normally after they are three weeks of age, they would have developed their immunity and what you normally see in these sick animals is diarrhoea.
“It is quite a bad diarrhoea because sometimes you find that the colour is like a pale colour, maybe creamish or yellowish. You also find that these animals don’t do too well. Once the young animals get diarrhoea, they get dehydrated quickly and they end up dying if they are not treated quickly,“ he says.
Marufu adds that the animals can also pass the disease on to the young ones. “Since cryptosporidium is released through the foetal matter anything that is contaminated in the foetal matter is transmitted to the food and on to the milk. So, when the neonatal animal feeds on the mother it also gets contaminated with cryptosporidium and you know adult animals like grooming the young ones and by grooming obviously they will be licking the young ones and they can also then transmit or spread that disease in that way.”
He says children, elders and people with HIV/Aids and TB are more vulnerable to the disease.
“We have had reports of children – especially those going to nurseries – and they get infected by what they eat. It also causes diarrhoea in human beings and as I indicated South Africa has one of the highest prevalence’s of HIV/Aids, so a lot of people’s immune systems are compromised in our population. So, if they do get infected with cryptosporidium it will cause problems and the elderly’s immune systems are also not strong enough and they can also get affected,” he says.
Effective drug for humans, but not animals
Marufu indicates that there is an effective drug called nitroxinil that is effective in humans, but they are still struggling to find a drug for animals. “We have used hyloquil, but it is not as effective at treating animals and so, at the moment, we are still in the process of trying to develop drugs to treat cryptosporidiosis in animals.”
“You must understand that we cannot normally use drugs that we use on normal human beings because the organism develops resistance in animals. Then it means in human beings it is going to be challenge so we reserve the drugs for human beings, and we do not normally use the same for animals. But at least it gets us to preserve the drugs for people,” he says.
In South Africa, cryptosporidiosis has been reported in humans and livestock in various locations according to a research paper released by the Onderstepoort Journal of Veterinary Research in 2016.
The paper states that in diarrhoeic children a prevalence of 24.8% was found in a hospital in Durban and more recently an overall prevalence of 12.2% was reported in hospitalised diarrhoeic children from four different provinces, with a prevalence of 8.6% in one of the four hospitals located in close proximity to their study area.
In cattle, data on cryptosporidiosis are scarcer: a prevalence of 33.6% (36/107) with Cryptosporidium has been reported in adult cattle from the southern Free State province and, more recently, a study conducted in a different area adjacent to the Kruger National Park reported a prevalence of 8% (4/51) in weaned calves.