Notes from the Field: Increases in Imported Malaria Cases - Three Southern U.S. Border Jurisdictions, 2023

Area of Science:

• Public Health
• Infectious Diseases
• Epidemiology

Background:

• Malaria, a severe mosquito-borne illness caused by Plasmodium parasites, is not endemic in the U.S.
• Imported malaria cases are annually reported, primarily affecting U.S. residents traveling to endemic areas.
• Sporadic locally acquired malaria cases were noted in the U.S. in 2023.

Purpose of the Study:

• To describe the increase in imported malaria cases in 2023 compared to 2022.
• To analyze trends in three public health jurisdictions along the U.S. southern border.

Main Methods:

• Retrospective analysis of imported malaria cases.
• Comparison of case data between 2022 and 2023.
• Focus on public health jurisdictions bordering endemic regions.

Main Results:

• A notable increase in imported malaria cases was observed in 2023 compared to 2022.
• This increase was particularly evident in specific public health jurisdictions along the U.S. southern border.
• The findings indicate a heightened risk of malaria importation in these areas.

Conclusions:

• The observed rise in imported malaria cases warrants attention and surveillance.
• Public health strategies may need to be adapted to address increased importation risks.
• Continued monitoring is crucial, especially in border regions and for travelers.