''Dermanyssus gallinae'' (also known as the red mite) is a

haematophagous Hematophagy (sometimes spelled haematophagy or hematophagia) is the practice by certain animals of feeding on blood (from the Greek words αἷμα ' "blood" and φαγεῖν ' "to eat"). Since blood is a fluid tissue rich in nutritious ...

ectoparasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

poultry Poultry () are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, Eggs as food, eggs or feathers. The practice of animal husbandry, raising poultry is known as poultry farming. These birds are most typ ...

. It has been implicated as a vector of several major pathogenic diseases. Despite its common names, it has a wide range of hosts including several species of wild birds and mammals, including humans, where the condition it causes is called

gamasoidosis Gamasoidosis, also known as dermanyssosis, is a frequently unrecognized form of zoonotic dermatitis, following human infestation with avian mites of the genera ''Dermanyssus'' or ''Ornithonyssus''. It is characterized by pruritic erythematous pa ...

. In both size and appearance, it resembles the northern fowl mite, '' Ornithonyssus sylviarum.''

Description

''Dermanyssus gallinae'' is an obligate blood feeder that will normally attack its host at night, but will occasionally feed during the day. Adults are long, with long legs and usually a grayish-white body, which becomes reddish-brown when engorged. After feeding, they hide in cracks and crevices away from light sources, where they mate and lay eggs. Mites progress through five life stages: egg,

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

, protonymph, deutonymph and adult. Under favourable conditions this life cycle can be completed within seven days, so populations can grow rapidly, causing

anaemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availab ...

in badly affected flocks of poultry. Young birds are most susceptible. The mites can also affect the health of the birds indirectly, as they may serve as vectors for diseases such as

Salmonellosis Salmonellosis is a symptomatic infection caused by bacteria of the ''Salmonella'' type. It is the most common disease to be known as food poisoning (though the name refers to food-borne illness in general). These are defined as diseases, usuall ...

, avian spirochaetosis, avian influenza A virus (AIV), and '' Erysipelothrix rhusiopathiae''. ''D. gallinae'' can survive for up to 10 months in an empty hen house. Temperatures greater than and less than , have been found to be lethal.

Infestation in hens

Signs and symptoms

The mites normally feed around the breast and legs of hens, causing pain, irritation, and a decrease in egg production. Pustules, scabs,

hyperpigmentation Hyperpigmentation, also known as the dark spots or circles on the skin, is the darkening of an area of Human skin, skin or nail (anatomy), nails caused by increased melanin. Causes Hyperpigmentation can be caused by sun damage, inflammation, or ...

and feather loss may develop. If they are present in large numbers, ''D. gallinae'' can cause

anemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...

in hens which presents as pallor of the

comb A comb is a tool consisting of a shaft that holds a row of teeth for pulling through the hair to clean, untangle, or style it. Combs have been used since prehistoric times, having been discovered in very refined forms from settlements dating ba ...

and wattle.

Diagnosis

A presumptive diagnosis can be made in flocks of laying hens, usually based on a history of decreasing egg production, anaemia and mortalities in young or ill birds. Blood spots on eggs indicate infestation within the cloaca of an affected hen. Definitive diagnosis is only achieved following identification of eggs, feces or the mites themselves.

Prevention

There are several methods for preventing infestation in hen houses including: * Heating the henhouse to temperatures above . * Regular washing down of the housing system. * Treatment of the walls and floors with silica dust or carbolineum prior to introduction of the new hens.

Treatment

Ectoparasiticides can be used to treat affected poultry, these chemical controls, if used, should be used in rotation to avoid the buildup of resistance. Organophosphates, HAL Id
03099408
carbamates, and

pyrethroid A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums (''Chrysanthemum cinerariaefolium'' and ''Chrysanthemum coccineum, C. coccineum''). Pyrethroids are used as commercial and hou ...

s are widely used. The first case of pyrethroid resistance was reported by Beugnet et al 1997 and new cases continue to be reported by Katsavou et al 2020. The insecticide

spinosad Spinosad is an insecticide based on chemical compounds found in the bacterial species '' Saccharopolyspora spinosa''. The genus '' Saccharopolyspora'' was discovered in 1985 in isolates from crushed sugarcane. The bacteria produce yellowish-p ...

