QUESTION

What are the treatments and management of malaria?

ANSWER

Treatment is actually part of the strategy for managing malaria, so I will come back to that later. The other main ways in which malaria is controlled is through prevention, diagnosis (followed by treatment if necessary) and education.

1) Prevention:

There are a number of ways to prevent malaria. These can be placed into two categories: medication and vector protection.

For medication, there are drugs you can take to prevent the malaria parasite from developing after someone is bitten by an infected mosquito. These drugs are known as “chemoprophylaxis.”

There are several different kinds, such as doxycycline, mefloquine (marketed as Lariam), atovaquone-proguanil (marketed as Malarone) and chloroquine—the type you use depends on the type of malaria present in the area. For example, in much of Africa and India, malaria is resistant to chloroquine, so this cannot be used as a prophylactic. In parts of Thailand, resistance to mefloquine has emerged. However, if the appropriate type of prophylaxis is used, it is very effective against malaria.

The problem is that these drugs have not been tested for long-term use, can be expensive and may have side-effects. Therefore they are of limited use for people who live in areas where malaria is endemic, and are more appropriate for travelers who are in malarial areas for short amounts of time. However, anti-malarial medication may be used in a very specific way for people at particularly high-risk for malaria, such as pregnant women and young children. In these cases, the high-risk individuals receive a dose or series of doses of malaria medication in order to prevent malaria. This form of prevention is known as intermittent preventive therapy (IPT).

Vector prevention involves protecting oneself against getting bitten by mosquitoes. This can involve wearing long-sleeved clothing in the evenings and at night, when malaria mosquitoes are most active, or wearing insect repellent on exposed skin. Indoor residual spraying, whereby repellent and insecticides are sprayed inside the house, can also be used to bring down the number of mosquitoes.

Another very effective technique for preventing malaria is to sleep under a long-lasting insecticide-treated bednet. The mesh acts as a barrier against the mosquitoes, and the insecticide impregnated in the mesh further repels the mosquitoes and prevents them from biting through the mesh.

2) Diagnosis

Diagnosis is considered a crucial step in controlling malaria, since it ensures that people are receiving correct medication, whether for malaria or for another condition which is causing their symptoms. Currently, the most commonly observed form of diagnosis is through microscopy of thick and thin blood films, which can be stained if necessary. These should be read by a qualified technician to determine both the species of malaria infection and the intensity of parasitaemia (number of parasites in the blood).

More recently, other methods for diagnosis have emerged. These include the use of rapid diagnostic tests (RDTs) which utilize a drop of blood applied to a reagent strip which very quickly reacts to show whether the patient is infected with malaria. While considered generally more sensitive than blood films, some RDTs don’t test for all types of malaria parasite, and many require that the reagents be kept cold in order for the test to be effective, which can be a problem in some developing countries.

Perhaps the most sensitive test for malaria is through PCR, which can theoretically detect a single malaria parasite in a drop of blood, and also determine the species. However, measures of infection intensity require an alternative form of PCR, called real-time PCR, which can be technologically challenging. All forms of PCR require a lot of expensive equipment and reagents, trained technicians and take several hours to run.

3) Treatment

Malaria treatment can be determined based on the diagnostic results, as well as other factors, such as:

• The area where the infection was acquired and its drug-resistance status
• The clinical status of the patient
• Any accompanying illness or condition
• Pregnancy
• Drug allergies, or other medications taken by the patient

Most uncomplicated (i.e. not severe) cases of P. falciparum can be treated with oral medication, such as artemisinin-based combination therapies (ACTs). Artemisinin is given in combination with another anti-malarial drug in order to prevent resistance from developing in the parasite. Patients who have complicated (severe) P. falciparum malaria or who cannot take oral medications should be given the treatment by continuous intravenous infusion, with quinine recommended by WHO as the first-line treatment.

Other drugs, which are used in some settings, are considered second-line or alternative forms of treatment. These include:

• chloroquine (very rarely used for P. falciparum, due to widespread resistance)
• atovaquone-proguanil (Malarone®)
• mefloquine (Lariam®)
• quinine
• quinidine
• doxycycline (used in combination with quinine)
• clindamycin (used in combination with quinine)

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses, for patients with P. vivax or P. ovale malaria. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.

4) Education

Through education, people living in at-risk areas for malaria transmission can learn about ways to prevent the disease (see above), as well as what to do if they suspect they are infected (i.e. seek diagnosis). Similarly, education is important for travellers visiting malarial areas, so they know the best ways in which to avoid being infected.