Polio, an enterovirus, is the most notorious illness caused by a summertime virus. In the 1940s and '50s, parents often refused to let their children go outside and play because of the fear of the poliovirus. Children who were infected would have a mild sore throat and fever, and then within a few days, could develop meningitis and/or paralysis. Thankfully, because of routine immunizations, polio is close to being irradiated in most parts of the world.
There are other enteroviruss which can cause illnesses, such as group A and B coxsackieviruses, echoviruses and enteroviruses. These viruses usually cause mild respiratory (cough and runny nose) and gastrointestinal (diarrhea and vomiting) illnesses, but they can also cause more severe infections, such as aseptic meningitis, encephalitis and myocarditis.
Other common childhood illnesses that are caused by nonpolio enteroviruses include Hand, Foot and Mouth disease, caused by the Coxsackie A16 and Enterovirus 71 viruses. Children with Hand, Foot and Mouth disease can have blisters or ulcers in their mouth and on their hands and feet. Or, they can have ulcers just in their mouth, which is called herpangina.
Another common summertime virus is the parainfluenza virus 3. This virus can cause croup , bronchiolitis, pneumonia or just a cold. The characteristic barking cough of croup, which is often described as sounding like a seal, makes this virus easy to identify in the summertime. Overall, though, croup is more common in the winter.
Adenoviral infections are also more common in the winter, but they can also occur in the early summer. Symptoms can include fever, sore throat and other upper respiratory tract infections. Adenovirus can also cause pharyngoconjunctival fever, with a sore throat, fever and red eyes without discharge or matting.