By: Freya Preimsberger

With summer comes sunscreen, popsicles, trips to the beach and an increased risk of contracting E. coli infections. Studies have found that E. coli infections peak in the summer, putting children at risk for illness. Although most children who become infected do not develop serious problems and recover without medical intervention, some may have severe complications. Children and their parents can take steps to prevent being infected with E. coli no matter what season it is.

E. coli is a species of bacteria that resides in the lower intestines of warm-blooded animals. While most strains of the bacteria are harmless or even an integral part of a healthy gut microbiome, some are pathogenic and secrete a toxin that causes their host to become ill.

In these cases, symptoms typically begin around a week after infection. They begin with severe abdominal cramps, which are followed by diarrhea a few hours later. The diarrhea may become bloody and be accompanied by a fever, nausea or vomiting. Although symptoms usually resolve within five to seven days without medical intervention, some people may develop severe complications that can put their health at risk. Certain populations, such as children, the elderly, pregnant women and those with compromised immune systems, are more prone to these complications. Children in particular are more prone to the complication hemolytic uremic syndrome, which is caused by the strain Shiga toxin-producing E. coli, according to the American Academy of Family Physicians. Those with hemolytic uremic syndrome need to be hospitalized and may show low red blood cell count, low platelet count, decreased urination, pale appearance, tiredness, seizures and kidney failure. If infected, it is advised to not give children anti-diarrheal medications or antibiotics because of the potential for increased complications. Children who are ill with E. coli should rest and drink fluids to prevent dehydration, and parents should contact a physician for medical advice.

Infection with E. coli is often caused by eating contaminated, improperly cooked food or by contact with contaminated animals. Healthy cows can carry E. coli in their intestines, and the bacteria may spread to the meat during the slaughtering process. Consuming beef infected with E. coli that has not been cooked to a high enough temperature can cause infection, in addition to drinking unpasteurized milk or juice and consuming produce or water contaminated with animal feces. Children may also come into contact with E. coli from their families or in child-care and institutional centers. Swimming in or drinking contaminated water can also transmit the bacteria. Lastly, bacteria can be spread from the feces of contaminated persons, especially if good handwashing practices are not being used. This is more commonly seen in toddlers, who may not be toilet-trained. Children will usually shed the bacteria in their feces for one or two weeks after their illness resolves, and should not swim during that time.

Multiple studies have shown that there is a rise in the number of E. coli infections during the summer months, although the bacteria thrive year round. One study, published in the journal Environmental Microbiology in 2010, examined this trend in Great Britain and found that a combination of changes in the bacteria, host, environment and human behavior is likely responsible for the increase in illness. One finding is that fecal shedding of the bacteria increases in the summer. Although the mechanism causing the spike in shedding is unclear, it increases the amount of bacteria departing from animal reservoirs and the number of infections. Other studies have linked the increase in infection to a decrease in melatonin levels, which have been implicated in immune function, in the summer, when days increase in length. More rainfall leads to more infections as animal feces is more likely to contaminate fields or bodies of water. The Environmental Microbiology study also pointed out people’s behavioral changes in warm weather as a factor; camping and spending time outdoors, which come with poor sanitation facilities and cooking and eating outside, can contribute to risk of infection. People also set up camp on contaminated fields, increasing their likelihood of becoming ill. A 2009 study published in Clinical Microbiology and Infection by Duke University Medical Center researchers looked at a population of Americans in Minnesota to shed light on why the increase in infections with E. coli in summer may occur, namely in bloodstream infections in the elderly. The incidence of bloodstream infections with E. coli increased by an estimated seven percent for each ten degree Fahrenheit increase in temperature. The study also names contamination of food and water with bacteria-causing E. coli during warm weather as a potential cause, but cautions that this link may be confounded by other variables not taken into account. It cites seasonal changes in human behavior as a possible factor, with changes in travel, dietary practices, sexual activity and water exposure potentially increasing risk of infection. The researchers call for additional research on seasonal infections of E. coli and using those results to reduce incidence of infection.

Children and their parents can take several precautions to prevent infection. The most common way infection occurs is through food. Meat, especially beef, should be cooked to a safe internal temperature and never consumed raw. When preparing food, parents should wash their hands after touching raw meat and take care to ensure that cross-contamination of food surfaces does not occur. Raw meat should be stored separately from other types of food and defrosted in the refrigerator or the microwave, rather than at room temperature. Food should be immediately frozen or refrigerated if not eaten. It is also important to rinse produce thoroughly, especially if they’re being eaten raw, as they might be contaminated with bacteria. Parents should make sure that their children do not consume unpasteurized juice or dairy products. E. coli can also be transmitted person-to-person, such as in daycare centers. Children and parents should wash their hands thoroughly after using the bathroom, especially if they have diarrhea. Parents should not send their children to daycare or allow them to swim if their child has diarrhea from E. coli to prevent spreading the infection to others. If you have questions on infections with E. coli, you can call 1-800-CDC-INFO for more information.