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Introduction and General Information

The importance of personal protective measures in the prevention of mosquito borne diseases has been recognised for many years.
  • Prevention and control of arboviral diseases is accomplished most effectively through a comprehensive integrated mosquito management program. 
  • Personal protection is an important adjunct to wider mosquito control and along with local habitat management for source reduction is a way in which members of the public can protect themselves against WN virus infection. 

Personal protective measures aim to reduce the risk of an individual becoming infected with WN virus. In general personal protective measures involve reducing the risk of being bitten by mosquitoes which act as vectors for WN virus. However, other basic precautions such as avoiding direct contact with dead birds (which may have died from WNV infection) may also be considered as personal protection.

  • Personal protection against mosquito bites involves time/place avoidance (not being in habitats known or likely to contain vector mosquitoes at times when vector mosquito species are active), physical barriers (sometimes supplemented with chemicals) on buildings to prevent or minimise entry of mosquitoes into the buildings, the use of appropriate clothing to minimise areas of skin exposed to mosquitoes and the use of repellents to make exposed skin unattractive to mosquitoes.
  • Protection of individual animals may be undertaken following the same principles as personal protection of individual humans.

(J136.128.w1, D67, D71, D72)

Published Guidelines linked in Wildpro

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Personal Protection for Humans

Personal protective measures for humans include:
  • Installation of screens (16-18 mesh) on the windows and doors of homes and commercial buildings.
  • Minimizing time spent outdoors between dusk and dawn.
  • Wearing shoes, socks, long pants (trousers), and a long-sleeved shirt when outdoors for long periods of time, or at times when mosquitoes are most active.
  • The use of mosquito repellents (particularly those containing N,N-diethyl-metatoluamide (DEET), diethyl phthalate, diethyl carbate or ethyl hexanediol), applied according to directions, when it is necessary to be outdoors for long periods or at times when mosquitoes are most active. When using repellents:
    • It is important to cover the skin evenly (including behind the ears), as mosquitoes will find and bite untreated areas;
    • Repellents may often be sprayed on outer clothing in addition to skin;
    • In general, protection may be expected for up to six hours after application of DEET (shorter times after application of other repellents);
    • Care must be taken when applying DEET as it may damage synthetic materials including plastics, rayon, spandex, as well as leather and painted or varnished surfaces.
    • Precautions when using repellents include: (W175.Nov01.wnv2)
      • Keep repellents away from the eyes, nostrils and lips;
      • Do not inhale or ingest repellents;
      • Do not apply to children's hands that are likely to come into contact with their eyes or mouth;
      • Minimise use in pregnant and nursing women;
      • Never use on wounds or irritated skin;
      • Avoid application of products containing greater than 30% DEET to the skin, especially for children;
      • Wash treated skin after coming indoors;
      • In the event of a suspected reaction to the repellent, wash treated areas of skin and consult a physician.

      (W175.Nov01.wnv2)

  • The use of permethrin clothing treatment.
  • Replacing outside lights around homes with yellow "big bulbs" or sodium vapour lights that are less attractive to mosquitoes than are standard bulbs.
  • Use window shades at night to avoid attracting mosquitoes in towards lights.

(J84.7.w35, J115.13.w2, J136.128.w1, N11.30.w1, D70, D72, D73, W175.Nov01.WNV2, B245.29.w29)

The following information regarding precautions to be taken in field collection of dead animals, laboratory manipulation of the West Nile virus and  handling of potentially infectious clinical specimens is taken directly from the Health Canada "Biosafety Advisory West Nile Virus (June 2001, Revised June 2003) (W181.28Jan04.WNV5) [Reproduced with the permission of the Minister of Public Works and Government Services Canada, 2004]

Precautions for the field collection of dead birds and other animals:

Persons involved in collecting dead birds and other animals should follow the recommendations of the Occupational Health Advisory West Nile Virus, Revised May 29, 2003: 

  • precautions for mosquito avoidance (i.e. wearing long sleeved shirts, full length trousers, socks, light coloured clothing, high boots) and the use of repellants (i.e. 20-30% DEET) should be implemented 
  • when possible, minimize outdoor activities where and when (e.g. dusk, night, dawn) mosquitoes are likely to be encountered 
  • bare-handed contact should be avoided when handling dead animals and birds and precautions should be taken to avoid direct contact with excretions 
  • rubber/nitrile/latex/vinyl/PVC gloves and double plastic bags turned inside out over hands can be used to collect dead birds 
  • cut-resistant gloves can be worn under rubber/nitrile/latex/vinyl/PVC gloves to avoid cuts or puncture wounds from bills, claws, or instruments during handling and dissection of birds and other animals 
  • hands should be washed after handling dead birds 

