In the United States, seven new cases of malaria have surfaced in Florida and Texas, according to the Centers for Disease Control and Prevention (CDC). These new cases have raised many questions and concerns. In a health advisory, the CDC notes that these seven cases were locally acquired and are the first in the U.S. since 2003.
According to the World Health Organization (WHO), nearly half of the world’s population was at risk of malaria in 2021, with nearly 247 million cases worldwide. WHO also notes that in 2021, 95% of malaria cases and 96% of malaria deaths occurred in Africa, with children under five accounting for about 80% of all malaria deaths.
How Is the Infection Transmitted?
According to the CDC, malaria is a serious and potentially deadly disease. It is transmitted through the bite of an infected female anopheline mosquito.
Malaria cases in the United States are mainly seen in travelers and immigrants returning from countries where malaria transmission occurs. Many of these countries are located in sub-Saharan Africa and south Asia.
This type of malaria is called “airport malaria.” It refers to malaria caused by infected mosquitoes transported rapidly by aircraft from a malaria-endemic country to a non-endemic country.
The CDC reports that every year, millions of U.S. residents travel to countries where malaria is present. About 2,000 cases of malaria are diagnosed in the United States every year, mostly in those travelers coming back from malaria-prone countries.
With an increase in international travel occurring after the COVID-19 pandemic, experts have predicted that more cases of malaria will occur in the U.S., according to a 2023 Clinical Infectious Diseases article written by researchers Jonathan S. Schultz, Kimberly E. Mace and Kathrine R. Tan.
Malaria is also transmitted when infected mothers transmit parasites to their child, either during pregnancy or during delivery. This type of malaria is called “congenital malaria.”
Blood transfusion is another way to transmit this disease. Getting malaria this way is very rare, but on average, only one case of transfusion-transmitted malaria occurs in the United States every two years according to the CDC.
The Florida Department of Health has urged people to protect themselves by using bug spray, avoiding areas where mosquitoes congregate and covering any exposed skin. Additional ways to protect yourself from malaria what’s known as “drain and cover.” For instance, you can stop mosquitoes from multiplying if you:
- Drain water from garbage cans, house gutters, buckets, pool covers, coolers, toys, flowerpots, or any other containers where water has collected.
- Discard old tires, drums, bottles, cans, pots, pans, broken appliances and other items that aren’t being used.
- Empty and clean birdbaths and pets’ water bowls at least once or twice a week.
- Cover boats and vehicles with tarps that don’t collect rainwater.
- Maintain your swimming pool and keep it appropriately chlorinated.
- Empty any plastic swimming pools when not in use.
Mosquitoes can also be kept out of homes by covering doors and windows with screens. It is also important to repair broken screens on any windows, doors, porches and patios so mosquitoes can’t fly into your home.
To protect yourself and other family members from malaria, cover your skin with clothing or use an appropriate repellent. For instance, you should:
- Wear shoes, socks, long pants and long sleeves in mosquito-prone areas. This type of protection may be necessary for people who must work in outdoor areas where mosquitoes are present.
- Apply mosquito repellent appropriately, and always use repellents according to the label. Repellents with DEET, picaridin, lemon oil, eucalyptus, para-menthane-diol, 2-undecanone and IR3535 are effective in keeping mosquitoes away from your skin.
- Use mosquito netting to protect children younger than 2 months old.
An individual risk assessment should be conducted for every traveler going to a malaria-prone country. For more information, check the CDC’s Malaria Risk Assessment for Travelers.
What Role Is Climate Change Playing in Malaria Transmission?
Climate change, coupled with higher global travel, may have increased the opportunities for malaria transmission, even in countries that have eliminated or controlled transmission. According to the United Nations and other sources, climate changes and higher temperatures may be a factor in increasing the migration of infected mosquitoes.
According to the United Nations, the El Niño weather cycle, higher rainfall and an increase in sea levels will results in more open areas and spaces with stagnant water that can attract mosquitoes. People traveling to countries where malaria cases are on the rise will bring their infections back to the United States, leading to the reemergence of locally acquired malaria.
What Are the Symptoms of Malaria?
According to the WHO, fever, headache and chills are the most common early symptoms of malaria. The symptoms usually start within 10–15 days of getting bitten by an infected mosquito. Severe illness and even death is possible among infants, children under five years, pregnant women, travelers, and people with HIV or AIDS.
If malaria is not treated promptly, it may progress to the life-threatening stage. Symptoms of advanced malaria include:
- Extreme tiredness and fatigue
- Impaired consciousness
- Multiple convulsions
- Difficulty breathing
- Dark or bloody urine
- Jaundice (yellowing of the eyes and skin)
- Abnormal bleeding
Anyone who has these severe symptoms should report to an emergency care center as soon as possible. Early treatment is crucial for stopping this infection and prevent it from becoming severe.
Also, malaria in pregnant women can lead to many complications. These complications include premature delivery or the delivery of a baby with a low birth weight.
What Is the Treatment and Vaccine for Malaria?
The CDC notes that treatment should be initiated as soon as possible after malaria’s symptoms are detected. Which drug regimen will be used to treat a patient with malaria depends on several factors, such as:
- The clinical status of the patient
- The type (species) of the infecting parasite
- The area where the infection was acquired
- The patient’s drug-resistance status
- The patient’s pregnancy status
- The patient’s history of drug allergies or use of other medications
Most medicines for treating this illness are taken in pill form, and the most common and effective drugs are called artemisinins.
Another medicine that has been used for decades is chloroquine phosphate, which is effective for treatment of infection with the Plasmodium vivax parasite, but only in places where the parasite is still sensitive to this medicine. Finally, another antimalarial drug called primaquine is also commonly offered to patients in conjunction with another treatment to prevent any relapse of infection.
In 2021, the World Health Organization recommended the use of a vaccine known as RTS,S/ASO1 for children who live in moderate- to high-risk areas. It is the first vaccine for a human parasitic infection to be developed. According to WHO, “More than 260,000 African children under the age of five die from malaria annually.”
Additional information regarding prevention, diagnosis, and treatment are available at the CDC’s website, including:
- Guidelines for Clinicians (United States)
- A treatment summary in decision-tree format
- A treatment summary in table format
- A malaria management algorithm document for the diagnosis and treatment of malaria
- CDC malaria clinicians, who are on call 24/7 to provide advice to healthcare providers
- Recommendations for hospitals and laboratories
- Recommendations for public health officials. Public health officials who are concerned about potential cases of locally acquired malaria should contact CDC’s Malaria Branch at firstname.lastname@example.org or 770-488-7788 during regular business hours. For assistance with recommendations and testing outside of business hours, another resource is the CDC’s Emergency Operations Center, available at email@example.com or 770-488-7100.
- Diagnostic procedures for healthcare providers
- The 2024 CDC Yellow Book
- Malaria information and prophylaxis, by country
- Malaria 101 for healthcare providers (a continuing education resource)
- Advice for preventing mosquito bites
The CDC continues to work closely with state health authorities to identify, investigate, and monitor any new or potential cases. If you plan to travel, be sure to research the risk of malaria at your destinations and talk to your doctors about preventive measures.