Malaria

article055Malaria is a serious disease, transmitted to humans by the bite of an infected female Anopheles mosquito. The Plasmodium parasite, in the saliva of the mosquito, infects red blood cells, causing them to burst (lyse), spilling their contents. Fever results from the immune system’s response to the toxins released from the lysed red blood cells.

Of the four Plasmodium species, Plasmodium falciparum is the only one capable of causing cerebral malaria, which if not treated promptly, will cause death. In most parts of the world P.falciparum has developed varying degrees of resistance to the drugs used for malaria prevention and treatment.

The mosquito is intrinsic to the life-cycle of the parasite, thus factors such as altitude, climate, mosquito-breeding sites and human behaviour are responsible for the successful transmission of the disease.

These THREE RULES will aid in preventing infection, illness and death from the malaria disease. 

AVOID MOSQUITO BITES The Anopheles mosquito feeds between dusk and dawn. In high-risk areas, especially during or immediately after the rainy season, avoid mosquitoes. Wear long sleeves shirts, long pants and shoes. Apply mosquito repellant to exposed skin every 4 hours. If you are not staying in a well-screened and air-conditioned environment, sleep under a repellent-impregnated bednet.  

 

DIAGNOSE AND TREAT MALARIA PROMPTLY Any fevers and flu-like illness (chills, headache, muscle aches and fatigue, sometimes with diarrhoea and vomiting) beginning 7-10 days after entering a malaria area should be presumed to be malaria. Onset of symptoms could occur up to 6 months after leaving an infected area. If not immediately treated, Plasmodium falciparum infections may cause kidney failure, coma and death. If you experience any of these symptoms, a doctor must be consulted urgently whether you have or have not taken malaria-preventative drugs. Remember to tell your doctor your travel history. 

 

USE PREVENTATIVE ANTI-MALARIAL DRUGS Anti-malarial drugs work by killing the Plasmodium parasite before the traveller becomes ill. Medication is started before entering the malaria area, to ensure that protective levels are reached and that the drugs are tolerated. Drugs administration should be continued for up to 4 weeks after leaving the area to ensure that parasites still emerging from the liver are elminiated. The drugs are ineffective against the parasites when they are in the liver.

Malaria Prevention Drugs
While no drug is 100% effective, they do confer 90% protection over and above mosquito avoidance measures.

Anti-malarial drugs do not mask the symptoms of the disease. They do reduce the numbers of infecting parasites, minimising symptoms and the severity of the disease. When the drug is stopped, symptoms may appear, but by this stage the traveller should be in an environment where they are able to receive adequate medical attention.

The decision whether to use preventative drugs or not should be based on the relative risk in the area to be visited as well as the potential side effects of the anti-malarial drugs.

MEFLOQUINE (brand name: LariamTM and generic)
The adult dosage is one 250mg tablet weekly, on the same day each week, after a meal with plenty of fluid. Dosage starts 1 week before entering a malaria area and ends 4 weeks after leaving the area. Heavy alcohol consumption should be avoided for 24hrs before and after the weekly dose.

The most common side effects include headache, nausea, dizziness, difficulty sleeping, anxiety, vivid dreams, and visual disturbances. If minor side effects occur, the dose can be split i.e. half a tablet on Sunday and the other half on Thursday. If major symptoms such as dizziness, agitation, depression or racing pulse result, stop medication and seek advice.

People with epilepsy, psychological illness, abrnomal heart beats or heart conditions, pilots, scuba divers and high altitude hikers should avoid mefloquine.

DOXYCYCLINE (many brand names and generics are available)
The adult dosage is one 100mg tablet daily, taken after a heavy meal. Medication starts 2 days before entering a malaria area and ends 4 weeks after leaving. Doxycycline is related to the antibiotic tetracycline and must be taken with plenty of food and liquid, otherwise is may cause nausea and heartburn.

Sun sensitivity (you get sunburnt more easily) is a common side effect. More care must be taken when out in the sun i.e. sunblock and protective clothing. Women who use doxycycline may develop a vaginal yeast infection.

Children, pregnant women and people allergic to the tetracycline group of antibiotics should not take this drug.

ATOVAQUONE/PROGUANIL (brand name: MalaroneTM)
Atovaquone/proguanil is a fixed combination of two drugs, 250mg atovaquone and 100mg proguanil. It is a section 21 medication and is available under special circumstances. The adult dosage is one tablet daily, taken at the same time each day, with food. Dosage starts 2 days before entering the malaria-risk area and ends 7 days after leaving the area.

The most common side effects reported are abdominal pain, nausea, vomiting, and headache.

Children weighing less than 11 kilograms, pregnant women, women breast-feeding infants weighing less than 11 kilograms (25 pounds), patients with severe renal impairment and people allergic to atovaquone or proguanil should not take this drug.

CHLOROQUININE & PROGUANIL
These drugs are no longer recommended.

DIAGNOSIS
If you suspect that you have malaria, do not delay. Go immediately for blood tests to confirm infection. Once infection has been confirmed appropriate treatment can be initiated.

For travel risk-area information, visit the Centre for Disease Control website at www.cdc.gov and your local travel clinic.

Author: Lisa de Speville