Anthrax risk still exists for 2007

Source: Saskatchewan Agriculture and Food

Saskatchewan producers are not out of the woods yet when it comes to the anthrax threat.

Last summer, the province experienced its largest outbreak of anthrax ever. The cases mostly occurred in the northeast part of the province, but other areas were not immune.

Authorities are warning that the risk of livestock contracting anthrax this summer has not disappeared. In fact, three cases have already developed in February 2007.

“Anthrax is a reportable disease under the Health of Animals Act. All suspected cases must be reported to a CFIA (Canadian Food Inspection Agency) veterinarian,” said Tracy Evans, a Livestock Development Specialist with Saskatchewan Agriculture and Food (SAF).

Three types of anthrax exist: inhalation (breathing in spores), cutaneous (contact with skin), and gastrointestinal (through digestion), which is the most common form in livestock.

Anthrax is considered to be an “environmental” disease, meaning that it is contracted through animals ingesting anthrax spores from the environment, such as soil, water, and forage, and not from other animals.

The anthrax spores enter the animal’s blood stream, causing a rapidly fatal blood infection. When the infected animal dies and the bacilli are exposed to oxygen, more spores are produced and enter the environment.

Due to the hardiness of the anthrax spores to climate and the environment, decades may pass without other cases showing up. Anthrax outbreaks can then occur when the spores are brought to the soil surface by digging or flooding.

The livestock producer’s best defence is to vaccinate. The vaccine is economical and is available from your local veterinarian. Protection occurs seven to 21 days after delivery, and is estimated to be effective for six to 12 months.

“Your veterinarian may or may not recommend a booster shot depending on herd history and the prevalence of anthrax in your area,” Evans noted.

Vaccinated animals cannot be treated with antibiotics within eight days before or after administering the vaccine, as it will inactivate the vaccine. Withdrawal time for slaughter is 42 days after the last dose was administered.

Care in handling the vaccine is important to the success of the vaccine. As per label recommendations, it must be stored between two and seven degrees Celsius, shaken well before use, and not used in conjunction with antibiotics or disinfectants used to sterilize equipment.

Vaccinating for anthrax can be done at the same time as inoculating for blackleg, infectious bovine rhinotracheitis (IBR), bovine virus diarrhoea (BVD), parainfluenza-3 (PI3) and bovine respiratory syncytial virus (BRSV).

Anthrax does not discriminate by age. Therefore, calves, replacement heifers, yearlings, cows and bulls should all be vaccinated. This vaccine does not pass along passive immunity to an unborn calf, as do some other MLV (modified live vaccines). The minimum age for vaccination is eight weeks, and optimal is four to six months.

“CFIA recommends that if you are within 10 kilometres of a positive premise, meaning a quarter of land where a positive case was diagnosed, you should vaccinate,” Evans said.

“Given the size of last year’s outbreak, and the comparable environmental conditions between now and then, there is some concern we could see a similar scenario in 2007. Local veterinarians can provide producers with the recommendations for their areas.”

A map highlighting the location of anthrax outbreaks in Saskatchewan in 2006 and 2007 can be found on the Farm Animal Council of Saskatchewan website at www.facs.sk.ca.

Additional information on anthrax can be also obtained from SAF, CFIA, Saskatchewan Health, the Public Health Agency of Canada, and your local veterinarian.

For more information, contact:
Tracy Evans, Livestock Development Specialist
Saskatchewan Agriculture and Food
Phone: (306) 878-8847
E-mail: tevans@agr.gov.sk.ca

Dr. Mary VanderKop DVM, Disease Surveillance Veterinarian
Saskatchewan Agriculture and Food
Phone: (306) 787-8661