martes, 10 de junio de 2008


Unpasteurized 'queso fresco' involved in resistant tuberculosis cases
A rare form of [human] tuberculosis [TB] due to Mycobacterium bovis has emerged and has been traced to the ingestion of illegal, unpasteurized dairy products, including tainted 'queso fresco' cheese. The outbreak is rising among Hispanic immigrants in Southern California and is also raising fears about a revival of this strain that was nearly completely destroyed in the USA in the 1900s.
The increase in this TB is being seen chiefly in San Diego, particularly among children who drink or eat dairy foods made from the milk of infected cattle, but Mycobacterium bovis TB can infect anyone who eats contaminated fresh cheeses sold by street vendors, smuggled across the Mexican border, or produced as so-called "bathtub cheese" made in home tubs and backyard troughs. The problem originates from cattle in Mexico, where _M. bovis_ infects about 17 percent of herds; occasional outbreaks among isolated herds affect the USA.
This rare TB accounts for about 10 percent of all new TB cases in the California border region. "M. bovis TB is a disease of antiquity," said Timothy Rodwell, a researcher who led a study published by the federal Centers for Disease Control and Prevention (CDC). "It is important that it not be allowed to re-emerge as a cause of TB in this country."
Unfortunately, this species is uniformly resistant to one of the front line anti-TB drugs [pyrazinamide]. Adults who contract M. bovis TB are more than twice as likely as those with traditional TB to die before completing treatment.
Researchers analyzed nearly 3300 culture-confirmed cases of TB in San Diego between 1994-2005. Approximately 265 were identified as due to M. bovis; this increased by nearly 65 percent, rising from 17 to 28 cases annually. By 2005, over half the M. bovis cases were diagnosed in children under 15. The majority were in Hispanics, 60 percent from Mexico. Between 2001-2005, 19 adults with M. bovis died before or during treatment. Dr. Kathleen Moser, director of TB control programs for San Diego County, said: "It's clearly being seen in places where people drink unpasteurized milk and eat unpasteurized dairy products."
In California, 108 million pounds of legal, properly pasteurized 'queso fresco' and other cheeses were produced last year [2007], according to the California Department of Food and Agriculture. Last year, Moser launched a public health campaign, and agricultural officials seized over 375 pounds of "bathtub cheese" from an open-air market in San Bernardino, according to Steve Lyle, the agency's director of public affairs. Such illegal cheeses have been infected with Salmonella, Listeria, Escherichia coli, and M. bovis.
Source: ProMED-mail <>
Aporte: Guillermo Figueroa

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