Laboratories in Turkey have diagnosed five more people with the lethal H5N1 strain of the virus bringing the total number of human cases in the country to 14, all but one of them children and teenagers, including a brother and sister who have already died.
In Istanbul, Turkey's largest city and business hub on the doorstep of Europe, 12 people suspected of being infected tested negative, the health ministry said, after bird flu was detected in dead chicken in the city.
Four of the positive cases were from three northern provinces, confirming that the virus is steadily advancing from remote, rural eastern areas to the more urbanised west, with three H5N1 carriers already hospitalised in the capital Ankara.
Tourism industry hit
The crisis unnerved Turkey's tourism industry, a vital source of revenue, as hoteliers feared the virus may jump to the Mediterranean coast, home to posh resorts that welcome millions of foreigners each year.
"The situation is alarming," said Osman Ayik, the head of a hoteliers' association in the Mediterranean province of Antalya.
Russia and Britain, whose tourists are among the most frequent visitors of Turkish seaside resorts, have already advised their citizens against traveling to the country.
The European Union sought to bolster its defences, announcing new import bans on six countries surrounding Turkey as its experts assessed the situation in the worst-hit areas in the east together with a World Health Organisation (WHO) team.
A brother and sister from Dogubeyazit, near the border with Iran, died last week, becoming the first H5N1 victims outside Southeast Asia and China, where more than 70 people have perished since 2003.
A third sibling also died but the cause of her death is yet to be determined.
Of the five new cases, two siblings from Kastamonu, aged four and five, were hospitalised in Ankara but showing no sign of illness yet, senior health ministry official Turan Buzgan told the Anatolia news agency.
A five-year-old boy from Corum, initially treated for pneumonia, was brought to the same hospital in Ankara and is now improving, he said, and a 12-year-old is undergoing treatment in Samsun, on the Black Sea coast.
The fifth patient, aged 18, was hospitalised in the eastern city of Van, where four other children infected with H5N1 are currently undergoing treatment.
Poultry breeding ban
As the emergency cull of fowl continued across the country, the agriculture ministry was drafting legislation to ban outdoor poultry breeding, largely blamed for the spread of the virus, Anatolia reported.
Most of the infected patients come from impoverished rural areas, where people breed poultry in their homes and often take them indoors during the winter, providing ideal conditions for contamination.
Prime Minister Recep Tayyip Erdogan pleaded with citizens to hand over sick birds for slaughter amid reports that many are hiding their poultry, reluctant to part with what are often their sole livelihoods.
Many in the mainly Kurdish east are also illiterate and do not speak Turkish, further complicating efforts to raise their awareness.
Adding a political twist to the crisis, an angry crowd mobbed and booed Health Minister Recep Akdag as he visited Dogubeyazit, accusing the government of neglecting them because they are Kurds.
"We need doctors," "Go see our villages with the dead chickens, where no one dares to tread," people shouted as some 80 villages in the area still awaited slaughter teams.
Surrounded by a phalanx of policemen, Mr Akdag promised the town a new hospital and more experts to enlighten residents about the disease.
Despite the popular anger, the head of the WHO team accompanying Mr Akdag said the fundamental problem was the large size of the infected areas.
"They reacted rapidly... and their reaction was structured," Guenael Rodier said. "The problem is the scope of this man-animal frontline, it must be reduced."
Boy discharged
In one refreshing development, the youngest brother of the dead children was discharged from hospital after doctors decided he was free from danger.
Greeted by an army of reporters outside the Van hospital, a beaming Hasan Ali Kocyigit, 6, returned home to Dogubeyazit, his immediate plans to collect sweets from neighbors during the Muslim al-Adha feast, which begins on Tuesday.
The boy appeared to have miraculously escaped infection from the H5N1 virus after the four siblings played with the head of a sick chicken the impoverished family slaughtered and ate.
The hospital discharged four other children, brothers and sisters of a boy and a girl identified as H5N1 carriers and currently in intensive care.
Culling began in the outskirts of Istanbul and several hospitals were put on alert.
Istanbul, a city of about 12 million people, is the westernmost point where the virus has been found in Turkey since it resurfaced last month after a first outbreak in nearby Balikesir in October was successfully contained.
Currently, humans are believed to contract bird flu only through close contact with infected birds, but scientists fear millions could die if the virus mutates with human flu strains to become highly contagious.
Ukraine outbreak
Another outbreak of bird flu has been discovered in the Crimean peninsula in Ukraine, said a regional government minister.
Crimea's minister for agrarian policy, Oleh Roussetski, told the Interfax news agency that tests had confirmed that the deaths of large numbers of farmyard birds in late December and early January in the eastern Crimean village of Promorski had been caused by bird flu.
On January 5, a bird flu outbreak was discovered in a village near Simferopol, also on the Crimean peninsula.
"We have almost finished destroying the affected birds," said the minister, adding that the total number slaughtered in farms in Promorski was around 171,500. He did not specify the type of bird flu involved.
The presence of the potentially deadly H5N1 strain was confirmed in Crimea in December, after bird flu was first detected in the peninsula's northeastern corner near a migratory site for wild birds.