A case of whooping cough has been reported at Riley Avenue School, according to Riverhead School District Superintendent Nancy Carney.

Letters were sent home to parents Tuesday and officials were planning to post a notice on the district website.

“The student has been treated and is cleared to return to school,” Ms. Carney said, though she wouldn’t disclose the age of the student.

In December, a Riverhead High School student was diagnosed with the disease. And four students in Southold Town were also diagnosed late last year.

More than 250 cases have been reported in Suffolk County since June, according to Suffolk County Department of Health Services director Grace Kelly-McGovern. That compares with just 11 cases in the first six months of 2011.

Whooping cough, which is transported through the air by coughing, is especially dangerous and can be fatal for infants.

Early symptoms of whooping cough are a mild cough, a runny nose and a low fever, according to the Center for Disease control. As the disease persists the traditional symptoms of a high pitched “whooping” cough, vomiting and exhaustion after coughing fits may appear. Coughing fits may persist for weeks. The best way to prevent the disease is immunization, the CDC states on its website.

Adults and children, however, may develop pertussis even if they are up to date on their vaccination since immunization wanes over the years, according to the county Department of Health and Human Services. If you suspect that your child has contracted whooping cough, it is urged you contact their physician and request your child is tested for the disease using a special nasal/throat swab.

Those suffering from whooping cough are asked to stay home until he or she has completed five days of antibiotic treatment, according to the county health department.

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