"Before this study, the transmission of TB from a cadaver to an embalmer had never been demonstrated," says Timothy Sterling, M.D., an assistant professor of infectious diseases at the Johns Hopkins School of Medicine and lead author of the study. "Previous studies had shown that funeral home workers had unexpectedly high rates of TB infection and disease, but it was not known if this was due to exposure in the workplace."

TB is spread through the air by infectious aerosols, tiny particles that enter the body through the nose or mouth and lodge deep in the lungs. In the new study, doctors identified an individual with active TB whose only known exposure to the bacterium was through the embalming of an infected cadaver.

During the embalming process, blood is removed and fluids are injected into the body to preserve it. "Aerosols can be generated by the injection of fluids, or by the frothing and gurgling of fluids through the mouth and nose," said Sterling. "In addition, the cadaver can spasm during the embalming process, which can cause the release of respiratory secretions." Embalming fluids are often dumped into a drain after the embalming process and this also could release infectious aerosols.

The doctors identified this unusual route of transmission through an ongoing tuberculosis surveillance initiative. As part of this initiative, every case of the disease in Baltimore reported to the Baltimore City Health Department undergoes DNA fingerprinting at Johns Hopkins. When two or more TB cases have similar DNA fingerprints, researchers become concerned about whether recent transmission of TB has occurred.

For this reason, when researchers discovered that two TB patients had the same DNA fingerprint, they set out to investigate possible times of exposure between the two patients. They subsequently noticed that the mortician had signed the death certificate of the other patient. The diagnosis of TB was not established in the first patient until after death.

"Currently the Centers for Disease Control and Prevention and the Occupational Safety and Hazard Administration guidelines for the prevention of the spread of TB are not applied to funeral homes," said Sterling. "This case report suggests that they should be, to prevent the transmission of TB through the embalming process."

Tuberculosis is the second leading cause of death from an infectious disease. Worldwide, 2 million people die of TB annually, and 7 million to 8 million new TB cases are diagnosed each year. Therapy for tuberculosis requires a multidrug regimen of four drugs. For more TB facts or more information about TB research at Johns Hopkins, visit http://www.hopkins-tb.com.

Other authors of the study are Diana Pope, R.N., M.S.; Susan Harrington, M.P.H.; William Bishai, M.D., Ph.D.; Robyn Gershon, M.H.S., Dr.P.H.; and Richard Chaisson, M.D. Funding for the study was provided by the Baltimore City Health Department, the Centers for Disease Control and Prevention, and the National Institutes of Health.

Note: If no author is given, the source is cited instead.

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