Kids are off school, it's sunny, it's warm -- so how is it that people are still being sidelined with a runny nose, fever, cough, or intestinal infection?
Contrary to popular belief, there are still plenty of viruses going around, and two in particular are especially common even with nice weather. In the summer we don't usually have to contend with influenza -- that is mainly a winter illness -- and it is true that viruses that cause colds are more prominent in the winter.
But there are countless viruses that can cause problems for people in the summer. We do see an increase in enterovirus infections. These viruses spread in the usual way: from touching contaminated surfaces or via coughing and sneezing. But they also spread from exposure to stool, which makes public pools a potential source of spread.
Most of us aren't old enough to remember the times of polio epidemics, but polio is a type of enterovirus, and it most commonly spread in late summer through swimming pools before chlorination became common. In recent years a different non-polio enterovirus called EV-D68 has been in the headlines for its association to acute flaccid myelitis, a condition that seems to mimic elements of polio. EV-D68 infections are more common closer to the end of summer. Enteroviruses most commonly cause a fever, sore throat, vomiting and diarrhea.
Coxsackievirus is technically a type of enterovirus but it causes a very distinctive illness in children called hand foot and mouth disease. This also typically increases over the summer -- fever, painful ulcers in the mouth, sore throat, and a rash on the hands and feet are the most common symptoms.
Because we're talking about viruses, prevention really comes down to the same things: hygiene and handwashing. The fact is just about every virus still circulates in the summer, even winter rhinoviruses. So don't be surprised if you catch a cold even on a hot summer day.