Six confirmed West Nile cases in Alberta, all the less serious form

By Gillian Slade on August 31, 2018.

gslade@medicinehatnews.com  @MHNGillianSlade

The first West Nile virus cases of 2018 have been confirmed in Alberta, and of the six affected, five patients are in the south zone.

“The south zone in particular is a high-risk area,” says AHS medical officer of health Lizette Elumir, adding the cases are scattered across the south zone and not isolated to any particular community.

A number of factors influence the prevalence of West Nile-carrying mosquitoes, including an accumulation of hot weather.

Government documents suggest a temperature of 18 C would mean about 30 days for Culex tarsalis (the larvae carrying the virus) to be able to transmit the virus. With temperatures of 30 C, it takes less than a week.

West Nile can cause West Nile Non-neurological Syndrome, or on rare occasions the more serious West Nile Neurological Syndrome.

The good news is that none of the six cases recently confirmed were the Neurological Syndrome, said Elumir.

Those with West Nile Non-Neurological Syndrome may experience fever, chills, nausea, vomiting, fatigue, skin rash, swollen glands and headache. People who develop West Nile Neurological Syndrome may experience tremors, drowsiness, confusion, swallowing problems, high fever, unconsciousness, paralysis and even death.

Elumir says three cases actually had no symptoms of West Nile, and the diagnosis must have been made as a result of a blood test for some other reason. When people donate blood one of the tests is for West Nile.

There were seven confirmed cases in 2017.

“I’m always concerned. There is always a risk,” said Elumir. It is preventable though — don’t get bitten by mosquitoes.

Use an insect repellent that contains DEET and limit your time outdoors at dawn and dusk when mosquitoes are most active. Cover up with long-sleeved shirts and long pants in light colours, she explained.

There were 275 Alberta cases of West Nile in 2003, and 320 in 2007.

The numbers dropped dramatically after that with only one in 2008, two in 2009, and nine in 2012, including a local man who died that October from West Nile Neurological Syndrome. There were 21 cases in 2013 and then nothing until 2016 when there were five, three of which were in the south of the province, according to data on Alberta Health’s website.

In 2017, there were seven cases in Alberta, with four in the south zone, two in Calgary and one in central Alberta.