SAN DIEGO — San Diego County health officials are monitoring a spike in hepatitis A infections after five cases were confirmed in the region over the last few weeks, including one death.

All the of the identified cases had an onset of illness between Jan. 10 and Feb. 6. Health officials say they normally see about two to three cases a month — an increase that does not yet meet the threshold to be considered an outbreak.

Three of the cases confirmed, including the death, were individuals experiencing homelessness, the county said in a press release.

None of the individuals with a confirmed case of hepatitis A had any known direct contacts or connections to the other cases. No common food, beverage or drug sources have been identified, the county said.

“While the investigations continue, we are asking health care professionals to be alert for patients who may show signs of hepatitis A,” deputy public health officer Dr. Ankita Kadakia said in a release. “Early identification of contacts and isolation are keys to prevention, as is the vaccination of at-risk populations.”

Those with confirmed cases had no record of vaccination for the virus.

County officials said they administered about 50 vaccines Monday to residents of a homeless shelter with an identified infection. They said the would be on site again Tuesday.

The last major hepatitis A outbreak in San Diego County residents began in 2016, impacting unhoused individuals and people using illicit drugs. 592 probable and confirmed cases were identified during that outbreak, as well as 20 virus-related deaths, before ending in late 2018.

The county said that the monitoring of hepatitis A cases in the county is an ongoing process for early detection to avoid another widespread outbreak.

San Diego County encourages those at risk for a hepatitis A infection to get vaccinated if they have not already as part of childhood immunizations.

According to the Centers for Disease Control and Prevention, those groups include international travelers, men who have sex with men, people who use illicit drugs, individuals experiencing homelessness, anyone with occupational risk for exposure and people with chronic liver disease or HIV.