Dermanyssus gallinae is an ectoparasite of poultry

Poultry

Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...

 and other bird species.

Description

The mite

Mite

Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...

s are blood feeders and attack resting birds at night. They are generally white or greyish in colour, becoming darker or redder when engorged with blood. After feeding, they hide in cracks and crevices away from daylight, where they mate and lay eggs. The mite progresses through 5 life stages: egg, larva

Larva

A larva 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...

, protonymph, deutonymph and adult. Under favourable conditions this life cycle

Biological life cycle

A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...

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

Salmonellosis is an infection with Salmonella bacteria. Most people infected with Salmonella develop diarrhea, fever, vomiting, and abdominal cramps 12 to 72 hours after infection. In most cases, the illness lasts four to seven days, and most people recover without treatment...

, avian spirochaetosis

Borrelia anserina

Borrelia anserina is a helical filiform spirochete bacteria with dimensions of approximately 8-20/0,2-0,3 µm and with about 5 to 8 spirals. Their mobility is very high. B. anserina can be colored with the May Grunwald-Giemsa method.-Cultivation:...

 and Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae is a gram-positive, catalase-negative, rod-shaped bacterium. It grows aerobically and anaerobically and does not contain endotoxin. Distributed worldwide, E. rhusiopathiae is primarily considered an animal pathogen, causing a disease known as erysipelas in animals...

.

Dermansyssus gallinae can also feed on some species of mammals, including humans, - causing dermatitis

Dermatitis

-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...

 and skin lesions. However the mite needs an avian host to reproduce.

Clinical signs and diagnosis

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

Scab

Scab can refer to the following:* Scab, a hard coating on the skin formed during the wound healing reconstruction phase* Derogatory term for a strikebreaker, a person who works despite strike action or against the will of other employees...

s, hyperpigmentation

Hyperpigmentation

In dermatology, hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.-Causes:Hyperpigmentation may be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris...

 and feather loss may develop.

If they are present in large numbers, D. gallinae can cause anaemia in hens which presents as pallor of the comb

Comb (anatomy)

Anatomically, a comb is a fleshy growth, caruncle, or crest on the top of the head of gallinaceous birds, most notably turkeys, pheasants, and domestic chickens...

 and wattle

Wattle (anatomy)

A wattle is a fleshy dewlap or caruncle hanging from various parts of the head or neck in several groups of birds, goats and other animals. In some birds the caruncle is erectile tissue.The wattle is frequently an organ of sexual dimorphism...

.

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. Definitive diagnosis is only achieved following identification of eggs, faeces or the mites themselves

Treatment and prevention

Ectoparasiticides can be used to treat affected poultry. These chemical controls, if used, should be used in rotation to avoid the build up of resistance

Pesticide resistance

Pesticide resistance is the adaptation of pest population targeted by a pesticide resulting in decreased susceptibility to that chemical. In other words, pests develop a resistance to a chemical through natural selection: the most resistant organisms are the ones to survive and pass on their...

. Red mites can survive for up to 10 months in an empty hen house. Creosote

Creosote

Creosote is the portion of chemical products obtained by the distillation of a tar that remains heavier than water, notably useful for its anti-septic and preservative properties...

 treatment of wood will kill mites.

External links

• Dermanyssus gallinae, at WikiVet
  WikiVet
  WikiVet is a wiki of veterinary content, run using the MediaWiki software. The project is a collaborative initiative involving UK veterinary schools with external support...