What is malaria and how concerned should people be in the US? Our medical analyst explains

CNN

In an alert issued this week, the US Centers for Disease Control and Prevention warned clinicians of locally acquired malaria cases in Florida and Texas. Four cases were identified in Florida and 1 in Texas in the last two months. The vast majority of malaria cases occur outside the United States, even though thousands of Americans are sickened each year by the disease. According to the CDC, these cases are the first malaria transmissions in the US for 20 years.

Malaria, a mosquito-borne illness that causes 241 million cases of infection worldwide each year, is 95% found in Africa and the World Health Organization's African Region. Many readers are curious about the disease, which is rare in America.

What are the symptoms of malaria? Is it spread by casual contact? How is it treated and diagnosed? Is there a vaccine or another way to prevent malaria? Why have there been cases in the US recently? How worried should people feel about contracting the disease?

Leana WEN, CNN Medical Analyst, helped me answer these questions. Wen is a professor of health management and policy at George Washington University Milken Institute School of Public Health. She is also an emergency physician. She was previously Baltimore's Health Commissioner.

CNN: What are the symptoms of malaria?

Dr. Leana WEN: Malaria can be a life-threatening and serious disease caused by parasites that are spread by Anopheles mosquitoes. Five types of malaria parasites are found in a family called Plasmodiidae. Plasmodium flaciparum, the most common type of malaria parasite that causes severe and fatal infections in sub-Saharan Africa as well as parts of South Asia, is responsible for a large amount mortality.

The type of Plasmodium that has been found in locally acquired cases is P. vivax. Although it causes a less severe illness than P. falciparum it is still an emergency situation and should be treated immediately. Plasmodium can remain in the liver, causing relapsing diseases. This is yet another reason to diagnose and treat promptly.

Malaria symptoms can range from mild up to severe. High fevers, throbbing head pains, shaking chills and muscle aches are some of the symptoms. A person may develop anemia and jaundice, as well as yellowing of the skin and eyes due to destruction of red cells. Untreated malaria can cause seizures, kidney failure and coma.

According to the World Health Organization, in 2021, malaria will kill approximately 619,0000 individuals worldwide. The majority of deaths are in children under the age of 5. Pregnant women and people with HIV/AIDS are also at a higher risk for severe outcomes.

CNN: Can malaria spread by casual contact?

Malaria is an infectious illness, but it does not spread person-to-person. It's a vector-borne illness, which means that it is spread by another organism, in this case the Anopheles Mosquito. The mosquito has to bite a person with malaria, and then bite another individual in order to spread the disease. It is not possible to get malaria from breathing the same air as someone with the disease or by sharing utensils. Malaria cannot be transmitted sexually. Malaria can spread via blood transfusions and by sharing needles with infected people.

CNN: How can malaria be diagnosed and treated?

Malaria can be diagnosed by a blood test, which looks for the Plasmodium parasite using a microscope. A prompt diagnosis is crucial because it allows for treatment to be started, which is essential to prevent the progression of severe disease. If malaria is detected in an area that does not have a local transmission of the disease, public health officials can trace its origin and take measures to prevent further spread.

Malaria can be treated with a variety of medications. According to CDC guidelines they are tailored according to the type and location of Plasmodium detected, as well as any specific characteristics. There may be different treatment options for pregnant women or children. Malaria that is severe will usually be treated by an injection, while milder forms can be treated using an oral medication. These antimalarials work quickly and should be taken as soon as possible. The CDC alert was issued so that hospitals and clinicians could be aware of possible malaria cases.

CNN: Is there a vaccine available?

Wen: The World Health Organization began recommending the widespread use of the only and first malaria vaccine, in 2021. This was for sub-Saharan Africa as well as other areas of the globe where malaria transmission is moderate to high. According to WHO, this vaccine, also known as RTS/S/AS01, or Mosquirix has been shown to reduce deadly and severe malaria by 30%.

CNN: How can malaria be prevented?

It is generally recommended that travelers to malaria-endemic areas take preventive medications or prophylactic medication during their trip. At this time, the vaccine is not generally recommended for travel.

In addition to what doctors call chemoprophylaxis (prevention through medication), people can also prevent mosquito bites using DEET-containing insect repellant, wearing long sleeves, pants and mosquito nets, among other measures. The CDC offers excellent tips on how to control mosquitos in your area, including removing any standing water which could be a breeding ground for mosquito larvae. These steps not only reduce the risk for malaria, but also other mosquito-borne diseases.

CNN: What is the cause of the recent malaria cases in America?

Wen: The situation is not new. Malaria was once endemic to warmer areas of the US. A federal agency, which is now the CDC, was able to eliminate malaria. The methods used included improved sanitation, widespread use of insecticides and medical treatments which interrupted transmission.

Since 2003, the US has not seen a case of locally transmitted malaria. This recurrence of malaria is alarming and threatens to reverse the progress that was made in previous decades. The new cases may be due to increased travel, which brings in more cases of malaria. Also, warmer temperatures could facilitate greater Anopheles activity. Clinicians must remain alert to possible cases of malaria, even in patients without a history of travel to malaria-endemic regions.

CNN: What should we be worried about when it comes to malaria?

The chances of contracting malaria for people who live in the US and do not travel to malaria-endemic regions is very low. There are currently five locally transmitted cases of malaria in Florida and Texas. Public health officials and clinicians should be on alert, but the general public shouldn't be. The public should not try to get the malaria vaccine or take medications to prevent it.

Everyone should, of course, work to reduce mosquito populations around them and avoid mosquito bites wherever possible. If people travel to areas where malaria transmission is widespread, they should take preventive measures and possibly even preventive medication, as well as be alert for symptoms upon their return. Those who live in hot climates, and have an unexplained high fever, should consult their doctor.