` It is not clear why we are seeing more activity than in recent years , '' said Marc Fischer , a CDC medical epidemiologist . NEW : Officials will offer aerial insecticide spraying to communities hit by virus . NEW : Virus kills 175 people and infects nine more people in Texas , Dallas County . A county judge declares a public health emergency . The country is experiencing its biggest spike in West Nile virus since recent years .
NEW : Officials will offer aerial insecticide spraying to communities hit by virus . NEW : Virus kills 175 people and infects nine more people in Texas , Dallas County . A county judge declares a public health emergency . The country is experiencing its biggest spike in West Nile virus since recent years .