This article is part of a series of articles educating livestock owners and farmers about the importance and effect of the Animal Diseases Act, 1984 (Act 35 of 1984). It explains the reasons for the existence of this Act, what farmers’ general rights and duties are, and goes into more detail regarding the control measures for some of the most important controlled animal diseases, such as anthrax.
Part 3: Control of Anthrax
Anthrax, one of the oldest known diseases, is often associated with biological warfare. The link between anthrax in animals and humans has been recognised since early references to the disease. It is therefore not surprising that anthrax was one of the first controlled diseases in South Africa. However, there are still thousands of people and animals worldwide that die of anthrax every year.
Understanding the disease
Anthrax is caused by the spore-forming bacteria Bacillus anthracis. It can affect all domestic animals, wild animals and humans, although some species are more susceptible than others. Once the organisms enter the body, they multiply and produce a toxin that can cause death. In typical cases blood oozes from openings in the carcass. The blood contains the anthrax bacteria, which form spores once outside the body. Anthrax bacteria in spore form may survive for extended periods. Bones and animal skins harbouring these bacterial spores are potential anthrax reservoirs.
The best way to control anthrax is to immunise susceptible animals. Regulations stipulate that all cattle in South Africa must be vaccinated against anthrax annually. Although it is not mandatory to vaccinate sheep and goats annually, vaccination should be done in areas where the disease is endemic, such as parts of the Northern Cape, and in regions where outbreaks have previously occurred. Other animals, including game, may also be vaccinated.
During disease outbreaks
In the event of any suspected anthrax outbreak or animal mortality where the cause of death is unknown, the responsible state veterinarian must be notified immediately. Carcasses should not be handled or moved until the state veterinarian has examined them. Any animal that has been in contact with suspect carcasses must be removed from the area, and quarantined.
Regulations stipulate that infected animals must be isolated and destroyed under the supervision of the State Veterinary Services. Contact animals, including domesticated game animals, must be quarantined and vaccinated. The relevant State Veterinary Services will usually put up a quarantine perimeter, with a radius of 10 to 15km, around the outbreak. No animals may be moved into, or out of, the quarantined area without the necessary permits. All animals in that area are regarded as contact animals and must be vaccinated.
Carcass handling and disposal, proper disinfection protocol
Due to the nature of anthrax organisms, it is very important that the handling and disposal of carcasses and the disinfection and handling of products must be properly done in accordance with the regulations. Important requirements when dealing with anthrax are:
- Only a veterinarian and/or responsible technician may make an incision in the carcass of an animal that is suspected of being infected with anthrax.
- The animal carcass, or any part of that carcass, may not be removed from the place where death occurred.
- The carcass must be disposed of by: Burning or incinerating it and burying the remains in a hole at least 1,3m deep; burying the carcass in a hole at least 1,8m deep and covering it with quicklime before filling the hole.
- Items such as instruments, ropes, shoes and clothing that have come into contact with the infected animal or carcass must be burned and buried unless these items can be properly disinfected with effective disinfectants.
- No quarantined animal/s may be slaughtered without the written authorisation of the responsible state veterinarian.
- The milk and meat of an animal infect with anthrax, or suspected of infection, may not be used under any circumstances. Milk must be boiled for at least ten minutes or treated with an effective disinfectant before disposal. Meat is treated in the same way as an infected carcass.
The livestock owner, or the owner of the farm on which the outbreak has occurred, must notify all neighbours on land adjacent to the anthrax outbreak. He or she must also notify buyers who have bought animals from him or her in the 30 days prior to the outbreak.
Although it is not a legal requirement in the Animal Diseases Act, 1984 (Act 35 of 1984), it is important to notify the Department of Health if there has been any human contact with anthrax infected carcasses, or if there is any suspicion that people have consumed infected meat or milk. Penicillin and other antibiotics are effective in preventing and treating human infections, and it is important to seek medical help immediately, if there is any possibility of contact with anthrax.
Anthrax is a deadly disease that could cause huge livestock losses in a very short period. It can also infect and kill humans. However, there are effective vaccines available. By vaccinating all cattle annually as well as vaccinating other animals in high risk areas, the risk of infection can be minimised. The correct handling and disposal of infected carcasses and products play an important role in preventing future infections. – Dr Trudie Prinsloo, director of Legalvet Services
Read part one, The Animal Diseases Act: What farmers should know about control of certain diseases by clicking on the link. Part two, The Animal Diseases Act: Foot-and-mouth disease can also be read by clicking on the link. Read the latest article on anthrax by clicking here.