DEXTER, Maine — Officials here hope they have seen the last of a whooping cough outbreak that has infected 33 students in the district so far this school year.

The district’s last reported whooping cough case occurred on Nov. 17. When SAD 46 students return to school from winter break on Jan. 3 there will have been more than the 42 days — or two complete incubation cycles — for the pertussis virus, also known as whooping cough, to dissipate.

School officials had hoped the Nov. 17 whooping cough outbreak was an isolated incident. Ridge View Community School Principal Michael Tracy told the school board that he believed the illness had slowly run its course and when students returned in January that Ridge View would return to a normal routine. Of the 33 cases of whooping cough in SAD 46, 32 were in students at the pre-K through grade 8 Ridge View school.

Pertussis is a highly contagious bacterial disease that causes uncontrollable and violent coughing. In the 1930s and 1940s, it resulted in the deaths of thousands of people. It is now under control through the practice of routine vaccinations. Pertussis has returned as a medical threat in the recent years as more parents have opted against vaccinations due to concerns about possible side-effects.

In 2010, California saw the worst outbreak of pertussis in 50 years. according to the state’s Public Heath Department. The first outbreaks in Maine began to occur in December 2010.

The first pertussis outbreak struck SAD 46 in September, and the next wave was discovered in October, when six SAD 46 students contracted the illness.

District officials ordered any students who had contracted whooping cough to stay home for five days until antibiotics could destroy the infection.

The district also conducted a clinic to provide students with a booster shot. Medical officials recommend that children receive a booster shot at age 11 and that adults have one every 10 years.