Alberta Anthrax Response Plan: For Veterinarians

With the record amounts of rainfall this spring, there is a risk that anthrax could be seen this summer in Alberta. Cases in Western Canada since 1999 have mostly occurred from July through mid- September, and have followed periods of hot and dry or hot and wet weather.

Anthrax is a bacterial disease that kills animals rapidly, often within hours. Most herbivores (cattle, bison, sheep, camelids and horses) are susceptible. Anthrax can also occur in carnivores and pigs. A few cases of anthrax are reported in western Canada nearly every year as spores are present in the soil. Anthrax can be prevented by vaccination.

Anthrax is a federally reportable disease in Canada. However as of April 1st 2013, the Canadian Food Inspection Agency (CFIA) will no longer be responding to cases of anthrax.

Alberta Agriculture and Rural Development (ARD) will now be assisting veterinarians and producers with cases of anthrax.

Anthrax is a notifiable disease in Alberta. Veterinarians must report all suspect and confirmed cases within 24 hours. ARD will assist with diagnostic testing for anthrax in cases where anthrax is suspected and with advising on management and recovery from outbreaks. No compensation will be paid by ARD to the owners for death losses due to anthrax. The owner is responsible to pay for the cost of veterinary visits, vaccination, disposal and management procedures.

Suspect Anthrax if:

• Sudden death of healthy livestock occurs on pasture with no other previous clinical signs.
• There is leaking of blood and blood tinged fluids from orifices of carcass.
• Blood is not clotting, and there are ecchymotic hemorrhages in tissues, gross enlargement of the spleen and an absence of rigor mortis.

• Other clinical signs observed are weakness, febrile, or excited, followed by depression, difficulty breathing, lack of coordination and convulsions. In horses there may be ventral swelling.
• History of anthrax in the area, even as long as 10 years previously.
• Warm weather (above 20^oC) with history of flooding, drought or soil disturbance.
• Season – July to mid-September.

• Contact the CFIA District Office and the Office of the Chief Provincial Veterinarian (OCPV) within 24 hours (during office hours call 780-427-3448, or after hours call 1-800-524-0051).
• Follow all instructions from the OCPV for sample submission and testing.
• DO NOT open the carcass, do not do a post mortem, do not submit any tissues for testing.
• Wear gloves, long sleeves and protective clothing when handling carcasses.
• Take a blood sample from the tail vein of the freshest carcass (within 36 hours of death).
• If it is not possible to obtain a blood sample, then a swab of excreted blood and blood tinged fluids will suffice.
• Obtain samples as soon as possible after the death of the animal.
• Cover all suspect carcasses with heavy duty plastic or tarp and stake down for 72 hours.
• Remove surviving animals from the pasture and monitor them for signs of illness.
• Prevent scavenging of carcasses.
• DO NOT move dead animals, especially by dragging.
• DO NOT call for dead stock pick-up.
• Wash and disinfect boots and all exposed clothing before leaving the farm, and destroy disposables by incineration.
• Wash your hands and arms afterwards.

When Bacillus anthracis bacteria are exposed to air, they form spores that are very hardy and survive in the soil for years. If the carcass is opened through post mortem, scavenging or moving, more spores will be formed. If the carcass is not opened, the high temperatures achieved in the decaying carcass will destroy the vegetative form of the bacteria and reduce the risk of spore formation.

The OCPV will provide instructions on carcass disposal. Follow all instructions from the OCPV. Do not move the carcasses unless absolutely necessary.

Incineration is the preferred disposal method as this destroys the spores. The goal is to completely reduce the carcass to ash to avoid attracting scavengers and flies.

Burial of positive carcasses should only be considered as a last resort if burning is not possible. There is always a risk that the carcass may be accidentally opened during burial or uncovered at a later date, allowing for spore formation and soil contamination.

Management of Anthrax

Vaccination will protect susceptible animals within 7-10 days. Preventive antimicrobial treatment of exposed animals can be effective. Do not treat animals with antibiotics if they have been vaccinated less than 2 weeks previously, and do not treat with antibiotics if you plan to vaccinate them within the next 2 weeks.

Human Health Risk

In rare cases, people can contract cutaneous anthrax if infected tissue or blood comes into contact with broken skin. People handling infected animals, carcasses, meat or equipment may be infected through a cut or skin abrasion. Symptoms generally appear within 7 days of exposure. A raised itchy bump like an insect bite appears and develops into a painless ulcer (1-3 cm in diameter). A black spot appears in the center within 2 days. Contact your doctor if you see these symptoms. There is about a 20% mortality rate if untreated; mortality is rare if treated with antibiotics. The disease does not spread from person to person.