As health officials in the United States grapple with one of the largest outbreaks of West Nile virus infections in the country’s history, the number of cases in Canada is starting to climb as well.

The Centers for Disease Control and Prevention in Atlanta said 1,118 human West Nile cases have been reported so far this year in the U.S., about half of them in Texas. Forty-one people have died.

Fewer than 300 cases are reported in an average year by mid-August.

"We're in the midst of one of the largest West Nile outbreaks ever seen in the United States," Dr. Lyle Petersen, who oversees mosquito-borne illness programs at the CDC, said during a teleconference Wednesday.

As a result, aircraft have been spraying insecticide over the worst-hit area of Dallas County in an effort to kill disease-carrying mosquitoes.

Meanwhile, 49 confirmed and probable human cases of the infection have been reported in Ontario as of earlier this week. The majority of cases are in Toronto, where 30 people have fallen ill.

Alberta also recently reported its first human West Nile virus case since 2010. Manitoba, Saskatchewan and Quebec have also reported at least one case each this year.

Health officials are not exactly sure what’s causing the spike in West Nile infections, but they suspect that a mild winter and hot summer have created perfect conditions for the virus to spread from birds to humans via mosquitoes.

"I suspect this year will be another outbreak year, maybe even as big as 2007 or 2003, given the early activity in Ontario," Dr. Bonnie Henry, medical director of communicable disease prevention and control services at the B.C. Centre for Disease Control, told The Canadian Press.

The Public Health Agency of Canada says most people infected with West Nile virus have no symptoms or confuse signs of the infection with flu symptoms: fever, fatigue and body aches.

However, the virus can also cause serious illness and death in severe cases, so it’s important to minimize your exposure to potentially infected mosquitoes.

Doctors are advising people to apply mosquito repellent while outdoors and wear long-sleeved shirts and pants whenever possible.

With files from The Canadian Press