Human brucellosis outbreak acquired through camel milk ingestion in Southern Israel

Background: Human brucellosis is common in southern Israel among the semi-nomadic Bedouin, a population that consumes unpasteurized dairy products. Though camel milk ingestion is a known mechanism for brucellosis acquisition, only a few reports of sporadic cases have been published in the medical literature. Objectives: To describe a local brucellosis outbreak in 15 extended Bedouin family members, following ingestion of infected camel milk. Methods: Data regarding patient's clinical manifestations, laboratory findings, treatment and outcome were collected from the hospital and the health fund clinics' computerized database. Camel's blood and milk were tested for Brucella serology and culture. Cases were defined by positive Rose Bengal test, symptoms correlating with brucellosis, and consumption of infected camel milk. Results: Fifteen patients were diagnosed with acute brucellosis from March to June 2011. Sixty percent of cases had serum agglutination test titers of 1:160 or higher and 4/8 (50%) had positive blood culture for Brucella melitensis. Arthralgia and fever were the most consistent clinical manifestations. Blood and milk serology and milk culture taken from the female camel were positive for Brucella melitensis. Conclusions: The treating physicians must consider the possibility of infected camel milk ingestion as the mode of infection, both in sporadic cases and in outbreaks of brucellosis.