Southern California has declared a public health emergency following an outbreak of tuberculosis that has left at least nine people hospitalized and one person dead.

Long Beach's health officer, Dr. Anissa Davis, declared the emergency after the city's health department detected 14 tuberculosis cases in a hotel.

Officials have not named the hotel. In a press release, health officials reported that the outbreak is currently isolated to "a specific population" and that the risk to the general public is low.

"The at-risk population in this outbreak faces significant barriers to care, including homelessness and housing insecurity, mental illness, substance abuse, and serious medical comorbidities," the statement reads.

At least 170 more people are likely to have been exposed.

However, the health department's tuberculosis control staff has identified another 170 people who have likely been exposed.

The exposed individuals were undergoing testing.

What is tuberculosis?

Tuberculosis (TB) is a disease caused by a bacterium called Mycobacterium tuberculosis. According to the Centers for Disease Control and Prevention, the bacterium usually attacks a person's lungs, but it can also attack their kidneys, spine, and brain.

The disease is transmitted through the air from person to person, and exposure to TB can occur when people are in a small, enclosed area for an extended period.

Not all individuals infected with TB bacteria become ill, according to the CDC.

What are the symptoms of tuberculosis?

Symptoms of tuberculosis, according to the CDC, include:

- A persistent and severe cough

- Chest pain

- Coughing up blood or sputum

- Fatigue

- Weight loss and decreased appetite

• Chills, fever, or night sweats.

In an update, San Diego health authorities warn of tuberculosis exposure on the Blue Line of the Trolley. Passengers between January 27th and February 29th are at risk, as infections may occur at irregular times from different stations.