''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 pro ...

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

poultry Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quail ...

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

Ornithonyssus sylviarum ''Ornithonyssus sylviarum'' (also known as the northern fowl mite) is a haematophagous ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, ca ...

.''

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 (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...

, protonymph, deutonymph and adult. Under favourable conditions this

life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia * Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring * Life-cycle hypothesi ...

can be completed within seven days, so populations can grow rapidly, causing

anaemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...

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, more commonly known as food poisoning is a symptomatic infection caused by bacteria of the ''Salmonella'' type. It is also a food-borne disease and are defined as diseases, usually either infectious or toxic in nature, caused by a ...

, avian spirochaetosis and ''

Erysipelothrix rhusiopathiae ''Erysipelothrix rhusiopathiae'' is a Gram-positive, catalase-negative, rod-shaped, non-spore-forming, nonacid-fast, nonmotile bacterium. Distributed worldwide, ''E. rhusiopathiae'' is primarily considered an animal pathogen, causing the diseas ...

''. ''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 A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this sy ...

, scabs,

hyperpigmentation Hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin. Causes Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris.James, William; Berg ...

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

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, ...

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 Prehistory, prehistoric times, having been discovered in very refined forms from settlemen ...

and

wattle Wattle or wattles may refer to: Plants *''Acacia sensu lato'', polyphyletic genus of plants commonly known as wattle, especially in Australia and South Africa **''Acacia'', large genus of shrubs and trees, native to Australasia **Black wattle, c ...

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

Ectoparasiticide An ectoparasiticide is an antiparasitic drug used in the treatment of ectoparasitic infestations. These drugs are used to kill the parasites that live on the body surface. Permethrin, sulfur, lindane, dicophane, benzyl benzoate, ivermectin ...

s can be used to treat affected poultry, these chemical controls, if used, should be used in rotation to avoid the buildup of resistance.

Organophosphates In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered a ...

, HAL Id
03099408

carbamates In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally ...

, and

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

s are widely used. The first case of

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

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-pink ae ...

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 Fluralaner (INN) is a systemic insecticide and acaricide that is administered orally or topically. The U.S. Food and Drug Administration (FDA) approved it under the trade name Bravecto for flea treatment in dogs in May 2014 and Bravecto Plus as a ...

, 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 Eprinomectin (MK-397) is an avermectin used as a veterinary topical endectocide {{Short pages monitor