Whooping cough cases in Suffolk County have reached 216 this year, marking the highest annual number for a New York county since 1999, according to health officials and state records.
Most of the cases -- 205 -- have occurred since June and involve students in 16 Suffolk school districts where the highly communicable bacteria have been passed through an unbroken chain of coughing and close contact, Suffolk health department spokeswoman Grace Kelly-McGovern said Tuesday.
Also known as pertussis, whooping cough is a respiratory infection characterized by spasmodic coughing and spread by contaminated airborne droplets.
Unvaccinated infants are especially vulnerable to infection, which can be fatal, according to the Centers for Disease Control and Prevention.
More than half of infants younger than 1 year who are infected must be hospitalized, data from the federal agency show.
Antibiotics can effectively treat pertussis; vaccines exist in pediatric and adult formulations.
The most recent case, reported Monday in the East Northport-Northport school district, involves a student at Fifth Avenue Elementary School.
The remaining 11 of the 216 cases include preschoolers and adults who acquired the infection in their communities, Kelly-McGovern said.
Dr. Dennis Russo, director of the department's public health and emergency preparedness division, said most students in the widening cluster of Suffolk infections were vaccinated.
"For kids who have been vaccinated, their cases have been less severe," Russo said Tuesday. "We know that no vaccine is 100 percent effective."
The pertussis vaccine, he said, is about 80 percent effective.
An additional concern, Russo noted, involves parents who have unsubstantiated beliefs about vaccines and avoid immunizations altogether. He said vaccine avoidance puts entire communities at risk.
"Vaccines are our best defense against pertussis," Russo said.
Although Suffolk has experienced a record number of cases, the upsurge has not occurred in Nassau, where 55 pertussis cases have been reported so far this year. Last year, there were 27.
A Nassau infant died in April of probable pertussis, but there were "other complicating factors and the final cause of death is not yet known," said Mary Ellen Laurain, spokeswoman for the Nassau County Department of Health.
Lisa Warner, 47, of Massapequa Park developed pertussis in September and broke three ribs, she said, in severe coughing spells.
"I thought I was dying," Warner said of the infection that succumbed to antibiotics. Her ribs, she said, are still mending.
Each cough, Warner said, ended in a high-pitched crowing sound -- the whoop -- which left her gasping.
The CDC has found that upsurges in whooping cough occur in three- to four-year cycles.
CDC medical epidemiologist Dr. Thomas Clark said cases have occurred in significant numbers nationwide this year.
"So far in 2011, just over 12,000 cases have been reported. This is still a large number ... but by this time in 2010, over 21,000 cases had been reported. The lowest incidence in the past 5 years was about 8000 cases," Clark said.
With Gary Dymski
The disease usually starts with cold-like symptoms and progresses to severe coughing. Treatment is with antibiotics.
Mild, occasional cough
Apnea (in infants)
After one to two weeks
Coughing fits, often followed by a high-pitched "whoop"
Exhaustion after coughing
Source: Centers for Disease Control and Prevention