A record 13 cases of human brucellosis in Dallas County, TX, are being blamed on unpasteurized Mexican-style cheeses. Mexican-style-soft-cheeseDallas County officials issued an advisory last week asking local clinicians to be aware of possible cases of brucellosis and elicit travel history and risk exposures from all patients with compatible clinical symptoms. When brucellosis is suspected, they are urged to notify hospital and commercial microbiology laboratories so they can take precautions to prevent exposures. According to the advisory, all 13 of the brucellosis cases confirmed so far this year were connected to consuming unpasteurized cheese brought into the U.S. from Mexico by friends and relatives of the victims or sold by local street vendors. The 13 cases stand in contrast with the two to six cases usually reported annually in Dallas County. The previous annual record was 11 cases, recorded in 2004. This year’s victims range in age from 6 to 80 and typically required inpatient evaluation and treatment, according to public health officials. All Brucella infections are identified by blood culture. Two incidents of high-risk occupational exposure of hospital laboratory personnel have occurred during handling of clinical Brucella isolates. Brucelles bacteria in livestock is much more common in the U.S. than in humans, but it is also fairly rare. The U.S. Centers for Disease Control and Prevention in Atlanta reports that brucellosis infections can take a variety of routes. Eating or drinking raw milk dairy products is by far the most common way. When sheep, goats, cows or camels are infected, their milk — if not pasteurized — can transmit the disease to people. But simply breathing in the bacteria is also a route to infection. It is a risk laboratory personnel must guard against, but such direct exposure to the bacteria can also threaten those who work in slaughterhouse and meat-packing facilities. The bacteria can enter and cause the infection through skin wounds and mucous membranes. This can occur through the air or by contact with infected animals, putting hunters at risk. Bison, elk, caribou, moose and wild hogs are among the animals that can become infected. Hunters may become infected by inhaling the bacteria while they are dressing game or accidentally ingesting undercooked meat. Finally, veterinarians and others who work in close contact with animals or animal excretions, such as newborn animals, fetuses and birth-related excretions, are also at risk. (To sign up for a free subscription to Food Safety News, click here.)