Mosquitoes.

They make people itch. They make people mad. And sometimes, they make people sick.

Heavy spring rain, followed by warm weather and frequent rain in June, have led to a high mosquito population this year, which raises concern over disease awareness and effective repellents, said John VanDyk, an entomology graduate student.

The mosquito-borne encephalitis viruses can affect birds, small mammals and occasionally horses and humans.

“In the spring there are a lot of nestling birds with no feathers—easy targets for mosquitoes. At some point, as the mosquito population increases, there are not enough birds to go around anymore. Plus, the birds are beginning to spout feathers and defend themselves from mosquitoes,” VanDyk said. “If the birds run out, that’s when the mosquitoes can turn to humans.”

Dr. Robert Patterson, director of the Iowa State Student Health Center, said that cases of mosquito-related disease are very rare in Iowa, but are still a concern.

In Iowa, there were four cases of encephalitis reported last year, but Patterson said those cases were probably contracted by travlelers who returned to Iowa.

Malaria used to be the main disease associated with mosquitoes, but community mosquito control programs have all but eliminated the disease in Iowa, Patterson added.

DEET-based insect repellents provide the best repellent, but high concentrations of the substance can be harmful to children, Patterson said. He recommended a 15 percent solution of DEET for children.

The most common health hazard from mosquitoes, itchy bites, can be treated with antihistamines and ice, Patterson said. Heat makes bites itch more, and scratching bites can lead to secondary infections.

Citronella candles can be effective mosquito repellents in enclosed rooms with no wind, but outdoors they will not repel mosquitoes like a repellent that is applied to the skin, VanDyk said.

Mosquito bites can be avoided by not going near mosquito-infested areas along water without proper insect repellents, especially at peak mosquito hours in the morning and the evening, Patterson said.