F30
Anthrax (Wool Sorters Disease)

Clinical Signs in Animals: Sheep and goats infected with anthrax generally die suddenly. Sick animals are rarely seen because death usually occurs within 1 to 2 hours of showing any signs. When signs do occur, affected animals can be weak, stager, have a fever, and have difficulty breathing. Affected milking animals may stop producing milk, and their milk and urine may be stained with blood. Bloody discharge may be seen coming from body openings (mouth, anus). In an outbreak, one or two animals can die initially, followed by many other deaths occurring about a week later. Prompt action will avoid further losses.

Disease Transmission in Animals: Generally, animals pick up the infection through contaminated food or water. Sources of contamination include pasture, infected meat and bone meal, carcasses, or even ingestion of soil containing anthrax spores. Inhalation of spores is not considered a significant method of spreading the infection in animals. Direct contact with live animals infected with the bacteria will not spread the disease unless anthrax spores are present.

Outbreaks often occur after a major climate change, such as heavy rain after a prolonged drought when the daily temperature is more than 59° F. These conditions often expose animals to spores that were once buried and were in a "vegetative" state.

Clinical Signs and Disease Transmission in Humans: Humans can develop the cutaneous (skin), gastrointestinal, or inhalation forms of anthrax. People can be infected by handling carcasses, skins, or wool of animals that have died from anthrax or have anthrax spores on them. The cutaneous form of anthrax starts as a localized skin sore. The lesions appear commonly on the hands and arms where cuts or abrasions have contacted the spores. An itchy, pimple-like sore begins 2 to 3 days after contact is made. It rapidly becomes a small boil-like blister with clear fluid that later becomes blood stained. In 2 to 6 days the sore grows in size and develops a central black scab with swelling. Sometimes more blisters surround the original lesion.

The inhalation and gastrointestinal forms of the disease are contracted by inhaling anthrax spores or by ingesting contaminated meat. Most cases develop clinical signs within 7 days after exposure. The first signs of inhalation anthrax mimic the flu. General aches and pains, fever, and cough are some of the common signs. The gastrointestinal form of anthrax causes nausea, vomiting, abdominal pain, and diarrhea.

All forms of the disease, particularly the inhaled and gastrointestinal forms, are LIFE THREATENING and should be treated immediately with antibiotics. If anthrax is suspected, an early medical diagnosis is vital to avoid serious illness or death. Vaccines are available to help prevent the disease in humans, and antibiotics can be used to successfully treat infections.

Diagnosis: A diagnosis of anthrax can be made from blood and tissue samples using various laboratory tests. Because the organism can contaminate the environment, a necropsy (particularly in the field) is not recommended.

Treatment/Prevention: The sudden nature of the disease in sheep and goats means treatment is rarely possible. However, if sick animals are identified, they can show a dramatic response to high doses of doxycycline, penicillin, or other antibiotics administered under veterinary supervision.

There is a vaccine available that can be used in areas where anthrax is a severe problem or in situations where an outbreak is occurring. Use of the vaccine should be under the direction of state and local authorities, particularly if dairy animals are involved.

How to Handle a Suspected or Known Anthrax Case: The anthrax spores need oxygen to form. Organisms in discharges from a dead animal react with oxygen to form anthrax spores that can survive for many years in the environment. This spore formation can occur in as little as 1-2 hours. Organisms left inside an unopened carcass are destroyed when a carcass decomposes. Because of these attributes, carcasses infected with anthrax should be left unopened (unless done by a professional) and then burned. However, if burning is not practical, then infected carcasses should be left intact and buried at least 6.5 feet (2 meters) below the ground surface. This will kill the bacteria and prevent the spores from forming. Calcium oxide (quicklime) should be applied to contaminated areas and spread over the soil on top of the buried carcass. If the spores have already formed, they are difficult to kill. Solutions of formaldehyde (10%) or aqueous lye (5%) should be placed in contact with the spores for at least 15 minutes to help decontaminate soil, walls, and equipment.

If a case of anthrax is suspected, laws require that the state and federal authorities be contacted.