Officials in Pakistan have informed the World Health Organization of the country's first suspected human cases of H5N1 avian flu infection.

"The Ministry of Health in Pakistan has informed WHO of eight suspected human cases of H5N1 avian influenza infection," a statement from the WHO read Saturday.

The WHO reported that at least two people suspected of having the virus died.

The number of confirmed cases remains unknown. Six cases were found positive for H5N1 avian influenza virus, the Ministry of Health said in a statement. Five of them have fully recovered.

"The numbers are still sketchy. The information is not complete," Dr. Donald Low, chief of microbiology at Toronto's Mount Sinai Hospital, told CTV Newsnet on Saturday.

"It's obviously disconcerting that we're seeing H5N1 avian influenza at least now being reported out of Pakistan."

The WHO reports the cases were detected following a series of culling operations in response to outbreaks of H5N1 in poultry.

Officials are still investigating how the infection was spread. Low said the threat of human-to-human transmission remains a possibility, but is usually reserved for blood relatives.

"It's usually been limited to one or two generations, so the question here is has human-to-human transmission occurred because that's obviously a key factor and whether or not it stayed within a family," he said.

Multiple poultry outbreaks of H5N1 influenza have been occurring in Pakistan since 2006. There have also been outbreaks in wild birds this year, the WHO reports.

There is concern over whether developing countries openly report human cases of H5N1 because of potential economic repercussions, Low said.

He said the likelihood of recent visitors to Pakistan transmitting the virus to other parts of the world remains low.

"I imagine, once the story is out, that this occurred in a village where there was close contact with domestic poultry in a backyard and a case occurred," he said.

The WHO is aiding Pakistan's Ministry of Health with the investigation of the suspected cases and the containment process.

On Friday, the WHO confirmed the first human case of the deadly strain in Myanmar. A seven-year-old girl from Keng Tung in northeastern Myanmar fell ill in late November. She has since recovered.

The first outbreak of highly pathogenic influenza A H5N1 virus in humans occurred in Hong Kong in 1997, the U.S. Centre for Disease Control reports.

Pakistan is the 14th country to announce a case of human infection with the potentially deadly virus.