is effective against mites resistant to the veteran acaricides and can even be used on premises in the presence of the laying hens. A novel product, Exzolt was introduced in the EU in 2017, it contains fluralaner, an isoxazoline, and is highly effective against ''D. gallinae'', included those resistant to old acaricides. It is approved for oral administration mixed with the drinking water and has a systemic mode of action, i.e. it acts through the blood of the treated birds. The macrocyclic lactones eprinomectin, moxidectin or

ivermectin Ivermectin is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, it is used to treat infestations including head lice ...

have been shown to impact mite reproduction and blood-meal digestion in one study, though other studies found ivermectin to be ineffective except at doses "unfavourably close to those causing toxicity". Predatory mites such as '' Androlaelaps casalis'' and '' Hypoaspis miles'' can be used to control ''D. gallinae'' populations. Exposing mites to

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

using

dry ice Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and Sublimation (phase transition), sublimes directly from the solid state to the gas ...

and direct-spraying has been proposed as a novel treatment. Vaccines are currently under active development for the treatment of poultry, which seek to "stimulate a protective response" in the birds and increase ''D. gallinae'' mortality. Some plant

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...

products can act as repellents. Birkett et al 2011 and George et al 2009 identify particular plants whose EOs successfully repel ''D. gallinae''.

Infestation in humans

In humans, ''D. gallinae'' infestations are known as gamasoidosis or dermanyssosis. The mites are capable of digesting and reproducing entirely on human blood, so infestations can be persistent. Due to the nocturnal feeding habits of ''D. gallinae'', infested people may experience itching and notice bites when they wake up in the morning. The severity of symptoms vary, with

dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

pruritus An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both ...

and papular urticaria being common. Prevention of infestation in human habitation consists of eliminating potential vectors such as destroying pigeon and sparrow nests and treating infested backyard poultry. Elimination of an infestation in a human habitation is best achieved through a combination of eliminating potential vectors (nesting pigeons, backyard poultry, etc.); reducing potential hiding places (rugs, clutter); judicious use of pesticides; consistent use of dehumidifiers to maintain a low humidity environment; maintaining a low temperature in the environment; frequent thorough cleaning; minimizing the amount of time spent in the home; and maintaining excellent hygiene.

Infestation in other animals

''Dermanyssus gallinae'' will also feed on mammals, including cats, dogs, rodents, rabbits, horses. Infestation by ''D. gallinae'' is rare in cats and dogs; usually the extremities and the back are bitten, causing itching.

Gallery

Naturalis Biodiversity Center - RMNH.ART.1252 - Dermanyssus gallinae (de Geer) - Mites - Collection Anthonie Cornelis Oudemans.jpeg, Immature form

Nymph A nymph (; ; sometimes spelled nymphe) is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature; they are typically tied to a specific place, land ...

I of ''Dermanyssus gallinae'' by A.C. Oudemans Naturalis Biodiversity Center - RMNH.ART.1253 - Dermanyssus gallinae (de Geer) - Mites - Collection Anthonie Cornelis Oudemans.jpeg, Immature form Nymph II of ''Dermanyssus gallinae'' by A.C. Oudemans Naturalis Biodiversity Center - RMNH.ART.1255 - Dermanyssus gallinae (de Geer) - Mites - Collection Anthonie Cornelis Oudemans.jpeg, Male ''Dermanyssus gallinae'' by A.C. Oudemans Dermanyssus gallinae, microscopic view.jpg, Red mite (''Dermanyssus gallinae'') from a hen, microscopic view

References

External links

Red Mite Guide on poultrykeeper.com
A comprehensive guide to identifying and controlling red mite, including life cycle diagram, photos and FAQs.
Red Mite Page on keeping-chickens.me.uk
Photographs of typical red mite infestations including macro photograph in backyard poultry coops
Red Mite infestation in houses
Infestation is not limited to chicken coops.
Red Mite Information on Accidental Smallholder
and close up photos for smallholders and backyard chicken keepers.
''Dermanyssus gallinae''
at WikiVet
Red Mite Treatment
Information on products being used by back garden poultry fanciers to control Red Mites. {{Taxonbar, from=Q1272501 Mesostigmata Agricultural pest mites Poultry diseases Veterinary entomology Animals described in 1778 Parasites of birds Parasitic arthropods of humans Ectoparasites Parasitic acari