Introduction:
Brucellosis is a disease that has received significant attention in recent years. It is one of the diseases that state and federal vaccination/slaughter programs have successfully controlled. Because of this, many states do not currently require that the vaccine be administered. Veterinarians and scientists have varying opinions on continuing or discontinuing the program. No matter what the state and federal laws demand, a local veterinarian familiar with the herd and local environment should be consulted when the decision to continue or discontinue Bangs vaccination is considered.Cause/Disease Transmission:
Brucellosis is caused by the bacteria Brucella abortus. The bacteria are often shed in the environment when an abortion takes place. Infection occurs when animals ingest contaminated feed and water, or lick the genitals of infected animals. Infected bulls may transmit the bacteria to cows during breeding, but this is uncommon. These organisms also may enter the body through mucous membranes, conjunctivae (lining and surface of the eye), wounds, and in some cases, intact skin.Clinical Signs:
The chief sign of brucellosis is abortion, usually occurring after the fifth month of gestation. Stillborn calves, retained placentas, and reduced milk production are also some signs that may indicate an infection.Diagnosis:
A culture is often performed using samples of stomach, lungs, and fetal membranes from an aborted fetus; or with uterus or mammary secretions from an adult. Blood or serologic testing can also be done to identify infected animals.Treatment:
There are treatments for brucellosis available, however, they are seldom used. Most operations use a "test and slaughter" program, culling any animals that test positive. This is the most effective method for eradicating a brucellosis infection from a herd.Prevention:
Presently, vaccination of heifers is the most effective prevention for brucellosis. The vaccination should occur when the heifer is between 4-12 months of age and ideally before she is 8 months of age. Maintaining a closed herd is important and replacement animals from an outside source pose the greatest risk to a noninfected herd. If replacements from an outside source are necessary, vaccinated calves or nonpregnant heifers are the least likely to be carriers. If pregnant or fresh cows are purchased, they should be from brucellosis-free regions and test negative for the disease. All replacements, regardless of age or origin, should be quarantined for at least 30 days and retested before they are added to the herd.Public Health Concerns:
Materials contaminated with B. abortus and syringes/needles that contain brucellosis vaccine are hazardous to humans and should be handled carefully.