The Resurgence of Malaria in the United States: A Medical Entomology Perspective 

If you’ve ever lived or vacationed in a mosquito-friendly environment, you’re probably all too familiar with the itchy frustration that comes with always being on the lookout for those pesky insects. With the unexpected reappearance of malaria in the United States, the need to spray ourselves with mosquito repellant and continually pour out any stagnant water in our backyards has become even more of a necessity. 

There were just nine reported cases of malaria in the U.S. in 2023. But should we be concerned about a possible resurgence? Today, we’re delving into the reemergence of malaria to discern whether a widespread return of this ancient disease is possible. 

What Is Malaria? 

Malaria is a disease caused by a parasite. It’s not transmitted directly from person to person but rather through infected mosquitoes that transmit the parasite to the host when they bite. The disease can cause several severe symptoms, including: 

  • Fever 
  • Headaches 
  • Nausea and vomiting 
  • Fatigue 
  • Body aches 

According to the World Health Organization, there were approximately 249 million cases of malaria globally in 2022, with around 608,000 resulting in death. The disease is most prevalent in warmer climates, particularly in parts of Africa south of the Sahara, where transmission rates are highest. Within that area, children under five years old account for approximately 80% of deaths related to malaria. 

How Society Eradicated Malaria in North America 

Cases of malaria within the United States persisted until the 1950s, when it was finally eradicated from the country. Before that, however, it was believed that a malaria-causing parasite was brought to North America by people from Africa who had been enslaved and brought by force, as well as by travelers from nations such as Spain and Portugal. 

Upon their arrival in North America, Anopheles mosquitoes were already present, ready to greet the newcomers by feeding on their infected blood. From there, mosquitoes carrying the disease would transmit the malaria-causing parasite to new hosts as they continued to feed. 

It wasn’t until hundreds of years later, when scientists better understood how malaria was transmitted, that they could begin the difficult work of reducing the spread of the disease. Prevention efforts began during World War I and consisted of: 

  • Building improved housing that included window screens. 
  • Implementing malaria-preventing drugs. 
  • Crafting better diagnostics for malaria. 
  • Reducing the mosquito population using several strategies, including: 
  • Fumigating mosquito-prone areas with insecticides. 
  • Eliminating breeding grounds for mosquitoes by draining standing bodies of water. 

The Comeback Kid: Potential for a Malarial Resurgence in North America 

The United States remained free of locally acquired malaria for 20 years. In August of 2023, however, the U.S. reported nine new cases: one in Texas, one in Maryland and seven in Florida. 

While the U.S. typically sees approximately 2,000 cases of imported malaria (where individuals become infected in other countries and bring the infection back) annually, these nine new cases were reported to be locally acquired. This indicates that individuals contracted the disease from mosquitoes local to the area that were already infected by the parasite. 

Fortunately, no additional cases were noted in the following weeks, and there is no serious concern from the perspective of the medical entomology community. Here’s why experts aren’t ready to sound the alarm just yet: 

  • Winter temperatures decrease mosquito populations. 
    As temperatures drop during the winter months, mosquito populations across the country decline until temperatures begin to rise again in the spring. 
  • Mosquitoes in the U.S. don’t bite humans as often. 
    The Anopheles mosquitoes responsible for most malaria cases in sub-Saharan Africa typically feed on humans 98% of the time. In contrast, the type of Anopheles mosquito found in the U.S. only feeds on humans 30% to 50% of the time, resulting in significantly fewer opportunities to infect potential hosts. 

Investigate the World of Arthropod-Borne Diseases at UF 

While a new malaria endemic isn’t a current cause of panic in the States, that doesn’t make it any less of a concern in many other areas around the world — and malaria isn’t the only disease that mosquitoes carry and transmit to innocent, unsuspecting hosts. If helping to eradicate this and other arthropod-borne diseases ignites a flame that can’t be put out, consider steering your path toward a career in entomology by earning a graduate credential in medical entomology. 

UF offers two entirely online medical entomology programs tailored to suit your interests and future career, including: 

Master’s Degree in Medical Entomology 

This 30-credit program combines the courses from our graduate certificate in medical entomology with a broad selection of courses that provide foundational knowledge of entomology, insect classification and ecological concepts. When you complete this program, you’ll have earned not one, but two career-advancing credentials you can add to your resume: 

  • Master of Science in Entomology and Nematology 
  • Graduate Certificate in Medical Entomology 

Graduate Certificate in Medical Entomology 

Our online graduate certificate comprises 15 credits of engaging courses that dive into advanced medical and veterinary entomology and mosquito biology. You can complete your certificate in as little as one year but have up to seven years to finish your coursework, giving you the ultimate flexibility to earn your certificate on your timeline

We’re proud to be the world’s number-one ranked entomology and nematology program, and we’re thrilled to have you join us as you prepare to advance your career in entomology. 

Apply today! 


Learn More About the Program

Click for details about the Entomology and Nematology program.