Malaria surveillance--United States, 1999

Area of Science:

• Infectious Diseases
• Parasitology
• Epidemiology

Background:

• Malaria is a mosquito-borne protozoan disease caused by Plasmodium species.
• Most U.S. malaria cases are imported from endemic regions.
• Surveillance is crucial for identifying local transmission and informing prevention strategies.

Purpose of the Study:

• To report and analyze malaria cases in the U.S. during 1999.
• To identify trends in malaria incidence and geographic sources of infection.
• To assess compliance with malaria chemoprophylaxis among travelers.

Main Methods:

• Data collected through the National Malaria Surveillance System (NMSS).
• Analysis of confirmed malaria cases with symptom onset in 1999.
• Comparison of 1999 data with 1998 reported cases.

Main Results:

• 1,540 malaria cases reported in 1999, a 25.5% increase from 1998.
• Plasmodium falciparum was the most common species (46.0%).
• Increases in cases acquired in Africa (27.6%) and the Americas (19.7%) were noted.

Conclusions:

• The rise in malaria cases may be linked to reporting system changes, increased travel, or reduced chemoprophylaxis use.
• Many U.S. civilians acquiring malaria abroad were not on recommended preventive medication.
• Prompt diagnosis and treatment are vital; travelers must follow prevention guidelines.