USA - Officials in two Arizona counties are warning the public after fleas in the region tested positive for the plague, the infamous infectious disease that killed millions during the Middle Ages. Navajo County Public Health officials confirmed on Friday that fleas in the area have tested positive for the rare disease. The public health warning follows a similar notice from Coconino County Public Health Services District in Arizona warning of the presence of plague in fleas found there too. Both counties are situated in the northern part of Arizona.