TROPICAL RAT MITE
Scientific Name: Ornithonyssus bacoti
Order & Family: Order Mesostigmata, Family Macronyssidae
Size: Approx. 0.5 mm to 1.0 mm (hardly visible to the naked eye except when moving or engorged with blood)
Natural Habitat
Found worldwide in association with rodents (rats and mice). They often enter human dwelling spaces through cracks, vents, or walls when their primary rodent host dies or moves away.
Diet & Feeding
Obligate blood-feeders. They primarily feed on rodents but are opportunistic and will bite humans and domestic pets if rodents are unavailable.
Behavior Patterns
They are highly mobile and crawl long distances to find a host. They do not live on the host but visit to feed, usually completing their life cycle in 10-12 days under optimal conditions.
Risks & Benefits
Risks include painful, itchy skin rashes (dermatitis) and papular urticaria in humans. While not major vectors for human disease, they can potentially transmit murine typhus and plague between rodents. There are no ecological benefits to humans.
Identified on: 12/26/2025