Bovine Tuberculosis (TB) is a progressive,
chronic bacterial disease caused when bacteria attack the respiratory
system of primarily cattle, but also deer. The
disease compromises the immune system and can lead to death from
related causes. If left unchecked, the disease would likely spread
and become established within the deer population. As a result of
this, there would be permanent risk of continuous deer-to-deer or
deer-to-livestock transmission of the disease. Bovine TB in animals
typically presents in the lungs but may also occur in the intestines
and other parts of the body.
As a chronic disease, Bovine TB can take years to
develop. The disease grows very slowly and only replicates every 12-20 hours.
The lymph nodes in the animal's head usually show infection first and as the
disease progresses lesions will begin to develop on the surface of the lungs
and chest cavity. In severely infected deer, lesions can usually be found throughout
the animal's entire body. Read the Bovine
Tuberculosis Fact Sheet
How is bovine TB transmitted?
Bovine TB is spread primarily through the exchange of respiratory
infected and uninfected animals. This transmission usually happens
when animals are in
close contact with each other. Animals may also become infected with
TB by ingesting
the bacteria. Thus, animal density plays a major factor in TB transmission.
released into the air through coughing and sneezing can spread the
disease to uninfected
animals. Research also suggests that bovine TB can also be contracted
How can I tell if my deer is infected with bovine TB?
Severe disease can develop in some deer within a few months of infection,
while other deer do not become symptomatic for years. Hunters do not
always readily recognize small lesions in deer. Abscesses may not be visible
to hunters when field dressing deer. Infected animals may have yellow to tan,
peasized nodules in the chest cavity or lungs. Lymph nodes of the head and
neck can be swollen and soft. In fact, most infected white-tailed deer appear
healthy. View images
Is there any treatment for bovine TB?
There are no effective vaccines for disease prevention and no effective
treatment of bovine TB in wild deer. Instead, a combination of wildlife
surveillance and deer management strategies can be used to eliminate
the disease if
present in wild deer. Wildlife surveillance monitors the spatial
prevalence of the disease, while hunters are also asked to examine
Can bovine tuberculosis infect humans?
Bovine tuberculosis, an infectious disease found
in white-tailed deer, elk, and domestic livestock, has been a problem
since the 19th century when it was introduced by European cattle. According
to DNR records, TB was the leading cause of death in humans in 1917.
The outbreak was initially brought about by people drinking raw milk
from infected cows. Because of modern pasteurization and meat inspection
laws, humans are not particularly at risk for contracting the disease.
In the U.S. today, the threat of humans contracting
bovine TB from animals is extremely
remote. Most human tuberculosis is caused by the bacteria M. tuberculosis,
spread from person to person and rarely infects animals. Bovine TB
is caused by the
closely related bacteria M. bovis, which is capable of infecting
all mammals including
people. The United States has actively pursued a bovine tuberculosis
since 1917. This program, together with food safety initiatives,
has been very effective in
reducing the likelihood of people contracting tuberculosis from M.
What precautions should hunters take when
field dressing deer or handling meat?
Good field-dressing techniques are important to
avoid contact with TB and other wildlife
pathogens. The best way to insure your safety is to wear disposable
rubber gloves when
gutting a deer. Special attention should be paid to the lungs and
chest cavity where small
lesions may be evident in an infected deer. Every precaution should
be taken to avoid
cutting yourself when field dressing a deer.
Is it safe to eat venison?
While it is possible to transmit bovine TB from animals to people,
the likelihood is
extremely rare. It is highly unlikely that a person field dressing
or eating the cooked meat
of animals infected with bovine TB would become infected. The TB
bacterium is very
rarely found in meat (muscle tissue). Since bovine TB is primarily
respiration, the bacterium is generally found in lung tissue. As
a precaution, all meats
(including deer), should be thoroughly cooked to an internal temperature
of 165 degrees
F. This effectively kills all known bacteria, including TB and E.