First Suspected Local Malaria Case in Washington State Raises Concerns

Health officials in Pierce County, Washington, are investigating a potential local case of malaria after a woman tested positive for the disease without recent travel history. This incident, reported by the Tacoma-Pierce County Health Department, marks a significant concern as it could represent the first locally acquired case of malaria in the state.

The woman was diagnosed with malaria on August 2 and is currently undergoing treatment. If the investigation confirms that her infection was contracted from a mosquito within Washington, it would be the first documented instance of malaria transmission west of the Rocky Mountains.

In collaboration with the Washington State Department of Health and the Centers for Disease Control and Prevention (CDC), local health officials are conducting an investigation to trace the source of the infection. Dr. James Miller, the health officer for Tacoma-Pierce County, emphasized that the risk of malaria transmission in the area remains very low. He noted that malaria is a rare disease in the United States, with the majority of cases occurring after individuals have traveled to regions with known outbreaks.

To effectively trace the source of the infection, health officials plan to trap and test local mosquito populations. Typically, cases of malaria in the U.S. are linked to international travel, particularly from sub-Saharan Africa, where malaria is prevalent. Each year, the United States records approximately 2,000 to 2,500 malaria cases, while Washington State sees between 20 and 70 reports of malaria among travelers annually. In 2023, the U.S. experienced its first locally acquired malaria case in two decades, with ten cases reported across four states: Florida, Texas, Maryland, and Arkansas, between May and October.

According to the CDC, about 95% of individuals who contract malaria in the U.S. have not used preventive medication. The disease is transmitted by mosquitoes and can cause symptoms such as fever, chills, body aches, headaches, and fatigue. If left untreated, malaria can lead to severe complications and may be fatal. However, effective treatment options are available through antimalarial medications.

Malaria has an incubation period that ranges from seven to thirty days, and it is important to note that it does not spread directly from person to person. Preventive measures against malaria include the use of antimalarial drugs, insect repellents containing DEET, and wearing long-sleeved clothing to minimize mosquito bites.

Currently, there are two malaria vaccines available, primarily targeted at children in regions with high rates of transmission, and they are not widely distributed in the U.S. The situation in Pierce County highlights the importance of vigilance and preparedness in addressing potential health threats from infectious diseases.