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Summer colds offer lessons on the profusion of viruses

Everyone looks forward to summer – time to get away, get outside and have some fun. So what could be more unfair than catching a cold when it’s hot outside? How can cold symptoms arise when it’s not cold and flu season? Is there any way to dodge the summertime sniffles?

Cold symptoms can be caused by more than 200 different viruses. Each can bring the sneezing, scratchy throat and runny nose that can be the first signs of a cold. The colds we catch in winter are usually triggered by the most common viral infections in humans, a group of germs called rhinoviruses. Rhinoviruses and a few other cold-causing viruses seem to survive best in cooler weather. Their numbers surge in September and begin to dwindle in May.

During the summer months, the viral landscape begins to shift. Enteroviruses can infect the tissues in your nose and throat, eyes, digestive system and elsewhere. They’re the second most common type of virus – after rhinovirus – that infects humans. Nationwide, enteroviruses cause an estimated 10 million to 15 million illnesses each year, usually between June and October.

Enteroviruses can cause a fever that comes on suddenly. Body temperatures may range from 101 to 104 degrees. There can also be mild respiratory symptoms, sore throat, headache, muscle aches and gastrointestinal issues like nausea or vomiting. The summer colds generally clear up without treatment within a few days or a week. But see a health care provider if you have disconcerting symptoms, like a high fever or a rash.