Four more hepatitis A cases have been linked to a Chipotle restaurant in La Mesa, California, bringing the total number of confirmed cases to 18.  Local Health and Human Services officials said no employees at the Chipotle restaurant tested positive for hepatitis A.   Health officials are recommending that anyone who ate at the restaurant between March 1 and April 22 get checked by a doctor.  Hepatitis A is commonly transmitted when an object contaminated with the stool of someone with hepatitis A comes in contact with another person’s mouth.  Exposure also can occur when an individual consumes food or water contaminated with the Hepatitis A virus, according to the health department.  Symptoms of hepatitis A include fever, fatigue, nausea and jaundice.