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Handout for Nova Travel Clinic Clients regarding diseases caused by insects (Developed in conjunction with Canadian Paediatric Society Guidelines)

Protection Against Insect Bites

Insects transmit several tropical diseases including Malaria, Dengue, Yellow Fever, Japanese Encephalitis, Leishmaniasis, Zika Virus, Chikungunya fever and West Nile virus.  For some diseases, avoiding bites is the only way to prevent them.

Insect Repellents

  • Repellents containing DEET are the most effective and are available in several different strengths and formulations.  There is no need to use anything stronger than 35% DEET.  Lower concentrations may warrant more frequent application.  DEET should not be used in travelers with skin diseases such as psoriasis or eczema.
  • Products containing picaridin or natural substances such as lemon eucalyptus are also available and effective, though may need to be applied more frequently than DEET.
  • Repellents should be applied carefully to exposed skin, avoiding the eyes and mouth.
  • Always follow manufacturer’s instructions, and reapply regularly especially after swimming.  All products, including those purchased in a spray form, should be spread over the entire surface by hand.
  • Particular care should be taken when applying repellents to infants and children, and products stronger than 20% DEET should be avoided.  Avoid applying DEET to portions of children’s hands likely to contact eyes or mouth.  Do not allow children to apply insect repellent to themselves.
  • Infants less than 6 months – do not use DEET – use mosquito netting tucked over baby carriers.
  • Children 6 months  to 2 years – one application daily 10% DEET or less – apply sparingly avoiding face and hands
  • Children 2 to 12 years – DEET 10% or less, do not apply more than 3 times per day, avoid face and hands.
  • Adults and children over 12 years – use 30% DEET or less.
  • As soon as the repellent is no longer needed, it should be washed off the skin with soap and water
  • There is no evidence that vitamin B or garlic protect against mosquito bites.

Mosquito Nets

  • In basic accommodation without screening or air conditioning, consider sleeping under a mosquito net.  Bed nets should be tucked under mattresses before it gets dark.
  • Nets should be impregnated with the insecticide permethrin.
  • A small sewing kit is useful for making repairs to the net if necessary.


  • Tucking trousers into socks can help protect against ticks.  Shirts should be tucked into pants.
  • Clothing can also be purchased or treated with the insecticide permethrin (Permanone) which survives 20 washings.  Wearing long pants and long sleeved shirts minimizes area of exposed skin, in which case insect repellent need only be applied to exposed skin, chiefly the face and backs of hands.  Wearing shoes and socks (not sandals) will minimize exposure.

Knock Down Sprays (canned aerosol sprays)

  • Knock down sprays containing pyrethrum can be used to rid sleeping areas of insects.
  • Plug in devices which release an insecticide vapour are also available, as are coils which can be burned in a well ventilated area.

What to do if you’ve been bitten:

  • Try not to scratch insect bites as they may become infected.
  • Apply a mild steroid cream to reduce swelling.
  • Antihistamine tablets can be taken to reduce itching.
  • Ticks should be removed from the skin carefully with tweezers.
  • The Centre for Disease Control and Prevention website has an illustration of the correct method of tick removal at

Travellers who develop a fever more than one week after being in a malaria risk area, or who develop any symptoms suggestive of malaria within a year of return should seek immediate medical care.

Professional Education Committee International Society of Travel Medicine

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