Stock farmers who have experienced a very wet rainy season and are going into a cooler season, take precautions to avoid Rift Valley Fever. The first sign of its presence may be widespread abortions in flocks and herds – this is to be avoided at all costs.
RVF is a viral disease, transmitted by mosquitoes to cattle, sheep, goats and certain species of game animals. It can also occur in humans. During years when there has been above average rain, mosquitoes and the virus can multiply to a greater extent than normal and at these times there may be outbreaks of RVF.
Affected animals have high temperatures, so we need to call on our trusty friend the rectal thermometer once more to check the temperature of an animal with suspected RVF. Cattle often have a bloody (haemmorhagic) diarrhea and livestock can be jaundiced showing pale eye and gum membranes.
RVF can cause widespread abortion in sheep, goats and cattle,which is a nasty and profit-taking effect of the virus. However, it doesn’t always happen. Lambs may die from RVF, while adults are less dramatically affected. This is usually the case since the youngest animals are also the most vulnerable.
People who contract RVF usually have flu-like symptoms from which they can recover, but in some cases the disease becomes more serious and people die from it in spite of treatment. Handling sick or dead animals can transmit the infection, so protective hygiene protocols must be observed if RVF is suspected.
Those who have compromised immune systems or liver disease are more at risk than the general population and should therefore be more careful of exposure.
COMMUNICATION AND ACTION
The safest thing to do if an animal dies and you suspect RVF is to call the vet or the vet tech to look at the carcass. The liver is pale grey-yellow instead of the normal healthy dark colour and there can be widespread bleeding.
Contact and communication is key with reporting and warning others about diseases like RVF. Farmers are good at this; no stockman wants the herds and flocks of his brother farmer to die. This highlights the importance of maintaining farmer networks through study groups or even through whats app groups. Once again the vet tech is a good resource, if you have one, because he can tell you what is going on in your area.
Try and keep animals out of wet and marshy places on your farm or grazing platform and dip to keep mosquitoes off.
Because of RVF’s seasonal dependence be more cautious about wetland grazing when there has been more rain than usual. Wetland grazing can be an important component for stock farmers, especially when it’s dry. At these times there would be significantly reduced risk of RVF.
Seasons can pass without RVF rearing its head and farmers who have a lot to deal with anyway can be unprepared for an outbreak.
A live vaccine is recommended for sheep and goats that are not pregnant, a killed vaccine for cattle and pregnant sheep and goats. Like all vaccines they do not guarantee freedom from disease but they do provide some protection.
Plan your strategy in case of a RVF outbreak and act on it.
One doesn’t want to be in a knee-jerk position with viral diseases. It can make things worse and lead to panic which doesn’t help anyone – least of all the farmer.
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