At Broadalbin-Perth, the school district's Web site reported there was one confirmed case in each of its two buildings, while the Burnt Hills-Ballston Lake school system said two students have come down with whooping cough.
Saratoga County Health Department officials said they were concerned that some children are returning to school too soon after being tested for the highly contagious illness, also known as pertussis, and said if a pediatrician tests a child's throat for whooping cough, it means the doctor feels the child may have the illness, the Albany (N.Y.) Times Union reported.
If a child has the disease, he or she must stay home until test results are confirmed or until antibiotic treatment is completed, health officials said.
"If your child is healthy, there is no need to keep them home from school," Stephen Tomlinson, superintendent of the Broadalbin-Perth district, said in a statement. "The students who have been diagnosed with pertussis are being treated at home and will not be in school for the duration of their illness. That being said, if your child displays any of the symptoms of whooping cough, please keep them home from school and contact your child's school nurse as soon as possible."
Earlier in the month, the New York City school system reported a three-fold increase in whooping cough cases in the city.
Several upstate counties have reported one of two cases of whooping cough.
The newspaper said the number of cases of whooping cough in the United States has trended upward since the 1980s, with 25,000 reported cases in 2005, the most since 1959.