Malaria surveillance--United States, 2011.

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health Surveillance

Background:

• Malaria is transmitted by Anopheles mosquitoes and primarily affects travelers to endemic regions.
• While rare, domestic malaria transmission, laboratory exposure, and transfusion-related cases occur in the U.S.

Observation:

• In 2011, 1,925 malaria cases were reported in the U.S., a 14% increase from 2010, marking the highest count since 1971.
• Plasmodium falciparum was the most common species (49%), followed by P. vivax (22%).
• Severe malaria cases increased significantly, and five deaths were reported.

Findings:

• Only 6% of U.S. civilians with known travel history and chemoprophylaxis use reported adherence to recommended antimalarial drugs.
• Visiting friends or relatives (VFR) travelers were a key demographic, with low adherence to chemoprophylaxis.
• Incomplete data reporting on case forms increased in 2011, impacting trend analysis.

Implications:

• Inadequate malaria prevention among travelers, particularly VFRs, necessitates targeted public health strategies.
• Improved data collection and reporting are crucial for effective malaria surveillance and prevention.
• Prompt diagnosis and appropriate treatment are vital for preventing severe outcomes and fatalities from malaria.