Precautions for the handling of suspect specimens in animal necropsy suites: 

  • where practical, animal carcasses should be manipulated in a certified biological safety cabinet (BSC)
  • larger carcasses should be manipulated using equivalent protective measures (e.g. splash protection on eyes, protective solid-front gowns with tight fitting wrists, rubber/latex/vinyl/PVC gloves, and respiratory protection1 (NIOSH certified N-95 to N-100 respirator filter mask, half or full face, depending on splash protection)

Precautions for the handling of human and animal (including avian) suspect clinical specimens:

  • potentially infected human and animal clinical specimens (e.g. blood, serum, CSF, tissues) may be handled in a Containment Level 2 facility2 using Containment Level 3 operational practices2 as outlined below 
  • blood collection should be carried out using standard universal precautions3 (e.g. wearing gloves, hand washing, avoiding needle sticks)
  • sorting of mosquitoes for species identification, where possible and practical, may be performed in a Containment Level 2 facility2 
  • certified biological safety cabinets should be used for laboratory manipulations of suspect clinical specimens 
  • centrifugation of clinical specimens (e.g. for serum separation) should be carried out using sealed centrifuge cups or rotors that are loaded and unloaded in a biological safety cabinet 
  • aliquots used for serology should be heat inactivated at 56° C for 30 minutes 
  • PCR testing may be performed in a Containment Level 2 facility1 using Containment Level 3 operational practices2 

Precautions for virus isolation and laboratory manipulation of the WN virus: 

  • virus isolation and propagation should be performed in a Containment Level 3 facility2 using Containment Level 3 operational practices
  • animal studies should be performed in a Containment Level 3 animal facility1 using Containment Level 3 operational practices
  • studies involving infected mosquitos should be performed in a Containment Level 3 facility2 using Containment Level 3 operational practices2

Dead birds and sera to be tested (eg. sera collected from sentinel chickens) should be packaged adequately and labelled and shipped as “Diagnostic Specimen”. 
Shipping, packaging and transport of the WN virus and suspect clinical specimens and sera should follow the Transportation of Dangerous Goods Regulations, Transport Canada.

  1. Further biosafety information may be obtained from the Office of Laboratory Security, Population and Public Health Branch, Health Canada at (613) 957-1779 or fax (613) 941-0596.
  2. Further occupational health and safety information is available in the Occupational Health Advisory, Occupational Health and Safety Agency, June 24, 2003.

References: 

  1. Containment Standards for Veterinary Facilities, Agriculture and Agri-Food Canada, Publication No. 1921, July 1996.
  2. Laboratory Biosafety Guidelines, Health Canada, 1996. 
    http://www.hc-sc.gc.ca/pphb-dgspsp/publicat/lbg-ldmbl-96/index.html
  3. Preventing the Transmission of Bloodborne pathogens in Health Care and Public Service Settings, Canada Communicable Diseases Report - Supplement Vol. 23S3, May 1997.
    http://www.hc-sc.gc.ca/pphb-dgspsp/publicat/ccdr-rmtc/97vol23/23s3/index.html

[Source: Biosafety Advisory West Nile Virus, Health Canada, (June 2001, Revised June 2003) & Reproduced with the permission of the Minister of Public Works and Government Services Canada, 2004.]

(W181.28Jan04.WNV5)

  • A study undertaken in Mississippi in 2002 found that the use of personal protection including staying inside during peak mosquito biting times, avoiding areas which were apparently mosquito-infested, wearing long sleeves and long pants did appear to reduce the risk of WNV infection. (P48.4.w9)
  • Public education is important to provide information about personal protective measures which they can use and why they should use them. (D71)

REASONS WHY PERSONAL PROTECTION MAY NOT BE UTILISED FULLY

There are a variety of reasons why personal protection may not be utilised fully. These include:

