SAN DIEGO -- Another hepatitis A case with a possible link to a Chipotle restaurant in La Mesa has been confirmed, bringing the number to 21, the San Diego County Health and Human Services announced Tuesday.

Health officials are still working to determine the source of the outbreak.

Twenty-six employees at the Chipotle on Fletcher Parkway have been tested, and all have been negative for hepatitis A, according to the HHSA.

Hepatitis A is commonly spread through fecal contamination due to poor hygiene, according to the HHSA. Exposure can also occur when someone consumes food or water contaminated with the hepatitis A virus.

Symptoms of the disease include fever, fatigue, loss of appetite, nausea, abdominal discomfort, dark urine and jaundice.