DHAKA, April 4 (Reuters) - Bangladesh said on Wednesday that bird flu had spread to a new poultry farm despite the best efforts of struggling veterinary and health workers.

"The latest farm confirmed to have H5N1 virus is in northern Jamalpur 200 km (125 miles) from the capital Dhaka," an official of the Fisheries and Livestock ministry said.

Some 72,000 chickens have been culled so far from 26 farms since the avian influenza was detected in six farms at Savar near the capital March 22.

More than 500 workers at the infected farms have been given a local version of the Tamiflu anti-viral drug as a precaution, health ministry officials said.

No humans have tested positive for the disease in the country.

Bangladesh says it has sufficient Oseflu, a local version of Tamiflu, produced and marketed by a local firm since last year.

At least 170 people have died of bird flu in 11 countries, mostly in Asia, since 2003.

Health experts fear the virus could trigger a pandemic if it mutates to form a strain that can transmit between humans.

Bangladesh has 125,000 small and large poultry firms producing 250 million broilers and 6 billion eggs annually.

About four million Bangladeshis are directly or indirectly associated with poultry farming.