A sudden spike in cases of an extremely rare, but potentially deadly virus south of the border has prompted health officials in Canada to expand their monitoring of ticks for the disease.

Testing for Powassan virus is being broadened to include blacklegged ticks, says the Public Health Agency of Canada.

Human cases of the virus, which can cause encephalitis, or inflammation of the brain, have been reported this spring in New York, New Jersey, Massachusetts and Maine, prompting several other states to be on the lookout for the disease.

"To date, screening for Powassan virus has focused on groundhog ticks," the health agency said in a statement emailed to The Canadian Press.

"As a result of increased cases of the disease in the United States, the agency is expanding its screening program this spring to include blacklegged ticks."

The virus, which falls under the same family as the West Nile virus, was first identified in 1958 in Powassan, Ont., where a child who contracted the disease later died.

Since then, only 16 human cases have been reported in Canada and all have been in eastern provinces — New Brunswick, Quebec, and Ontario.

But health officials say the numbers of blacklegged ticks have expanded rapidly in Canada over the last 10 years.

Powassan virus has been detected in ticks from New Brunswick, Nova Scotia, Prince Edward Island, Quebec, Ontario, Alberta and British Columbia.

Several species to be tested

Several species of mammals will also be tested for the illness.

"We also have plans to develop a universal serological test so we can test a wide variety of animals to gain a better understanding of the current incidence of Powassan virus in Canada," the agency said.

Symptoms of the Powassan virus are similar to those of the more prevalent, slower-acting Lyme disease, but much worse.

Once contracted, the incurable virus attacks the central nervous system, often within minutes, causing vomiting, fever, headache, weakness, confusion, seizures, swelling of the brain and memory loss.

Cases of Lyme disease, which is caused by a bacteria, have also been on the rise.

In 2012, 338 probable and confirmed cases were reported by eight provinces, more than double the 144 cases reported in 2009.

Those most likely to come in contact with ticks that can carry Powassan virus, Lyme disease and other illnesses are outdoor enthusiasts, such as hikers, hunters and campers.

Health experts recommend using tick repellent and wearing long sleeves and pants when spending time in wooded or bushy areas.

"And certainly, one of the things we advise is that, as soon as you get home, take your clothes off and have a shower," said Curtis Russell, a program specialist for the enteric, zoonotic and vector-borne disease unit at Public Health Ontario.

"That way, if the ticks have not started to feed, there's a chance of washing them off," he explained.

"Also, if you take your clothes off and put them in the dryer for at least an hour, there's a chance that you can kill off the ticks."

The Public Health Agency advises anyone who is bitten by a tick to remove the tiny arachnid and place it in an airtight bag or pill bottle. Then, note the location and date of the bite, watch for symptoms and see a health care professional immediately, should symptoms appear.