- Click here for full review (subscribers only).
Abstract
- Our last review on arthropod
repellents in 1994 concluded
that DEET was the cutaneous
repellent with the best risk-benefit
balance. Other insect repellents,
including icaridin and citriodiol, are
now better evaluated. We have conducted
a review of the evidence available
in mid-2008, in order to determine
how to prevent mosquito bites
both effectively and safely.
- Different repellents provide protection
for varying lengths of time, mainly
depending on the insect species, the
environment, the user, and the concentration
of repellent applied. DEET
remains the best-assessed repellent.
In a randomised placebo-controlled
trial conducted in Pakistan, cutaneous
application of DEET and permethrin
reduced the frequency of
malaria attacks.
- Studies of repellent efficacy against
the main vector mosquito species, in
the laboratory or in the field, have
shown that the effect of IR35/35
lasts as long or almost as long as that
of DEET.
- Icaridin is at least as effective as
DEET against Anopheles gambiae, the
principal vector of malaria in Africa,
and Aedes aegypti, a vector of dengue
fever. One field study showed that
citriodiol was about as effective as
DEET against Anopheles gambiae.
- The adverse effects of DEET are
well known, due to its extensive use.
French and American poison control
centres report that serious neurological
adverse effects are rare. DEET causes skin and eye irritation and can
cause urticaria. Icaridin is also an irritant,
and adverse effects have about the
same frequency as with DEET. According
to French poison control centres,
IR35/35 is better tolerated than DEET.
In early 2008, no serious adverse
effects had been reported with
IR35/35, icaridin or citriodiol. Experience
with citriodiol is limited.
- Recommendations on repellent use
by children and pregnant women differ
from one country to another.
DEET is often recommended from
the age of 2 months, but at a moderate
concentration of about 30%. A
placebo-controlled trial of DEET in
897 women who were in their 2nd or
3rd trimester of pregnancy showed no
effect on the outcome of pregnancy or
on the unborn child. The United
States, United Kingdom and Canadian
health authorities recommend
DEET for pregnant travellers. In
France, only IR35/35 is recommended
for pregnant women, with no
explanation for this preference.
- Many studies in Africa and Asia
have shown that permethrin-treated
nets offer more effective protection
against insect bites than standard
nets, and that they reduce the risk of
malaria. They have few adverse
effects, apart from skin, eye and nose
irritation for a few days after the
nets are treated with permethrin.
- The protection provided by various
devices that release insecticides in
the home is poorly assessed and their
possible long-term toxicity is not
known. However, randomised trials
have shown that spraying of homes
with long-acting insecticides in
endemic areas reduces the risk of
malaria attacks.
- In practice, combined use of ample
clothing covering as much exposed
skin as possible, cutaneous DEET (or
perhaps icaridin), insecticide-treated
nets, and chemoprophylaxis helps
to prevent malaria and, by extrapolation,
the other more or less serious
infections carried by mosquitoes.
©Prescrire January 2009
Source: Prescrire International 2008; 17 (98): 250-253.
- Click here for full review (subscribers only).
- More articles in Prescrire's "Spotlight"...
