AUSTIN, Texas (AP) – Health experts are trying to locate people who attended a church conference in Corpus Christi to try to figure out what caused dozens of participants to become ill.

Gastrointestinal illnesses affected at least 70 of the 1,500 people at the United Methodist Church’s Southwest Texas Conference, held June 1-4.

At least one person had to be hospitalized, according to a statement late Wednesday from the Texas Department of State Health Services and the Corpus Christi-Nueces County Public Health District.

The source of the infections is sought, the statement said.

Conference attendees who became ill were advised to contact their local public health department, or their doctor.

Participants were from Texas and 21 other states: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Florida, Georgia, Illinois, Kentucky, Maine, Maryland, Montana, North Carolina, Ohio, Oklahoma, New Mexico, New York, Tennessee, Virginia and Washington. Some attendees were from Costa Rica.