PARIS, TX -- A mysterious rash of Whooping Cough has been reported in one North Texas county.

Pertussis, known as Whooping Cough, can be especially dangerous to young infants who are too young to receive a vaccine.

Just in Lamar County, 20 cases have been reported this year. There have only been two in Grayson, Fannin and Cooke counties combined, and 13 total in all of Oklahoma.

The numbers are certainly shocking, but health department officials say they will get to the bottom of it, and hoping a new vaccine will help it keep the disease from spreading any more.

The Lamar County Health Department is flooded with phone calls and paperwork, with an unusual number of cases of Pertussis.

The last time Whooping Cough was in Lamar County was one case in 2005 until this year. Since January, they have seen 20 cases, mostly children ages 9 to eleven.

"We'll go out and talk to a family where had had a case reported and then it seems like that leads us up 30 more people that need to be immunized for being with that child."

Anthony Bethel, Administrator with the Paris Lamar County Health Department says it's a mystery why the number of cases is so much higher this year.

"It's quite contagious, but its main danger is for very young infants. Not only do they get a terrible cough but there are rare cases of apnea which is where they stop breathing."

Doctors say the Pertussis shots a person receives as a baby tend to wear off by the time they reach age 10.

In 2005, a new vaccine came out called T-Dap. It contains Tetanus, Diptheria, and Pertussis. Adults can take it too, in place of a Tetanus shot.

"Older children may not even know they've got it. Adults may not even know if they've got it. But they need to be immunized to keep from taking it home to the small kids if they're around them."

Nurses say the T-Dap vaccine can leave a small red welt, much like a Tetanus shot. Also, healthcare professionals say it's a good idea for anyone around infants to get the vaccine, even if there have not been reported cases in your area.

For more information and a list of symptoms, check http://www.cdc.gov/doc.do/id/0900f3ec80228696.