First Suspected Local Malaria Case in Washington Raises Public Health Concerns

United States: Health officials are investigating what may be the first locally acquired case of malaria ever recorded in Washington.

A woman in Pierce County, who has not traveled recently, was diagnosed with the disease on Saturday. She is receiving treatment, and her condition is being closely monitored.

While malaria in the US is usually linked to travel, officials believe the most likely explanation is that a local mosquito bit someone with a travel-related case of malaria and later transmitted it to the patient.

“The risk of getting malaria in Pierce County is very low,” said Dr. James Miller, the county’s health officer. “It’s a rare disease in the US, and almost all cases happen after travel to countries where malaria is still common.”

In response, the Tacoma-Pierce County Health Department and the Washington State Department of Health are setting and testing mosquito traps in the area.

Washington typically reports 20 to 70 malaria cases each year — all tied to travel. Across the US, there are usually 2,000 to 2,500 cases annually. Between May and October 2023, however, 10 locally acquired cases were reported in four states — the first in two decades.

Malaria is transmitted by Anopheles mosquitoes, which are found in parts of the US. If they bite someone carrying the parasite, they can infect others.

Symptoms include fever, chills, sweating, and headaches. In some cases, it can also affect the stomach, lungs, muscles, and nervous system.

Malaria in the US — Rare but Possible

• Washington reports 20–70 malaria cases annually, all of which are linked to travel.
• Across the country, 2,000–2,500 cases are reported annually.
• Last year, 10 locally acquired cases were found in four states — the first such cases in 20 years.

Malaria is transmitted by Anopheles mosquitoes, which are found in certain regions of the US. If they bite an infected person, they can carry the parasite to others.

Symptoms to Watch For

• Fever and chills
• Sweating
• Headaches
• In some cases: stomach upset, cough, muscle pain, or confusion

If you develop these symptoms — especially after travel — seek medical help immediately. Early treatment is critical.

How to Protect Yourself and Your Family

1. Use insect repellent — Choose one with DEET, picaridin, or oil of lemon eucalyptus.
2. Cover up — Wear long sleeves and pants when outdoors, especially at dawn and dusk when mosquitoes are most active.
3. Install window and door screens — Keep mosquitoes from getting inside your home.
4. Remove standing water — Empty buckets, bird baths, clogged gutters, or anything else where mosquitoes can breed.
5. Use mosquito nets if camping — They create a physical barrier while you sleep.
6. Stay alert after travel — If you return from a malaria-prone country, watch for symptoms and get checked if you feel unwell.