CDC reports first severe human case of bird flu in U.S.

• Officials said the patient was exposed to sick and dead birds in backyard flocks.
• There have been 61 human cases of bird flu detected in the U.S. since April.

Between the lines: This virus is part of what's known as the D1.1 genotype, officials said. The same type was found in recent human cases in Canada and Washington state.

• The case in Canada raised alarms because scientists discovered it may have had a variation that made it easier to transmit to other humans, though there was no evidence it spread. They were also unable to track down where the teenage patient contracted the illness.
• The D1.1 genotype is different from the B3.13 genotype detected in dairy cows, sporadic human cases in multiple states, and some poultry outbreaks in the United States, officials said.

• The CDC is performing additional genomic sequencing on the Louisiana case.

The bottom line: Officials said that there is still no evidence of human-to-human transmission and that the risk to the public's health from H5N1 remains low.

• However, they say the case illuminates the risk for exposure and the need for taking steps to mitigate the spread of the illness among commercial and backyard operations involving animals.