WASHINGTON, Sept 12 (Reuters) - Epidemiologists have not

yet identified exactly how a person in Missouri contracted bird

flu last week, said the U.S. Centers for Disease Control and

Prevention on Thursday.

The human case was the 14th diagnosed in the U.S. this year.

The other 13 cases were among farm workers and linked to bird

flu outbreaks on poultry or dairy farms.

The infected individual was admitted to the hospital with

symptoms including chest pain, nausea, vomiting and diarrhea,

said CDC principal deputy director Nirav Shah on a Thursday call

with reporters.

It was unclear whether the patient's underlying

conditions caused the symptoms or the flu.

The investigation into the origin of the infection is

ongoing and the CDC has been unable to determine if the case was

related to the current outbreak of bird flu in dairy cattle,

Shah said.

"Right now, evidence points to this being a one-off case,"

said Shah.

Bird flu has infected more than 200 dairy herds in 14 states

since March, the U.S. Department of Agriculture said.