Insect and Mosquito Repellents

Many diseases are spread by insects and mosquitoes. Such diseases include malaria, dengue fever, Zika, Chikungunya, Japanese encephalitis, tick typhus and yellow fever. Insect-borne diseases pose a serious threat to travellers and it is important to reduce the number of insect and mosquito bites as much as possible. 

Insect and mosquito repellents date back to ancient times when smoke, plant oils and tars were used. Modern insect repellents are subject to rigorous efficacy and safety testing prior to licensing and approval by the  Australian Pesticides and Veterinary Medicines Authority (APVMA).

De-bunking the "natural" myth

There are a number of registered "all natural" insect repellents such as wrist band, herbs, oils and plant extracts that claim to repel insects and mosquitoes. These products can contain anywhere from <1% to only 8.5% concentration of the active ingredient. While some formulations show an ability to repel insects and mosquitoes, they would need to be re-applied far more regularly (i.e. between every 1 and 30 minutes, which is not practical), to maintain any form of effectiveness. 

Selecting an insect and mosquito repellent

When selecting an insect and mosquito repellent, the type of repellent should match the risk. In situations where the risk of serious disease is high, a repellent containing either DEET or Picaridin should be selected.  

DEET (N,N-diethyl-metatoluamide)

DEET containing insect repellents were developed in the 1950s following military entomological trial. The chemical works by vaporising. The vapour barrier deters the insect by the smell and taste. DEET is very effective against mosquitoes, tick and biting flies. The higher the concentration the longer it protects. There seems, however, to be no added benefit beyond 50% concentration.  A product with 30% DEET will be protective for about 6 to 7 hours and 10% for 3 hours.  Effectiveness may be influenced by temperature, sweating, humidity, water sports etc.

DEET is toxic when ingested and may cause skin irritation in some people. DEET containing products have been used over a long period of time and by many millions of people with few reported serious side effects.  Despite this, a few precautions should be undertaken.

  • Apply DEET lightly to exposed areas only
  • Where possible, wash off on returning indoors
  • Do not apply to open cuts or sores
  • Do not used aerosol applications to the face directly. Apply to the hands and rub on the face, avoiding eyes and mouth
  • Do not allow young children (under 10 years) to apply it to themselves. Weaker formulations are available for children. If they have never used it before, it is wise to test a patch on the arm for a few days before applying all over
  • Do not apply to children's hands which they may subsequently lick
  • Always stick to the age restrictions stated on the product
  • If sunscreens are to be used with repellents, apply sunscreen first and wait 20 minutes before using the repellent.

CONCENTRATION OF DEET

PROTECTION TIME (approx)

30%

6-8 hrs

15%

5 hrs

10%

3 hrs

5%

2 hrs

 

Our Travel Medicine Doctors recommend: Repel 60ml spray  |  Repel 75g stick  |  Repel 25g stick  |  Repel 60ml rollon  |  Repel Junior 50ml rollon

Picaridin (KBR-3023)

Picaridin is a newer insect repellent that is widely recommend by health authorities in Australia and internationally. At 20% concentration it is as effective as 20-30% DEET for 4-6 hours. It does have a few advantages to DEET, as it does not have an odour and is less of a skin irritant. The recommended 20% formulation of picaridin is still relatively hard to find in Australia. 

Our Travel Medicine Doctors recommend:  Protect 100ml spray  |  Protect 50ml spray  |  Repel New Era 

Both DEET and Picaridin are considered safe to use on pregnant and breastfeeding women.

Repellent and sunscreen

We often get asked: "what do I put on first, repellent or sunscreen?" 

If sunscreens are to be used with repellents then the sunscreen should be applied first. Wait at least 20 minutes before using the repellent.