Salmonellosis Associated with Chicks and Ducklings ---- Michigan and Missouri, Spring 1999
During the spring of 1999, outbreaks of salmonellosis associated with handling chicks and ducklings occurred in Michigan and Missouri. This report summarizes the epidemiologic information for the outbreaks and provides an overview of legislative efforts to control the distribution of chicks and ducklings. These outbreaks demonstrate that handling chicks and ducklings is a health risk, especially for children, and highlight the need for thorough handwashing after contact with chicks, ducklings, and other young fowl.
In May 1999, the Michigan Department of Community Health (MDCH) was notified of an increase in Salmonella serotype Infantis infections with closely related pulsed-field gel electrophoresis (PFGE) patterns; 21 case-patients were reported with onset of illness during April 1--July 31, 1999. Ages of infected persons ranged from 8 days to 82 years (mean: 25 years); eight (38%) were aged <10 years. Twelve (57%) were female. Symptoms reported during patient interviews included diarrhea (81%), fever (57%), bloody diarrhea (24%), and vomiting (14%). Three patients were hospitalized. Overall, 17 (82%) patients reported direct and/or indirect contact with young fowl: eight (38%) with chicks, two (10%) with ducklings, one (5%) with pheasant, and six (29%) with multiple species, including chicks and ducklings. Of the young fowl that were traceable, 88% were shipped from a single hatchery.
MDCH conducted a case-control study to identify exposures associated with illness. Nineteen patients were enrolled and were matched by age and place of residence to 37 healthy controls using sequential-digit dialing. During the 5 days before illness onset, 14 (74%) of 19 patients had direct contact with young fowl or resided in a household that raised fowl (chicks, ducklings, goslings, pheasants, and/or turkeys) compared with six (16%) of 37 controls (matched odds ratio [MOR]=20; 95% confidence interval [CI]=3--378). In several households, young birds were kept inside the home. One child kept young birds in his bedroom and another carried chicks inside his jacket.
MDCH, with assistance from the Michigan Department of Agriculture (MDA), visited the implicated hatchery in September 1999. During the spring, the hatchery shipped approximately 100,000 birds per week by mail order directly to customers and to several feed and farm supply retail outlets across the state. Fowl were shipped in lots of 25 to 100 birds, and usually were raised for backyard use (i.e., meat and egg production for the family). S. Infantis with the outbreak PFGE pattern was recovered from three of 47 environmental samples and five of 33 bird samples taken at the hatchery. Other Salmonella serotypes also were isolated from the environmental samples, including serotypes Montevideo (seven), Chester (one), and Mbandaka (one).
In April 1999, the Missouri Department of Health (MDOH) noted a cluster of Salmonella serotype Typhimurium infections with an identical PFGE pattern; 40 case-patients were identified with onset of illness during April 4--May 30, 1999. The ages of infected persons ranged from 8 months to 46 years (mean: 13 years); 28 (70%) were age <20 years; 23 (58%) were male. Symptoms reported by the 33 patients interviewed included fever (42%), bloody diarrhea (27%), stomach cramps (27%), and vomiting (21%). Three patients were hospitalized. Overall, 32 (97%) persons reported exposure to young fowl: 18 (56%) were exposed to chicks, 10 (31%) to ducklings, three (9%) to both chicks and ducklings, and one (3%) to a young turkey.
MDOH conducted a case-control study of persons exposed to chicks or ducklings to identify whether specific behaviors were associated with illness. Twenty case-patients were enrolled; 40 controls who had been exposed to chicks and ducklings during the same time were identified through media advertisements and word-of-mouth. During the 4 weeks before onset of patient illness, chicks or ducklings that were identified as ill by the patient or handler were associated with human illness (odd ratio [OR]=21; 95% CI=2--508); handwashing after handling fowl was protective against illness (OR=0.0; 95% CI=0.0--0.2).
During February 2000, CDC contacted 51 state and territorial public health departments to ascertain laws on the sale of baby fowl to noncommercial distributors and private persons; 28 (55%) responded. Ten (36%) states have laws restricting the sale of baby fowl for noncommercial purposes, including the sale of fowl aged <3 weeks (Indiana and Maryland), <4 weeks (Ohio and Pennsylvania), <8 weeks (Massachusetts and Virginia), and <12 weeks (Connecticut). In addition, Connecticut, Ohio, and Virginia require fowl to be sold in groups of greater than five birds. Illinois prohibits the sale of chicks during the Easter season, and Kansas requires persons to have a temporary or permanent license to sell chicks.
Reported by: S Bidol, MPH, MG Stobierski, DVM, B Robinson-Dunn, PhD, J Massey, DrPH, W Hall, MD, M Boulton, MD, State Epidemiologist, Michigan Dept of Community Health. M Warwick, MD, M Borst, S Wiedlocher, Missouri Dept of Health. State Br, Div of Applied Public Health Training, Epidemiology Program Office; Foodborne and Diarrheal Diseases Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases; and an EIS Officer, CDC.
Although most of the 1.4 million human salmonellosis cases that occur annually in the United States are caused by foodborne sources (1), direct contact with animals, particularly reptiles and occasionally birds, also may be a source of infection (2--4). Most reptiles and many birds shed Salmonella in their feces. Humans become infected when contaminated food, hands, or other objects are placed in the mouth; therefore, handwashing is critical to prevent Salmonella infections following direct or indirect contact with animals. The Missouri outbreak described in this report and previous outbreaks (3,4) demonstrate that handling young fowl can be a risk for Salmonella infections, particularly in children who receive fowl as gifts during Easter; children have more frequent hand-to-mouth contact and are less likely to practice handwashing after handling fowl. The Michigan outbreak describes the risk for infection associated with the backyard production of fowl.
Prevention efforts, such as sales restrictions and consumer education, may be difficult because selling pet fowl and raising backyard fowl are largely unregulated. Several states responding to the survey reported laws that restrict the sale of chicks, ducklings, and other young fowl. Some of these restrictions are based on previous reports of chick-associated and duckling-associated salmonellosis during Easter (5). Enforcement also may be difficult because young fowl can be purchased by mail and Internet orders from out-of-state hatcheries. State-mandated point-of-sale educational material may be effective in educating consumers about the risk for salmonellosis. States may wish to join Michigan and Missouri in issuing a press release during the spring of 2000 to raise public awareness about the risk for Salmonella infections posed by young fowl. MDCH, MDA, and MDOH have developed safety instructions to be distributed with young fowl that emphasize the importance of handwashing and supervision of young children interacting with young fowl.
To prevent the transmission of Salmonella from chicks, ducklings, and other young fowl to humans, persons should avoid contact with feces and carefully wash their hands with soap and water after handling young fowl or anything that has come in contact with them. Chicks, ducklings, and other young fowl may not be appropriate pets for children and should not be kept in households with infants, children aged <5 years, or immunocompromised persons. During investigations of Salmonella infections, especially during spring and Easter, health-care workers and public health personnel should consider contact with young fowl as a potential source and obtain cultures from these animals if they are suspected as the source of infection.
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