The mites 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, protonymph, deutonymph and adult. Under favourable conditions this life cycle 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, avian spirochaetosis and Erysipelothrix rhusiopathiae.
Dermansyssus gallinae will also bite some species of mammals, including humans, sometimes causing dermatitis and skin lesions, Ectoparasites from feral pigeons affecting humans. D. gallinae is being increasingly implemented in dermatological complaints in non-avian hosts, suggesting that its significance may extend beyond poultry. The main objective of the current work was to review the potential of D. gallinae as a wider veterinary and medical threat. Results demonstrated that, as an avian mite, D. gallinae is unsurprisingly an occasional pest of pet birds. However, research also supports that these mites will feed from a range of other animals including: cats, dogs, rodents, rabbits, horses and man. Increasing reports of bird-mite attacks on humans and mammalian companion animals suggest that avian mite ectoparasitosis/dermatitis (gamasoidosis) may be of increasing medical and veterinary concern. Though several species of bird mite from multiple genera may be responsible for gamasoidosis, D. gallinae is most commonly implemented as the causal agent. In cases of human infestation, positive identification of species (or at least functionally similar groups based on life-history patterns) and recommendation of suitable treatment requires an understanding of mite taxonomy and ecology that many healthcare professionals and pest control organizations do not currently possess.
Clinical signs and diagnosisEdit
The mites normally feed around the breast and legs of hens, causing pain, irritation, and a decrease in egg production. Pustules, scabs, hyperpigmentation and feather loss may develop.
If they are present in large numbers, D. gallinae can cause anemia in hens which presents as pallor of the comb and wattle.
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.