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By Christopher Doering

WASHINGTON, May 4 (Reuters) - The United States will test fewer wild birds during 2007 for the avian influenza virus than it did a year ago, but government officials said on Friday surveillance efforts will focus on species and locations with the greatest chance of detecting the virus.

The U.S. Agriculture and Interior departments, which jointly monitor for avian influenza, told Reuters they plan to take about 77,000 samples from wild birds during the April 2007 to March 2008 period.

As part of an effort to rapidly boost domestic surveillance following the spread of the virus overseas, USDA and Interior worked with states to collect more than 111,000 samples during the same period a year ago.

Interior will test about the same number of birds, 27,000, but this time it will spend more effort on dead and sick birds that are more likely to show symptoms of the disease.

A reduction in so-called environmental samples by USDA, such as testing of bird droppings, also will be cut in half to 25,000.

"Last year we ramped-up efforts to learn as much as we possibly could about avian influenza viruses in wild birds and they took that information and developed a targeted surveillance plan for this year," said Karen Eggert, a spokeswoman with USDA's Animal and Plant Health Inspection Service.

Worldwide, the highly pathogenic H5N1 avian influenza virus has killed 170 people since 2003, according to the U.N.'s World Health Organization. An estimated 200 million birds have died or been culled. This strain has not been found in the United States so far.

U.S testing will focus on four major flyways-- the Pacific, Atlantic, Central and Mississippi -- along with Hawaii in the South Pacific. The lion's share of the monitoring will be on mallard ducks, American Wigeons and Northern Pintails, which have been found to be some of the most common carriers of of the virus.

Alaska has been targeted because it is near the Pacific Flyway to Asia. USDA said Alaska will command the largest share of its wild bird tests this year, about 2,000, compared with other states where samples will range from 750-1,500. Interior also said it will closely watch Alaska.

"There are several theories on how (high-pathogenic H5N1) could get here, if you go by the wild migratory birds theory Alaska is the most likely spot," said Nicholas Throckmorton with the Interior Department.

Other vehicles being targeted for spread of the virus are illegal smuggling of imported birds, trade of poultry products and humans transporting it in on an airplane.

The U.S. testing program last year detected a low-pathogenic bird flu strain in six states -- Delaware, Illinois, Maryland, Michigan, Montana and Pennsylvania. It is common for mild and low pathogenic strains of bird flu to appear in the United States and other countries.

Chris Waldrop, director of the Food Policy Institute at Consumer Federation of America, said the reduction in testing was similar to what U.S. officials did with mad cow disease after it was first detected in late 2003. USDA boosted testing soon after before cutting it last July to focus on animals with the greatest risk of getting the disease.

"It looks like they are thinking this one through a little more," said Waldrop, whose group was critical of USDA's decision to reduce mad cow surveillance. "In that respect we wouldn't be that concerned with them cutting testing (for bird flu) and hopefully focusing their resources where they can best use them."

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