With the lethal virus now raging at the threshold of Europe, officials from half of the world's nations gathered in Beijing for a two-day meeting aimed at raising 1.5 billion dollars to help fight the disease.
A team of experts from the United States have begun work in Turkey to help local officials in their efforts to stem the outbreak as the Turkish government said it had the situation under control.
The Turkish health ministry identified the new case of H5N1 infection as a child from the remote eastern town of Dogubeyazit, near the border with Iran, from where the four dead also hailed.
Illness from eating chicken
The child, aged four-and-a-half years, fell sick after eating chicken and was put under intensive care in a hospital in the eastern city of Erzurum when he began to suffer difficulties in breathing, said the head of the hospital, Akin Aktas.
"The patient's general condition is good," Dr Aktas said of the latest case, without specifycing whether the patient was a boy or a girl.
Meanwhile, in Van, further east, five-year-old Muhammed Ozcan, the brother of one of the four victims, was reported in deteriorating condition.
"The infection in his lungs advanced a bit more last night," Dr Huseyin Avni Sahin, the chief physician of the Van hospital said. "His condition is now worse than yesterday."
The boy, described as the gravest case so far among the H5N1 carriers under treatment, did not require an artifical respirator yet, he said.
The disease has killed four teenagers in Turkey since January 1, including the boy's sister, all of whom were in close contact with sick birds that their impoverished families bred in backyards.
The 16-year-old Fatma Ozcan died on Sunday, about two weeks after she and her brother slaughtered a sick duck for food.
The other three victims, a brother and two sisters, perished earlier this month, becoming the first human fatalities of the virus outside its origins in Asia.
Dr Sahin said late diagnosis and treatment were likely a "primary factor in fatality cases".
The four dead adolescents were brought to the hospital days after they began showing the symptoms of the disease, doctors said.
US animal experts
The US embassy in Ankara said the US team, including experts in animal and health surveillance, laboratory capacity and public health communications, would hold talks with Turkish officials in Ankara before heading out to regions stricken with the virus.
Neighbouring Bulgaria offered to help with Turkey to combat the outbreak by offering a meeting between agriculture ministers from the two countries to discuss joint measures.
"This meeting could take place at the border and they (the two ministers) could talk about the necessary measures," Bulgarian Prime Minister Sergei Stanishev told a press conference.
Turkish Prime Minister Recep Tayyip Erdogan said there was nothing to fear, adding that the government was stepping up efforts to increase the people's awareness.
"Turkey's struggle against the disease has been successful so far and the current situation is not of a dimension that should cause citizens to worry," he said.
The government has told villagers to halt backyard breeding, blamed for most of the human H5N1 infections in Turkey, a vast country which lies on the routes of migratory birds who are believed to be spreading the virus.
Officials said 932,000 birds had been slaughtered as of Monday afternoon, since the outbreak started late December in an area near Dogubeyazit and then steadily spread west.
Scientists fear that the more the virus spreads, the greater the chance H5N1 will mutate into a form that is easily transmissible between humans, possibly sparking a global pandemic that could claim tens of millions of lives.
Since reappearing in Southeast Asia in 2003, the virus has killed about 80 people and infected some 150 in six countries, according to a World Health Organisation toll. Most of the dead were in Vietnam.
Funding boost
The European Commission will increase its financial pledge to fight bird flu to 100 million euros (A$161.02 million), said a senior official at a donors' conference in Beijing.
"The European Union (EU), we're dedicating a pledge of 100 million euros," Markos Kyprianou, EU commissioner for health and consumer protection, said.
The EU's offer is A$26 million more than the initial pledge it said last week it would make at the international conference, which aims to raise A$1.99 billion to help prevent bird flu from becoming a pandemic.
Mr Kyprianou said the EU pledge will be on a par with the pledge from the United States.
It will come from the European Commission and will be in addition to promises from individual countries in the 25-member EU, he said.
The sum will include 35 million euro or A$56.36 million earmarked for Asian countries and is seen as essential to fight avian influenza at its source.
Around 90 countries, almost half the world’s nations and 20 international organisations gathered at the two-day conference that opened on Tuesday.
Mr Kyprianou said he was confident the conference would reach its goal of raising $A1.99 billion but the funding was just one part of the plan to stop bird flu from mutating into a form that could kill millions.
Roche donation
In Geneva the Swiss pharmaceutical group Roche said that it would donate another batch of a key anti-flu drug to the World Health Organisation to treat an additional two million people in the event of a pandemic.
The new donation will raise the WHO's emergency stockpile of Tamiflu (oseltamivir) to 5.125 million treatments, Roche said in a statement.
The antiviral drug is regarded as a key frontline treatment that could slow the development of a global influenza pandemic when a new, more virulent form of the human virus appears, provided it is administered quickly.
A senior official at the UN health agency had earlier announced the fresh donation at a conference in China.
Roche said the new batch would be stored in regional stockpiles mainly for developing countries, while the existing stocks donated in 2004 and 2005 were being held centrally by the WHO.
About 50 countries have also placed orders for their own national stockpiles.