Anthrax is a deadly disease that affects warm-blooded animals, including humans. It is caused by the bacterium Bacillus anthracis . The disease gives veterinary doctors nightmares.
The best approach for a veterinary doctor or any other veterinary service provider when an animal dies suddenly is to take anthrax as a priority probable cause.
That calls for extreme caution and quick mental review of the anthrax signs. The service provider should quickly refresh the presentation of anthrax before proceeding to examine the carcass.
Farmers and any other person handling animals should know the signs of anthrax, especially sudden death, bleeding through body openings and having dark oily non-clotting blood.
The extreme caution on anthrax is merited since the illness is highly infectious. Once the bacteria gets exposed to air, they form spores that can easily lead to infection when inhaled or swallowed.
The bacteria may also enter the body through eating contaminated material like food, soil, water or through skin contact.
There have been many cases of anthrax in Kenya, mostly after villagers are reported to have consumed meat from dead animals, sickly animals or uninspected meat.
The signs reported in many cases in the people affected include headaches, stomach pains, throwing up, blisters and wounds on the skin, body weakness and bleeding.
The disease has mainly been reported in cattle, sheep and goats. Farmers and meat consumers need to know that all warm-blooded animals can get anthrax. I have in my practice encountered the disease only once in non-food animals.
The dogs and cats were on a farm in which a cow had suddenly died. Farmhands had cut up the carcass and given the meat to the dogs and cats. Fortunately, no worker had eaten meat from the dead cow.
As required for someone exposed to anthrax, they were taken to hospital and none developed the disease.
The cats and dogs died despite my treatment because the disease was already advanced and they had consumed a lot of meat. This obviously meant that the animals had a heavy load of the bacteria.
The main reason the disease is rare in pigs is the methods of production. Pigs are mainly, and by law, reared in confined shelters whose floors must be cemented.
The requirement under the Pig Industry Act and applicable regulations primarily serves to protect the hogs from getting infested with the pig tapeworm.
It lodges in pig muscles but when humans consume it in pork, the worm seeks the spinal cord and the brain where it causes nervous illness and death.
The pig tapeworm is found in the soil. Cementing the floor of the sty prevents infection. Anthrax is a soil bacteria. In protecting pigs from getting the tapeworm, cementing also protects the animals from anthrax and many other diseases.
Some Kenyans have started breaking the law by raising pigs in the open. The practice endangers pork consumers.
It is advisable not to eat pork from pigs reared in the open as the country does not have areas that are certified free of anthrax and the pig tapeworm.
This article is motivated by a farmer who asked why pigs do not contract anthrax. The perception is incorrect.
Anthrax in pigs in confined production is rare because there are very few opportunities for the animals to consume large numbers of the bacteria sufficient to cause the illness.
Most anthrax outbreaks in confined pigs have been associated with consumption of infected or contaminated feed.
Farmers have been known to feed other animal carcasses to pigs since the swine is an omnivore like humans. Feeding carcasses is discouraged as it may result in diseases in pigs.
Reports of anthrax in the United States started in 1952 and 1953 when an epidemic swept mid-western states.
The outbreak was due to imported contaminated bone meal used in preparing pig feed. The feed was widely distributed in the region before anthrax was diagnosed.
Another outbreak occurred in 1989-90 and lasted more than 14 weeks at a farm with at least 500 sows. There are no similar occurrences in Kenya but the reports indicate the disease can occur in pigs reared in confinement. Pigs are more resistant to anthrax than cattle, sheep and goats and have been known to recover from mild infections. The disease is fatal in cattle, sheep and goats once signs appear.
Once the anthrax bacteria establish in the body of a pig, they produce a toxin that gets into the bloodstream and causes depression of the nervous system.
The toxin also causes tissue death in the throat and intestines. In ruminants, the bacteria gets into the blood stream but rarely does so in pigs.
Unlike in cattle, sheep and goats, anthrax has a long incubation period of about 20 days in pigs. Sudden deaths without showing signs may be the only indication of anthrax in the herd.
Signs of the disease depend on the site of the body the bacteria settle. The bacteria may settle in the throat to cause pharyngeal anthrax, intestine resulting in intestinal anthrax or get into the bloodstream to cause septicaemic anthrax.
The most common form is pharyngeal anthrax where infected swines have breathing difficulties and marked swelling of the neck. Such animals may die of suffocation. Infected pigs also have fever, depression and poor appetite, with vomiting at times.
Swines with intestinal anthrax may show the same signs as ones with pharyngeal anthrax but have no swelling of the neck. Faeces may be bloody. The animal may die suddenly when the bacteria in the throat and the intestines get into the bloodstream. Bloodstream anthrax is more common in young pigs.
Carcasses suspected of anthrax should not be opened on the farm or abattoir. They should be taken to the National Veterinary Research Laboratories fully covered to prevent contaminating the environment.
The vehicles and premises in contact with the carcasses should be disinfected. People exposed to the carcasses or sick animals should go for preventive treatment. Animals exposed to the disease should be given preventive antibiotic cover. Farm animals need to be vaccinated against anthrax once a year.
