Travel Article
From Sunday Times (London)
HEADLINE:
Wherever You Are - Aim To Make It a Malaria-Free Zone Dr. Matthew Ellis Offers Simple Steps To Keep Mosquitos - and Malaria - at Bay
BYLINE: By Dr. Matthew Ellis
DATELINE: October 24, 1999, Sunday
SECTION: Features
Malaria. It's enough to give you the shivers. For the non-immune traveller,
which includes virtually all UK citizens, regardless of birthplace, the risk of
catching malaria in a two-week period without prophylaxis in east and west
Africa is about 0.5% and 3.5% respectively.
Despite the fact that most of us take the decision to protect ourselves, about
2,000 cases are detected in returning travellers in the UK each year, over half
of which are caused by the more serious falciparum strain. Up to 10% of
non-immune travellers who contract [falciparum] malaria die, and once cerebral malaria has
set in, the death rate climbs to 20%, even with treatment.
Eleven people died from the disease in the UK in 1997. The first step to
protecting yourself is to become aware of the risk. The next step is bite
avoidance.
Anopheles mosquitoes, which transmit malaria, are evening and night-time
biters.
Therefore, if possible, retire at dusk to a mosquito-screened or
air-conditioned
room. No room is entirely mosquito-proof and most travellers to the
tropics have
had the experience of tossing and turning while being tortured by whining
squadrons of these irritating creatures.
Environmental control with an insecticide is the next line of defence.
Permethrin is the most widely used agent and has an excellent safety profile.
The most efficient delivery system is to heat an impregnated mat on a small
electric hotplate. Although this sounds fiddly, if not downright hazhardous, in
practice both the mats and the hotplates are widely available, easily portable
and of such low wattage as not to be a fire hazhard. The alternative,
smouldering coils, are far more likely to irritate your lungs and tend to run
out before the night is out. If your lodgings are partially open to the
outdoors
(as many are in hot climates), you will need a mosquito net to sleep under. The
relatively recent innovation of treating the net with permethrin has improved
the protective effect enormously.
If you must be outside after dark (to spot nocturnal wildlife perhaps), long
trousers, long sleeves and good ankle protection are the order of dress. But
mosquitoes can bite through thin material so insect repellent is essential and
those containing diethyl toluamide (Deet) are the most effective. Concerns
about
Deet toxicity are now largely discounted, with most reports citing accidental
ingestion, so families might opt for a roll-on preparation. Remember,
mosquitoes
prefer to hunt near ground level so pay particular attention to the ankles
- old
hands swear by tubular bandage anklets treated with Deet.
You should also comply with an appropriate anti-malarial chemo-prophylactic
regime - which means taking the drugs at the right intervals, commencing prior
to travel and continuing after your return, as per the instructions.
Most studies show that 20%-40% of travellers fail to comply with their regimes,
mostly for trivial reasons. Which regime is recommended depends on the
individual's particular circumstances. The variables to
be considered include the prevalence of malaria at your destination, the
strain(s) of malaria and the pattern of malarial resistance to particular
chemical agents, and the side-effect profile of the agents. These factors
are in
turn dependent on your own medical history and what you plan to do when you get there. The beach bum and the bird-watcher may sit next to each other on the plane but their requirements are likely to be completely different. There is no substitute for a personalised travel-clinic consultation.
The three commonly used agents (and their tradenames) are chloroquine
(Avloclor, Nivaquine), proguanil (Paludrine), and mefloquine (Lariam).
Where the risk is very low, as in Bali or Egypt, chemo-prophylaxis is not currently recommended. Where there is a low risk and resistance is still poorly developed (parts of Central America) a single agent - either chloroquine or proguanil - is sufficient. Most people would opt for the once-weekly chloroquine rather than the daily proguanil.
Where the risk is high and resistance is more of a problem (south and southeast
Asia and Oceania), the choice generally lies between chloroquine plus proguanil
or mefloquine alone. When the risk rises to very high and resistance is
widespread, as in much of sub-Saharan Africa, mefloquine is increasingly
seen as
the first choice. Much of the current debate (which exercises medical
scientists
as well as travellers) revolves around the choice between these two regimes.
The key information when balancing risks and benefits are, first, the efficacy
of the drug(s), and second, their side-effect profile. There is a broad
consensus that at present mefloquine is significantly more effective, with
a 90%
protective effect, compared with chloroquine plus proguanil, which was rated as
being 70% effective in west Africa and only 50% effective in east Africa in the
late 1980s.
Where does this leave the traveller who wishes to be well informed? It seems
clear to me that people who expose themselves to malaria without taking the
available precautions are risking their lives needlessly.
Local medical assistance should be sought at an early stage in the event of
strange reactions in friends and family on mefloquine. If the drug has to be
stopped, exercise particular attention to bite prevention while converting
to an
alternative regime. In the presence of additional personal risk factors for
neuropsychiatric disease (including epilepsy, mental illness and recreational
substance abuse) mefloquine is probably best avoided and an alternative regime
sought.
No regime is 100% effective and therefore prompt diagnosis is essential: any
unexplained fever developing seven days or more after arrival in a malarious
area needs to be investigated. And finally, if venturing off the beaten
track, I
pack quinine for self-treatment. You know the old adage that if you've got it
you won't need it.
Webmaster's Note:- Consult a travel clinic or tropical medicine specialist before travelling to a malaria area
- Doxycycline and artemesinin are other drugs used in treatment of malaria. Doxycycline may be used for prevention, while artemesinins are used for treatment [only] of resistant malaria.
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