Students at Central Catholic High School in Toledo, Ohio may have become infected with Hepatitis A after a cafeteria worker at the school was diagnosed as being infected with the virus, reports the Toledo Blade.

The Toledo-Lucas County Health Department encourages students who ate food prepared in the school’s cafeteria between Jan. 6 and Jan. 30, and who have not already been vaccinated, to see a doctor and get the immunization.

The risk of acquiring Hepatitis A is greatly reduced for students who already have been vaccinated with the vaccine, completed the series, or previously had Hepatitis A. The vaccination should be given on or before next Friday to be most effective.

Hepatitis A is found in feces of the infected person and can be spread by direct contact with food, beverages or crockery. An infected food handler may not know they are ill, as symptoms often do not present until 2 to 6 weeks after infection. Proper hand washing reduces the spread of illness. Symptoms of illness include nausea, yellow skin, fatigue, loss of appetite, and abdominal pain.

Hepatitis A outbreaks are common among food establishments. There’s even a section of barfblog devoted to them.