The United Nations Food and Agriculture Organization (FAO) on Monday warned that the bird flu situation in Bangladesh remains serious and called for action to get it under control.

"In response to recent outbreaks, the government and veterinary authorities have applied immediate control and containment measures in affected areas," Joseph Domenech, the FAO's chief veterinary officer, said. "But there is an urgent need for vigorously stepping up and extending current H5N1 control campaigns in order to prevent the virus becoming widely entrenched."

Since the first officially announced avian influenza outbreak in Bangladesh in

February, the virus has spread to 10 out of 64 districts.

"Bangladesh has already prepared a National Avian Influenza and Human Pandemic Preparedness Plan and an Emergency Operational Plan to meet the threat of bird flu and is implementing these plans to control the disease," Domenech said. "The situation remains of serious concern and will require further national engagement and coordinated international support."

He also said Bangladesh has a "real chance to get the virus under control if it commits itself to a full-scale comprehensive national control campaign" and pledged the FAO's assistance in the effort.

There have so far been over 280 confirmed human cases worldwide, more than half of them fatal, the vast majority in South-East Asia. The so-called Spanish flu pandemic of 1918-1920, which also originated from birds, is estimated to have killed from 20 million to 40 million people worldwide.