There are many diseases that follow seasonal patterns, especially infectious diseases.
For many people, it is not common to associate infections with the summer season because we are all most familiar with the winter cold and flu season. Yet certain infections are most common in the summer.
Among young children, common summer viral infections include a group of viruses known as enteroviruses. Some members of this family are notorious, such as poliovirus.
Members of my parents’ generation recall public-health admonitions to avoid swimming pools during the summer because of concerns about polio, a virus that can infect the nervous system and produce chronic paralysis. Like other enteroviruses, poliovirus is transmitted by the so-called fecal-oral route, in which fecal material contaminates water or hands and is transmitted to the mouth when the mouth is touched.
Fortunately, the development of an effective vaccine and its routine use has virtually eliminated polio except in a few remote areas of the world.
Other common enteroviruses, for which vaccinations do not exist, continue to produce summer illness, albeit not as severe as poliovirus. Common symptoms of enteroviral infection in young children can include fever and rash. Most such infections resolve without treatment or complication. Such infections can be avoided altogether through effective hygiene, such as hand-washing.
Other summertime infectious illnesses include those transmitted by bugs, such as mosquitoes and ticks.
Tick-borne diseases are endemic to many areas of the United States, including Colorado. Colorado tick fever affects up to 15 percent of campers in the state. It is caused by a tick-borne virus and produces fever and flu-like illness within a few days of the tick bite. Fortunately, symptoms usually resolve without treatment or complications once the tick is removed.
Lyme disease, which can cause rash, arthritis and neurological problems, is not common locally, but can affect summer travelers in the Northeast, Midwest and Pacific Northwest. Many other tick-borne illnesses are common in other parts of the United States.
Tick-borne diseases are preventable by wearing protective clothing, use of permethrin-containing insect repellants on clothing and skin and also by carefully inspecting for ticks after activities such as hiking or camping.
Summer infectious diseases are also transmitted by mosquitoes, including viral diseases caused by the arbovirus and flavivirus families of viruses.
Many such illnesses actually infect birds, horses and livestock, and are transmitted to people through a mosquito bite. Examples are western and eastern equine encephalitis, St Louis encephalitis and West Nile virus.
Most persons infected with mosquito-borne viral diseases such as West Nile virus remain asymptomatic but a small percentage of those infected will develop a flu-like illness. This often resolves without complication, but a very small percentage of those infected may suffer from serious neurologic problems including meningitis or encephalitis.
Preventing mosquito-borne diseases involves avoiding mosquito bites. Mosquitoes are most commonly found near water and are typically active in the cooler early morning and evening hours.
Dr. Matthew A. Clark is a board-certified physician in internal medicine and pediatrics practicing at the Ute Mountain Ute Health Center in Towaoc.