EL PASO, Texas -- More than 700 patients and 40 employees were exposed to an employee in a West Texas hospital nursery who had an active case of tuberculosis, the El Paso Department of Public Health says.

The exposure took place over a period of about a year, from September 2013 through last month, when the employee of Providence Memorial Hospital tested positive for TB and was placed on leave.

The hospital is working closely with the health department to determine which infants and employees may have been exposed. The families of each patient will be contacted by phone and certified letter with screening instructions for their babies, health officials say.

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So far, 706 patients and 43 exposed employees have been identified, the department says. The post-exposure screenings and follow-up will be provided free through the DPH and the hospital. Public Health officials are working with state officials and the federal Centers for Disease Control and Prevention (CDC) to facilitate the screenings.

Tuberculosis can be spread when a person with active TB coughs or sneezes, releasing secretion droplets with the germs into the air, explains CBS El Paso affiliate KDBC-TV. However, TB isn't highly contagious and generally requires close contact over an extended period of time to spread.

Once in the body, KDBC says, the bacteria usually lay dormant for months or years before they begin to grow and cause an active case of TB. That's is why it's so important to identify people who may have been exposed, screen them, and provide treatment that can prevent them from developing active TB. Only those with active TB can spread it to others.

The hospital says it will work with federal authorities to show its procedures were adequate.

A Centers for Medicare and Medicaid Services deputy regional administrator, David Wright, says an inspection of the hospital by regulators revealed several violations. He says the violations could threaten the hospital's Medicare funding and posed "an immediate jeopardy to patient safety."

Providence Memorial spokeswoman Audrey Garcia says hospital officials look forward to collaborating with CMS to prove their actions were effective.