Abstract
Ornithodoros hermsi is a small, multi-host soft tick that feeds rapidly on blood in all life stages, including larva, 2 to 5 nymphal instars (primarily 3), and male and female. As adults, they can feed repeatedly and reproduce for many years. O. hermsi is nidicolous and primarily inhabits nest cavities and burrows of small rodents and birds, with chipmunks and tree squirrels serving as its primary hosts. When no hosts are available, they can fast for several years. O. hermsi is found in restricted habitats where their hosts live in coniferous pine and Douglass fir forests at elevations of 1,500–10,000 feet in western North America. Rustic forest cabins infested with rodents and O. hermsi are the primary exposure sites for humans, who may be bitten while sleeping by these nocturnally active ticks. O. hermsi bites cause erythema and local discomfort, but compared to other species, effects appear benign. Other bite effects like toxicosis and paralysis remain unknown.