LONDON (Reuters) -The World Health Organization is working with Cambodian authorities after two confirmed human cases of H5N1 bird flu were found among one family in the country. Describing the situation as “worrying” due to the recent rise in cases in birds and mammals, Dr Sylvie Briand, the director of epidemic and pandemic preparedness and prevention, told reporters in a virtual briefing that WHO was reviewing its global risk assessment in light of the recent developments. The U.N. health agency last assessed the risk to humans from avian flu as low earlier this month.