Canadians are being advised to be extra cautious against the rare enterovirus D-68 (EV-D68) which has already infected 18 in Alberta and three in British Columbia.

The Public Health Agency of Canada has sent out an alert to the country's over than 4,000 infectious disease doctors, pediatricians and epidemiologists urging them to monitor cases in their respective jurisdictions.

Danuta Skowronski, the lead on emerging respiratory viruses with the B.C. Centre for Disease Control, said it would be impossible for the province not to experience having cases of the EV-D68 this year.

"There is no way we could have considered B.C. a D68-free zone. If it was picked up elsewhere, it was going to be picked up here," Vancouver Sun quoted Skowronski.

Since end August, the number of respiratory-related admissions to Alberta Children's Hospital have spiked up. Officials are trying to determine through laboratory tests if the patients have the same strain as the one circulating in the U.S.

EV-D68 first was identified in California in 1962, but has been rarely reported in the U.S. in the last 40 years. Most people who get infected are infants, children and teens. Most start with common cold symptoms of runny nose and cough. Some may also have fever. For the more severe cases, difficulty breathing, wheezing or problems catching one's breath may occur. There have been no known deaths due to the 2014 virus.

The U.S. Centers for Disease Control and Prevention had said at least 12 states in their country have been affected, including Alabama, Colorado, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Missouri, New York, Oklahoma, and Pennsylvania.

The virus, as with most, spreads from person to person when an infected person coughs, sneezes, or touches contaminated surfaces.

Not all, however, may require a speedy travel to the emergency department. "If there's no shortness of breath, no difficulty breathing, no wheezing or extremely high fever, there would be no reason to go and seek help. But if it's affecting the breathing in those ways, then it's time to get help," Dr. Dick Zoutman, Queen's University infectious diseases expert, told CBC.

"We don't want people rushing over just because they got a runny nose."

Zoutman advised parents to constantly monitor their children once they show symptoms.

Children, particularly aged five years old and below, as well as those who have existing respiratory troubles, such as allergies or asthma, are the one most susceptible to contract the EV-D68.

More information on EV-D68 is available on the CDC Web site.