By CRAIG FREILICH

The number of flu cases confirmed in St. Lawrence County since October appears to have spiked by more than 50 percent in the last week of January.

And the flu “season” is likely to last for several more months, according to Kindra Cousineau, communicable disease program coordinator for the St. Lawrence County Public Health Department.

From Oct. 1, 2017, the beginning of the season, through Jan. 24, 2018, 171 confirmed flu cases had been reported to the St. Lawrence County Public Health Department, according to Cousineau.

But eight days later, the number of reported cases had increased by 88, or 51 percent, for a new total of 259 cases confirmed by tests. Those figures come from hospital labs in St. Lawrence County and represent what is probably just a fraction of total flu cases.

That’s because many people with flu symptoms don’t see a doctor or visit an emergency room.

And even those suspected of having the flu who see a medical professional are often not tested because “the test results usually do not change how you are treated,” according to the Centers for Disease Control and Prevention. And false negative results are common in those who are tested, the CDC says.

If a medical professional suspects a case of flu, a rapid swab test of nasal material can produce results confirming the presence of an influenza virus the same day, Cousineu said.

“Most people with flu symptoms do not require testing because the test results usually do not change how you are treated,” a U.S. Centers for Disease Control (CDC) flu question-and-answer web page says.

“Your respiratory illness might be the flu if you have fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue,” the web page advises.

“Some people may have vomiting and diarrhea. People may be infected with the flu and have respiratory symptoms without a fever. Flu viruses usually cause the most illness during the colder months of the year. However, influenza can also occur outside of the typical flu season. In addition, other viruses can also cause respiratory illness similar to the flu. So, it is impossible to tell for sure if you have the flu based on symptoms alone. If your doctor needs to know for sure whether you have the flu, there are laboratory tests that can be done.”

“Your health care provider may diagnose you with flu based on your symptoms and their clinical judgment or they may choose to use an influenza diagnostic test,” the CDC said.

As for declaring the end of the season, there is no fixed date, Cousineau said.

“It usually ends in April or May, but last year it went right through June,” she said. “It’s usually in the spring.”

Statewide, 11,683 laboratory confirmed influenza cases were reported to the state Department of Health last week, and 2,221 New Yorkers were hospitalized with confirmed influenza, according to Gov. Andrew Cuomo’s office.

These numbers are the highest weekly numbers in both categories since reporting began in 2004 and exceed last week's record high 7,779 confirmed cases and 1,759 hospitalizations.

So far, 69 percent of cases were influenza A, 30 percent were influenza B, and 1 percent undetermined.

A study published by the CDC in May 2017 said cases caused by those two types of influenza virus produce similar degrees of severity. “This contradicts a common misconception that flu B viruses are associated with milder disease than flu A viruses,” the study said.