FRANCAIS

September 03, 2004

·         A third probable human case of West Nile virus infection this year has been identified in Manitoba following a blood test analyzed at Cadham Provincial Laboratory. The individual, a resident of the Assiniboine Regional Health Authority in her twenties, was not hospitalized. The individual has been reported to Health Canada as a probable case of West Nile fever.

·         The likeliest period of exposure to West Nile virus for this individual was the last week of July and the location of exposure was likely in the Town of Killarney.

·         Usually, people infected by West Nile virus have no symptoms and do not become ill.  Of those who do become ill, most will develop West Nile fever, an illness with symptoms such as fever, headache, fatigue and body aches.  Less frequently, the virus can cause more serious illness (West Nile neurological syndrome) including encephalitis, an inflammation of the brain.

·         Encephalitis can have serious complications.  These complications may include weakness, paralysis, confusion, coma and death and are more likely to occur among older adults and people with chronic diseases and weakened immune systems.

·         There is no vaccine or specific treatment for West Nile virus.  Milder symptoms of West Nile fever usually improve without medical care.  Anyone experiencing severe symptoms (such as persistent high fever, muscle weakness, headache) should seek medical attention promptly for diagnosis and care.

·         Based on mosquito surveillance, the time of year and the life cycle of the Culex tarsalis mosquito, the current risk of becoming infected with West Nile virus in Manitoba is considered low and continues to decrease. 

·         While it is anticipated that additional human cases of WNV will be identified in Manitoba this season, it is expected that exposure to the virus in most newly identified cases will likely have occurred in late July or early August.

·         The most current mosquito surveillance information for southern Manitoba indicates that the activity of Culex tarsalis, the main mosquito species that carries West Nile virus in Manitoba, remained low in all regional health authorities during the week of Aug. 22 to 28. 

·         Although counts of Culex tarsalis have been low, there may still be low numbers of infected mosquitoes in southern Manitoba which may become more active, particularly during warmer evenings or during humid, overcast days.  Personal protection should be considered at any time when mosquito activity is noticed, especially for people over the age of 50 or with chronic medical conditions or weakened immune systems.

·         Public information about West Nile virus is available by calling Health Links-Info Santé at 788-8200 in Winnipeg or toll-free at 1-888-315-9257.  Additional information is available on the Manitoba Health website at http://www.gov.mb.ca/health/wnv, which is updated with surveillance data weekly.

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