Insect and tick bite avoidance

Protection from insect and tick bites is essential to help prevent vector-borne diseases such as malaria, yellow fever and Zika Insect and tick bite avoidance

Key Messages

Insect bites are relatively common in travellers, usually causing only minor irritation, but occasionally may cause more significant problems such as allergic reactions, secondary skin infections or transmission of infectious disease such as malaria, yellow fever, and Zika.
For many vector-borne diseases, avoiding insect bites is the only means of prevention and is best achieved by avoiding infected habitats, together with personal protective measures such as wearing protective clothing, using insect repellent and sleeping under impregnated bed nets.
Where vaccines or malaria tablets are recommended, travellers should seek a pre travel appointment with their health care provider.
Travellers should pack appropriate equipment for their destination; this may include protective clothing, insect repellents, mosquito nets, fine tipped tweezers and a first aid kit.
Travellers with a high fever of 38°C or more or other worrying symptoms should seek prompt medical advice. Malaria symptoms may occur up to a year after travel.

Overview

Insect and tick bites are relatively common in travellers, usually causing only minor irritation. However, bites can result in local skin trauma, allergic reactions (ranging from small local reactions to life-threatening systemic reactions), secondary skin infections or transmission of infectious disease (vector-borne diseases) (see Table 1) [1 - 4].

Vector-borne diseases account for more than 17 percent of all infectious diseases. Every year diseases such as malaria, dengue, yellow fever, and Japanese encephalitis cause more than 700,000 deaths globally [5]. The highest burden of disease occurs in tropical and subtropical areas where the poorest populations are disproportionately affected.

Vaccines or medications are available to help prevent a number of these diseases, but for many, bite avoidance is the only way to prevent infection.

Insect bites and stings

Arthropods include insects such as mosquitoes, gnats and flies and arachnids, such as spiders, mites and ticks [3]. The term ‘insect’ will be used here to include both insects and arachnids.

Insect bites or stings generally occur as a result of insect feeding (e.g. mosquitoes, bed bugs) or defence (e.g. bee and wasp stings or spider bites) and can range from being immediately painful to completely unfelt.

When an insect bites, substances such as anticoagulants (to prevent blood clotting) and vasodilators (to open blood vessels) are injected to ensure a flow of blood. These substances can lead to local skin or systemic reactions [3].

Bees, wasps and hornets are stinging insects and inject venom into the skin. Stings are usually painful immediately and the venom may cause reactions ranging from mild localised pain to severe systemic reactions including anaphylaxis (serious allergic reaction). In the UK, insect stings are the second most common cause of anaphylaxis outside of medical settings [3].

Insect vectors and diseases they transmit

Mosquitoes

The female mosquito requires a blood meal to reproduce. There are many species of mosquitoes, some bite during daylight hours (e.g. Aedes spp) and others are more active from dusk to dawn (e.g. Anopheles spp). The biting times of some mosquitoes can vary within the same species (e.g. Anopheles mosquitoes which transmit malaria) [6].

Mosquitoes are attracted by several factors, including the presence of carbon dioxide (from skin and breath), heat (from skin), odours (including fragrances from perfumes and soaps), lactic acid and movement; some individuals may also be more attractive to mosquitoes than others [7].

Ticks

Ticks typically live on the ground in long grassy areas and usually feed on small mammals. They become attached to humans after brushing against grass, after which they crawl on skin or clothing until they find a suitable place to attach and feed, often at a skin fold in the groin, under the arm, at the scalp line or at the edge of underclothes. The bite is generally painless [8]. As prompt removal of ticks may prevent transmission of some infectious diseases, it is important to check for ticks on the body after outdoor activities.

Table 1. Examples of diseases transmitted to humans by mosquitoes, ticks and other vectors [5]
Vector Vector-borne diseases
Mosquitoes Anopheles spp Malaria
Lymphatic filariasis
Aedes spp Chikungunya
Dengue fever
Eastern equine encephalitis
La Cross encephalitis
Lymphatic filariasis
Rift Valley fever
Ross River virus
Yellow fever
Zika
Culex spp Japanese encephalitis
Lymphatic filariasis
Ross River virus
St Louis encephalitis
West Nile virus
Ticks Babesiosis
Borreliosis
Crimean Congo haemorrhagic fever
Lyme disease
Rickettsial diseases (spotted fever, Q fever)
Rocky mountain spotted fever
Tick-borne encephalitis
Tularemia
Flies Tsetse Fly

African trypanosomiasis

Sand Fly

Leishmaniasis

Black Fly Onchocerciasis
Fleas Plague
Murine typhus
Reduviid bug American trypanosomiasis (Chagas disease)
Lice Louse-borne relapsing fever
Typhus
Chigger Mites
(Trombiculid mites)
Scrub typhus
Bed bugs

There has been a resurgence of bed bug infestations in recent years [9]; there is no evidence that they transmit disease-causing pathogens. There are few published studies investigating the role of insect repellents in protecting against bed bug bites [10].

