Malaria

Last Reviewed: October 2011

What is malaria?

Malaria is a mosquito-borne disease caused by any one of four different blood parasites, called Plasmodia. The disease is transmitted to people by the Anopheles mosquito. This disease is a leading cause of debilitating illness, with over 300-500 million cases and 1 million deaths each year from around the world. Almost all of the cases reported in New York State each year are acquired in foreign countries. However, a few locally acquired cases have occurred on Long Island and in Queens.

Who gets malaria?

Any person residing in or traveling to a country where malaria is prevalent is at risk for contracting the disease. Malaria is currently a problem in tropical or subtropical areas of Asia, Africa and Central and South America.

How is malaria spread?

Malaria is spread by the bite of an infected Anopheles mosquito. With certain malaria species, dormant forms can be produced which may cause relapses of malaria months to years later. Malaria may also be transmitted by transfusion of blood from infected people or by the use of contaminated needles or syringes.

What are the symptoms of malaria?

Symptoms include high fever, chills, sweats and headache, and in some instances may progress to jaundice, anemia, blood coagulation defects, shock, kidney or liver failure, central nervous system disorders, coma and death. Cycles of chills, fever and sweating occurring every one, two or three days is a good indicator of malaria in a person recently returning from a tropical area.

How soon do symptoms occur?

The time between the infective mosquito bite and the development of malaria symptoms can range from 12 to 30 days depending on the type of Plasmodia involved. One strain of Plasmodium, called P. vivax, may have a prolonged incubation period of eight to 10 months. When infection occurs by blood transfusion, the incubation period depends on the number of parasites transferred but is usually less than two months.

When and for how long is a person able to spread malaria?

Untreated or inadequately treated cases may be a source of mosquito infection for one to three years depending on the strain of Plasmodium. Direct person-to-person transmission does not occur. Stored blood products can remain infective for 16 days.

What is the treatment for malaria?

Due to the changing pattern of drug-resistant strains, current recommendations can be obtained from your local, county or state health department.

What can be done to prevent the spread of malaria?

Since malaria is not native to the United States, exposure to American citizens occurs most frequently during foreign travel to malarious areas. It is very important to contact health officials to determine the proper preventive drug therapy. The liberal and frequent use of mosquito repellents as well as using a bed net can be very effective in preventing mosquito bites.