The Sunday News
THIS week we want to discuss one of the diseases that are very pertinent during this time of the year although they may occur throughout the year.
This is Botulism, a disease caused by clostridium botulinum.
Its spores are widely distributed in the environment in soils, sediments, and in the gastrointestinal tracts of fish and animals.
The bacterium exists in two states that is as dormant spores which are resistant to environmental degradation and as a vegetative state when the bacterium is growing under anaerobic conditions.
Toxin is produced when the bacterium is in the vegetative state and is either ingested in the feed or is produced by the botulism bacteria as it grows in the gut or in deep wounds.
This disease affects nerve transmission causing paralysis in animals.
The disease affects mostly cattle, goats and sheep.
Outbreaks of Botulism usually occur in winter and phosphorous deficient soils predispose animals to Botulism.
A clear sign that your area is deficient in phosphorous is your cattle showing an appetite for unconventional feed or objects such as bones, wood and even dresses.
The Botulism toxin may also occur in decaying plant material or silage of high alkalinity.
So if you notice that your animals seem to have an unusual liking of bones lying around in the veld you should know that you area is deficient in phosphorous and hence you need to provide supplements such as mineral licks.
Clinical signs of Botulism in cattle will appear three to 17 days after ingestion of toxic material.
The symptoms are muscular weakness starting in the hind quarter going forward. This can be followed by a paralysis of the jaw and throat muscles which manifests in inability to chew or swallow feed.
The animal may even fail to drink water because of the inability to swallow.
Botulism causes a progressive paralysis and animals die of respiratory failure from paralysis of the breathing muscles.
Affected cattle tend to have a stiff gait and saliva drools from their mouth. They are usually found sitting down, unable to rise and their breathing becomes progressively more laboured.
Frequently they extend their hind legs behind them in a frog legged position to make breathing easier.
The tongue of the affected animal will hang out of the mouth which causes drooling of saliva.
The animal will be recumbent due to paralysis but it will retain consciousness until death occurs one to three days later.
Botulism can be confused with hypocalcaemia or milk fever.
Milk fever generally occurs in recently-calved older cows and the response to calcium injection is usually rapid.
Botulism usually involves multiple cases, has no association with calving and does not respond to calcium injections.
Post mortem of a suspected Botulism case usually has no specific findings detectable although presence of bones or parts of carcasses in the stomach may be suggestive of the disease.
There might be cardiac haemorrhages and congestion of the gut in a Botulism case.
Also history of Botulism in the area and its prevalence can help to confirm a suspected case.
Unfortunately there is not much in terms of treatment that can be done to an animal affected by the disease. Animals usually die of dehydration as they will not be able to drink water on their own.
While water can be given through stomach tubes it is generally a practice which is not common and not many people at community level will have the skills and equipment to do it.
The most reliable way of dealing with the disease is to prevent it.
This is done through annual vaccines usually for areas where the disease is known to be endemic.
Animals that have not been previously immunised should be given two injections at four to five weeks intervals.
Thereafter only annual vaccinations are done.
Apart from vaccination, other management practices can reduce risk factors for botulism such as preventing stock access to animal carcasses, controlling vermin and pest animals to reduce the risk of spread of putrid material, providing nutritional supplements of protein and phosphorus to reduce bone chewing among grazing cattle, taking care of the harvesting and storage of feeds to reduce the possibility of rodents contaminating feeds and checking water sources for organic matter contamination.
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