Brucellosis is a contagious, infectious, and communicable disease affecting primarily cattle, bison, and swine that is caused by bacteria of the genus Brucella. Brucella abortus affects mainly bovine species, but can also affect goats, sheep, and horses. B. Suis affects mainly porcine species. A third strain, B. melitensis, affects mainly goats and sheep and is considered to be a foreign animal disease (FAD). B. ovis, does exist in the United States, but it does not cause significant disease problems and mainly affects sheep. Currently, there is no program and no initiative to establish a program for the control of B. ovis.
In its principal animal hosts, brucellosis causes loss of young through spontaneous abortion or birth of weak offspring, reduced milk production, and infertility. Both animals and humans can be affected, and it is mainly transmitted from animals by direct contact with infected blood, placenta, fetuses, or uterine secretions or through the consumption of infected and raw animal products (especially milk and milk products).
Brucellosis Abortus
Cattle Brucellosis is a reportable disease in Oregon caused by the bacterium Brucella abortus and mainly infects cattle. It is an economically important cause of abortions in cattle and there is no economically feasible treatment for livestock. The other species that it also affects are bison, buffalo, and elk. This disease has been eradicated in Oregon since January 14, 1993, and in the United States. There is a Designated Surveillance Area (DSA) where wild cervid populations are infected with Brucellosis which includes Montana, Wyoming, and Idaho. These states follow a rigorous management surveillance program that includes testing every animal prior to leaving the Greater Yellowstone Surveillance Area (GYSA) for Brucellosis and vaccinating those cattle between 4 and 12 months of age. Cattle can leave the GYSA if they are vaccinated and negative for Brucellosis, making the risk relatively low for other cattle in other states even without vaccination to contract Brucellosis.
Brucellosis abortus can be a human pathogen which can be a serious, debilitating, and sometimes chronic disease that may affect a variety of organs. Most cases are the result of occupational exposure to infected animals, but infections can also occur from ingesting contaminated dairy products, especially in unpasteurized milk. In addition, B. abortus could be used in a bioterrorist attack.
Brucellosis vaccination in cattle has been performed since 1941. Although it decreases the abortion storms seen in cattle when they have Brucellosis, it does not keep them from contracting the disease. The brucellosis vaccine, RB51, can only be administered by an accredited veterinarian because of the risks associated with handling the vaccine.
Official Calfhood Vaccination
Official calfhood vaccination may only be performed on female cattle and bison between 4 and 12 months of age. The animal is permanently identified with a tattoo in the right ear by the letter “R”, the US Registered Shield and “V”, and the last digit of the year in which the vaccination was performed. Official ID must also be placed in this animal at the time of vaccination if it doesn’t already have one.
Oregon Mature Vaccination
Oregon allows healthy females of breeding age, which were not vaccinated prior to 12 months of age, to be vaccinated for Brucellosis. The USDA does not recognize Mature Vaccination as an “official vaccine”, and many states will not accept mature vaccinated cattle. It is important that your veterinarian contacts the state of destination to determine their import requirements. USDA APHIS utilizes a term “adult vaccination” which designates the vaccination of a Brucellosis infected or exposed herd and does not equate to “mature vaccination”. The animal is permanently identified with a tattoo in the right ear by the letter “M”, the US Registered Shield and “V”, and the last digit of the year in which the vaccination performed. This animal will also need an official ID at the time of vaccination if it doesn’t already have one.
Brucellosis suis
Brucella suis is a bacterial organism that causes reproductive losses in animals while humans may suffer from a debilitating nonspecific illness or localized involvement of various organs. It is found commonly in domesticated pigs in some parts of the world, such as Asia and Latin America. It has been eradicated in domesticated pigs in North America however, it is still maintained in the wild or feral swine populations. This is of particular importance for pigs that are raised out on pasture and may be exposed to those feral swine populations.
Brucella suis is mainly transmitted when pigs ingest feed or water contaminated by birth products, such as, fetus, placenta or vaginal fluids, or from dead fetuses and fetal membranes. Pigs can also transmit Brucellosis through their milk, urine, and semen. Humans generally become infected by ingesting the organisms or via contaminated mucous membranes including the eye or respiratory tract. They can also become infected through abraded skin and in unpasteurized milk. This is why it is such a concern that it may be used as a bioterrorist weapon.
Brucellosis melitensis
Brucellosis melitensis is a disease in sheep and goats that can cause infections in humans. It is an economically important cause of abortion in small ruminants. This infection of sheep and goats causes significant losses from decreased productivity and lost trade in much of the developing world where it isn’t eradicated. In humans it is debilitating nonspecific illness or localized involvement of various organs. B. melitensis is considered to be a re-emerging pathogen in the Middle East. It has been eradicated from some nations, but the cost of surveillance to remain B. melitensis-free is significant.
In sheep and goats, they become infected by coming in contact with vaginal discharges and birth products. In humans, Brucella melitensis is the most common species of Brucella in human illnesses, and it is contracted by direct contact with infected animals or their tissues, or by ingestion of contaminated dairy products. B. melitensis could be used in a bioterrorist attack because of it is great impact on not only the livestock species but also humans.
Brucellosis canis
Brucella canis is an important cause of reproductive failure in dogs. Infections will cause abortions and stillbirths in females, and epididymitis, prostatitis, orchitis, and sperm abnormalities in males. It can also infect humans but it is still unclear the importance of human infection.