PORTLAND (AP) - There's still a lot of winter left, but it seems the flu season is winding down.

Flu is a tricky disease to predict, however, and epidemiologists warn that a spike in the number of cases could occur.

"We've had clusters of cases as late as March and one year even into May," said Dr. Fred Hoesly, epidemiologist with the Oregon Department of Human Services.

Despite reports of high numbers of flu deaths in other states, the Portland area has had fewer flu-related fatalities than last season.

Hoesly said he didn't know why the number of deaths is lower.

The national Centers for Disease Control and Prevention, which tracks deaths from those diseases, reports that the Portland area had 87 deaths from the beginning of October through the first week in January, compared with 112 deaths for the same period the previous season. Deaths from pneumonia, a complication of influenza, are included in those figures.

Hoesly said the state's flu status was downgraded last week from "widespread" to "regional." The new designation means that flu is concentrated in areas where less than 50 percent of the state's population lives.

Unlike AIDS and chickenpox, flu isn't a disease that doctors are required to report. Estimates of the number of flu cases are generally based on indirect evidence, such as the number of specimens doctors send to laboratories to be analyzed for flu.

Hoesly said that for the most recent week, ending Jan. 10, 53 culture-confirmed cases of influenza A were reported by laboratories in Oregon, compared with 73 the previous week.

The percentage of cultures that test positive for flu is also declining, he said. In early December, half of the specimens tested positive for the flu virus, compared with about 25 percent in early January.

Phyllis Shoemaker, a flu surveillance epidemiologist with the Washington State Department of Health, said the season began early in that state, like Oregon, and peaked in late November, when 79 schools reported more than 10 percent absenteeism because of influenza-like illnesses.

Since then, she said, "it's gone down gradually to nothing."