Officials say there has been an outbreak of norovirus at a shelter housing people who evacuated their homes to escape the massive wildfire in Northern California.

Butte County public health spokeswoman Lisa Almaguer said that lab tests confirmed the virus and those who were sick have been quarantined at the shelter in Chico, California, but in an area separate from healthy evacuees.

She said she did not know how many people had contracted the virus.

Staff mopped floors with bleach Wednesday at the Neighborhood Church in Chico, where a large room has been converted into a makeshift medical care center.

Norovirus is highly contagious and can cause diarrhea, fever and body aches. It spreads commonly when people are in close quarters.