Milk Bacterial Diseases - Brucellosis

Brucellosis, also known as Malta Fever, is a disease caused by bacteria of the genus Brucella.  It affects animals including sheep, goats, cattle, deer, pigs, and dogs.  The most pathogenic species for humans is B. melitensis (goats, sheep) followed by B. suis (pigs) and B. abortus (cows).

Bucellosis is not very common in the US, but the World Health Organization estimates that worldwide there are about 500,000 cases every year.      

Sources of Infection

• Ingesting raw milk or milk products from infected cows or goats
• Contact with aborted fetuses and placentas - abattoir workers, hunters as well as veterinarians are most at risk
• Inhalation of Brucella organisms - not a common route of infection but can be a hazard for laboratory workers where the organism is cultured
• Eating undercooked infected pork meat or sausage
• Human to human transmission is extremely rare via breastfeeding and sexual contact

Clinical signs in people

• Undulant fever, sweating, chills, headache, weight loss, depression, and joint pain
• Complications include infections of the central nervous system and lining of the heart
• Chronic symptoms may exist and include recurrent fevers, depression, arthritis and fatigue

Control and Prevention  

• Elimination of brucellosis in domestic animals via animal disease control measures. 
• Pasteurization of milk.  Brucella has been known to survive in soft cheeses made from raw milk for as long as 6 months.   
• Avoid eating undercooked meat
• Wear gloves when handling viscera of animals
• Follow proper laboratory protocols

My dog has been diagnosed with brucellosis.  Is there a risk for me?

B. canis is the species that infects dogs and this species has on rare occasions been transmitted to humans.  However, the majority of dog infections do not result in human illness because to become infected you need to come into contact with blood, semen or placenta of the dog.