Malaria – Basic Information
Malaria is a mosquito-borne illness caused by a parasite. Malaria is most prevalent where mosquitoes are active – the warm and wet regions of the world. The CDC estimates there were over 200 million cases of malaria world-wide resulting in almost half a million fatalities (2016). The WHO estimates over 90% of malaria fatalities occur in Africa. 1700 malaria cases were reported in the US – mostly among travelers to malaria-endemic regions of the world.
CDC Malaria Prevalence Map – 2018
There is no effective malaria vaccine. Medications are available to prevent malaria infections for short stays. Other protective measures typically target prevention of mosquito bites – bed nets, protective clothing, repellants (DEET), and insecticides, especially Permethrin, are useful. Permethrin treated clothes may offer some additional protection.
Symptoms
In a non-immune individual, symptoms usually appear 10–15 days after the infective mosquito bite. The first symptoms – fever, headache, and chills– may be mild and difficult to recognize as malaria. If not treated within 24 hours, P. falciparum malaria can progress to severe illness, often leading to death. Children with severe malaria frequently develop one or more of the following symptoms: severe anemia, respiratory distress in relation to metabolic acidosis, or cerebral malaria. In adults, multi-organ involvement is also frequent. Pregnant women are particularly at-risk for severe malaria. In malaria endemic areas, people may develop partial immunity allowing largely asymptomatic infections to occur – WHO Fact Sheet. Travelers should make their healthcare providers aware of their travel history if they exhibit these symptoms within a few weeks of returning from an endemic region.
Diagnosis
Malaria may be diagnosed from a finger-stick blood specimen. Microscopy, or rapid immunodiagnostic tests are most common. Nucleic acid amplification tests perform well but are not yet widely available at low cost.
P. falciparum in human blood.
Treatment
Several medications are available to treat malaria infections. Treatment selection depends on the parasite species. Further, the location where infection most likely occurred must also be considered due to potential therapy resistance. Note that sales of counterfeit malaria medications are common in Asia.