If cattle die suddenly this summer, anthrax may be the culprit.
The disease is expected again in Saskatchewan this year because the weather conditions that support it will also be back.
Anthrax killed a record number of cattle in the province last year and was also found in Manitoba and in an isolated case in Alberta.
Anthrax spores can remain viable deep in alkaline soil for more than 100 years.
Chris Clark of the University of Saskatchewan’s Western College of Veterinary Medicine said the disease is usually easy to diagnose.
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“The cattle are lying in the pasture dead,” he said.
“The bacteria takes about five days from infection to death and in that five days it multiplies and multiplies until there is enough of it to produce enough toxins to kill the animal.”
Those toxins kill quickly. It takes about 12 hours from the time the animal shows significant symptoms until death, which means catching it during the early stages is difficult.
Symptoms include bloody discharges from the nose, anus or vagina and a fever of 41 or 42 C. Clark said death is often the first clue that there is a problem and producers can then vaccinate the remaining animals.
The 80-year-old Stern live vaccine is almost completely effective at creating immunity to the bacteria because it contains a mutant anthrax strain without the more virulent strain’s protective coatings, which means it is highly vulnerable to immune system defences. Immunity occurs quickly so producers can often obtain whole herd protection within a few days at about $2 per dose.
Clark said producers should keep the carcasses of dead animals closed if possible. Opening them exposes the bacteria to oxygen, which starts a process that creates the hard to kill spores.
The presence of the disease can be determined by a blood test, which is possible to administer on a dead animal because blood doesn’t clot well if anthrax is in the body.
A new Canadian Food Inspection Agency polymerase chain reaction test will be used in Saskatoon this year. It amplifies the bacteria’s DNA and allows it to be compared to a standard, which potentially shortens the test time to less than an hour from the usual 24 to 48 hour wait.
It is best to burn dead animals and the soil beneath, but if there is a lack of wood, burial is preferred.
Clark said a pit more than two metres deep will put the spores where spread is unlikely, but still possible. Equipment that comes in contact with the carcass can be cleaned with formaldehyde or by using a propane tiger torch to heat steel surfaces of tractor buckets and shovels.
Clark said producers should consider spring vaccinations if their area has experienced saturated soil, drought following flooded pastures or drought causing animals to venture into riparian areas. Recent excavations are another cause of concern.
“If you are in one of these areas and you find a dead animal, don’t go performing an autopsy,” he said.
“Call your vet. Let him get up to his elbows in anthrax infected tissues and fluids.”
The risk to humans is low and requires broken skin to allow the bacteria to enter the body. Even then the disease can be easily treated with antibiotics.
Sandra Stephens of the CFIA in Saskatoon said federal law requires producers to report the disease.
