DETROIT (AP) _ When Dr. Thomas Dobbins finished inoculating others against an outbreak of hepatitis A, he went home to care for his 8-year-old daughter _ one of the 150 students and teachers in the area who contracted the virus.

The illnesses broke out last month, long before reports that people in six states may have been exposed to the disease by more than 2.6 million pounds of tainted frozen strawberries _ many of which ended up in school cafeterias.

The symptoms of hepatitis A don't usually appear until 28 days after exposure, and so far the only reports of illnesses have been in Michigan. Strawberries with the same lot numbers were also sent to Arizona, California, Georgia, Iowa and Tennessee.

Dobbins' daughter Kehvren has recovered and is getting ready to go back to school, where she likely contracted the virus. When she first got sick, Kehvren was so dehydrated Dobbins considered giving her fluids intravenously.

``It's kind of a miserable thing all around for people that get a good case of it,'' Dobbins said Wednesday.

Amanda Bischoff's parents thought she had a stomach virus. Then she began vomiting constantly and her eyes turned yellow.

``She looked like a daffodil,'' Patty Bischoff said.

The U.S. Department of Agriculture said Wednesday it will investigate how Mexican-grown strawberries got into the school lunch program, which is required to buy only U.S. products.

Health officials on Wednesday worked to remove strawberry supplies from school menus and educate people about the illness. The virus can be transmitted orally or through human waste, by food handlers with poor hygiene, through undercooked shellfish from infected waters or through tainted water or ice.

Symptoms include jaundice, fatigue, abdominal discomfort, vomiting, fever and dark urine.

``This is an unusual outbreak because it is linked to one source that has nationwide implications,'' said Ian Williams, an epidemiologist with the Centers for Disease Control and Prevention in Atlanta.

In Michigan, thousands got protective gamma globulin shots after the illnesses began _ including many who lined up at school basketball games where the shots were offered.

Although most hepatitis A patients do not require hospitalization, nine people in Marshall needed treatment for dehydration, said Oaklawn Hospital spokeswoman Jill Kingsley-Hinde.