  • Incorrect perceptions of risk: lack of understanding that this disease continues to be a problem, lack of recognition that is a threat in the local area, lack of understanding that older persons, rather than children, are most at risk from the disease.
  • Incomplete understanding of transmission routes and overriding importance of transmission by mosquito bite.
  • Unwillingness to reduce time spent outdoors between dusk and dawn due to conflicts with e.g. social interactions and physical activity such as outdoor sports.
  • Regular application of insect repellents may be considered inconvenient.
  • There may be concerns regarding the use of products containing DEET, particularly for use on children.
    • A recent review of the evidence available fount that "the evidence does not support increased risk in young children" and that the available data were reassuring also regarding safety of use during pregnancy and lactation. (J257.169.w1)
  • Incomplete acceptance of personal responsibility for protection: perception that public control of mosquitoes should be sufficient for disease control.
  • Economic or physical barriers to activities such as replacing or repairing damaged insect screens.
    • Individuals who are homeless present special challenges as they have extensive outdoor exposure and limited financial resources to engage in personal protection; individuals in residences lacking effective window screens also have an increased risk of exposure to mosquito bites and should be targeted for assistance with screen repair. 
  • It is not easy to change personal behaviours.

(J257.168.w1, J257.169.w1, P39.4.w25, P39.4.w26, D147)

Associated techniques linked from Wildpro

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Individual Protection for Horses

Individual protective measures for horses to decrease their exposure to biting mosquitoes can be applied by their owner/caretaker and are very similar to measures described for humans.
  • Avoiding turning horses out into fields during the periods of the day when the prevalent vector mosquitoes are most active (dawn and dusk). (P51.49.w3)
    • Preferably keep them stabled from dusk to dawn in insect-proofed stables.
  • Keep mosquitoes out of barns/stables:
    • Install screens on the entrances and windows of horse barns/stables and maintain screens in good condition.
      • It is important to ensure mosquitoes are first eliminated from inside the building; this may involve the use of mosquito adulticides. (W30.Nov01.WNV3)
    • If stables are not insect-proof, use of insecticides in the stable may be beneficial.
    • Fans in the stables may help keep mosquitoes away. (P51.49.w3)
    • Avoid turning on lights in the stables during the evening/night as these may attract mosquitoes. Incandescent lights outside (stable perimeter) may attract mosquitoes to the lights and away from the horses. (P51.49.w3)
    • Note: A study in Saskatchewan found that horses housed in barns with fans, or sealed at night, were least likely to become infected; smudges also provided a significant degree of protection. (J240.71.w1)
  • Keep horses covered with a summer-weight rug.
  • Applying insect repellent to individual horses:
    • These should be used according to their label instructions regarding appropriate species for use, method of application and any other appropriate precautions;
    • It has been suggested that topical application of products containing permethrin or other synthetic pyrethroid compounds as the active ingredient may offer the best combination of safety and efficacy;
    • It is important to remember that insect repellents should not be relied on to fully protect a horse from mosquito bites; there are practical limitations in the area of any horse over which coverage may be achieved with particular product formulations.
    • A study in Saskatchewan found that horses sprayed with insecticide were not less likely to become infected. (J240.71.w1)
  • NOTE: Exposure of horses to mosquitoes can also be achieved by reducing local mosquito habitats. (P51.49.w3) See: Habitat Management for Control of West Nile Virus
  • NOTE: Horses can also be protected against WNV infection by vaccination. See: Vaccination for West Nile Virus
    • It has been recommended by APHIS (USDA) that owners both vaccinate their horses against WN virus and also take measures to avoid exposure of their animals to mosquitoes. (W30.28Jan04.WNV2)
(J4.218.w2, J84.7.w12, J89.16.w1, J240.71.w1, J484.35.w1, P51.49.w3, W30.Nov01.WNV3, W30.28Jan04.WNV1, W30.28Jan04.WNV2)
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Individual Protection for Other Domestic Animals including Poultry

If a risk to livestock or poultry of developing disease due to WNV infection were recognised in the USA in the future, protective measures could be applied similar to those recommended for horses. (W30.Nov01.WNV3)
  • Mosquito netting has been used to protect key bird enclosures in zoos, alongside other protective measures (introduction of larvivorous fish into permanent water bodies, use of larvicides in other potential mosquito breeding areas and ground spraying of insecticides (resmethrin and malathion). (P30.1.w1)
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Authors & Referees

Authors Debra Bourne (V.w5
Referee Suzanne I. Boardman (V.w6); Becki Lawson (V.w26); Dr Robert G. McLean (V.w42)

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