A whooping cough outbreak in Texas may be the worst the state has seen in half a century, the Texas Department of State Health Services said this week, after releasing a health alert to state doctors advising them of diagnosis and treatment.

The Texas health department reports nearly 2,000 cases so far this year and expects the total to surpass the recent high of 3,358 cases reported in the state in 2009. Nearly a quarter of the cases have been reported in Tarrant County, home to the cities of Fort Worth and Arlington, according to the Star-Telegram of Fort Worth, which reported 433 confirmed cases in the country as of Tuesday.

"This is extremely concerning. If cases continue to be diagnosed at the current rate, we will see the most Texas cases since the 1950s," said Dr. Lisa Cornelius, infectious diseases medical officer with the Texas Department of State Health Services (DSHS). "Pertussis is highly infectious and can cause serious complications, especially in babies, so people should take it seriously."

Whooping cough, also called pertussis, is a bacterial infection that can lead to debilitating fits of coughing. A highly contagious disease, it is easily spread through the air when a person coughs or breathes.

Infants are considered to be the most at risk of contracting whooping cough, but people of all ages can get the disease. This disease can be life-threatening for babies because of the risk of apnea, or interrupted breathing. Two infants have died from pertussis-related causes this year in Texas, both were too young to be vaccinated against the disease, the DSHS reported.

"To better protect babies, DSHS recommends pregnant women get a dose of pertussis vaccine during every pregnancy, preferably between 27 and 36 weeks of pregnancy," the health department wrote. "This helps protect the baby before he or she can start the vaccination series at 2 months old and helps keep the mother from getting sick and infecting the baby. Fathers, siblings, extended family members, medical providers and others who will be around newborns should also be vaccinated."

Russell Jones, Tarrant County chief epidemiologist, told the Star-Telegram that people with coughs should stay away from babies. Anyone who knows they have been exposed to pertussis should see a doctor, he said.

The Star-Telegram reports that the pertussis vaccine seems to lose effect, particularly between young people between ages 8 and 11.

"The pertussis vaccine isn't doing what we had hoped it would do, but it's still our best tool," said Jones.