Brucellosis Overview

Definition: Brucellosis is a bacterial disease caused by Brucella abortus.
Hosts: Primarily affects livestock but can also infect humans, domestic pets, and wildlife.
Common Names: Known as Malta fever, Mediterranean fever, Undulant fever, or Bang’s disease.

Epidemiology Changes: Significant changes in epidemiology, diagnosis, treatment, and control measures over the years.

Livestock: Primarily cattle, sheep, goats, pigs, and dogs.
Wildlife: Affects species such as bison, elk, and feral swine.
Human Transmission: Humans can contract brucellosis through direct contact with infected animals.

Methods:
- Touching birthing fluids or animal blood with injured hands.
- Eating or drinking unpasteurized dairy products.
- Breathing in bacteria during butchery.
- Eating raw meat or blood.

Endemic Regions: In endemic areas, can affect millions of livestock and wildlife.
U.S. Context: Infection rates are low in domestic livestock; wildlife still report cases.
Human Cases: Approximately 500,000 cases annually worldwide in endemic regions.

Bacterial Group: Caused by a group of bacteria known as Brucella, transmitted via contact with infected birthing tissues and fluids.
Vectors of Transmission: Can be spread through contaminated objects, equipment, clothing, and feed.
Nature of Disease: Mainly a reproductive disease affecting placenta and fetal fluids; can cause recurring fevers and arthritis.
Transmission Entry Points: Oral ingestion, contact with mucous membranes, or broken skin.

In Cows: Mostly reproductive system affected, with abortion being a common symptom.
In Bulls: Affects reproductive organs, causing inflammation and swelling.
Other Symptoms: Eye inflammation, weight loss, poor hair coat, lethargy, and decreased productivity.

Moderate Infections: Mimic flu-like symptoms including fever, chills, sweating, headaches, and joint pain.
Severe Cases: May lead to serious conditions such as encephalitis, meningitis, and endocarditis.

Testing: Blood tests for herds typically around six months old.
Vaccination: Vaccines like B. Abortus Strain 19 or RB51 help increase resistance to infection.
Risks with Vaccination: Some vaccinated calves may still become infected, which can lead to misleading diagnostic results.

Current Options: No practical treatment available for brucellosis.
Control Programs: Focus on detection of infected herds and culling of positive animals.