An email from Sonny Krishnan, a communications officer for WHO in Cambodia, in response to my questions about any possible links between the three H5N1 cases:
Our epidemiologists are with the Ministry of Health's Rapid Response Teams carrying out investigations in Phnom Penh, Takeo and Kampong Speu. We're also helping the RRTs do contact-tracing.
There seems to be heightened movement of poultry across the areas where the cases were because of Chinese New Year which is next week.
Also all there had contact with poultry.