The illness has stricken five people in the Moses Lake area with flulike symptoms. Officials also have traced infected goats to Cascade and Teton counties in Montana, where six people have become ill, officials said.

Washington Agriculture Department spokesman Jason Kelly told The Spokesman-Review that goats at a Moses Lake farm that had trouble birthing in April were found to be infected with the Q fever bacteria. Goats from that farm have been traced to nine other counties in Washington: Spokane, Adams, Pend Oreille, Walla Walla, Franklin, Clark, Thurston, Kittitas and Chelan.

"We have established a direct link to the herd in Montana," Kelly said.

State Health Department spokesman Donn Moyer said human cases of Q fever are rare, with no more than three confirmed cases per year. People associated with the goat farms became ill starting in May, he said.

Investigators are trying to determine if the rise in cases is due to awareness of Q fever or something different.

People can become ill with the bacteria if they inhale barnyard dust particles contaminated by infected animals.

They suffer flulike symptoms and can develop pneumonia or hepatitis, Moyer said. High fever, headaches, malaise, abdominal pain, chills, muscle pain, chest pain, nausea, vomiting and diarrhea can be caused by the bacteria. The disease is treated with the antibiotic doxycycline.

Left untreated, serious cases of Q fever can lead to chronic illness that may affect a person's heart, liver, brain and lungs and may be fatal.

Moyer said the most vulnerable people are pregnant women, the elderly and those with chronic illness or weakened immune systems.

The infected goats were used in shows and possibly for meat, the newspaper said.

Information from: The Spokesman-Review

Copyright 2011 The Associated Press.