Travellers should be encouraged to inspect their sleeping accommodation for bed bugs on mattresses and bedding, which might present as blood spotting on linens; keep suitcases or rucksacks off the floor when not in use and inspect clothing before replacing them in luggage [10].

Risk for travellers

The risk of insect bites, and possible vector-borne disease, to the traveller will depend on exposure to insects. This will be determined by destination, season and rainfall patterns, as well as activities undertaken, length of stay and measures taken to avoid insect bites. Destination-specific information on some of the diseases spread by insects can be found on the Country Information pages.

Vaccines and tablets are available to help protect against some of the diseases, but may not be suitable for all travellers, placing them at higher risk of disease. Avoiding bites from insects and ticks may be the only way to reduce the risk of disease.

Before travel

Travellers should research their destination to determine possible risks for vector-borne diseases (see our Country Information pages). Vaccinations and/or malaria tablets may be recommended, in which case a pre-travel appointment should be booked with a health care provider ideally four to six weeks before departure. Although last-minute advice is still useful if time is short.

Travellers should consider if they need to pack protective clothing, insect repellents, insecticide treated bed/cot nets, plug-in insecticides and a first aid kit with items to manage insect bites, for example fine-tipped tweezers to remove ticks, painkillers and antihistamine to reduce itching.

During travel

Travellers should be advised to protect themselves against insect and tick bites possibly both day and night depending on the vector and risk of disease at destination. A combination of the measures listed below is considered the most effective way to prevent bites.

Key points to reduce insect and tick bites:

  • Avoid areas of stagnant or standing water, where mosquitoes are likely to breed.
  • Keep to footpaths and avoid long grass when walking to avoid tick bites.
  • Wear loose-fitting clothing, with long sleeves, long trousers, tucked into socks.
  • Light coloured clothing will help see ticks and other insects, avoid dark blue clothing where tsetse fly is present [11].
  • Clothing can be sprayed or impregnated with insecticide (e.g. permethrin); insect repellents such as DEET can be applied to natural fibres.
  • Use insect repellents on exposed skin: DEET based repellents are considered the most effective currently available.
  • Avoid using products with strong perfume (e.g. soaps) which might attract insects.
  • In areas with vector-borne diseases, use air conditioning where available or sleep in screened accommodation, under a mosquito net impregnated with insecticide.
  • Insecticide vaporisers can be used to inhibit mosquito bites and mosquito coils can be used outdoors.
  • For those staying long-term in areas with vector-borne diseases it is possible to reduce mosquito breeding sites around the home by removing any pools of water in ditches, plant pots, gutters, drains and rubbish collected in the area.
  • Check body for ticks after outdoor activity and remove them promptly (see below).

Insect repellents

DEET

DEET (N, N–diethyl-m-toluamide) has been used as an insect repellent for more than 50 years. A number of studies have concluded that the risks of adverse effects from DEET are low for all groups, including infants and children as well as pregnant and breastfeeding women, when applied according to the product instructions [6, 12].

Repellent containing DEET, at 20 to 50 percent concentration, is recommended for travellers over 2 months provided it can be tolerated [6]. Intervals between applications of DEET will vary according to activity as well as formulation and concentration used.

DEET percent concentration Time to reapplication (hours)**
20 1-3
30 6
50* Up to 12
*Duration of protection plateaus at concentrations above 50%, there is no benefit to using higher concentrations [6]

** Repellents may need to be reapplied more regularly, for example after swimming and in hot, humid conditions when they may be removed by perspiration

DEET and sunscreen

Several studies have shown that DEET decreases the protection of SPF 15 sunscreen, although there is no evidence that sunscreen reduces the efficacy of DEET when used at concentrations above 33 percent [6]. When both are required, DEET should be applied after the sunscreen, and 30 to 50 SPF sunscreen should be used to compensate for the reduction in SPF induced by DEET [6, 13].

Alternatives to DEET

If DEET is not tolerated (or unavailable), and travellers are visiting areas where malaria or other vector-borne diseases are present, Icaridin (Picaridin) at concentrations above 20 percent, or Lemon eucalyptus preparations (PMD or chemical name: para-menthane-3,8-diol) are the most useful alternatives [6, 12].

Icaridin (Picaridin)

Icaridin has repellent properties similar to DEET with a comparable duration of protection when both are used at 20 percent. If used for mosquito bite prevention against malaria, at least a 20 percent preparation is advised [6].

Lemon eucalyptus (p-menthane 3,8 diol) or PMD

Thousands of plants have been tested for their insect repellent properties. Although none of the plant-derived chemicals so far tested demonstrate the broad level of effectiveness and duration of DEET, a few do show repellent activity. Lemon eucalyptus (PMD) provides similar protection to 15 percent DEET but provides a shorter period of protection [6].

