Published Date: 2008-08-18 17:00:31
Subject: PRO/AH/EDR> Anthrax, bovine - USA (05): (SD), corr.
Archive Number: 20080818.2569
ANTHRAX, BOVINE - USA (05): (SOUTH DAKOTA), CORRECTION
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 17 Aug 2008
Source: ArgusLeader.Com [edited]
[The url for this article, Archive 20080817.2559 should have been:
A livestock disease that has been known to veterinary medicine for
generations and regularly appears in South Dakota has been detected
in 3 cattle herds in Douglas and Hutchinson counties. The Animal
Disease Research and Diagnostic Laboratory at South Dakota State
University is closely tracking the outbreak of anthrax in those herds.
"It is one of the oldest diseases known to man," says South Dakota
State Veterinarian Sam Holland. "We are in what is known as an
anthrax belt, from Canada to Texas. Historically, the soil in this
part of the country is known to be contaminated with spores of the bacteria."
Holland is quick to point out the cattle disease is not the same form
of weapons-grade anthrax that was mailed to the office of former Sen.
Tom Daschle and several others in 2001. Holland says the anthrax
spores that afflicted the South Dakota cattle are large and difficult
to inhale. "The human health concern is handling carcasses without
protective clothing such as long-sleeve shirts," he says. Human
exposure to anthrax spores in this manner typically results in
"rather nasty skin infections" but usually is not fatal, says Russ
Daly, extension veterinarian and SDSU assistant professor.
Daly says the positive tests from the 3 South Dakota herds indicate a
relatively small outbreak. He describes the mechanism of infection as
cattle ingesting anthrax spores while grazing in pastures containing
A good veterinary anthrax vaccine exists, and livestock producers are
urged to annually vaccinate their herds before the grazing season,
Holland says. "Yes, but you don't know when the conditions are right
for anthrax to appear, so that vaccine is not used routinely," says
John Gay, a Washington State University veterinary professor and researcher.
Once an outbreak is detected, Holland says, his staff contacts nearby
livestock owners and urges them to vaccinate their animals. Within a
week to 10 days after vaccination, effective immunity is achieved.
Within herds where anthrax is confirmed, Holland says, the entire
herd should be vaccinated, simultaneously treated with antibiotics
and be given a booster vaccine within 7 to 10 days.
Anthrax can be effectively treated with antibiotics, Holland says.
However, "the incubation period is short. Once an animal starts
exhibiting signs of the disease, they are usually dead within hours.
That's why treating sick animals is rarely done," he says.
Daly surmises abundant rain this year  might have left pastures
with standing water that flushed out anthrax spores. Holland adds
that outbreaks often are associated with hot, humid weather but that
it rarely is that simple. "It's extremely unpredictable," he says.
"One year, I saw it in all corners of the state in one week. They
didn't all have the same climate. But it was in Lemmon, Milbank and
Parkston all within a 4 to 5-day period."
[Byline: Peter Harriman <email@example.com>]
[Vaccinating an exposed herd and simultaneously treating with
antibiotics is a waste of vaccine, as the antibiotics kill the
germinating Sterne organisms. It is better to leave out the 1st round
of vaccine when treating with long acting antibiotics and vaccinate
7-10 days later when the antibiotic level in the blood has fallen so
low as to not impact on the germinating vaccine organisms.
Frankly, we need to develop a better and more efficient annual
vaccination and outbreak surveillance system so as to be able to
accurately target (and fuss at the owners of) those herds at a real
risk of having outbreaks and keep the other ranchers alert to
unexpected deaths during the summer. At present, the rule of thumb is
that when any herd has had an outbreak within the past 3-5 years, the
neighboring herds should be vaccinated each spring. We can do better.
Reacting after an outbreak is fine, but many farmers find themselves
harvesting crops during this time, and collecting up and vaccinating
a herd is difficult if not impossible. - Mod.MHJ]