San Bernardino County health officials declared an outbreak of hepatitis A on Thursday, saying dozens of people have contracted the viral disease.

Since the start of 2019, there have been 42 confirmed hepatitis A cases in the county, according to information released by the San Bernardino County Department of Public Health. By comparison, only three cases were reported in all of 2018, the health department said.

An outbreak occurs when people in an area contract a particular disease at a rate that is “in excess of normal expectancy,” according to the World Health Organization.

Officials said clusters of the recent hepatitis cases were confirmed in the cities of Redlands and San Bernardino. People contracting the disease were predominantly in high-risk populations, such as drug users and people who are homeless, the county statement said.


The outbreak in San Bernardino is the latest to hit the state and comes amid a national rise in the disease. In 2017, hundreds of people in San Diego County were diagnosed, including 17 who died. From there, the disease spread to Santa Cruz and Los Angeles counties, which both declared outbreaks. At the time, health officials warned it could take months or years before the spread of the disease stopped.

Nationally, the number of cases reported each year is down significantly from 2001, when about 11,000 people contracted the disease, according to the Centers for Disease Control and Prevention. After years of steady declines, however, the disease began a comeback beginning in 2014, statistics show.

Hepatitis A is commonly transmitted through contaminated food. California’s outbreaks, however, have spread from person to person, mostly among the homeless community.

The virus is transmitted from feces to mouth, so unsanitary conditions make it more likely to spread. The city of San Diego installed dozens of hand-washing stations and begun cleaning streets with bleach-spiked water in recent weeks.


“The most effective way to prevent hepatitis A is to receive the vaccine,” said Dr. Erin Gustafson, San Bernardino County assistant health officer. “It is also very important to wash your hands with soap and water regularly to protect yourself from this virus.”

The disease affects patients’ livers and typically causes fatigue, poor appetite, fever and nausea.

Times staff writer Soumya Karlamangla contributed to this report.