Malaria is transmitted by the bite of the female Anopheles mosquito. The disease is also transmitted through the blood, so while contact with an infected person is not sufficient to transmit the disease, blood transfusion and sharing of intravenous needles will spread the parasite.
As the disease is transmitted by a simple mosquito bite, infection can occur during such a limited time as a flight stopover within an infectious area. Travellers should also be aware that due to the disease's incubation period (greater than 7-8 days), symptoms may not appear until the sufferer is in such an area that malaria is not immediately considered as the cause.
Signs and Symptoms
The disease causes:
- aching muscles and joints
- vomiting and diarrhoea
The period between the mosquito bite and onset of symptoms is at least 8 days, but can be much longer. It is potentially fatal if not treated quickly.
Malaria is a danger in certain areas of Central and South America, Africa, Asia Minor, the Indian subcontinent and South East Asia. In general, resorts in Asia have a low risk for malaria, and the longer they have been a resort, the more likely malaria is not a risk, e.g. Bali. The risk is, however, never zero. So use your repellant. We recommend using Repel, a tropical strength repellent containing 30% DEET and is effective for 6 hours (unless you jump in the pool of course!). If venturing to places with high levels of humidity causing signifcant sweating you may want to consider the 80% DEET Bushman Insect Repellent.
Unless you venture into the Amazon region, South America is a low risk for malaria . Many of the attractions in South America are above 2000m and mosquitoes find it too hard to fly that high! (The lower temperature prevents breeding). However, malaria is widespread in tropical and subtropical areas of the world. Africa is the highest risk for malaria, along with the Solomon Islands.
As there is no effective vaccine for malaria, it is recommended travellers avoid mosquito bites, and take prophylactic medication to prevent contracting the disease.
Wearing long trousers, skirts, sleeves and socks will help discourage mosquito bites. This is especially recommended after sunset, when the mosquitoes that transmit the disease are most active. Insect repellent should be used on exposed skin. Mosquito netting over bedding and windows can also be impregnated with insect repellent. Permethrin 0.5gm/m2 will provide protection for three months. Avoid areas of still water, as this is where mosquitoes breed. Dengue Fever is spread by mosquitoes which are active in daylight, so caution is advised during the daylight too!
There a number of prophylactic drugs used to prevent malaria (see malaria page in travel tips and handouts). Which drug is prescribed depends upon the area the traveller is visiting, which form of the parasite exists in the region and the personal details of the patient. It is important for the traveller to visit a doctor who specialises in travel medicine, to be assured that all these factors have been taken into account when obtaining their prescription. Please make sure you have up-to-date information about your area of travel and your medication. Most medications are unsuitable for pregnant mothers and infants. If you are pregnant or hoping to become so soon after your trip, please advise your doctor when requesting your medication. It is very important to continue the medication after you have left the malarious area, and complete the entire course recommended by your doctor.
The malaria parasite first develops in the liver, and can take a number of weeks to re-enter the blood stream where some medications are effective.
Some malaria medications can cause side effects such as nausea and dizziness. Ask your doctor about possible side effects of your medication. If you suffer any adverse effects, contact your doctor immediately. Malaria medications are sometimes ineffective. This may be due to incorrect dosage or irregular administration (you are on holidays after all!). Gastrointestinal upsets causing vomiting and diarrhoea can affect absorption of the medication. The parasite's long incubation period can mean that disease may appear after the traveller ceases taking medication, especially if ceased prematurely (4 weeks is the usual time medication needs to be taken after leaving the malarious area), and malaria parasites have been known to become resistant to medications.