16 2 Mosquit oes Mosq uit oes and blackfies are a no t orious nuisance in nor thern latitudes especially when conditions are cool and w e t T o a v oid bit es Use rep ellent containing DEET N Ndie th yl me ta t oluamide on y our skin with the under standing that higher concentrations ma y cause reactions as it is absorbed thr ough y our skin T reat y our feld c lo thing with perme thrin pr oducts t o repel insects fies ticks leeches e tc W ear treat ed bugjack e ts and headne ts t o reduce insect bit es where the number s of insects indicat e needed pr o t ection A v oid using cosme tics or soaps with fragrances W est Nile Virus Since 1 999 when the disease w as fr st f ound in Nor th America it has spread acr oss the USA and thr ough most of southern Canada Although e xtremely rare the W est Nile virus has been de t ect ed in British Columbia We st Nile virus is transmitt ed t o humans thr ough the bit e of an inf ect ed mosq uit o and v er y rarely thr ough blood transfusion andor organ transplant One canno t recognize mosq uit oes that carr y W est Nile virus so it is prudent t o pre v ent mosq uit o bit es b y using appr opriat e insect repellent containing DEET A bout one in fv e people bitt en b y an inf ect ed mosq uit o will de v elop sym pt oms of the disease One per cent of inf ect ed individuals will de v elop se v ere sym pt oms that ma y include encephalitis meningitis andor paralysis