Missouri resident infected with bird flu had no contact with animals – that's why experts are concerned

A person in Missouri has been diagnosed with bird flu despite never having had contact with animals, the Centers for Disease Control and Prevention announced Friday.

Although the adult, who was hospitalized on August 22, has recovered, the case adds to growing national fears about the virus as the patient is the first in the country to contract the disease without having contact with poultry and dairy animals.

The CDC assured that the risk to the general population “remains low.”

“The question now is: How did this patient acquire the infection?” Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center in Nashville, told NBC News. “We need a very, very thorough investigation.”

While the Missouri patient is only the 14th person in the U.S. to be infected with H5N1 avian influenza this year, CDC data show that outbreaks of the virus have been confirmed in at least 196 dairy herds in 14 states since the outbreak was first reported in March.

Outbreaks in poultry have been confirmed in 48 states.

Outbreaks of the disease have been reported among cattle in Missouri, but poultry from commercial and hobby poultry farming have also been infected with the virus, the CDC said.

There is no evidence that this latest strain of bird flu is transmitted from person to person.

The sample from the Missouri patient must be examined in the laboratory to determine whether the virus may have mutated, making it easier for it to be transmitted from person to person, Schaffner told NBC News.

“The results of this investigation will be particularly important because there is currently no apparent exposure of animals,” the CDC said in its statement on Friday. “It is important to note that while there are rare but novel [bird flu] Cases where an animal source cannot be identified.”

In a separate press release, Missouri health officials said there were no signs of unusual flu activity among the state's residents, nor had there been an increase in emergency room visits or laboratory-confirmed flu.

A sample from the infected patients was sent to the CDC by the Missouri State Public Health Laboratory for further testing, state officials said.

The patient, who has underlying medical conditions, has been discharged from hospital and is recovering at home.

No transmission of the virus was detected in the patient’s vicinity.