Infectious Disease Epidemiology Program

Salmonellosis summary

Salmonellosis is a gastrointestinal illness caused by Salmonella bacteria. Symptoms include fever, cramping, diarrhea, nausea and vomiting. This illness may be asymptomatic or invasive and may lead to an infection outside of the intestines, or a more severe infection in the bloodstream. The severity of this illness depends on the age and health of the infected person, the serotype of salmonella and the site of the infection. Salmonella bacteria are most often transmitted through ingestion of contaminated meat, poultry, eggs, unpasteurized dairy products and fresh produce.

Transmission also occurs through handling reptiles, chicks, domestic birds and pets, without thoroughly washing hands. Salmonella cases may go unreported despite clinical symptoms.

In 2007, a total of 138 salmonellosis cases were reported to the Maine CDC, 119 culture-confirmed cases and 19 probable cases (clinically compatible and epidemiologically linked cases). This represents an overall rate of 10.5 cases per 100,000 population. This rate is consistent with the previous five years and is below national rates (see graph). Eighty-three (60%) of the reported cases were female and fifty-five cases (40%) male. The median age was 41 years, with a range of 3 months to 90 years.

Serotypes enteritidis, typhimurium and newport were the three most commonly reported serotypes. There were no cases of Salmonella typhi (Typhoid Fever). Eighty-seven cases (70%) were from exposures within the state of Maine, three cases (2%) were from exposures in other states and twelve cases (10%) were from exposures in other countries. Twenty-two cases (18%) had no known origin of infection.

Five cases (4%) were child care attendees; 62 cases (50.8%) had contact with reptiles, birds or other animals. Five cases (3.9%) were food handlers at the onset of illness. Thirty-seven cases (30.1%) were hospitalized due to the illness.

Salmonella is more common in the summer months. The graph of cases by month shows this trend. The increase in the number of cases in September and October was due to two outbreaks.

Consumers should recognize the risk associated with consuming improperly prepared or cooked eggs, poultry, or meat, raw milk or unpasteurized dairy products and juices. Thorough washing of produce, consuming pasteurized products and following proper cooking instructions reduces this risk. Individuals having contact with reptiles (snakes, lizards, turtles, frogs, water dragons, iguanas, etc.), birds, farm animals and pets should wash their hands immediately after handling these animals. Reptiles, chicks and baby ducks are not recommended in households or childcare facilities with children under 5 years of age. All childcare, healthcare and food handlers with symptoms of Salmonellosis should have stool specimens tested and remain out of work until asymptomatic.