Ornithonyssus

Ornithonyssus is a genus of mites belonging to the family Macronyssidae. These mites are commonly known as bird mites or tropical mites. They are obligate ectoparasites, meaning they live on the external surface of their hosts and are dependent on them for survival. The primary hosts for Ornithonyssus mites are birds, but they can also infest mammals, including humans, when their bird hosts are absent or scarce.

The most well-known species within this genus is Ornithonyssus sylviarum, the northern fowl mite, which is a significant pest of domestic poultry worldwide. Another common species is Ornithonyssus bacoti, the tropical rat mite, which is found in tropical and subtropical regions and can transmit diseases to rodents and humans.

Ornithonyssus mites are small, typically less than a millimeter in length, and have a flattened, oval-shaped body with eight legs. They feed on blood, feathers, and skin debris of their hosts. While they primarily inhabit birds' nests and roosting sites, they can venture onto the host's body to feed. When bird populations decline or are removed, these mites may seek alternative hosts, leading to temporary infestations in humans. These human infestations are usually characterized by itchy, red papules or vesicles, often on exposed areas of the skin. The mites do not burrow into the skin and typically die within a few days without a host. Their life cycle involves several developmental stages, including egg, larva, nymph, and adult.