The bacteria are often spread through contact with aborted fetuses, placentas, or vaginal discharges. In the United States, wildlife reservoirs like bison and elk in the Yellowstone area maintain the pathogen, occasionally transmitting it back to livestock. Zoonotic Transmission and Human Health

Brucella abortus is a Gram-negative, facultative intracellular bacterium that primarily targets cattle and serves as a major etiological agent of . This zoonotic disease is a critical global concern, causing significant economic losses in the livestock industry and posing a persistent public health threat to humans. While some countries have successfully eradicated the pathogen, it remains endemic in regions including Latin America, the Middle East, Africa, and parts of Asia. Impact on Livestock

Contagious abortion, often occurring in the last trimester of pregnancy, is the most common sign.

Even with treatment, relapse occurs in 5–15% of cases due to the presence of "persister" cells that remain metabolically active within protective intracellular niches. Current Control and Prevention Strategies

Infected animals frequently experience decreased fertility and retained placentas.

In humans, it can cause a debilitating, chronic illness characterized by undulant fever, joint pain, and fatigue.

In its primary host, cattle, B. abortus typically localizes in the reproductive tract. The hallmark clinical signs of infection include:

The bacterium's ability to persist inside host macrophages makes it difficult to treat, often requiring long-term combination antibiotic therapy.