Anthrax claims hundreds of cattle; experts push vaccination

WASHINGTON — From North Dakota to Texas, cattle have been dying by the hundreds from what some claim is the largest anthrax outbreak on record.

Vaccination is an efficient, effective defense, experts say.

At presstime, North Dakota officials estimated 500 dead bison and cattle and 101 quarantined premises. South Dakota claims at least 400 cattle have died from anthrax exposure on 53 premises. In Texas, two ranches were quarantined following anthrax detection among deer, cattle and horses.

Cutaneous anthrax: This carbuncle appears on a veterinarian's finger infected with cutaneous anthrax. "What you don't see is that this veterinarian is flat on his back in the hospital receiving intravenous antibiotics," says Dr. Charles Stoltenow, extension veterinarian for North Dakota State University. Untreated cutaneous anthrax has a 5 percent to 20 percent case fatality rate. Naturally occurring anthrax is sensitive to penicillin.

Although the term "anthrax" often incites bioterrorism fears, the naturally occurring bacterial spore is endemic from the Gulf of Mexico through the Great Plains, experts say.

The right soil type and weather conditions allow anthrax to self-perpetuate. This year's scorching heat index and extraordinary amount of rainfall have created the "perfect environment" for anthrax, says Dr. Charles Stoltenow, extension veterinarian for North Dakota State University.

"On the average we estimate we'll see one or two cases a year here," he says. "Now we've had at least 500 animals infected. After the outbreak is over, we're going to try and survey to see just how many animals died."

'Just devastating'

Cattle ranchers report they've been hard hit economically. Stoltenow estimates losses in North Dakota run in the millions of dollars when factoring in costs associated with animal fatalities, management and veterinary care. With 1 million head of cattle in the state, he says vaccination likely will become a top priority for producers.

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"I'm sure that in affected areas, they'll start vaccinating again," Stoltenow says. "It's very inexpensive, but if producers don't see anthrax for five years, they think, 'Why do I vaccinate?' Now they're realizing that the only real treatment is prevention."

With 3.7 million head of cattle, State Veterinarian Dr. Sam Holland confirms South Dakota's similar situation.

"There's no question they should be vaccinating, and veterinarians should be reminding producers to do that," he says.

What to expect

While the incubation time for anthrax can last up to seven days, veterinarians might not notice signs of illness aside from sudden death, which even then can be misdiagnosed as a lightening strike.

"Animals ingest anthrax, and they die of shock and septicemia," Stoltenow says. "They tip over and that's it."

Holland suggests quick diagnosis and rapid vaccination.

"You can just shut anthrax off overnight with the right antibiotics and the vaccine. We've had hundreds of thousands of cattle vaccinated since seeing our first case on July 14," he says.

Message to veterinarians

Mass vaccination has occurred, in part, because veterinarians have "done an excellent job" in recognizing anthrax infection, Holland adds.

The Centers for Disease Control and Prevention (CDC) charges veterinarians with notifying state and federal authorities within 24 hours of anthrax identification. Protocols for disease detection include wearing gloves, long-sleeved clothing and disposable boots when handling carcasses. After invasive procedures, instruments and the operating area should be decontaminated using either disinfectant strength iodine disinfectants or chlorine as calcium or sodium hypochlorite. Corpses should be cremated, CDC says.

Cases of veterinarian exposure occasionally arise; occupational transmission usually occurs through a wound or cut. Holland reports a DVM contracted cutaneous anthrax in 2002 and was successfully treated with antibiotics. A symptom of infection can appear as a malignant carbuncle that eventually develops into a black eschar (see related photo). For safety reasons, North Dakota officials have created anthrax-sampling kits. South Dakota veterinarians should contact the state health department for a list of anthrax safety directives.

"You've got to be thinking anthrax out there," Stoltenow says. "We need our veterinarians to be very careful when collecting samples. They're our defense against this."