Maine is on pace to see its highest number of positive tests for rabies in five years.

According to data kept by the U.S. Centers for Disease Control and Prevention, Maine has had 19 confirmed cases in the first quarter of 2016, from Jan. 1 through March 31. During that same period last year, there were five and only 31 in all of 2015.

John Martins, a spokesman for the Maine CDC, acknowledged that it has been a busy year so far, but he said rabies cases tend to be “cyclical.”

Keel Kemper, a regional wildlife biologist for the Department of Inland Fisheries & Wildlife, said the mild winter likely is the reason for the increase.

“Generally, we see more cases in springs after mild winters,” he said.

Although Maine has seen more cases of rabies so far this year, there has been a 39 percent drop nationally in positive cases compared to the first quarter last year. Most states have seen fewer cases, but some have seen increases like Maine. In New York, there have been 138 confirmed cases in 2016, more than twice as many as in the first quarter of 2015.

Over the last decade, the number of rabies cases in Maine has fluctuated widely. In 2006, there were 127 confirmed cases, but that was the only year the number topped 100. In the last five years, the highest number was 87 in 2012. Since then, there have been 51 cases in 2013, 43 in 2014 and 31 last year.

Raccoons and skunks have been the most common animals to test positive for rabies, but foxes, bats and even an occasional cat or dog has tested positive as well. The disease is transmitted primarily through bites.

The 19 cases so far this year have involved 13 skunks and six raccoons.

Kemper said all mammals are capable of carrying the viral disease, which affects the central nervous system. Human cases are extremely rare. Since 2003, there have been only 34 cases of human rabies reported nationally, none in Maine. The last human case in Maine was 1997, according to the CDC, and resulted in the person’s death.

Once symptoms appear – typically fever, encephalopathy (damage to the brain), drooling and hydrophobia (extreme fear of water) – rabies is almost always fatal in animals. Humans can survive the disease, but it is considered serious.

Kemper said the best thing Mainers can do is vaccinate their pets against rabies and not approach wild animals. He said there is no telltale sign for rabies in a wild animal, although often they will exhibit an uncoordinated gait because of partial paralysis in the hind quarter.

“Everyone thinks of the classic foaming of the mouth, but that really only happens just before they die,” he said.

Some states use baiting programs that administer a vaccine to wild animals through the bait. Kemper said he knows baiting is done heavily in bordering Canada, but he was not aware of any baiting programs in Maine.