Ornithonyssus sylviarum

Ornithonyssus sylviarum (northern fowl mite) is a blood-feeding ectoparasite of birds including swallows, robins,sparrows, and chickens. It often shares the same hosts and environment with Dermanyssus gallinae mites.

The infestation effects range from immune system changes, decreased body condition, and anemia to death.

The mite has a rapid reproductive cycle (egg to adult in 5 to 7 days) due to the ability of unmated females to produce male offspring. Thus, unmated females could disseminate to a new host and initiate an infestation by producing and mating with sons. Mated NFM produced female and male offspring in isolation, or when paired with a male. When paired with their sons that had developed to maturity, the "virgin" females are able to mate and subsequently produce female offspring.2 The mite completes its entire life cycle on the host, although the mite can survive off an animal for as long as 3 weeks and does not need direct contact between birds to disseminate quickly throughout bird housing.

Adult mites are vicious, non-burrowing parasites that spend most of their life on the body of the bird host reaching peak burdens of over 70,000 mites per bird.1

The northern fowl mite may attack a human when its normal host is not available. The mites enter the buildings through open windows or window air-conditioning units. Infestation with the parasites may also occur in persons in direct contact with infested birds, especially those employed in the poultry industry.

The bite of the northern fowl mite induces dermatitis, usually consisting of red rash, blisters and necrosis at the site of the bite. The lesions do not require specific treatment as they go away after the mites are eliminated.3

Ornithonyssus sylviarum mites have developed resistance to many pesticides. Chemical treatments can be toxic to birds, personnel, and the environment.


  1. Use of Beauveria bassiana to Control Northern Fowl Mites (Ornithonyssus sylviarum) on Roosters in an Agricultural Research Facility Matthew SW Rassette,1 Elizabeth I Pierpont,2 Tina Wahl,1 and Mark Berres3,* J Am Assoc Lab Anim Sci. 2011 Nov; 50(6): 910–915.
  2. Arrhenotoky and oedipal mating in the northern fowl mite (Ornithonyssus sylviarum) (Acari: Gamasida: Macronyssidae) John B McCulloch1 and Jeb P Owencorresponding author1,2 Parasit Vectorsv.5; 2012
  3. Northern fowl mite dermatitis. Huynh Congly

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