TULSA, Okla. (AP) _ Health officials investigating the deaths of two large groups of birds in Tulsa do not suspect West Nile virus.
The first group of ``a few dozen'' dead birds was found Sunday in south Tulsa, and gardeners found about two dozen dead birds Saturday, according to the Tulsa Health Department.
The birds found by gardeners were too decomposed to be tested but officials do not suspect West Nile because it normally does not kill large number of birds in the same area, officials said.
The initial investigation indicates the other group of birds died of natural causes, possibly from the weather, officials say. But samples of those birds have been collected to test for West Nile.
As of July 1, six birds, including two in Tulsa County, and two horses have tested positive this year for West Nile virus, the Oklahoma Department of Health said.
No humans in Oklahoma have been infected this year after 79 contracted the disease last year, without fatalities. In 2002, two of 21 persons contracting the illness died.
In humans, West Nile causes flu-like symptoms and, in about 1 percent of cases, can cause a serious illness that includes encephalitis, an inflammation of the brain.
The virus is carried by mosquitoes, who bite infected birds and then transmit it to other birds, horses or people in subsequent bites.