Vibrio parahaemolyticus infections are associated with consumption of raw or undercooked shellfish, contaminated food, and exposure of wounds to warm seawater. Foodborne outbreaks and sporadic infections from Vibrio species in 4 Gulf Coast states are reported routinely to the Centers for Disease Control and Prevention (CDC). Between 1988 and 1997, 345 sporadic V. parahaemolyticus infections were reported: 59% were gastroenteritis, 34% were wound infections, 5% were septicemia, and 2% were from other exposures. Forty-five percent of patients suffering from these conditions were hospitalized for their infections, and 88% of persons with acute gastroenteritis reported having eaten raw oysters during the week before their illness occurred. Between 1973 and 1998, 40 outbreaks of V. parahaemolyticus infections were reported to the CDC, and these outbreaks included >1000 illnesses. Most of these outbreaks occurred during the warmer months and were attributed to seafood, particularly shellfish. The median attack rate among persons who consumed the implicated seafood was 56%. To prevent V. parahaemolyticus infections, persons should avoid consumption of raw or undercooked shellfish and exposure of wounds to seawater.

Salmonellosis is a major cause of illness in the United States. To highlight recent trends, data for 1987-1997 from the National Salmonella Surveillance System were analyzed. A total of 441,863 Salmonella isolates were reported, with the highest age-specific rate among infants (159/100,000 infants at 2 months). Annual isolation rates decreased from 19 to 13/100,000 persons; however, trends varied by serotype. The isolation rate of Salmonella serotype Enteritidis increased until 1996, whereas declines were noted in Salmonella serotypes Hadar and Heidelberg. Overall, serotypes that increased in frequency were significantly more likely than those that decreased to be associated with reptiles (P=.008). Salmonella infections continue to be an important cause of illness, especially among infants. Recent declines in food-associated serotypes may reflect changes in the meat, poultry, and egg industries that preceded or anticipated the 1996 implementation of pathogen-reduction programs. Additional educational efforts are needed to control the emergence of reptile-associated salmonellosis.

The etiologic agents and food vehicles associated with the 7458 outbreaks (involving 237,545 cases) of foodborne disease reported to the Centers for Disease Control between 1973 and 1987 were examined. Bacterial pathogens accounted for 66% of outbreaks and 87% of cases, viruses 5 and 9%, parasites 5 and <1%, and chemicals 25 and 4%, respectively. Salmonella accounted for 42% of outbreaks and 51% of cases due to bacterial pathogens. When data from 1973–75 were compared with 1985–87, a 75% increase in the proportion of outbreaks and 130% increase in the proportion of cases due to Salmonella were observed; in particular, outbreaks due to Salmonella enteritidis increased markedly. The proportion of Salmonella outbreaks with a known vehicle that were associated with beef (the food most frequently associated with Salmonella outbreaks) peaked at 30% in 1981, dropped to 4% in 1982, and has since risen gradually. The proportion of Salmonella outbreaks due to chicken and eggs increased over the study period. Bacteria not previously recognized as important foodborne pathogens that emerged during the study period include Campylobacter jejuni, Escherichia coli 0157:H7, and Listeria monocytogenes. Bacterial pathogens accounted for 90% of deaths, with L. monocytogenes (317/1,000 cases) and Clostridium botulinum (192/1,000 cases) having the highest death-to-case ratios. The proportion of outbreaks in which the food was prepared in a commercial or institutional establishment and the median outbreak size both increased. Investigation and analysis of foodborne disease outbreaks continue to play a key role in understanding foodborne illness and in designing and evaluating control measures.