Three Hudson Valley children have been diagnosed with a life-threatening highly contagious disease.

On Friday, Sullivan County Public Health Services announced three confirmed cases of whooping cough (pertussis) have been identified in children of varying ages in Sullivan County.

“This is an important advisory,” Public Health Director Nancy McGraw stated. “As recently as 2016, Sullivan County had a pertussis outbreak of nearly 30 cases, and dozens of additional probable cases were investigated, interviewed and individuals treated.”

According to health officials, if you or your child has been around someone with whooping cough, you may become sick with whooping cough. This is especially true when you or your child has not received all the pertussis vaccine shots. Sometimes even if your shots are up to date, you may still get pertussis.

Pertussis is known as whooping cough because of the “whooping” sound that is made when gasping for air after a fit of coughing makes it hard to breathe. Coughing fits due to pertussis infection can last for up to 10 weeks or more.

Whooping cough is a highly contagious disease that is spread through the air by cough. It begins with cold symptoms and cough, which becomes much worse after one to two weeks. Symptoms usually include a long series of coughs followed by a “whooping” noise. However, older children, adults and very young infants may not develop the “whoop.” There is generally only a slight fever.

People with pertussis may have a series of coughs followed by vomiting, turning blue, or difficulty catching a breath. The cough is often worse at night, and cough medicines usually do not help alleviate the cough.

If you or your child has been diagnosed with pertussis, it is very important to complete the antibiotic regimen before returning to work, school or community functions, to reduce the spread of the disease to others. People who have or may have pertussis should stay away from young children, infants and all people with pre-existing health conditions that may be exacerbated by a pertussis infection (for example, immune-compromised persons and patients with moderate to severe medically treated asthma).

Pertussis can cause serious illness in babies, children, teens, and adults and can even be life-threatening, especially in babies, officials say. Approximately half of the babies less than 1-year-old who get pertussis need treatment in the hospital.

The most effective way to prevent pertussis is through vaccination, according to the Sullivan County Public Health Services. Pertussis is generally treated with antibiotics, which are used to control the symptoms and to prevent infected people from spreading the disease.

Worldwide, there are an estimated 24.1 million cases of pertussis and about 160,700 deaths per year, according to the most recent data. In 2012, the most recent peak year, 48,277 cases of pertussis were reported in the United States, but many more go undiagnosed and unreported. This is the largest number of cases reported in the United States since 1955 when 62,786 cases were reported, officials say.