BILLINGS (AP)
A Yellowstone County woman has tested positive for West Nile virus, the first reported case in Montana this year, state health officials said Friday. Local health officials believe the 57-year-old woman may have picked up the infection while traveling in North Dakota earlier this month, said Elton Mosher, disease surveillance specialist for the Montana Department of Public Health and Human Services. The North Dakota Department of Health announced its first human West Nile case of 2007 in June. The woman, whose names was not released, developed “West Nile fever,” a mild illness that usually lasts three to six days and generally does not require treatment, the state said. Human West Nile cases are typically preceded by reports of positive West Nile tests in mosquito pools and horses, the state said. Acting state veterinarian Jeanne Rankin said Friday that West Nile has been confirmed in horses in Blaine and Phillips counties. Neither of the two horses was vaccinated against the disease and both are still alive, officials said. In addition, mosquitoes captured this summer in Yellowstone and Cascade counties have tested positive for the virus, officials said. Dr. Doug Moore, chief of public health for the Yellowstone City- County Health Department, said Friday that he has also heard of positive testing pools in Sanders County. At least 200 young pelicans at the Medicine Lake National Wildlife Refuge had died of the disease by the third week in July and another 50 appeared sick, said refuge manager Jerry Rodriguez. The virus is spread through the bite of an infected mosquito, which became infected by feeding on infected birds. Many people who become infected with West Nile experience no symptoms. Some may develop West Nile fever, while fewer than one out of 150 become severely infected with West Nile encephalitis or West Nile meningitis, the state said. Symptoms may include headache, rash, high fever, stiff neck, mental confusion, muscle weakness, tremors, convulsions, coma and paralysis. “More severe symptoms associated with West Nile virus is most common in people over 50 years old than in someone under that age,” Mosher said. Clinical signs of encephalitis in horses include loss of appetite and depression, in addition to any combination of weakness or paralysis of hind limbs, muzzle twitching, impaired vision, lack of coordination, head pressing, aimless wandering, convulsions, inability to swallow, circling, excitability, or coma
