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Frequently Asked Questions
What is brucellosis?
Brucellosis is an infectious disease caused by the bacteria of
the genus Brucella. These bacteria are primarily passed
among animals, and they cause disease in many different vertebrates.
Various Brucella species affect sheep, goats, cattle, deer,
elk, pigs, dogs, and several other animals. Humans become infected
by coming in contact with animals or animal products that are
contaminated with these bacteria. In humans brucellosis can cause
a range of symptoms that are similar to the flu and may include
fever, sweats, headaches, back pains, and physical weakness. Sever
infections of the central nervous systems or lining of the heart
may occur. Brucellosis cab also cause long-lasting or chronic
symptoms that include recurrent fevers, joint pain, and fatigue.
How common is
brucellosis?
Brucellosis is not very common in the United States, where100
to 200 cases occur each year. But brucellosis can be very common
in countries where animal disease control programs have not reduced
the amount of disease among animals.
Where is brucellosis
usually found?
Although brucellosis can be found worldwide, it is more common
in countries that do not have good standardized and effective
public health and domestic animal health programs. Areas currently
listed as high risk are the Mediterranean Basin (Portugal, Spain,
Southern France, Italy, Greece, Turkey, North Africa), South and
Central America, Eastern Europe, Asia, Africa, the Caribbean,
and the Middle East. Unpasteurized cheeses, sometimes called "village
cheeses," from these areas may represent a particular risk for
tourists.
How is
brucellosis transmitted to humans, and who is likely to become
infected?
Humans are generally infected in one of three ways: eating or
drinking something that is contaminated with Brucella,
breathing in the organism (inhalation), or having the bacteria
enter the body through skin wounds. The most common way to be
infected is by eating or drinking contaminated milk products.
When sheep, goats, cows, or camels are infected, their milk is
contaminated with the bacteria. If the milk is not pasteurized,
these bacteria can be transmitted to persons who drink the milk
or eat cheeses made it. Inhalation of Brucella organisms
is not a common route of infection, but it can be a significant
hazard for people in certain occupations, such as those working
in laboratories where the organism is cultured. Inhalation is
often responsible for a significant percentage of cases in abattoir
employees. Contamination of skin wounds may be a problem for persons
working in slaughterhouses or meat packing plants or for veterinarians.
Hunters may be infected through skin wounds or by accidentally
ingesting the bacteria after cleaning deer, elk, moose, or wild
pigs that they have killed.
Can brucellosis
be spread from person to person?
Direct person-to-person spread of brucellosis is extremely rare.
Mothers who are breast-feeding may transmit the infection to their
infants. Sexual transmission has also been reported. For both
sexual and breast-feeding transmission, if the infant or person
at risk is treated for brucellosis, their risk of becoming infected
will probably be eliminated within 3 days. Although uncommon,
transmission may also occur via contaminated tissue transplantation.
Is there a way
to prevent infection?
Yes. Do not consume unpasteurized milk, cheese, or ice cream
while traveling. If you are not sure that the dairy product is
pasteurized, don't eat it. Hunters and animal herdsman should
use rubber gloves when handling viscera of animals. There is no
vaccine available for humans.
My dog has been
diagnosed with brucellosis. Is that a risk for me?
B. canis is the species of Brucella species that
can infect dogs. This species has occasionally been transmitted
to humans, but the vast majority of dog infections do not result
in human illness. Although veterinarians exposed to blood of infected
animals are at risk, pet owners are not considered to be at risk
for infection. This is partly because it is unlikely that they
will come in contact with blood, semen, or placenta of the dog.
The bacteria may be cleared from the animal within a few days
of treatment; however re-infection is common and some animal body
fluids may be infectious for weeks. Immunocompromised persons
(cancer patients, HIV-infected individuals, or transplantation
patients) should not handle dogs known to be infected with B.
canis.
How is brucellosis
diagnosed?
Brucellosis is diagnosed in a laboratory by finding Brucella
organisms in samples of blood or bone marrow. Also, blood tests
can be done to detect antibodies against the bacteria. If this
method is used, two blood samples should be collected 2 weeks
apart.
Is there a
treatment for brucellosis?
Yes, but treatment can be difficult. Doctors can prescribe effective
antibiotics. Usually, doxycycline and rifampin are used in combination
for 6 weeks to prevent reoccuring infection. Depending on the
timing of treatment and severity of illness, recovery may take
a few weeks to several months. Mortality is low (<2%), and
is usually associated with endocarditis.
I am a veterinarian,
and I recently accidentally jabbed myself with the animal vaccine
(RB-51 or B-19, or REV-1) while I was vaccinating cows (or sheep,
goats). What do I need to do?
These are live vaccines, and B-19 is known to cause disease in
humans. Although we know less about the other vaccines, the recommendations
are the same. You should see a health care provider. A baseline
blood sample should be collected for testing for antibodies. We
recommend that you take antibiotics (doxycycline and rifampin
for B-19 and REV-1, or doxycycline alone for RB-51) for 3 weeks.
At the end of that time you should be rechecked and a second blood
sample should be collected. (The sample can also be collected
at 2 weeks.) The same recommendations hold true for spraying vaccine
in the eyes (6 weeks of treatment in this case) or spraying onto
open wounds on the skin.
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