GENEVA, May 23 (Reuters) - The World Health Organisation (WHO) on Friday confirmed the first human case of bird flu in Bangladesh, a baby boy who has recovered, bringing the number of countries which have recorded human infections to 15.

Bangladesh authorities announced the case on Thursday, and the WHO said it had been confirmed by a laboratory at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta.

"The case was confirmed by CDC in Atlanta. It is the first in Bangladesh," WHO spokesman Gregory Hartl told Reuters.

The 16-month-old boy was infected in January and has since recovered, he said. Bangladesh authorities informed the United Nations agency promptly about the case but it took time for the international laboratory testing to be completed, Hartl said.

The H5N1 virus was first detected in Bangladesh in March last year and since then the authorities have culled around 2 million chickens and destroyed more than 2 million eggs.

Avian influenza has spread through 47 of Bangladesh's 64 districts, causing losses of about 45 billion taka ($650 million) for the growing poultry sector, which accounts for 1.6 percent of the impoverished nation's gross domestic product.

"When a disease is so widespread in poultry, it is really a matter of time before you get a human case. It shows the need to control the disease in animals if you are going to reduce the chances of transmission to humans," Hartl said.

The virus rarely infects people but experts fear it could mutate or combine with the highly contagious seasonal influenza virus and spark a pandemic, which could kill millions of people.

Prior to the Bangladesh case, 14 countries had reported 382 cases including 241 fatalities since 2003, according to the WHO. (Reporting by Stephanie Nebehay; Editing by Catherine Evans)

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