Possible Local Malaria Case Under Investigation in Pierce County

Tacoma–Pierce County Health Officer Dr. James Miller emphasized that, even if this transmission is confirmed, the risk remains extremely low: malaria is exceedingly rare in the U.S., and most cases are linked to travel abroad, he noted.

Malaria is caused by a parasite passed through mosquito bites. Symptoms can include fever, chills, body aches, headaches, fatigue, nausea, vomiting, and diarrhea, and generally appear seven to 30 days after infection. Importantly, the disease does not spread person-to-person without mosquitoes as the vector.

Annually, the U.S. records about 2,000 to 2,500 malaria cases, most tied to travel, while Washington typically sees between 20 and 70 reports per year. Notably, the state’s latest prior locally transmitted case was reported in 2023, the first such event in two decades.

In response to the current situation, public health teams are trapping and testing local mosquito populations in Pierce County. Fortunately, officials report that mosquito numbers are declining this season.

Malaria can be effectively treated with prescription antimalarial medications, but it can be life-threatening if diagnosis or treatment is delayed. To lower the risk, health advisors recommend avoiding mosquito bites through the use of insect repellent, wearing long-sleeved clothing, and seeking prompt medical care—especially for people returning from malaria-prone regions.