Malaria

Quick Overview

What is malaria?

Malaria is caused by a blood-borne, microscopic, single-celled parasite which is transmitted to humans through mosquito bites; it is a serious infectious disease, present mainly in tropical areas, and characterised by high fevers and chills.

Each year, 250 millions of cases causing nearly 1 million deaths, mostly among African children are reported. It is estimated that a child dies of malaria every 30 seconds; 41% of the world's population is at risk of malaria, particularly those living in lower-income countries. Currently, the disease is endemic in 109 countries, 45 of which are located in Africa. It is estimated that 30,000 tourists become ill with malaria each year after travelling to endemic areas.

There are four types of human malaria:Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. P. vivax and P. falciparum are the most common, the latter being the most deadly.

Immunity

People residing in malaria-endemic regions may acquire immunity to malaria through natural exposure to malaria parasites.

Risks for Travellers

Vector

Malaria is a mosquito-borne disease: it is transmitted to humans by mosquito bites.

High-risks populations

Travellers from malaria-free regions, with little or no immunity, who go to areas with high infection rates are very vulnerable. Pregnant women with little or no immunity, HIV-positive persons, children under the age of 5 and elderly people are considered to be part of the high-risk population as they are particularly vulnerable to the disease.

What are the consequences of malaria?

Incubation period

The first symptoms usually appear between 10 and 15 days after the contaminating mosquito bite.

Main symptoms of malaria

Malaria symptoms may vary depending on the type of parasite that caused the infection. Common symptoms include fever, chills, headaches, nausea, etc.

Malaria is known for causing malaria attacks, which occur when a mass of parasites is released into the blood. The attack usually begins with a high fever (as high as 40°C), a poor general condition as well as headaches, and sometimes diarrhea, nausea and vomiting. When the fever drops, the patient usually sweats profusely. Over the weeks, the attacks become less and less frequent, as the patient develops an immunity against the parasite. With an appropriate treatment, the attacks can disappear within a few days. If left untreated, malaria can cause anemia and an enlargement of the spleen.

In the more serious form of the disease, known as malignant malaria, symptoms include hypotension, hemorrhage, kidney failure and jaundice. The disease can prove fatal. Malignant malaria can also affect the brain and the nervous system.

Prevention and Treatment

Protection against mosquitoes and preventive measures

There are two methods for malaria prevention: protecting yourself from mosquito bites, and the use of preventive medecine (chemoprophylaxis).

In order to prevent mosquito bites, travellers should wear clothing that covers both arms and legs, and use an insect repellent. Travellers should, if possible, sleep under an insecticide treated bednet.

Preventive medecine commonly prescribed for malaria includes chloroquine, mefloquine, doxycycline, atovaquone/proquanil and primaquine, depending on the area in which you are travelling. These drugs act by inhibiting parasite development during the incubation period of the disease. See a doctor at least one month prior to departure for specific dosing and schedule information, and keep in mind that anti-malarial drugs can sometimes cause serious side effects. All malaria medications must be started prior to departure and some must be continued weeks after you return.

Treatment

Treatment aims to ease the symptoms rather than to diminish the number of parasites carried by an infected person. According to the World Health Organization, the best available treatment, particularly for P. falciparum malaria, is a combination of drugs known as artemisinin-based combination therapies (ACTs). However, the growing potential for parasite resistance is undermining malaria control efforts.