Most travellers have heard of malaria and already know that it can be:

• A potentially dangerous mosquito-borne disease risk for travellers in some destinations (or for certain high-risk individuals), requiring the prescription of prophylactic anti-malarials and/or standby emergency treatment
• A lower risk in other areas (or for other individuals), still requiring awareness and bite prevention measures but no medication, and:
• No risk whatsoever in the remainder

→ We shall therefore keep the info on this page relatively brief and simple, but try and focus on practical, salient points to help you make a decision about which precautions you may need to take to minimise your risk of malaria...

Basic science:

Malaria is an ancient disease of reptile, bird and mammals, caused by a large number of species of parasite, known as Plasmodium. There are four human-specific species of Plasmodium which have co-evolved with us over time, plus a couple of new zoonotic species which have jumped species from other primates in recent years, notably P. knowlesi in SE Asia.

All Plasmodium species are 'obligate parasites', meaning they have to spend part of their life cycle within a specific mosquito (Anopheles species) and part within their preferred, larger animal host. This means that for a transmission cycle to continue in an area, all three have to be present: the 'right' host (i.e. us), the 'right' mosquito and the parasite. If any one of these is missing, or if the life cycle can be interrupted at any point, the risk of malaria in that area is significantly reduced. This forms the basis of most traditional malaria prevention efforts.

So, for example, even if there are millions of biting mosquitoes in a forest, but almost no nearby people to act as a reservoir of infection, the risk of malaria is correspondingly low.

Species of Plasmodium commonly affecting humans:

• P. falciparum: This is the most common malaria species worldwide and generally the most serious risk to travellers and local people alike, since it can cause cerebral malaria. It is particularly common in parts of Africa. Once successfully treated, you can only get it again if re-infected by another mosquito.
• P. vivax: Second most common, P. vivax is widespread in Asia and South America, although can also occur in some parts of e.g. East Africa. Vivax malaria generally causes less severe symptoms than falciparum malaria, but like all malaria species, it can still kill if not recognised and treated. Its main claim to fame is that this species - as well as P. ovale below - can also recur after conventional treatment, sometime months or years later, due to the formation of hypnozoites (sleeping cells). 'Radical' or 'curative' treatment with additional drugs is often needed to rid the body of the infection for good.
• P. ovale: As per P. vivax above, this is the cause of the other, potentially recurrent form of malaria. It is rarer and found in more localised pockets in West and Central Africa.
• P. malariae: Typically a milder, Asian species, this one is reducing in incidence…

P. knowlesi: Replacing P. malariae (at least in terms of incidence figures) in countries like Malaysia and other parts of SE Asia, this new human species has jumped species from crab-eating macaques in Borneo in recent decades, due to the pressure of deforestation. Its mosquito host still hasn't fully adapted to human patterns of behaviour, so transmission of this one is more of a risk outdoors and during the daytime, particularly when trekking in inland, more highland parts of Borneo (esp. Sarawak) and other inland forested parts of SE Asia. The main clinical significance of P. knowlesi malaria is that it can present with much more severe and frequent fever symptoms than other Asian species, although it is still very sensitive to all anti-malarial treatments once recognised. For all the above reasons, we take the risk of this one seriously for certain travellers' jungle itineraries, even though most official malaria maps may not make that quite so obvious.

The ABCDE of malaria prevention:

A: Be aware of the relative risk of malaria in your intended destination(s): → Check the recommended EU maps here by selecting country. These are better evidenced and more up-to-date than either the UK or US maps.

B: Take bite avoidance measures to reduce the risk of mosquito bites, i.e. effective mosquito repellents such as Mosiguard Natural or DEET, use fans/air-con during the day and sleep under a mosquito net at night when most human-specific Anopheles mosquitos bite... (This last measure is not quite so reliable in West Africa, where an outdoor-biting sub-species, 'Goundry', of An. gambiae occurs - and/or in forested parts of SE Asia, see above).

C: Stands for chemoprophylaxis, or taking anti-malarial tablets for prevention.

D: Always seek a prompt and early diagnosis to confirm or exclude malaria in the event of any symptoms (severe headache, fever, flu-like symptoms, malaise, diarrhoea etc.) while in country or in the weeks to months after travel to an endemic area... Malaria is a medical emergency: If you suspect it, attend a local doctor, A&E or call your GP / 111 to arrange a blood test ASAP!

E: Finally, standby emergency treatment packs of malaria treatment may also be prescribed at TrExMed Travel Clinic for certain high-risk travellers to carry, if they are likely to be off the beaten track when symptoms occur, or simply for additional peace of mind in borderline risk areas (instead of or in addition to prophylactic anti-malarials).

Common anti-malarial drugs used for prophylaxis (prevention):

• Atovaquone/proguanil (Malarone): Daily tablet, taken with a meal, from 1-2 days before entry to malarious area until 7 days after leaving. Side effects: mild insomnia or mood disturbance in a very few, mouth ulcers if taken long term without folic acid supplements. Not cheap, at £1.90 per tablet.
• Doxycycline: Daily tablet, taken in the morning, from 1-2 days before entry to malarious area until 4 weeks after leaving (the latter being the chief downside). Side effects: acid reflux, thrush, photosensitivity in 3-5%. Cheap and cheerful.
• Mefloquine (Larium): Weekly tablet, taken ideally from 2½ weeks before entry until 4 weeks after leaving malarious area. Side effects: Insomnia, weird dreams (common), mood disorder (1 in 200), very rarely psychosis (1 in 10,000), so contraindicated for use in people with a history of neuropsychiatric problems. Even if not, best to take a 3-week trial course first (assuming no contraindications) for peace of mind. Limited stock.
• Tafenoquine (Arakoda): Taken with loading dose of one tablet on each of successive 3 days, then weekly while in risk areas, followed by only one dose upon leaving malarious area. Few side effects. Very convenient and promising 'new' drug for long-term travellers who cannot take mefloquine... However, tafenoquine has two major downsides:
  1. You need to check your G6PD deficiency status by a blood test the first time you are prescribed it.
  2. It is ridiculously expensive due to the greedy drug company shamelessly marketing this in the USA first in order to set a high price, instead of rolling it out to needy patients who can’t take mefloquine (especially unethical, considering all the R&D was already done in the 1980s!).

Previous history of bad side effects with anti-malarials:

→ Please write to us to discuss in advance: We may have some creative solutions to suggest, or to prescribe ‘off-label’ on a named patient basis.