Brucella abortus

Brucella abortus is a Gram-negative, aerobic, non-spore-forming, coccobacillus that is primarily responsible for causing brucellosis in cattle, also known as contagious abortion or Bang's disease. It is a member of the Brucella genus of bacteria, which are known to cause a range of diseases in various animal species and humans.

Characteristics

Brucella abortus is a small, non-motile, non-encapsulated coccobacillus. It is oxidase and urease positive, and can survive in both intracellular and extracellular environments. The bacterium is capable of surviving and multiplying within both phagocytic and non-phagocytic cells, which contributes to its ability to cause chronic infections.

Pathogenesis

The primary route of infection with Brucella abortus is through the mucous membranes, particularly those of the gastrointestinal and reproductive tracts. Once inside the host, the bacteria are taken up by macrophages, where they can survive and multiply. This ability to survive within host cells allows the bacteria to evade the host's immune response, leading to chronic infection.

In cattle, infection with Brucella abortus typically results in abortion or infertility. The bacteria localize in the reproductive organs and mammary glands, leading to the shedding of the bacteria in milk and reproductive fluids. This can result in the spread of the bacteria to other animals and, in some cases, to humans.

In Humans

In humans, infection with Brucella abortus can result in a disease known as brucellosis, which is characterized by fever, fatigue, and muscle and joint pain. In severe cases, the disease can lead to complications such as arthritis, endocarditis, and neurological disorders.

Humans can become infected with Brucella abortus through direct contact with infected animals or by consuming contaminated milk or meat. The bacteria can also be transmitted through the air, making it a potential bioterrorism agent.

Prevention and Control

Prevention and control of Brucella abortus infection in cattle involves a combination of vaccination, testing and culling of infected animals, and pasteurization of milk. In humans, prevention involves avoiding contact with infected animals and consuming only pasteurized milk and thoroughly cooked meat.