B.C. health officials say they still don't know how a teenager became infected with the H5N1 strain of avian flu but say no further cases have been identified.Earlier this month, health officials announced they were investigating what was believed to be the first human case of H5N1 avian influenza caught in Canada.

The Centers for Disease Control and Prevention confirmed the first human case of avian influenza A(H5N1) in a child in California last week. According to the CDC, the child experienced mild symptoms,

As a Canadian teen remains in critical care with an H5N1 avian flu infection in a British Columbia hospital, health investigators said today they haven't identified the source, but have found other clues such as virus changes that may have led to a more severe lower respiratory infection.

As an investigation continues into how a B.C. teenager became infected with avian flu, there are ways British Columbians can protect themselves. The teen, who lives in the Fraser Health Region, has made some progress but remains in critical condition with H5N1 bird flu. This is the first case of H5N1 avian flu in Canada.

California's public health department had reported the case on Tuesday, but said there was no evidence of human-to-human transmission of the virus. The CDC affirmed that currently there was no evidence of person-to-person spread of H5N1 bird flu from this child to others,

The first child case of avian influenza (H5N1) was detected in California this week, according to the CDC, which is conducting an investigation into the case, including contact and exposure tracing

The US The Centers for Disease Control and Prevention confirmed the country's first H5N1 bird flu infection in a child.

The first US case of H5N1 bird flu in a human was detected in a child in California. The child experienced mild symptoms and recovered. While the child had contact with poultry, there is no evidence of person-to-person transmission.