County health officials declared a local public health emergency on Sept. 1. Since November 2016, 421 cases of hepatitis A have been reported, according to the California Health Alert Network, with the onset of symptoms between Nov. 22, 2016, and Sept. 8. Patients have ranged from 5 to 87 years old.
RELATED: Superbugs: Victims and outbreaks
Superbugs: Victims and outbreaks
Superbugs: Victims and outbreaks
Kelly and Ryan Breaux stand holding a portrait of their deceased daughter Emma Breaux, at their home in Breaux Bridge, Louisiana, on June 16, 2016. The husband and wife lost twins, Emma and Talon, to different superbugs that they contracted while in the neonatal unit at Lafayette General Hospital. U.S. Picture taken June 16, 2016. TO MATCH SPECIAL REPORT USA-UNCOUNTED/SURVEILLANCE REUTERS/Edmund Fountain
Kelly and Ryan Breaux sit holding a portrait of their deceased daughter Emma Breaux in their home in Breaux Bridge, Louisiana, on June 16, 2016. The husband and wife lost twins, Emma and Talon, to different superbugs that they contracted while in the neonatal unit at Lafayette General Hospital. U.S. Picture taken June 16, 2016. TO MATCH SPECIAL REPORT USA-UNCOUNTED/SURVEILLANCE REUTERS/Edmund Fountain
Four-year-old Luke Reimer, of Batavia, Illinois, holds a photograph, June 18, 2009, of his twin sister Madeline who died after being born with MRSA (Methicillin resistant Staphylococcus aureus), a bacterium that is resistant to many antibiotics. (Photo by Chuck Berman/Chicago Tribune/MCT via Getty Images)
Stephanie Hall (L), sits on the couch with her sister, Crystal Silva (R), and their ten year old niece Destini and nephew Kane in El Paso, Texas, U.S. on July 2, 2016. The children's mother, Natalie Silva, contracted Methicillin-resistant Staphylococcus aureus, more commonly known as MRSA, a skin infection that can turn fatal once it enters the bloodstream, when she went to the hospital to deliver Kane. After a 10 month battle with MRSA, Silva died, leaving Hall and the family to raise the two children. TO MATCH SPECIAL REPORT USA-UNCOUNTED/SURVEILLANCE REUTERS/Dan Dalstra
Monica Berckes, poses with the funeral program of her late mother Marianne Rumsey, who died at 61, several months after contracting MRSA during heart surgery, at her home in Secaucus, New Jersey, June 2, 2016. Picture taken June 2, 2016. TO MATCH SPECIAL REPORT USA-UNCOUNTED/SURVEILLANCE REUTERS/Mike Segar
Zachary Rubin (C), medical director of clinical epidemiology and infection prevention, and Robert Cherry (R), chief medical and quality officer for UCLA Health System, attend a news conference by UCLA Health System and county officials at the Ronald Reagan UCLA Medical Center in Los Angeles, California February 19, 2015. The large Los Angeles teaching hospital has told scores of patients they were possibly exposed to a drug-resistant bacterial "superbug" during endoscopy procedures that infected seven patients and may have contributed to two deaths. REUTERS/Jonathan Alcorn (UNITED STATES - Tags: HEALTH DISASTER)
A sample bottle containing E. coli bacteria is seen at the Health Protection Agency in north London March 9, 2011. For decades scientists have managed to develop new medicines to stay at least one step ahead of the ever-mutating enemy, bacteria. Now, though, we may be running out of road. Methicillin-resistant Staphylococcus aureus, commonly known as MRSA, alone is estimated to kill around 19,000 people every year in the United States -- far more than HIV and AIDS -- and a similar number in Europe, and other drug-resistant superbugs are spreading. Picture taken March 9, 2011. To match Special Report ANTIBIOTICS/ REUTERS/Suzanne Plunkett (BRITAIN - Tags: HEALTH SCI TECH)
An employee displays MRSA (Methicillin-resistant Staphylococcus aureus) bacteria strain inside a petri dish containing agar jelly for bacterial culture in a microbiological laboratory in Berlin March 1, 2008. MRSA is a drug-resistant "superbug", which can cause deadly infections. REUTERS/Fabrizio Bensch (GERMANY)
A view of the UCLA Medical Center in Los Angeles, California March 19, 2015. UCLA, the hospital at the center of the "superbug" outbreak that killed two people and infected seven last month has received poor patient safety scores and had its payments cut by Medicare for high rates of hospital-acquired infections. REUTERS/Lucy Nicholson
This digitally-colorized scanning electron micrograph depicts four magenta-colored, spherical methicillin-resistant Staphylococcus aureus (MRSA) bacteria in the process of being phagocytized by a blue-colored human white blood cells in this undated handout photo. TO MATCH SPECIAL REPORT USA-UNCOUNTED/SURVEILLANCE National Institute of Allergy and Infectious Diseases (NIAID)/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. EDITORIAL USE ONLYONLY
MIAMI - OCTOBER 17: Miami VA Medical Center hospital registered nurse, Rafael Sepulveda, pulls on rubber gloves while attending to patients in the Emergency room October 17, 2007 in Miami, Florida. The hospital has strict policies in place to ensure that the staff uses procedures in the fight against methicillin-resistant Staphylococcus aureus bacteria, commonly referred to as MRSA. The staph bacterium is resistant to most common antibiotics and has been responsible for more than nearly 19,000 deaths each year, according to the Centers for Disease Control and Prevention (Photo by Joe Raedle/Getty Images)
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"The majority of people who have contracted hepatitis A are homeless and/or illicit drug users, although some cases have been neither," the Health and Human Services Agency said.
Additionally, officials have installed dozens of hand-washing stations in San Diego County, and the Health and Human Services Agency is distributing hygiene kits that contain hand sanitizer, cleansing wipes, bottled water, an informational flyer and a waste bag.
Hepatitis A is a potentially deadly disease that attacks the liver. The San Diego County outbreak is being spread person-to-person and through contact with a fecally contaminated environment, officials said.
Vaccines are available to those without insurance at county public health centers. A list can be found here.