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Case-control study of disease determinants for non-typhoidal Salmonella infections among Michigan children

Muhammad Younus127, Melinda J Wilkins134, Herbert D Davies15, Mohammad H Rahbar16, Julie Funk3, Chau Nguyen12, Azfar-E A Siddiqi1, Seongbeom Cho2 and Mahdi Saeed123*

Author Affiliations

1 Department of Epidemiology, Michigan State University, East Lansing, Michigan 48824, USA

2 National Food Safety and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA

3 Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan 48824, USA

4 Communicable Disease Division, Michigan Department of Community Health, 201 Townsend Street, Lansing, Michigan 48913, USA

5 Departments of Pediatrics and Human Development, Michigan State University, East Lansing, Michigan 48824, USA

6 Division of Epidemiology, The University of Texas School of Public Health at Houston, Houston, Texas 77030, USA

7 East 235 42ndStreet, (MS:150-3-78), Safety and Risk Management, Pfizer Inc, New York, NY 10017

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BMC Research Notes 2010, 3:105  doi:10.1186/1756-0500-3-105

Published: 16 April 2010



Infections with Salmonella serotypes continue to be a significant global public health problem. In addition to contaminated foods, several other sources contribute to infections with Salmonella serotypes. We have assessed the role of socioeconomic factors, exposure to food, and environmental sources in the etiology of non-typhoidal Salmonella infections in Michigan children.


A case-control study among Michigan children aged ≤ 10 years was conducted. A total of 123 cases of children with laboratory-confirmed Salmonella infections and 139 control children, who had not experienced symptoms of gastrointestinal illness during the month prior to the interviews, were enrolled. The cases and controls were matched on age-category (<1 year, 2-<6 years and 6-10 years). Data on socioeconomic status, food intake, and environmental exposures, were collected on the queried case and control subjects. After adjusting for race and household-income the final regression multivariable model revealed that Salmonella infections were significantly associated with attendance of a daycare center (adjusted matched odds ratio = 5.00, 95% CI: 1.51 - 16.58), contact with cats (MOR = 2.53, 95% CI: 1.14 - 5.88), and contact with reptiles (MOR = 7.90, 95% CI: 1.52 - 41.01), during the 3 days prior to the onset of child's illness.


Study results suggest that exposure to environmental sources may play an important role in sporadic infections with Salmonella serotypes in children. Additional efforts are needed to educate parents and caretakers about the risk of Salmonella transmission to children from these sources.