The three most common types of human ectoparasitic infestations found in Canada are lice infestations caused by Pediculus humanus capitis and Phthirus pubis, scabies caused by Sarcoptes scabiei, and myiasis caused by different species of fly. Outbreaks of head lice occur most notably in the autumn because of the increased close contact among school children. Although there have been no surveys to document the prevalence of lice in the Canadian population, it has been estimated that between 1 and 10% of school children are infested with head lice at any one time (Chunge et al. 1991). Reports of body lice or pubic lice infestations are rare. Scabies has become relatively uncommon in Canada but continues to be of concern in certain high-risk groups, such as hospitalized populations and travellers (Belle et al. 1979; Jack 1993). Medical and public health authorities occasionally mention sporadic cases of scabies in immunosuppressed individuals and among preschool children attending daycare centres. Several different kinds of myiasis have been reported from each region in Canada (Gyorkos 1977). The most common fly species implicated in endemic myiasis has been the flesh-fly, Wohlfahrtia vigil, which causes furuncular myiasis. Imported cases also occur.
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