A study suggests that humans can contract the H5N1 flu virus but not show noticeable symptoms in rare cases, according to a Reuters report. 

In a survey of Cambodian villages where two children died after contracting the virus, it was found there were seven more who were apparently infected without knowing it. The study, published in the Journal of Infectious Diseases, said the virus could spread to people who swam in the same ponds as infected birds. However, researchers conducting the study said the transmission from sick birds to humans in Cambodia was rare in 2006.


According to the World Health Organization, the H5N1 virus has killed 261 people out of 424 infected since 2003. It is feared that the virus could cause a pandemic if it changes into an easily transmittable form.