Malaria

About This Disease

Malaria is a serious mosquito-borne disease caused by a parasite. It is transmitted to humans by Anopheles mosquitoes. There are five types of malaria parasites of which Plasmodium falciparum is the most severe and can be fatal. Plasmodium vivax, P. malariae, P. ovale, and P. knowlesi also cause human disease that is generally far milder and not life-threatening. Malaria is a significant problem in areas of Asia, Africa, and Central and South America. Unless precautions are taken, any person living in or traveling to a country where malaria is present can get the disease. Malaria is not a problem in Hawaii because the Anopheles mosquito is not found here. However, persons who were infected overseas have been diagnosed with malaria after arrival in Hawaii.

 

Signs and Symptoms

Symptoms of malaria include fever, chills, backache, and headache. Cycles of chills, fever, and sweating that subside and then return every 1, 2, or 3 days (depending on the type of malaria) are common signs of malaria infection. Malaria can also cause vomiting, diarrhea, coughing, and yellowing (jaundice) of the skin or whites of the eyes. Patients with severe P. falciparum malaria may develop bleeding problems, shock, kidney or liver failure, central nervous system problems, and coma.

The period between the mosquito bite and the start of illness is usually 7 to 21 days. Certain types of malaria parasites can take several months to cause symptoms.

 

Transmission

Malaria is spread through the bites of infected Anopheles mosquitoes. When the female mosquito bites, she injects malaria parasites directly into the blood. The parasites then travel through the blood to the liver and infect the red blood cells. Malaria can also be transmitted by blood transfusion, organ transplantation, needle sharing or congenitally from mother to fetus.

 

Diagnosis

Rapid and acute diagnosis of malaria is integral to providing appropriate treatment and prevention of further spread of infection in the community. Diagnostic laboratory testing can be done on individuals with clinical signs and symptoms compatible with malaria infection by microscopic analysis and nucleic acid detection using polymerase chain reaction of the patient’s blood.

Treatment

Because different types of malaria have become drug resistant, treatment of malaria infection depends upon the geographic region where a person is infected. Effective medication for each type of malaria must be prescribed by a doctor. As patients infected with P. falciparum malaria can die (often as a result of delayed treatment), immediate treatment is critical. Chloroquine is the drug of choice for acute malaria in sensitive strains.

Immunity

After repeated infection to malaria, a person may develop partial immunity to malaria. These individuals can become infected with malaria, but may develop milder and less severe symptoms.

Risk in Hawaii

Malaria is not a problem in Hawaii because the Anopheles mosquito is not found here. However, persons who were infected overseas have been diagnosed with malaria after arrival in Hawaii.

Prevention

  • If you are traveling to an area with risk of malaria, your doctor can prescribe preventive medicines to take. Be sure to take them as directed.
  • Avoid exposure to mosquitoes. Wear appropriate clothing such as long-sleeved shirts and long pants especially when outdoors.
  • Apply insect repellent to exposed skin or clothing. The recommended repellent contains 20%–35% DEET. Higher concentrations of DEET may have a longer repellent effect, however, concentrations over 50% provide no added protection.
  • Use mosquito nets treated with insecticides over beds and screens over windows and doors.
  • Spray permethrin or a similar insecticide in the bedroom before going to bed.

If you are going to be traveling, check before leaving if there is a risk of malaria at your destination, and if so, be sure to take precautions against mosquito bites. One source of travel health information is CDC’s Traveler’s Health website and the Malaria risk assessment page.

Additional Resources

Information for Clinicians

Centers for Disease Control and Prevention (CDC) – PART 1

Centers for Disease Control and Prevention (CDC) – PART 2

Centers for Disease Control and Prevention (CDC) – PART 3

Malaria is a reportable disease Hawaii Administrative Rules Title 11 Chapter 156, Communicable Diseases, under the Routine category which requires a report by telephone, fax or mail to the Disease Outbreak Control Division on Oahu or to the District Health Offices on the neighbor islands. A written Communicable Disease Report (CDR) may be submitted by mail or fax.