Oil of citronella-based products do have repellent properties but provide short lived protection [6]. They are not recommended for protection against malaria by the Advisory Committee for Malaria Prevention for UK Travellers (ACMP), and Citronella has been withdrawn in Europe.

Use of Insect Repellents in pregnancy and breastfeeding

Avoidance of mosquito bites is extremely important in pregnancy as pregnant women are particularly attractive to mosquitoes [6].

The use of 20 percent DEET during the second and third trimesters of pregnancy was not associated with adverse effects on the infants in pregnancies followed for up to 12 months after birth [6, 13]. Because malaria is a serious disease in pregnancy, DEET based repellents in concentrations up to 50 percent are recommended for all pregnant women, at any stage of pregnancy, travelling to areas where malaria or other insect-borne diseases are a risk [6, 14].

Icaridin and PMD are alternatives to DEET. However, there is no data concerning exposure in human pregnancy, although animal studies have not demonstrated any features of maternal or developmental toxicity [14].

DEET may also be used in concentrations up to 50 percent in breastfeeding. Nursing mothers should wash repellents off their hands and breast skin before handling infants.

Use of insect repellents in infants

Recommendations on the use of DEET in young children vary between countries. According to Public Health England Advisory Committee on Malaria Prevention (ACMP) DEET may be used at a concentration of up to 50 percent in infants and children aged over 2 months. DEET is not recommended for infants under 2 months of age [6]. Manufacturer’s instructions on application should be followed. Infants under 2 months should be protected with protective clothing and insecticide treated nets draped over cots and prams secured around the edges to avoid gaps.

Children should not be allowed to handle repellents as they may inadvertently ingest them or get them in their eyes. Adults should apply repellent to their own hands, then onto the child’s skin, and avoid applying to children’s hands.

How to use insect repellents safely:

  • Use on exposed skin only, not under clothing.
  • Do not use over cuts, irritated or inflamed skin.
  • Do not apply directly to the face – apply repellent to hands, then to the face to avoid contact with lips and eyes. Wash hands after application.
  • Do not apply to children’s hands.
  • Apply and re-apply repellents according to manufacturers’ instructions.
  • Remove with soap and water when repellent is no longer needed.
  • Ensure repellents are not ingested or inhaled.
  • DEET can be used in concentrations of up to 50 percent in pregnant and breastfeeding women, and in infants and children older than 2 months (unless allergic).
  • When sunscreen and DEET are needed, DEET should be applied after sunscreen (use 30 – 50 SPF sunscreen to compensate for reduction in SPF induced by DEET).
  • Products containing both sunscreen and repellent together should usually be avoided.
  • DEET may damage plastics and artificial fibres so care is needed to avoid contact. DEET does not damage natural fibres such as wool, linen or cotton.
  • Picardin and lemon eucalyptus extract or PMD are available for those who prefer not to use DEET-based products. Picardin should be used in concentrations of at least 20 percent.

Mosquito nets

If sleeping or resting outdoors or in a room with no air conditioning, travellers should use a mosquito net to avoid being bitten. Nets should be impregnated with insecticide (e.g. permethrin) to improve protection – these will need to be re-impregnated every 6 to 12 months to remain effective, depending on the frequency of washing. Long-lasting impregnated nets are now available and have an expected useful life of at least 3 years [6].

Mesh size in mosquito bed nets should be no larger than 1.5 mm and nets should be free from tears and tucked in under the mattress. It may be useful for travellers to carry a small sewing kit so that repairs can be made if the net develops a hole. Extra equipment for hanging the net can be helpful including extra string or wire hooks.

Room protection (including air conditioning and screening)

Doors and windows to sleeping accommodation should be screened with fine mesh.

Air conditioning reduces night-time temperature in a building and therefore reduces the likelihood of mosquito bites. Ceiling fans reduce the nuisance from mosquitoes [6].

There is evidence that insecticide vaporisers inhibit mosquito bites and cause mosquito repellence and knockdown [12].

A systemic review demonstrated that mosquito coils can decrease bites by repelling and killing mosquitoes [15]. Coils, which contain synthetic insecticide, may be useful for some travellers but they should only be used outdoors [6].

Measures not recommended for repelling insects [6]

There is no evidence that any of the following products, have repellent effect on mosquitoes [6]:

  • Garlic
  • Vitamin B1
  • Vitamin B12
  • Yeast extract (e.g. Marmite)
  • Electronic buzzers
  • Tea tree oil or proprietary bath oils
  • Citronella oil-based repellents due to their short duration of action; they have been withdrawn in Europe.

Management of insect and tick bites

In addition to transmission of infectious diseases, complications from insect bites and stings include local skin trauma, allergic reactions and secondary bacterial infection.

