The Oklahoma State Department of Health (OSDH) continues to search for the source of a Salmonella outbreak among Mustang Public School students and other Oklahoma residents who became ill with salmonellosis in September.
Laurence Burnsed, an epidemiologist with OSDH, told Food Safety News that as of Oct. 1, 15 individuals had been identified as part of the outbreak. Two of those cases were included in the case-count Friday after interviews were conducted with Mustang elementary school students and their parents.
Burnsed said all cases had an onset of illness between September 2 and 13, and that additional cases could surface through the interview process or through laboratory testing. Thus far, 12 students from 4 Mustang Elementary Schools, which are located in Canadian County; 2 adults from Oklahoma County; and 1 adult from Carter County have been confirmed ill with Salmonella. The serotype, or strain, of Salmonella associated with the outbreak is Java.
As of Oct, 1 the state health department had interviewed 60 people, including 15 cases and 45 non-ill controls, in an attempt to determine which exposures could have led to illness. Burnsed said investigators are still considering all potential sources of illness and that food is not the only suspect source.
Salmonella is a zoonotic disease, or a disease that can be transferred from animals to humans. It can be isolated animals such as chickens, turkeys, pigs, cows, turtles, reptiles, and birds. Salmonella bacteria can be spread through various modes of transmission, including through food and water sources, animal-to-human contact, and person-to-person contact.
In a message to parents posted on the Mustang Public Schools Website, Deputy Superintendent Belinda Rogers stated, “There are many factors that could cause cases of [S]almonella and it’s important to provide as much information as possible. Mustang Public Schools’ Child Nutrition Department has a stellar record, and we want to assure our parents salmonellosis is not necessarily related to food preparation. Salmonella begins with a contaminated product, and we are working diligently with the State Department of Health officials to determine the origin of the cases.”
Editor’s note: Food Safety News learned Oct, 2 that public health officials in Nebraska and Iowa are investigating Salmonella outbreaks that may be linked to the Oklahoma Salmonella outbreak.
Sources of Salmonella
Salmonella is most commonly transmitted through contaminated food or water, and is often associated with the consumption of eggs or poultry products.
The introduction of pasteurization greatly reduced the number of foodborne illness outbreaks associated with milk and other dairy sources; however, the consumption of raw milk and unpasteurized cheeses remains a risk factor for Salmonella infection. Salmonella and other pathogens are shed in the feces of livestock such as cows and goats and can contaminate milk during the milking process.
Fresh fruits and vegetables can become contaminated before or after harvest. Contaminated seeds, irrigation water, and flooding have contributed to Salmonella outbreaks traced to sprouts, lettuce, and other fresh produce. Unpasteurized orange juice has been the source of several Salmonella outbreaks.
Water intended for recreation (e.g., pools, shallow lakes) and for human consumption can also become tainted with Salmonella. When lakes become contaminated with Salmonella, several weeks or months can be required for water quality conditions to improve or return to normal. Proper chlorination resolves Salmonella contamination issues in pools and municipal water systems.
Person-to-person transmission of Salmonella occurs through a fecal-oral route, and is particularly common among infants and young children who have not yet developed hygienic practices conducive to stopping the spread of Salmonella. Other person-to-person transmission of Salmonella has been known to occur between infected individuals and their caregivers, and between infected food handlers and people who consume the food they prepare.
Symptoms of Salmonella infection, or salmonellosis, include diarrhea, abdominal cramps, fever, nausea and/or vomiting. In mild cases diarrhea may be non-bloody, occur several times per day, and not be very voluminous; in severe cases it may be frequent, bloody and/or mucoid, and of high volume.
Fever generally occurs in the 100°F to 102°F (38°C to 39°C) range. Vomiting is less common than diarrhea. Headaches, myalgias (muscle pain), and arthralgias (joint pain) are often reported as well. Whereas the diarrhea typically lasts 24 to 72 hours, patients often report fatigue and other nonspecific symptoms lasting 7 days or longer.