"With the virus harder to detect, good biosecurity measures become even more essential to reducing the risk of virus transmission to humans and animals," said Juan Lubroth, the chief veterinary officer of the UN's Food and Agriculture Organisation (FAO).
Among the precautions, the FAO recommended farmers and other livestock handlers to regularly wash their hands and keep animals separate from living areas, warning that "close contact with infected animals can put people at risk".
The organisation also said people should avoid eating sick animals and that they should not be fed to other animals.It recommended keeping different types of animals and species apart and to cull infected animals "if the human threat is confirmed as animal in origin".
"It is important that all signs of illness or sudden and unexplained deaths in poultry, farmed birds, wild birds or other animals are reported to the authorities so that they can deal with them safely and help stop the virus spreading," it said.
Lubroth said that "with this virus we don't have a red flag that immediately signals an infection. This means farmers may not be aware that virus is circulating in their flock. Biosecurity and hygiene measures will help people protect themselves from virus circulating in seemingly healthy birds or other animals."
The number of confirmed human infections in China rose to 16 Friday, with four of the six fatalities in Shanghai. Officials said two new infection cases had been detected in the eastern province of Jiangsu, and a seven-year-old girl had been quarantined in Hong Kong for tests after returning from Shanghai, showing flu-like symptoms.