Ornithonyssus

Sambon, 1928

bird mites, fowl mites, rat mites

Species Guides

Ornithonyssus bacoti(tropical rat mite)
Ornithonyssus sylviarum(Northern Fowl Mite)

Ornithonyssus is a of mites in the Macronyssidae. The genus includes economically important poultry pests such as the (O. sylviarum) and (O. bursa), as well as the tropical rat mite (O. bacoti) which affects rodents and can bite humans. in this genus are obligate blood-feeders that complete their entire on the or in close association with host nesting material. Several species have significant veterinary and medical importance due to their impacts on poultry production and potential to cause human dermatitis.

Ornithonyssus bacoti infestation by Assafn. Used under a CC BY-SA 4.0 license.

Dermanyssus gallinae femelle by Di Palma et al.;"This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited".. Used under a CC BY-SA 2.5 license.

Vogelmilbe by No machine-readable author provided. Flodur~commonswiki assumed (based on copyright claims).. Used under a Public domain license.

Pronunciation

How to pronounce Ornithonyssus: //ˌɔːrnɪˈθɒnɪsəs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Identification to level requires microscopic examination. Key species include: O. sylviarum () — dark red to black, approximately 1 mm, found on vent, tail, back and legs of birds; O. bursa () — similar appearance but with different geographic distribution and preferences; O. bacoti (tropical rat mite) — associated with rodents, has a painful bite. Distinguishing Ornithonyssus from Dermanyssus (chicken mite): Ornithonyssus species typically remain on the host continuously, while hides in cracks and crevices during the day and feeds at night.

Images

Habitat

Associated with nesting material, poultry housing, animal houses, and crevices in structures housing birds or rodents. In poultry systems, mites inhabit feathers, nest boxes, and cracks in housing structures. For O. bacoti, include rodent burrows and animal house environments.

Distribution

Widespread distribution with -specific ranges. O. sylviarum occurs in temperate and subtropical regions globally; O. bursa in tropical and subtropical regions; O. bacoti has been documented in the La Plata Basin, Argentina, and occurs worldwide in association with commensal rodents. GBIF records indicate presence in Denmark, Norway, and Sweden.

Seasonality

Mite increase in cooler weather. In poultry systems, can persist year-round under suitable conditions. O. sylviarum populations peak during autumn and winter months in temperate regions.

Diet

Obligate . All stages feed on blood from avian or mammalian . O. sylviarum and O. bursa feed on poultry blood. O. bacoti feeds on rodent blood and will bite humans when host availability is limited.

Host Associations

Gallus gallus - domestic chicken; primary for O. sylviarum and O. bursa
Rattus norvegicus - primary for O. bacoti (tropical rat mite)
cricetid rodents - documented for O. bacoti in Argentina
Homo sapiens - accidental O. bacoti bites humans causing dermatitis; O. sylviarum can transfer to people handling infested birds but does not establish

Life Cycle

Holometabolous with four stages: , larva, nymph (with two instars), and . The entire is completed on the for O. sylviarum, requiring approximately one week under ideal conditions. Eggs are laid on the host or in nest material. Larvae are typically non-feeding; nymphs and adults are blood-feeding.

Behavior

O. sylviarum remains on the continuously, hiding in feathers around the vent, tail, back, and legs. O. bacoti is and will leave rodent hosts to seek alternative blood sources when host decline. occurs through host movement and nest material . Dust bathing by chickens can reduce mite populations through mechanical removal.

Ecological Role

of birds and mammals. In poultry systems, heavy reduce production by 10-15% and cause weight loss. O. bacoti has demonstrated potential for spp. and Bartonella sp. in poultry manure systems include macrochelid mites and hister beetles, which may contribute to .

Human Relevance

Significant economic pest of poultry worldwide. O. sylviarum is the most common of poultry in many regions. O. bacoti causes human dermatitis characterized by scattered papules on arms, shoulders, and legs, often misdiagnosed as bacterial , fungal infection, or allergy. in animal houses affect researchers and . Control methods include sulfur dust bags, dust baths, and such as fluralaner.

Similar Taxa

Dermanyssus gallinaeBoth are poultry-associated blood-feeding mites in Mesostigmata. D. gallinae hides in cracks and crevices during the day and feeds at night, while Ornithonyssus typically remain on the continuously.
Knemidocoptes mutansBoth affect poultry but K. mutans () burrows under leg causing lameness and crust formation, while Ornithonyssus feed on blood and remain on feathered areas.

More Details

Control in cage-free systems

Transition from battery cages to cage-free housing complicates mite control because solid floors and nest boxes provide hiding places and make spray penetration difficult. Research demonstrates that dust baths containing mixtures, combined with minimal beak trimming to allow effective , can maintain mite below economically damaging thresholds.

Insecticide resistance

Research has documented permethrin resistance in O. sylviarum from commercial poultry facilities. Sulfur dust bags have proven more effective than permethrin strips in controlled studies.