Texas and Florida have both identified local transmitted cases of malaria Plasmodium vivax strain. This is the first of such reports since 2003. Subsequently, the Center’s for Disease Control and Prevention (CDC) has advised clinicians to consider malaria for any patients presenting with fever of unknown origin, regardless of their travel history. Additionally, medical personnel with patients from these two sites of local malaria origin should adhere to any additional guidance from their state and local health departments.

In Florida, four cases were confirmed in Sarasota County and a single case identified in Manatee County. Per the CDC, those cases do not appear to have any connection to the single case in Texas, which was identified in Cameron County, located near Brownsville in the southernmost tip of the state. Active surveillance for additional cases is underway in both locations. This particular strain of malaria is carried by Anopheles mosquitos, which have historic range within the U.S. but have largely subsided since control measures were put in place in the 50s.

Although the CDC emphasizes that citizens are still at extremely low risk of contracting malaria, they encourage the public to remain vigilant about prevention methods (preventing mosquito bites as well as preventing mosquito breeding in general) to help avoid the spread of malaria and other mosquito-borne illnesses. Those traveling to areas where malaria is more common should consult with health professionals about preventive medications, they can take in advance to reduce the likelihood of infection.

Illness caused by P. vivax can be milder than other strains, especially P. falciparum or P. knowlesi, but still warrants prompt medical attention. The CDC emphasizes that suspect patients should seek medical evaluation and diagnosis within 24 hours of symptom onset. For most people infected, symptoms start approximately 10 days to a month after infection, but it can range from as little as a week to as long as a year. Symptoms include fatigue, fever, chills, headache, and myalgias (muscle aches and pains). Of more concern, P. vivax and P. ovale have the potential to stay dormant in the liver and, if left untreated, can result in chronic infection and further relapses for years.

For the full CDC Health Advisory visit: https://utmb.us/8zp

What you need to know:

• Four cases of locally acquired malaria (P. vivax) in Florida and a single case in Texas have been confirmed.

• With increased international travel forecast for this summer, there may be more imported malaria cases ahead.

• Clinicians should suspect malaria for patients with fevers of unknown origin and consider having first-line treatment options readily available.

What you can do

For Public:

• Prevent Mosquito Bites
  • Use insect repellent.
  • Wear loose-fitting, long-sleeved shirts and pants.
  • Proactively control mosquitos indoors and outdoors.
  • Take preventative measures when traveling internationally.

• Find tips and best practices for mosquito prevention from the CDC at:
  • Mosquito Control for Your Home: https://utmb.us/8zr
  • Mosquito Bite Prevention: https://utmb.us/8zs

For Clinicians:

       Malaria Prevention, Diagnosis, and Treatment

• CDC Treatment of Malaria: Guidelines for Clinicians (United States)
• CDC – DPDx – Diagnostic Procedures
• Malaria | CDC Yellow Book 2024
• CDC Malaria Information and Prophylaxis, by Country
• CDC – Parasites – Continuing Education – Malaria 101 for the Healthcare Provider
• CDC – Malaria – Travelers – Risk Assessment

       Mosquito-Borne Disease Prevention

• Prevent Mosquito Bites | Mosquitoes | CDC

References