TB Superbug exposure

<span style="color: #FFFFFF">NBC just reported that this man knew he had this particular strain of TB and traveled these flights anyhow. This strain is extemely drug resistant with a 50% mortality rate. </span>

ATLANTA, Georgia (CNN) -- Federal health authorities are looking for people who may have been exposed aboard a plane to someone infected with a drug-resistant form of tuberculosis known as XDR-TB.

The Centers for Disease Control and Prevention said Tuesday that the case involves a U.S. citizen who traveled on two international flights. XDR-TB was recently defined as a subtype of multiple-drug resistant tuberculosis. It can be fatal.

As with all TB, the disease can be spread through the air. "In this case, the infected patient traveled on two trans-Atlantic air flights and, in doing so, may have exposed passengers and crew to XDR-TB," the agency said.

"A federal quarantine order has been issued and CDC is currently collaborating with U.S., state and local health departments, international ministries of health, the airline industry, and WHO (World Health Organization)."

The infected patient traveled to Europe via Air France Flight 385, departing Atlanta on May 12 and arriving in Paris on May 13, the CDC said.

The patient returned to North America last Thursday aboard Czech Air Flight 0104 from Prague, Czech Republic, to Montreal, Canada, then drove into the United States.

"Since May 25, the patient has been hospitalized in respiratory isolation and is undergoing additional medical evaluation," the CDC said.

The patient, who has few symptoms, has radiographic evidence of pulmonary TB and tests positive for XDR-TB, the agency said.

"On the basis of the patient's clinical and laboratory status, and lack of receiving adequate treatment for XDR-TB, this patient was considered potentially infectious at the time of his airline travel, and meets the criteria in the WHO guidelines for initiating an airline contact investigation," it said.

Fellow passengers sought
CDC is recommending crew and passengers seated in the same row or two rows ahead or behind of the patient aboard either flight be evaluated for TB infection.

"This includes initial evaluation and testing with follow-up eight to 10 weeks later for re-evaluation," the CDC said.

But it acknowledged that they are not sure just who is at risk, and recommended anyone aboard the flights be tested. "As there has never been an airline contact investigation for XDR-TB, it is not known if the current recommendations are adequate to determine the possible range and risk of transmission of infection. Because of the serious consequences of XDR-TB and anticipated public concern, in addition to the contacts listed above, all U.S. residents and citizens on these flights should be notified and encouraged to seek TB testing and evaluation."

One in three people in the world is infected with dormant TB bacteria, according to the World Health Organization. Age, immune suppression and other medical conditions can activate the bacteria, which can usually be treated with a course of four standard, or first-line, anti-TB drugs.

But people with XDR-TB are resistant to first- and second-line drugs, and treatment options are limited.

People who are ill with TB of the lungs, the site most commonly affected, can spread the disease by coughing, sneezing or even talking.

"A person needs only to breathe in a small number of these germs to become infected (although only a small proportion of people will become infected with TB disease)," the WHO said in a description on its Web site.

"The risk of becoming infected increases the longer the time that a previously uninfected person spends in the same room as the infectious case," it added.

"The risk of spread increases where there is a high concentration of TB bacteria, such as can occur in closed environments like overcrowded houses, hospitals or prisons. The risk will be further increased if ventilation is poor."

Cure is possible for up to 30 percent of affected people, it added.

Though XDR is rare, WHO estimates that there were almost half a million cases of multiple-drug-resistant tuberculosis worldwide in 2004.

People with HIV infection are most at risk of catching TB and becoming sick.

"Anyone who has been in contact with someone known, or suspected of having, XDR-TB should consult their doctor or a local TB clinic and be screened to see if they have TB," the WHO said.

If tuberculosis bacteria are found in the sputum, the diagnosis of TB can be made in a day or two, but this finding will not be able to distinguish between drug-susceptible and drug-resistant TB. To evaluate drug susceptibility, the bacteria need to be cultivated and tested in a suitable laboratory.

Final diagnosis for XDR-TB can take six to 16 weeks.