DHAKA (Reuters) - Bangladesh said on Saturday bird flu hasspread to six more farms despite efforts to tackle the virus byveterinary and health officials and the

"The infection was detected at a farm in western Maguradistrict 200 km (125 miles) west of the capital Dhaka and fivefarms at Savar in the Dhaka district," a spokesman at thefisheries and livestock ministry said.

The H5N1 bird flu virus has been spreading in poultryflocks in Bangladesh ever since it was first detected on six ofthe country's farms on March 22 and despite culling and banningof the movement of chickens in areas with confirmed outbreaks.

Magura district is adjacent to India's West Bengal state ofIndia, where bird flu was detected earlier.

Bangladesh also shares a border with Myanmar, which isfighting the disease. But no one knows for sure how the diseasejumped to Bangladesh this March.

A 10-member FAO team arrived in Dhaka last week and hasvisited a number of affected farms and laboratories.

Since the detection of the H5N1 virus on March 22, some98,000 chickens have been culled on 38 farms in nine districts.

No humans have tested positive for the disease.

The virus is known to have infected nearly 300 people in 12countries since 2003, killing more than half of them.

Human cases of bird flu have generally been linked tocontact with infected poultry. Health experts fear the virusmay mutate into a form that passes easily from human to human,causing a pandemic that could affect millions.

The country has 125,000 small and large poultry firmsproducing 250 million broilers and six billion eggs annually.About four million Bangladeshis are directly or indirectlyassociated with poultry farming.