Reactions from most insect bites or stings will resolve within hours or days. The site should be cleaned with soap and water. Application of a cold compress (if available) to the bite site may provide relief from pain or itching [3, 16]. The pack should have a cloth barrier between the ice and skin to prevent local tissue damage. Applying the ice pack on and off at 15-minute intervals is a common regimen [4].

Mosquito bites should not be scratched and should be kept clean and dry to avoid infection. Antiseptic and basic wound dressings can be helpful if the bite is causing irritation and likely to become infected.

Following an insect sting, if the stinger is still visible in the skin, this should be removed as quickly as possible by scraping sideways with a fingernail or piece of card.

Oral analgesics (e.g. paracetamol and ibuprofen) are often recommended to ease pain, although there is a lack of evidence to support these treatments [3]. Itching may be reduced by taking antihistamine tablets or the topical application of a mild steroid cream, although good quality evidence to support their use is lacking [3].

Ticks need to be removed from the skin very carefully. This can be done with fine tipped tweezers or specially designed tick removers (see Figure 1).

The tick should be grasped as close to the skin surface as possible and pulled steadily upwards, taking care not to crush the tick’s body or squeeze the stomach contents into the site of the bite. After removing the tick, the bite area should be cleaned thoroughly with soap and water, or iodine/antiseptic if available. If tick mouthparts are not fully removed, persistent nodules (small lumps) can develop [3].

The tick should not be covered with solutions such as nail varnish or petroleum jelly and heat should not be used for tick removal.

Figure 1. How to remove a tick


Source: CDC. Tick removal

After travel

Those with a fever (38°C or more) or other worrying symptoms after travel should seek prompt medical help. Malaria symptoms can appear up to a year after travel.

If a rash or fever develops within several weeks of removing a tick, medical attention should be sought, providing details of the recent tick bite, including when and where the bite occurred.

Insect bites can sometimes become infected, become swollen, painful and red with pus where the bite occurred. Travellers should contact their GP if they are concerned about the symptoms; antibiotics may be required.

  1. Schlagenhauf P, Weld L, Goorhuis A et al. Travel-associated infection presenting in Europe (2008—12): an analysis of EuroTravNet longitudinal, surveillance data, and evaluation of the effect of the pre-travel consultation. Lancet Infect Dis. 2014; 15(1): 55-64.
  2. Hochedez P, Caumes E. Common Skin Infections in Travelers. J. Travel Med. 2008; 15(4): 252–62
  3. National Institute for Health and Care Excellence, Clinical Knowledge Summaries. Insect bites and stings. Revised October 2016 [Accessed August 2020]
  4. BMJ Best Practice. Insect bites and stings. British Medical Journal. Updated Feb 2020 [Accessed August 2020]
  5. World Health Organization. Vector-borne diseases Factsheet. Updated March 2020 [Accessed August 2020]
  6. Chiodini PL, Patel D and Whitty CJM. Guidelines for malaria prevention in travellers from the United Kingdom 2019. London: Public Health England; August 2019 [Accessed August 2020]
  7. Fradin MS. Insect Protection in Keystone JS (ed). Travel Medicine. 3rd ed. Elsevier: 2013.
  8. European Centre for Disease Prevention and Control. Personal protective measures against tick bites. January 2015 [Accessed August 2020]
  9. Mutebi J-P and Gimnig JE. Mosquitoes, Ticks and Other Arthropods. Chapter 3 in Centers for Disease Control and Prevention. Health Information for International Travel 2020. Oxford University Press [Accessed August 2020]
  10. Webb CE. Can travellers avoid bed bug bites? Travel Med Infect Di. 2012; 10(5-6): 281 –2.
  11. Burri C, Chappuis F and Brun R. Human African Trypanosomiasis in Farrar J (ed). Manson’s Tropical Diseases. 23rd ed. Elsevier, 2014.
  12. Goodyer LI, Croft AM, Frances SP et al. Expert review of the evidence base for arthropod bite avoidance. J Trav Med. 2010; 17(3):182-92.
  13. Murphy ME, Montemarano AD, Debboun M et al. The effect of sunscreen on the efficacy of insect repellent: a clinical trial. J Am Acad Dermatol. 2000; 43(2 Pt 1): 219-22.
  14. UK Teratology Information Service. Chemical Insect Repellents. May 2018 [Accessed August 2020]
  15. Lawrence CE, Croft AM. Do mosquito coils prevent malaria? A systemic review of trials. J Travel Med. 2004 11(2): 92-6.
  16. Management of simple insect bites: where’s the evidence? Drugs and Therapeutics Bulletin 2012; 50(4): 45-8. [Accessed August 2020]

First Published :   09 Aug 2020
Last Updated :   09 Aug 2020

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