The Centers for Disease Control and Prevention issued a warning as the summer approaches that insect-borne illnesses are on the rise.

The CDC says that diseases from insects like ticks, fleas and mosquitoes have been sharply increasing over the last decade. Cases of Zika, West Nile and Lyme disease have tripled since 2004, according to the center.

The CDC also says that state and local health care agencies are not prepared to deal with potential outbreaks.

Scientists say that there are several reasons for the increase in cases, including climate change and more Americans living in wooded areas.

The CDC advises people to wear long sleeves and long pants if they are out in fields or wooded areas. Wearing light colors is also advised so that the insects are easier to spot.

People should also carry and use insect repellant approved by the Environmental Protection Agency.  Boots and shoes can be treated with the insecticide permethrin, according to the CDC.