Poultry parasites: Northern fowl mites

Northern fowl mites (Ornithonyssus sylviarum) are one of the more common ectoparasites (external parasites) that can be present in a flock. These mites live on their host throughout their life and feed on poultry blood. They are most commonly found around the vent, tail, and breast of the birds. Although these mites prefer poultry as a host, they will move onto humans and will bite if trapped (for instance in tight clothing) (Wakenell, 2016). Transmission can come from equipment, wild birds (sparrows and starlings), pet birds (passerines), and people. These mites can be a severe pest in poultry flocks.

Biology of the Northern fowl mite

Mites are gray/black in color, but after a blood meal, mites may appear red. Mites move slowly and cannot fly.

Mites are between 0.5 mm - 1 mm in size (0.02 -0.04 in), thus visible to the naked eye as small specks.

Mites spend their complete lifecycle (5-12 days) on their host but can live in the environment without a host for 2-3 weeks.

Poultry parasites: Northern fowl mites - Image 2

Poultry parasites: Northern fowl mites - Image 3

Reproduction

An adult female will produce 1-3 eggs after a single feeding. An infestation can begin with a single adult female. The female can lay male (unfertilized) eggs and will mate with the male offspring. The life cycle is short which will result in a quick rise in mite numbers within a few weeks' time (Murillo & Mullens, 2013).

Signs and consequenses of infestation

Northern fowl mites are visible to the naked eye. Early infestations may be difficult to notice. Infestations will reach their peak after 4-5 weeks, and mites can then be easily spotted in feathers and on birds' skin. At peak infestation, a single bird may host over 100,000 mites. When infestations are severe, you may see blood stains and/or mites on the chickens' eggs. At infestations of > 50,000 mites/bird, birds can lose 6 percent of their blood daily.

Poultry parasites: Northern fowl mites - Image 4

Signs of Northern fowl mite infestation

Black crusted skin and feathers
Thickening of skin and possible lesions and scabs
Agitated birds with frequent preening, especially when birds are perching/roosting
Blood spots or mites on chicken eggs
Pale comb

Some consequences of severe infestation are:

Anemia and mortality
Inflammation and irritation at the site of the bite
Reduced egg production (-10 to -15%)
Reduced egg size
Poor feed conversion (more feed needed for the same or worse production) (Murillo & Mullens, 2013; Kaufman et al 2000)

Pest management

Pest control should ideally involve the monitoring and management of ectoparasites, and should include a rotation of approaches to avoid the mites developing resistance to a specific treatment.

Tip: Prevention is better than any treatment. The best way to prevent infestation is through biosecurity measures. More on biosecurity can be found here.

Consult a pest control specialist or veterinarian when considering any chemical treatment as pest management, especially for off-label use of products. Sprays are less effective for birds housed on the floor (rather than in commercial cages). Treatments work most effectively when mite abundance is low; less than 50 mites per bird. Dusts have inhalation risks, and sulfur can be combustible in confined spaces. Do not use carbaryl powder either on the bird or on the premises (Wakenell, 2016). Carbaryl is a possible carcinogen and product residues can be detected in eggs 56 days after treatment at 0.5% and 1% doses (Ivey et al., 1984). Always read product labels carefully before applying any pesticide; mix and apply as directed, do not overdose, do not treat too often, and follow all precautions exactly.

Sulfur (> 0.9% concentration) eliminated mite infestations for 4-8 weeks in caged laying hens (Mullens et al., 2012). Garlic spray (Birrenkott et al., 2000), kaolin (12%), DE (12%), and azadirachtin (at 0.06%) reduced but not eliminated mite infestations (Mullens et al., 2012).

For more pest management approaches, please see our previous newsletter on bed bugs here.
More information on integrated pest monitoring and management (Murillo and Mullens) can be found here.

Key messages

Northern fowl mites live on birds, but can transfer to the environment or people
Infestations can reach huge numbers, with 100,000 mites per bird
Infestations can cause discomfort and distress in birds and can impact the bottom line (production)
Early detection is key to manage infestations
Biosecurity measures are the best approach to PREVENT infestation

This article was originally published on Poultry Extension Collaborative (PEC) and it is reproduced here with permission from the authors.