The cryptosporidium parasite is an increasing problem on farms across South Africa. This is not a new problem and also not limited to animal health. Cryptosporidiosis, caused by this parasite, is a zoonotic disease and the second largest killer of children under five in Africa. “I think it has been around forever; it is not new. I believe it became significant with the drought. Less food was available and suddenly the general immunity in our animals was way down,” said Dr. Ariena Shepherd from Bergville in KwaZulu-Natal at the recent Ruvasa (Ruminant Veterinary Association of South Africa) congress.
“The more I read about this parasite the more I respect it. It is a clever little bugger and is not simple to combat. Following a few years of massive outbreaks, especially in KwaZulu-Natal and the Free State, there have been many recommendations doing the rounds; many options are given and tried. As an association and as production animal veterinarians, we have to discuss and put forward a standard recommendation to give to a farmer when he calls to tell you that he has 50 or 60 dead lambs or calves.” This, she says, is however, not a simple task.
The matter was put on the agenda at the Ruvasa congress and finding such a recommendation was the purpose of a presentation by Dr. Shepherd followed by an open discussion amongst the production animal veterinarians present.
The cryptosporidium parasite is highly infective and resistant. Following an outbreak on your farm, you can have many dead animals in a very short time. “The parasite can create two types of cysts. The first cyst develops in the intestine and creates a thin wall cyst. This travels down the intestine and re-infects it at the bottom. It is not excreted by the animal but gives it a second blow just as it starts recovering. A thick wall cyst is also created. This is the one that is excreted and goes into the environment.” According to Dr. Shepherd, this is where we often underestimate the parasite.
Treatment is a challenge
“Our challenge is treating the disease. What do you tell the farmer to do?” asks Dr. Shepherd. Animals mostly die of dehydration as they simply cannot absorb anything due to the fact that they have no enterocytes left in their gut. This often calls for a recommendation of treating with electrolytes, treating secondary infections, giving a multivitamin, probiotics and essential amino acids. “This treatment seems to work if it is started early.”
“There are some drugs used, such as Halocur. This is the only registered drug for cryptosporidium in Europe. The problem is, however, that this is the original treatment for east coast fever. Do we really want to bring that back into the mix?” The question further exists whether this treatment truly makes a difference. “Reading up on it, I found two sources that said it doesn’t work, or works only for a while, for every one source that said it works.” Other treatments exist as a preventative measure and seem to have a positive effect. Antibiotics can be used for the host of secondary infections. “From my personal experience, however, I do not think that these antibiotics help.”
Clean it up
The bottom line is that drugs only seem to slow down the disease and do not seem to have a real effect. The next important step is to clean up the disease, which is very hard to do as it lives in both water and organic matter. “The only disinfectants that can effectively kill this parasite are formalin and chlorine dioxide. Average disinfectants do nothing.” The recommendation is then to clean everything. “That is EVERYTHING with capital letters!” Mechanical cleaning is very important in this regard – physically, with a brush and soap – and seems to be one of the effective ways of control. Especially in increasingly intensive farming systems, mechanically cleaning, for example, the entire intensive lambing system infrastructure is very important.”
“Good biosecurity is, of course, a crucial factor. This is, however, a major challenge in rural areas and we have to look for practical solutions in this regard,” says Dr. Shepherd. The last important point is nutrition. “If the animals have any kind of nutritional deficiency it makes matters far worse.”
Questions to consider
There are many factors to consider. “Looking for an answer, I took a step back. Why are some of my farmers surrounded by cryptosporidium on neighbouring farms, but do not have a single case on their own farms? Why can some farms recover and go from a massive outbreak in one year to no or only a few cases in the next? And why are some farms hit hard year after year?”
“It is all about the management strategy,” says Dr. Shepherd. “We should focus on getting rid of the disease or making sure we don’t get it at all. Keeping the healthy animals healthy and getting everyone on the healthy list. We should shift our focus from treating sick animals to keeping animals healthy.”
She tells the story of one of her farmers:
“I have a beef farmer client who’s surrounded by cryptosporidium, yet he has not had a single case. Why? He is the most consistent vaccinator that I have ever come across. He is incredibly precise and consistent in each action he takes. His actions are consistent no matter what the circumstances. He also has a very strict culling policy on the farm. If a cow does not produce a calf by the time she’s 30 months old, she leaves the farm. She also has to produce a calf every 12 months after that. He gives the necessary vitamin and mineral supplements and makes sure that his farm is never overstocked.
This farmer has figured out that if you consistently do the right thing at the right time year after year, you don’t have sick animals. I believe that is the answer to questions relating to cryptosporidium.”
According to Dr. Shepherd it is about having good mothers and looking after them well so that they produce good babies. “The important focus here is innate immunity, which largely depends on genetics.” More research is being conducted, especially in human medicine, on foetal programming. Research suggests that incorrect nutrition in the first part of pregnancy switches on the wrong genes and leads to problems, such as obesity of humans, in later life. It is therefore about getting the environment right for the foetus, keeping the mothers healthy and creating a good intestinal environment in the lamb, so that he has innate immunity when he is born.”
The fact remains that it is a complicated matter. Dr. Shepherd recommends the following for prevention and controlled eradication:
Good nutrition, making sure that there are no deficiencies; following a consistent vaccination programme, suitable supplements to prevent mineral and vitamin deficiencies; extremely strict bio-security; a good breeding and culling regime that results in good genetics; well-trained labour that considers hygiene and ensuring clean water sources. Adding a filter to your water sources is one of the simple and affordable steps you can take to prevent cryptosporidium entering your farming system.
If the parasite does become your problem to deal with, it is crucial to do a controlled eradication. “Get rid of every sick animal and get rid of every mother that produced a sick offspring. Slowly and thoroughly start to clean up the entire farming system and environment. Correct faults in the nutrition of your animals and get your water sources clean.”
Dr. Shepherd opened the floor for comments. The following important suggestions were made:
- In dairy farming, and any other intensive systems, proper housing is vital. Housing should be lifted off the floor and should be easy to clean. This must be cleaned thoroughly and regularly.
- Micro-elements are very important. Issues such as selenium deficiencies make matters much worse.
- When cleaning infrastructure, consider the runoff and where the dirty water goes.
- In dairy systems it is recommended to wean the calves from the cows immediately. That way, you limit exposure to the udder and any dirty surfaces. Remove the animal from areas which may be infected as soon as possible.
- Handle equipment, such as buckets responsibly and keep them clean.
- Ensure that the mother offers enough good quality colostrum for the calves and lambs. Once again, it is about looking after the mom.
- There are no seasonal patterns for outbreaks; when it is calving time, it can be cryptosporidium time.
- Culling the animals that do get sick is crucial.
Concluding the discussion, Dr. Faffa Malan made a call to veterinary academia to have a master’s degree student look at the matter of cryptosporidium. “We need a single person or team to look at the available facts and statistics. This can be a national disaster and must be faced head on.”- Marike Brits, AgriOrbit