Over 50 % patients infected with new type of bird flu had no contact with poultry: WHO

The World Health Organization said today, that over 50 per cent of patients infected with a new type of bird flu in China had no contact with poultry. The revelation raised questions about whether the virus was transmitted between humans.

The H7N9 virus had infected 87 people in China so far and killed 17, it however remained unclear how they picked up the infection. A Chinese official earlier this week said around 40 per cent of patients had had no contact with poultry.

WHO China representative, Michael O'Leary who issued the new data said human-to-human transmission was rare.

O'Leary told a briefing that as the investigation got deeper, authorities were finding that over half had had no contact with poultry.

He said it was hard to definitively rule in or rule out chickens. He added, this was still an animal virus that occasionally infected humans. He said with rare exceptions, it was known that people were not getting sick from other people.

According to O'Leary investigators had tested 80,000 birds for the flu, but only 40 tested positive and none of those was sick.

He added this was unusual in that they had not been finding sick birds.

Over the next several days  in Beijing and Shanghai, an international team of epidemiologists and other experts led by the WHO and Chinese government officials would visit live chicken markets and hospitals.

According to the World Health Organization, China was investigating four possible cases of human-to-human transmission of a deadly bird flu that had killed 17 people, but so far there had been ''no sustained'' evidence of transmission between people.

According to Gregory Hartl, the spokesman for WHO in Geneva, who spoke in a telephone interview, three families in Shanghai and two young children in Beijing were being examined as possible examples of human-to-human transmission.

Hartl added that even if two family members were positive, it was not necessarily the case that they got it from each other. He added they might have gotten it from the same bird.

He added, with investigators looking at the possibility of human-to-human transmission, there was mounting concern that the new virus, known as H7N9, might not originate in poultry but in other animals.

Hartl said, because it seemed possible that the virus originated in animals other than poultry, the international investigating team would be casting a wide net for possible sources.

The outbreak of the disease had led to 17 deaths according to according to China's state-run news agency, Xinhua. It added, there were 83 cases of infection.