Brucellosis, a zoonosis, is an important cause of human disease in
many parts of the world. Brucellae are small, gram-negative nonsporulating
rods or coccobacilli that are transmitted from infected animals, mainly cattle
and other domesticated ruminants (e.g., camels). Brucellae are shed in the
feces, milk, and urine of infected animals and are transmitted to humans
through the ingestion of contaminated dairy products or through the inhalation
of aerosolized infected fecal particles. They can also be directly transmitted
through wounds in exposed individuals such as farmers, veterinarians, and
laboratory workers. Travelers usually acquire the infection after consuming
contaminated foods. Dairy products, especially soft cheeses, unpasteurized
milk, and ice cream, are the most frequently implicated sources. Various
Brucella species can produce human disease, including Brucella melitensis,
Brucella abortus, Brucella suis, and, rarely, Brucella canis.
Brucella melitensis is, by far, the most common cause of human disease
and is mainly acquired from sheep, goats, and camels. In Spain, where
brucellosis is still present in some rural communities, 861 new cases were
diagnosed in 20021.
Brucella melitensis was the main causative agent; Brucella
abortus and Brucella suis rarely cause disease in swine and
cattle in our environment.