Perhaps the most well-known mosquito-borne disease, malaria is a health concern in tropical and subtropical areas around the world, including Sub-Saharan Africa, South Asia, Central America, South America, the Caribbean, Southeast Asia, the Middle East and Oceania. According to the Mayo Clinic, the disease kills approximately 660,000 people worldwide each year.
Fortunately, malaria is not a major threat in the United States, with most cases being diagnosed in patients who have traveled to high-risk areas.
Read on to learn more about what causes malaria and its symptoms
What is Malaria?
Malaria is caused by a parasite. When an infected mosquito bites a human, it can transmit that parasite to the human. The Centers for Disease Control and Prevention (CDC) notes that there are four primary types of malaria parasites responsible for infecting humans: Plasmodium falciparum, P. vivax, P. ovale and P. malariae. Of these, P. falciparum is the most likely to cause serious illness.
The Anopheles mosquito is the only species capable of spreading malaria. When females of this species bite an infected individual, they are exposed to the disease. If malaria parasites are present in the mosquito’s system, they mix with its saliva and, after 10-21 days, are potentially spread when it bites a human. Though this mosquito is found in the U.S., it’s important to note that it doesn’t carry pathogens that can cause malaria here.
Environmental factors, including temperature and humidity, affect the likelihood that a mosquito will become a vector, or capable of spreading the disease. Higher temperatures can speed up parasite growth. This may partially explain why malaria is so common in tropical climates.
Malaria parasites are found in red blood cells and, according to the CDC, this means the disease can also be spread through blood transfusions, organ transplants and sharing needles. The disease may also be spread from mother to child.
According to the Centers for Disease Control and Prevention, malaria symptoms can range from mild to severe and may even lead to death. The incubation period, or the time before symptoms become present, can range anywhere from 7 to 30 days.
Symptoms most commonly resemble the flu and may include any of the following:
- Nausea and vomiting
- Body aches
- General malaise
Severe malaria occurs when the infection is coupled with additional complications. These may include:
- Cerebral malaria, including seizures, coma or abnormal behavior
- Severe anemia
- Acute respiratory distress syndrome
- Low blood pressure
- Acute kidney failure
- Hypoglycemia (low blood glucose)
According to the CDC, patients infected with the P. vivax or P. ovale parasite may experience relapses months or years after surviving the initial infection. These are caused by dormant parasites in the liver that become active.
Currently, there is no vaccine for malaria. However, the disease can be treated by a range of prescription medications. The Mayo Clinic recommends that travelers visiting areas where malaria is a concern consult their doctor ahead of their trip. Doctors need to know the location of travel, as different medications target different types of malaria parasites.
Mosquito Bite Prevention When Traveling
Defending yourself against mosquitoes is a good way to help keep yourself from being bitten. If you are in an area where malaria is common, which does not include the U.S., the Mayo Clinic suggests:
- Spraying the walls of your home or building with insecticide to help prevent mosquitoes from coming inside, if you are traveling in countries where malaria is found
- Sleeping under a mosquito net to help prevent the insects from biting you while you sleep
- Covering your skin by wearing long sleeves and pants
- Using a repellent containing permethrin on clothing and one using DEET on skin