Two weeks ago, WGFD personnel discovered caecal worms in some birds, which are not uncommon. However, last week, personnel at the Wyoming State Veterinary Laboratory also confirmed the presence of Chlamydiophila psittaci in some birds, which is the causative agent of the zoonotic disease, psittacosis. Because of potential health threats to humans and domestic poultry, the WGFD is working with the Wyoming Department of Health and the Wyoming Livestock Board to ensure all necessary precautions are in place.

WGFD employees at the bird farm are taking all necessary biosecurity precautions to protect themselves and pheasant chicks that have been hatched this spring. None of the employees at the Bird Farm have exhibited any signs of illness.

According to Dr Cynthia Tate, Assistant Veterinarian for the WGFD, there is still a lot that is unknown about the disease and how it was introduced into the bird farm.

She said: "We are doing additional necropsies and sampling now to try and understand how this disease got here, and how we can prevent future outbreaks. We are monitoring this situation closely and we will release additional information about this situation as we learn more."

WGFD Wildlife Chief, Brian Nesvik, said it is unclear whether this situation will impact this Fall's pheasant releases.

Speaking a week ago, he said: "We will know more details about this situation in the coming weeks. The birds that were euthanised this week were brood stock that were scheduled to be released this spring. These birds had already produced the eggs that will hatch birds for this Fall's releases. However we have increasing concerns with higher than normal newly hatched chick mortality."

He added that if this higher-than-normal chick mortality continues, the Department will evaluate options for this Fall's releases.

Psittacosis can affect humans with an acute respiratory illness often with fever and other flu-like symptoms.

"As the illness is readily treated with antibiotics, workers and other persons with exposure to the infected birds or their environment who develop symptoms should consult a health-care provider," said Dr Tracy Murphy, acting state health officer and state epidemiologist with the Wyoming Department of Health.

According to the Centers for Disease Control and Prevention, fewer than 50 human cases are reported in the United States each year. In Wyoming, there have been no human cases reported since 2000. There was one case each year for 1999 and 1998, three cases in 1996, and seven in 1989.