Mosquito bites are easy to treat as a nuisance until the trip, cookout or evening walk is already underway. This summer, the better habit is to check the risk before you pack, then make bite prevention part of the plan.

The reason is practical. On July 1, 2026, CDC said West Nile virus season in the United States had started earlier than usual, with the highest number of human disease cases reported by that point in the year since 2004. CDC also keeps a global dengue travel notice active for countries reporting higher-than-usual dengue activity or higher-than-expected cases among returning U.S. travelers.

That does not mean every mosquito bite is dangerous. It does mean travelers, parents and anyone spending time outside should know which mosquitoes are more likely to matter, what to pack, and when symptoms should prompt a call to a clinician.

The short answer is simple: treat repellent, sleeves and screened sleeping space like normal travel gear, not emergency gear. The checklist matters most when evenings are humid, lodging is open-air, or the itinerary includes parks, beaches, backyard gatherings or destinations with current dengue notices.

Do this first

  • Pack EPA-registered repellent. Use it as directed, especially around dawn, dusk and humid outdoor settings.
  • Choose clothing that blocks bites. Long, loose-fitting sleeves and pants make it harder for mosquitoes to reach skin.
  • Check screens and air conditioning. CDC recommends sleeping in air-conditioned rooms or rooms with intact window screens when traveling in dengue-risk areas.
  • Limit dusk-to-dawn exposure when West Nile is the concern. CDC says the mosquitoes that spread West Nile virus are most active during those hours.

Check these details before travel

For dengue, start with the destination. CDC says dengue is common in many parts of the Americas, Africa, the Middle East, Asia and the Pacific Islands, and nearly half of the world's population lives in areas with some risk. The agency's July 6, 2026 risk page says travelers should use country-specific travel information before they go.

For West Nile virus, think locally. CDC said 23 states had reported West Nile virus activity by June 30, 2026, and that state and local health departments may have more current data than national dashboards because reporting can lag.

Common mistakes

Do not rely only on the time of day. Dengue is spread by mosquitoes that can bite during the day, while West Nile prevention guidance emphasizes dusk and dawn. Do not wait until the last night of a trip to use repellent. And do not assume a high floor, hotel room or short walk removes the need for screens, sleeves or repellent.

When to get help

Dengue can cause fever, headache, nausea, vomiting, rash, muscle and joint pain, and minor bleeding, and severe dengue is a medical emergency. West Nile virus often causes no symptoms, but CDC says about one in five infected people develop fever and other symptoms, while fewer than one percent develop severe neurologic disease. Seek medical advice promptly for concerning symptoms after travel or after heavy mosquito exposure, especially for older adults or people with underlying conditions.