Bird Mite

Ornithonyssus sylviarum, commonly known as the northern fowl mite, is an obligate ectoparasite primarily of birds, though it will bite humans in the absence of its preferred hosts. Belonging to the family Macronyssidae (Order Mesostigmata, Class Arachnida), these mites are minute, typically 0.5-1.0 mm in length, with an oval body and eight legs. Unfed mites are pale, becoming reddish-black after engorging on blood. The entire lifecycle, from egg to adult, can be completed in as little as 5-7 days under optimal conditions (25-300C and 70-90% RH). Females lay eggs directly on the host, which hatch in 1-2 days into larvae. Larvae molt to protonymphs, then to deutonymphs, and finally to adults, with blood meals required at each motling stage (except for the larva). Adults can survive for up to 3-4 weeks off a host.

Bird mites are highly mobile and exhibit phototactic and thermotactic responses, often moving towards light and warmth to locate hosts. When their primary avian hosts abandon nests or die, mites will actively seek new hosts, frequently migrating into structures. This often results in human infestations, particularly in upper floors, near windows, or close to areas where birds have nested. Their bites cause pruritus and dermatitis, leading to significant discomfort. Mites are nocturnal feeders but can be observed during the day, especially when searching for hosts. Activity peaks during the warmer months when bird breeding is most prevalent and mite populations are highest.