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Insects such as mosquitos are attracted by our body heat, odours and carbon monoxide. Using an insect repellent helps not just to prevent transmission of diseases but to stop nuisance biting, which can lead to allergies.
There are several different commercial insect repellents available and all will protect against mosquitos, sand flies and ticks. These agents appear to work by affecting the insect’s antennae, stimulating avoidance behaviour or by blocking their receptors for attractive odours.
The most common repellents are:
DEET has been in use since 1946 and is considered the ‘gold standard’ repellent. It is safe to use in both pregnant women and children from two years of age. It is available in concentrations ranging from 20-100% and the duration of protection depends on the concentration.
However, there are no advantages to using products with more than 50% DEET and a 20% formulation should provide protection for between six and 13 hours, though it needs to be re-applied if a person sweats heavily or goes swimming. In addition, DEET can be used with sunscreens (see below) and patients should be advised to apply the repellent before or at the same time as a sunscreen. Recent studies have demonstrated that some species of mosquitos are tolerant to the effects of DEET and continue to bite.
All other agents appear to be effective and people should take note of the recommendations for use provided by the manufacturer since one of the main reasons for treatment failure is incorrect use. Another effective deterrent is the use of a diffuser device.
If bitten by mosquitos, hydrocortisone cream 1% will be effective in most cases. Alternatives include mepyramine maleate cream (Anthisan®) though this is less effective. Oral antihistamines can also be used and solutions will help children.
Protecting the skin against sunlight
Sunscreens can be used to provide a degree of protection against the risk of sunburn caused by radiation. The level of protection offered against burning is determined by the sun protection factor (SPF). This has been described as a measure of how much longer a person can stay in the sun without burning. For example, if someone normally burns after 20 minutes in the sun, applying a sunscreen with an SPF of 15, means that they can stay 15 times longer (i.e. 300 minutes or 5 hours) before they would burn.
Unfortunately, this is a common misconception because although increased time in the sun increases exposure, the intensity of solar radiation varies depending on the time of day, the season, latitude, altitude and reflection from sand, water or snow. The SPF can be thought of as providing a relative, rather than absolute, measure of protection. Sunscreens range in SPF from 15 to 50 though the difference in the amount of UVB radiation blocked is relatively small.
Protection against UVA radiation is measured using a rating system from 1 to 5 (highest). Patients should therefore look for a product that has a high SPF and UVA rating.
Sunscreens can be used in children but more important is seeking shade, covering up and wearing a hat and sunglasses. The elderly also need to practice sun protection since the risk of skin cancer increases with age and they should avoid going out in direct sunlight between 10am and 3pm.
Food can be a source of salmonella, campylobacter, E Coli and norovirus leading to travellers’ diarrhoea and it is advisable to avoid ice-cream or ice in drinks in places where tap water shouldn’t be drunk. Fortunately, most cases of traveller’s diarrhoea only require fluid replacement and it is advisable to carry oral rehydration sachets although anti-diarrhoeal treatments like loperamide can be used for one or two days to reduce the number of visits to the toilet, especially if travelling.
Pharmacist travel health clinics
Specific travel health clinics in pharmacies represent a potentially useful additional service for patients, particularly as some research suggests that more than half of travellers received no vaccinations before visiting high risk areas.6 The accessibility of pharmacists offers patients a convenient means of obtaining vaccinations and travel health advice. In fact, several pharmacists around the UK have already established a travel health service through which patients are vaccinated, offered advice and supplied with anti-malarial medicines, first-aid kits and insect repellent products.
Interested pharmacists should endeavour to undertake further training and Valneva has launched a support program for pharmacists wishing to become more involved in travel health services.7
Author: Rod Tucker