Infectious Diseases News Brief - August 20, 2010

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Norovirus, Salmonella responsible for most foodborne illness outbreaks in 2007

CDC researchers identified 1,097 foodborne disease outbreaks, which lead to 21,244 illnesses and 18 deaths, in the United States during 2007. Although Salmonella and norovirus were the most common culprits for both outbreaks and illnesses, these numbers were down 8% and 15% from the annual average reported from 2002 to 2006. CDC researchers gathered data on outbreaks occurring in 2007 from 48 states, the District of Columbia and Puerto Rico. Data reported include number of foodborne illnesses, hospitalizations and deaths; the confirmed or suspected etiologic agent and food vehicle involved, according to the researchers. A single etiologic agent was identified in 64% of outbreaks, resulting in 73% of illnesses. An etiology was unidentified for 363 outbreaks. Delayed reporting of illness to the health department, overconsumption and unavailable human or food sample test results were the most common reasons for not identifying an etiology or food vehicle, the CDC researchers said. Of 497 outbreaks with a single etiologic agent confirmed, 52% were caused by bacteria (with 6,441 illnesses), 40% by viruses (with 6,120 illnesses), 7% by chemical agents (with 141 illnesses) and 1% by parasites (with 65 illnesses). Norovirus and Salmonella were the most common cause of illness, causing 39% and 27% of outbreaks involving a single etiologic agent. Norovirus accounted for 97% of illnesses caused by a virus and Salmonella accounted for 53% of those caused by bacteria. Enteritidis was the most common Salmonella serotype identified and accounted for 28 single-etiology outbreaks. Forty of the single-etiology outbreaks were caused by shiga toxin-producing Escherichia coli, of which 39 were caused by serogroup O157. Among the 18 multi-state outbreaks, 10 were caused by Salmonella, six by E. coli O157:H7, one by C. botulinum and one by norovirus, according to the report. The CDC classifies foodborne disease outbreak-associated foods into 17 categories. According to the researchers, the largest outbreaks associated with a single food commodity were caused by a chicken dish contaminated with C. perfringens (132 illnesses), leafy vegetable salad contaminated with norovirus (128 illnesses), chili beans contaminated with C. perfringens (125 illnesses) and beef contaminated with E. coli O157:H7 (124 illnesses).

Source: Infectious Disease News August 16, 2010
http://www.infectiousdiseasenews.com/article/67623.aspx

Hantavirus Infections in Humans and Animals, China

Hemorrhagic fever with renal syndrome (HFRS) is a serious public health problem in the People's Republic of China. Although 7 sero/genotypes of hantaviruses have been found in rodents, only Hantaan virus (carried by Apodemus agrarius mice) and Seoul virus (carried by Rattus norvegicus rats) reportedly cause disease in humans. During 1950–2007, a total of 1,557,622 cases of HFRS in humans and 46,427 deaths (3%) were reported in China. HFRS has been reported in 29 of 31 provinces in China. After implementation of comprehensive preventive measures, including vaccination, in the past decade in China, incidence of HFRS has dramatically decreased; only 11,248 HFRS cases were reported in 2007. Mortality rates also declined from the highest level of 14.2% in 1969 to ≈1% during 1995–2007. However, the numbers of HFRS cases and deaths in China remain the highest in the world.

Source: Emerging Infectious Diseases Journal, volume 16, number 8, August 2010 http://www.cdc.gov/eid/content/16/8/1195.htm