RICHMOND, Va. (BP) — The International Mission Board is working closely with local health officials following a norovirus outbreak that infected more than 100 people following the organization’s annual staff retreat April 22-23.

The IMB’s International Learning Center, where health officials believe the outbreak started, has voluntarily suspended programs and conferences until May 12 while the facility is being cleaned and sanitized. The IMB also voluntarily closed its Richmond offices April 28-29 for cleaning, reopening April 30.

“Our primary concern is the health and well-being of our employees, their families and the community,” IMB President Jerry Rankin said.

The first signs of the outbreak were reported April 23 as the IMB wrapped up its annual two-day retreat at the learning center in Rockville, Va. Health officials were immediately contacted after several staff members reported symptoms consistent with food poisoning.

A total of 109 persons became ill. They included 100 staff members and nine others who were visiting the facility. Health officials soon determined the cause to be norovirus, a common, highly contagious, viral gastrointestinal disease that causes symptoms such as nausea, diarrhea, and low-grade fever. Symptoms usually last one to two days. Officials stated that this type of outbreak can and does occur in the best and cleanest of facilities and is in no way a reflection on the IMB or its learning center staff. An estimated 23 million cases of the virus are reported annually nationwide.