Anthrax not currently in area
So far this year, anthrax has been confirmed in six herds in Sully, Brown and Marshall counties, all east of the Missouri River. Losses are approaching 200 head, including the deaths that officials suspect are anthrax-related, according to Dr. Sam Holland, state veterinarian and head of the South Dakota Animal Industry Board. State officials continue to test dead animals for anthrax.
Anthrax infection was first discovered this year in a herd in northwestern Sully County. About 40 head died. The rest of the herd, was treated with antibiotics and vaccinated. The carcasses were properly burned and buried, under supervision by the Animal Industry Board.
In 2004, only one case of anthrax was reported in cattle in South Dakota. In 2003 there were two cases. In 2002, nine cases were reported and 53 cattle were destroyed in Butte and Meade Counties to stop the spread of the disease.
Anthrax isn't highly contagious in livestock, Holland said. "The primary way it's spread is by consuming spoors in the soil, either through grass or by grazing close to the ground." Anthrax spores can survive in contaminated soil indefinitely, and much of South Dakota has the potential for an outbreak, Holland said.
Major climate changes such as drought, floods and winds can expose anthrax spores to grazing livestock. Alkaline soils, high humidity and high temperatures also are conducive for anthrax spores to vegetate and become infectious to livestock.
Cattle ingest anthrax spores when they eat grass and take in air close to the ground. Russ Daly, South Dakota State University Extension veterinarian, said flooding can cause spores in the soil to be disturbed. Close grazing later in the season then may result in cattle ingesting anthrax spores.
Holland said producers finding dead cattle they suspect to have suffered from anthrax should contact their veterinarian and send a blood sample to the State Diagnostic Lab in Brookings. He adds that they should never open up or do an autopsy on the livestock because opening up the carcass will quickly spread the spores to other cattle.
"Anthrax is a very serious, quarantinable disease," because it can rapidly kill many animals in a short time, often before any symptoms of illness are detected. The bacteria can also be transmitted to humans or other animals from a carcass, though it is not usually spread between live animals.
Generally the vaccine is widely available and relatively inexpensive. For maximum immunity, animals should ideally be vaccinated two to four weeks before exposure to pasture. Vaccinated animals should be withdrawn from slaughter for at least 60 days.
Vaccinating in the face of an outbreak should only be undertaken with guidance from the Animal Industry Board and the herd veterinarian after proper diagnosis. A booster dose of vaccine should be given 7-10 days later. It may be advisable to vaccinate livestock other than cattle on the premises.
Jim Stangle of Golden Vet Services stated, “I am not recommending people in this area to routinely vaccinate unless there is a previous history on their place or cattle movement near or in an outbreak area.” Stangle did relate that one of his suppliers reported, “Because of all the orders, vaccine is almost flying out the door.”
Alice Harty, associate veterinarian with Headlee Enterprises, stated, “I am sure not going to discourage vaccinating, but we are not at high risk in this area at this time. Producers who have previously been at risk are already routinely vaccinating.” She echoed Stangle when she said, “Ranchers are to be extra aware if an area or neighboring area has had any history of anthrax, and especially if they are pasturing their cattle in a new area.”
Neighboring herds where losses due to anthrax have occurred should be vaccinated, especially if similar climatic or range conditions exist on their pasture (flooding, drought). Producers grazing cattle in areas historically known to produce anthrax cases should also vaccinate.
"The risk to humans is very small," Holland said. "Though, we advise reasonable precautions for those who may be handling the animals." Anthrax vaccine is available for people in high-risk occupations, such as military personnel, and individuals who work with imported animal hides, furs, wool, bonemeal, hair and bristles. The human vaccine must be given six times over an 18-month period for the initial series.
To prevent anthrax, use care when handling dead animals suspected of having anthrax; provide good ventilation when processing hides, fur, hair or wool; and vaccinate animals.