Anthrax and Food Safety - Questions and Answers
(Australia only)
Introduction
Anthrax is a disease normally associated with plant-eating animals (sheep, goats, cattle, and to a lesser extent swine). It is caused by the bacteria Bacillus anthracis and has been recognised as an illness for centuries. Once common where livestock were raised, it is now controlled through animal vaccination programs. Anthrax occurs mainly in countries where animals are not vaccinated. In many countries (such as Australia) it occurs rarely, due to effective compulsory control measures.
This fact sheet has been prepared by the Australia New Zealand Food Authority (ANZFA) to answer questions about anthrax and food safety.
How does anthrax usually infect humans?
Anthrax can infect humans but it is an extremely rare disease. Most anthrax infections in humans occur when the bacterium enters a cut or abrasion on the skin. The main risk is to rural workers handling animals which have died of anthrax or products from animals which have died of anthrax ( eg the raw hair, hides, wool or bones ). Only seven human cases of anthrax have been reported in Australia since 1977, the last being in 1998, and all have been the cutaneous form (i.e. through the skin). All cases were treated successfully with antibiotics.
Can humans get anthrax from eating animal products?
There have been no recorded cases in Australia of humans contracting anthrax through food. The swift onset of death in the paddock precludes livestock ( cattle, sheep and goats ) from conventional processing for human consumption. The infection in animals would be immediately obvious and they would not pass inspection prior to slaughter. There are strict animal health, disease control and quarantine regulations in place to prevent the spread of anthrax to consumers through meat, offal or milk products, including requirements in all abattoirs for rigorous inspection of animals prior to slaughter; only fit and healthy animals are processed for human consumption.
In environments such as water or milk, the bacteria dies spontaneously and is not able to produce spores. ANZFA has not been able to find any record of anthrax being transmitted to humans through the consumption of milk or dairy products anywhere in the world. Although there have been some recorded cases of transmission to humans from the consumption of infected under - cooked meat in countries without rigorous animal health systems, there are no known cases in countries with such systems, such as Australia.
What is anthrax?
The Anthrax organism exists in two states: as a bacteria or a spore. In its bacterial form, B.anthracis is quite fragile and is easily killed by disinfectants or exposure to moderate temperatures, such as through cooking or pasteurisation. It is also dies off quickly in an animal carcass after death. However, on exposure to air, it forms highly resistant spores that can remain viable for many years in certain soils. The spores are much more temperature resistant than the bacteria.
Where does anthrax occur?
Anthrax spores are widespread throughout the world, particularly in agricultural areas, especially in South and Central America, the Caribbean, Southern and Eastern Europe, Asia, Africa, and the Middle East. In these countries, outbreaks in cattle are commonly recorded. There are also less frequent cases of anthrax in cattle recorded in other countries such as Australia, USA, Canada and other developed countries.
In Australia, anthrax in animals is rare but does occur from year to year. It is almost always restricted to areas of New South Wales and northern Victoria. In NSW, the disease is sporadic, with occasional occurrences through the centre of the state during the summer months. In Victoria, the disease occurs sporadically with most cases occurring in the northern and north-eastern parts of the State. There was an outbreak of anthrax in a localised area of north central Victoria in 1997. There has been no evidence of the disease in South Australia or in Tasmania since the last reported cases in 1914 and 1933, respectively. No cases had occurred in Queensland for more than 70 years until one animal was infected on a single farm in 1993 and 12 animals died in January 2002. Similarly, Western Australia was free of the disease until 1994 when cases occurred on three farms in a localised area. No further cases have since occurred in Western Australia.
What happens when anthrax occurs in animals in Australia?
Anthrax is a scheduled (notifiable) livestock disease in all States and Territories so stock owners and veterinarians must report promptly to the government veterinarian or stock inspector any suspicion of anthrax. When anthrax is suspected or diagnosed on a property, comprehensive strict control measures such as quarantine are put in place, coordinated by the relevant State or Territory Agriculture Authority. Further details of these measures can be obtained from the Department of Agriculture, Fisheries and Forestry in Canberra or at www.affa.gov.au .
In the case of the recent outbreak in Queensland, the Queensland Department of Primary Industries, placed the properties concerned under quarantine, have supervised the disposal of the dead animals and are implementing surveillance and vaccination programs.
January 2002