An outbreak of E. coli bacteria linked to Chipotle Mexican Grill restaurants has spread, with the number of people sickened rising from 22 to 37, US authorities said.
In the northwest state of Washington 25 people have been infected, up from 19. Twenty-three of them reported eating at a Chipotle burrito outlet before getting sick and nine were hospitalized, the state health department said.
The victims range in age from five to 60.
In neighboring Oregon, the number has risen from three as of Sunday to 12 in and around Portland.
People with E. coli infection usually develop diarrhea and abdominal cramps within 1-10 days, with most illnesses resolving on their own within seven days. However, in rare cases, elderly and young children can develop a severe type of kidney failure, according to the Oregon Health Authority.
Chipotle, a very popular fast food chain in the United States, has shut down 43 restaurants because of the outbreak.
The chain founded in Denver, Colorado in 1993 boasts more than 1,900 outlets, mainly in the United States.
The chain is also known for its claim to avoid all genetically modified ingredients in its burritos and tacos.