LOS ANGELES, CA (Catholic Online) - Officials say 11 have died since 2007 and that 60 of the 78 cases were among the homeless people who live on and around skid row. The outbreak has been determined to a tuberculosis strain that is unique to Los Angeles, with a few isolated cases outside the area.

"This is the largest outbreak in a decade," Jonathan Fielding, director of the Los Angeles County Department of Public Health says. "We are really putting all of our resources into this."

About 4,650 people were probably exposed to the disease and are trying to track them down for testing and treatment. The cases are linked to one relatively small geographic area and one vulnerable population. Officials are concerned that the outbreak could spread beyond skid row if action isn't taken.

Homeless people are especially at risk of getting TB and of being undiagnosed due to poor hygiene and nutrition, limited access to healthcare and ongoing contact with infected people.

Tuberculosis is also common among the homeless as they live in overcrowded areas and are constantly moving among hospitals, shelters and the streets. In addition, many have substance abuse or mental health issues that can impede treatment.

"They go from place to place and the likelihood of passing it along is much greater," Paul Gregerson, chief medical officer of the JWCH Institute says. The organization runs a homeless healthcare program on skid row. "It makes everybody more susceptible."

Tuberculosis is easily transmitted by inhaling droplets from infected patients when they sneeze, cough -- or even laugh. TB can be deadly if left untreated. The skid row strain can be treated with all anti-TB medications. Treatment lasts six to nine months.

Most of the TB patients are men. Twenty percent are also HIV-positive, according to the alert. Six of the eight patients who also had HIV have died.

The increase of TB among the homeless population is occurring even as the county is seeing a decline in overall cases.

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