Prevalence of high-risk food consumption and food-handling practices among adults: a multistate survey, 1996 to 1997. The Foodnet Working Group

Risk factors for foodborne diseases include consumption of high-risk foods and unsanitary food-handling practices; however, little is known about the prevalence of these risk factors in the general population. A survey was done in five FoodNet sites (California, Connecticut, Georgia, Minnesota, Oregon) to determine the prevalence of these risk factors in the population. A total of 7,493 adults were interviewed by telephone between 1 July 1996 and 30 June 1997. Results showed that 1.5% drank raw milk, 1.9% ate raw shellfish, 18% ate runny egg, 30% preferred pink hamburger, 93% said they almost always washed their cutting board after cutting raw chicken, and 93% said they almost always washed their hands after handling raw meat or poultry, during 5 days before interview. The results differed by state and demographic group. Consumption of raw shellfish (3.2%) and undercooked hamburger (43%) were more common in Connecticut than other states. Raw milk consumption was more common among people who lived on a farm (8.6%) compared with people who lived in a city or urban area (1.1%). Preference for undercooked hamburger was more common among men (35%), young adults (18 to 25 years, 33%), people with college education (38%), and among people with household income of more than $100,000/year (49%). African-Americans were less likely to prefer undercooked hamburger compared to other racial groups (10% versus 30%). Young adults compared to older adults were less likely to wash their hands after handling raw chicken (88% versus 95%), and men washed their hands less often than women (89% versus 97%). Although there were statistical differences between demographic groups, they are insufficient to warrant targeted educational programs.

The changing epidemiology of meningococcal disease in the United States, 1992-1996

New meningococcal vaccines are undergoing clinical trials, and changes in the epidemiologic features of meningococcal disease will affect their use. Active laboratory-based, population-based US surveillance for meningococcal disease during 1992-1996 was used to project that 2400 cases of meningococcal disease occurred annually. Incidence was highest in infants; however, 32% of cases occurred in persons >/=30 years of age. Serogroup C caused 35% of cases; serogroup B, 32%; and serogroup Y, 26%. Increasing age (relative risk [RR], 1.01 per year), having an isolate obtained from blood (RR, 4.5), and serogroup C (RR, 1.6) were associated with increased case fatality. Among serogroup B isolates, the most commonly expressed serosubtype was P1.15; 68% of isolates expressed 1 of the 6 most common serosubtypes. Compared with cases occurring in previous years, recent cases are more likely to be caused by serogroup Y and to occur among older age groups. Ongoing surveillance is necessary to determine the stability of serogroup and serosubtype distribution.

Determining the burden of human illness from food borne diseases. CDC's emerging infectious disease program Food Borne Diseases Active Surveillance Network (FoodNet)

Food borne diseases cause a significant burden of illness in the United States. The Food Borne Diseases Active Surveillance Network (FoodNet), established in 1995, continues to monitor the burden and causes of food borne diseases and provide much of the data to address this public health problem.

Capsule switching of Neisseria meningitidis

The different sialic acid (serogroups B, C, Y, and W-135) and nonsialic acid (serogroup A) capsular polysaccharides expressed by Neisseria meningitidis are major virulence factors and are used as epidemiologic markers and vaccine targets. However, the identification of meningococcal isolates with similar genetic markers but expressing different capsular polysaccharides suggests that meningococcal clones can switch the type of capsule they express. We identified, except for capsule, isogenic serogroups B [(alpha2-->8)-linked polysialic acid] and C [(alpha2-->9)-linked polysialic acid] meningococcal isolates from an outbreak of meningococcal disease in the U. S. Pacific Northwest. We used these isolates and prototype serogroup A, B, C, Y, and W-135 strains to define the capsular biosynthetic and transport operons of the major meningococcal serogroups and to show that switching from the B to C capsule in the outbreak strain was the result of allelic exchange of the polysialyltransferase. Capsule switching was probably the result of transformation and horizontal DNA exchange in vivo of a serogroup C capsule biosynthetic operon. These findings indicate that closely related virulent meningococcal clones may not be recognized by traditional serogroup-based surveillance and can escape vaccine-induced or natural protective immunity by capsule switching. Capsule switching may be an important virulence mechanism of meningococci and other encapsulated bacterial pathogens. As vaccine development progresses and broader immunization with capsular polysaccharide conjugate vaccines becomes a reality, the ability to switch capsular types may have important implications for the impact of these vaccines.

Reptile-associated salmonellosis in New York State

To determine the association between reptile ownership and salmonellosis caused by certain rare serotypes of Salmonella, we reviewed 1993 New York State Salmonella case reports and conducted a matched case-control study. Cases were persons identified from 1993 New York State laboratory records who had salmonellosis caused by Salmonella serotypes commonly isolated from reptiles. Controls were selected from 1993 New York State shigellosis cases and matched for age and date of diagnosis. Of 674 Salmonella case reports 27 (4%) noted reptile exposure before onset of illness. For the case-control study we identified 42 persons with selected Salmonella serotypes, of whom we contacted 24 (57%). Twelve of 24 case patients and 2 of 28 controls owned reptiles (matched odds ratio, 6.6; 95% confidence interval, 1.4 to 31.0). Ten case-patients but no controls owned iguanas (MOR = undefined; 95% confidence interval, 2.24-infinity). Ten of 12 case patients who owned reptiles were < or = 6 months of age. Salmonellosis caused by certain serotypes is associated with reptile exposure. Reptiles may be unfit pets for homes with infants.