Epidemiology of Infant Salmonellosis in the United States, 1996-2008: A Foodborne Diseases Active Surveillance Network Study.

BACKGROUND: Infants have increased risk for salmonellosis; but epidemiologic information is limited. METHODS: We reviewed Foodborne Diseases Active Surveillance Network reports of laboratory-confirmed non-Typhi Salmonella infections in infants from 1996-2008. We calculated incidence, estimated relative risks, and assessed trends over the duration of the study period, using the first 3 years as reference. RESULTS: Average annual incidence of salmonellosis per 100 000 infants was 177.8 (95% confidence interval [CI], 152.7-202.8) in blacks, 129.7 (95% CI, 94.8-164.7) in Asians, and 81.1 (95% CI, 70.2-92.0) in whites. Our analysis of ethnicity independent of race showed salmonellosis incidence of 86.7 (95% CI, 74.6-98.9) in Hispanics and 69.4 (95% CI, 54.8-84.1) in non-Hispanics. Salmonellosis was invasive more often in blacks (9.4%) and Asians (6.4%) than whites (3.6%, P <.001 and P = .01, respectively). Asian infants with salmonellosis were older (median, 31 weeks [range, 0-52]) than black (24 weeks [range, 0-52], P < .001) or white infants (23 weeks [range, 0-52], P < .001). Incidence of all salmonellosis remained stable for whites from 1996-1998 through 2008, but blacks had a sustained decrease, with relative risk of 0.48 (95% CI, .37-.63) in 2008 compared with 1996-1998. However, 2008 incidence remained highest among blacks (141.0 of 100 000 vs 113.5 of 100 000 among whites and 109.9 of 100 000 among Asians). CONCLUSION: Black infants had a greater risk of salmonellosis and invasive disease than other racial groups, and despite the greatest decrease in incidence over the study period, they continued to have the highest incidence of salmonellosis. The decrease in salmonellosis in black infants suggests that future improvements may be possible for other population subgroups.