Gamasoidosis

]]Gamasoidosis is a frequently unrecognized ectoparasitosis occurring after contact with avian mites which infest canaries, sparrows, starlings, pigeons and poultry and caused by two genera of mites, Ornithonyssus and Dermanyssus. Avian mite species implicated include the red poultry mite (Dermanyssus gallinae), tropical fowl mite (Ornithonyssus bursa) and northern fowl mite (Ornithonyssus sylviarum). Mite dermatitis is also associated with rodents infested with the tropical rat mite (Ornithonyssus bacoti), spiny rat mite (Laelaps echidnina) and house-mouse mite (Liponyssoides sanguineus), where the condition is known as rodent mite dermatitis. Urban gamasoidosis is associated with window-sills, ventilation and air-conditioning intakes, roofs and eaves, which serve as shelters for nesting birds. Humans bitten by these mites experience a non-specific dermatitis with intense itching. ]]Gamasoidosis is a frequently unrecognized ectoparasitosis occurring after contact with avian mites which infest canaries, sparrows, starlings, pigeons and poultry and caused by two genera of mites, Ornithonyssus and Dermanyssus. Avian mite species implicated include the red poultry mite (Dermanyssus gallinae), tropical fowl mite (Ornithonyssus bursa) and northern fowl mite (Ornithonyssus sylviarum). Mite dermatitis is also associated with rodents infested with the tropical rat mite (Ornithonyssus bacoti), spiny rat mite (Laelaps echidnina) and house-mouse mite (Liponyssoides sanguineus), where the condition is known as rodent mite dermatitis. Urban gamasoidosis is associated with window-sills, ventilation and air-conditioning intakes, roofs and eaves, which serve as shelters for nesting birds. Humans bitten by these mites experience a non-specific dermatitis with intense itching. The most common symptoms are 'itching and punctiform, erythematous papules' with a 'central punctum', the itching and irritation are reactions to the saliva the mites secrete when feeding. Bites are normally located in groups around the neck and body areas covered by clothes (waist, trunk, upper extremities and abdomen), but can also be found on the legs, finger webs, axillae, the groin, and buttocks. D. gallinae is capable of infesting the ear canal, with symptoms including itching, internal inflammation and discharge. It can also infest the scalp, with severe itching—particularly at night as the primary symptom. Additional symptoms include pinpricks, secondary infections, scarring, hyperpigmentation as well as psychological trauma resulting in anxiety and depression. Diagnosis can be challenging as the small size of avian mites make them 'barely visible to the unaided eye'. Identification of the species is best carried out by a medical entomologist using a microscope, positive identification of species is critical for recommendation of suitable treatment. Samples can be obtained using corrugated cardboard traps, left in infested areas. Diagnoses of gamasoidosis have a long history, with 'cases reported since the 17th century, documented in the leading medical literature since at least the 1920s.' Avian and rodent mites have been documented infesting residential buildings, work spaces, schools and hospitals. Despite this, there is considered to be widespread ignorance and misinformation 'regarding human infestation with D. gallinae across healthcare, science and pest control fields', which in turn has led to increasing numbers of infestations and a dangerous propagation of the disease. Due to it being an uncommon diagnosis, gamasoidosis may be misdiagnosed as scabies or pediculosis or bites mistakenly identified as coming from bed bugs. Many cases of gamasoidosis go unreported, suggesting that the actual incidence is higher than generally believed. As a result, in cases of unexplained bites in residential areas, the involvement of D. gallinae should always be considered, especially during late spring and early summer when wild birds make their nests. The life cycle of the mite is another important method of diagnosis. Hematophagic mites generally feed at night but may also feed during the day if the room is sufficiently dark. O. bursa is an exception as it generally remains on its hosts and will feed during the day. D. gallinae may be commonly found in the bedroom or where the patient sleeps, as they prefer to stay close to their host for optimal feeding. They are attracted to warm hiding places that simulate the body temperature of birds (e.g. pigeons 42 °C), 'such as the electrical devices running in stand-by mode (e.g. laptop computers, television, radio clocks etc.)' which generate heat. As a result, 'it is strongly recommended to check these electrical appliances for the mite detection'. D. gallinae generally visit their host for up to 1–2 hours, leave after completing their blood meal and typically feed every 2–4 days. They are able to move extremely quickly and can take less than 1 second to bite, enough time to inject their saliva and to induce rash and itching. They locate potential hosts through temperature changes, vibration and CO². It has been hypothesized the D. Gallinae is capable of 'learning' 'to associate non-host skin with a blood-meal if the host selection process permitted feeding.' Combined with a generalist approach to finding hosts and the capability of digesting non-avian blood could potentially explain their documented host expansion to mammals and humans.