Mosquito-transmitted malaria acquired in Texas

Malaria was endemic in the United States before World War II. However, locally acquired malaria was thought to have been eradicated. Since the mid-1980s, cases of locally acquired malaria have been described. We report the case of a 62-year-old man who came to the Houston Veterans Affairs Medical Center with fever, malaise, and weakness and was found to have Plasmodium vivax infection on peripheral blood smear. He had not left the country for 37 years and had no previous history of malaria. On specific questioning, he mentioned heavy exposure to mosquitoes. Thus, malaria was presumably transmitted locally by mosquitoes. Subsequently, two other cases of apparently locally acquired, mosquito-transmitted malaria were identified in Houston. Symptoms, signs, and general laboratory test results do not typically suggest a specific diagnosis. Therefore, malaria should be considered in all patients with febrile illnesses, even those without a history of travel.