Gamasoidosis, or dermanyssosis, is a frequently unrecognized ectoparasitosis and source of growing concern in

human medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practic ...

, occurring after contact with avian mites which infest canaries,

sparrow Sparrow may refer to: Birds * Old World sparrows, family Passeridae * New World sparrows, family Passerellidae * two species in the Passerine family Estrildidae: ** Java sparrow ** Timor sparrow * Hedge sparrow, also known as the dunnock or hed ...

starling Starlings are small to medium-sized passerine birds in the family Sturnidae. The Sturnidae are named for the genus '' Sturnus'', which in turn comes from the Latin word for starling, ''sturnus''. Many Asian species, particularly the larger ones, ...

pigeon Columbidae () is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with short necks and short slender bills that in some species feature fleshy ceres. They primarily ...

s and

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, qu ...

and caused by two genera of

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...

s, '' Ornithonyssus'' and ''

Dermanyssus Dermanyssus is a genus of mites in the family Dermanyssidae. The etymology of the word ''Dermanyssus'' is from the Greek: ''derma'', meaning skin, and ''nyssein'', meaning bite. Genera *''Dermanyssus'' **'' Dermanyssus americanus'' Ewing, 1 ...

.'' Avian mite species implicated include the red mite ('' Dermanyssus gallinae''), tropical fowl mite (''

Ornithonyssus bursa ''Ornithonyssus bursa'' (also known as the tropical fowl mite) is a species of mite. It is most often a parasite of birds, but also has been found to bite humans and two species of mammals. It usually lives in birds' feathers, but for laying its ...

'') and northern fowl mite (''

Ornithonyssus sylviarum ''Ornithonyssus sylviarum'' (also known as the northern fowl mite) is a haematophagous ectoparasite of poultry. In both size and appearance, it resembles the red mite, ''Dermanyssus gallinae''. This blood-feeding parasite is broadly distribute ...

'')''.'' Mite dermatitis is also associated with rodents infested with the tropical rat mite (''

Ornithonyssus bacoti ''Ornithonyssus bacoti'' (also known as the tropical rat mite) is a hematophagous parasite. It feeds on blood and serum from many hosts. ''O. bacoti'' can be found and cause disease on rats and wild rodents most commonly, but also small mammals ...

''), spiny rat mite (''Laelaps echidnina'') and house-mouse mite (''

Liponyssoides sanguineus ''Liponyssoides sanguineus'' is a species of mite that infests the house mouse (''Mus musculus''). It can transmit human disease, is associated with causing rodent mite dermatitis in humans and is noted for carrying '' Rickettsia akari'', which c ...

''), where the condition is known as rodent mite dermatitis. Urban gamasoidosis is associated with window-sills, ventilation and air-conditioning intakes, roofs and

eaves The eaves are the edges of the roof which overhang the face of a wall and, normally, project beyond the side of a building. The eaves form an overhang to throw water clear of the walls and may be highly decorated as part of an architectural styl ...

, which serve as shelters for nesting birds. Humans bitten by these mites experience a non-specific

dermatitis Dermatitis is inflammation of the skin, 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. The area of skin involved c ...

with intense

itch Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

ing.

Clinical signs

The most common symptoms are pruritic

erythematous Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not asso ...

papule A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...

s, with a size of 1–3 mm, and 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,

axilla The axilla (also, armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage, bounded superior ...

e, the

groin In human anatomy, the groin (the adjective is ''inguinal'', as in inguinal canal) is the junctional area (also known as the inguinal region) between the abdomen and the thigh on either side of the pubic bone. This is also known as the medial comp ...

, and

buttocks The buttocks (singular: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are composed ...

. If feeding occurs while a patient is sleeping, bedclothes and pillows may show red spots caused by droppings or crushed mites. ''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 — as well as "the nares,

orbits In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...

and

eyelid An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eye ...

s, and genitourinary and rectal orifices.“ Additional symptoms include pinpricks, secondary

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...

scarring A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a na ...

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; Be ...

as well as

psychological trauma Psychological trauma, mental trauma or psychotrauma is an emotional response to a distressing event or series of events, such as accidents, rape, or natural disasters. Reactions such as psychological shock and psychological denial are typical ...

resulting in anxiety and depression.

Diagnosis

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 Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as ara ...

using a

microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisi ...

, 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, physicians are generally not aware of the condition, meaning gamasoidosis may be misdiagnosed as

scabies Scabies (; also sometimes known as the seven-year itch) is a contagious skin infestation by the mite ''Sarcoptes scabiei''. The most common symptoms are severe itchiness and a pimple-like rash. Occasionally, tiny burrows may appear on the ski ...

pediculosis Pediculosis is an infestation of lice from the sub-order Anoplura, family Pediculidae. Accordingly, the infestation with head lice is named pediculosis capitis, while this with body lice, pediculosis corporis. Although ''pediculosis'' in humans ma ...

or bites mistakenly identified as coming from

bed bug Bed bugs are insects from the genus ''Cimex'' that feed on blood, usually at night. Their bites can result in a number of health impacts including skin rashes, psychological effects, and allergic symptoms. Bed bug bites may lead to skin changes ...

s. 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. Attacks in public and office buildings tend to occur during the daytime. ''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, vibrations, chemical signals and . 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. There is documented "co-occurrence of gamasoidosis and various immunosuppressive disorders" and physicians should bear in mind that immunocompromised patients, patients that take corticosteroids, and patients with dementia may have a more severe infestation than healthy patients, Despite this, while immunosuppression can "increase susceptibility, it is not necessarily a pre-requisite for infestation".

Dermatoscopy Dermatoscopy also known as dermoscopy or epiluminescence microscopy, is the examination of skin lesions with a dermatoscope. It is a tool similar to a camera to allow for inspection of skin lesions unobstructed by skin surface reflections. The d ...

can help to exclude the diagnosis of

delusional parasitosis Delusional parasitosis (DP) is a mental disorder in which individuals have a persistent belief that they are infested with living or nonliving pathogens such as parasites, insects, or bugs, when no such infestation is present. They usually report ...

. Pets such as canaries, cats, dogs and gerbils can be infested also, diagnosis can be made by examining their feathers or fur for mites and is best carried out by a

veterinary Veterinary medicine is the branch of medicine that deals with the prevention, management, diagnosis, and treatment of disease, disorder, and injury in animals. Along with this, it deals with animal rearing, husbandry, breeding, research on nutri ...

professional.

Treatment

Treatment of gamasoidosis can be difficult; avian mites have developed resistance to multiple pesticides and the different species concerned display varied ecologies that necessitate divergent treatment approaches. For a patient to achieve full recovery, the mites must be eradicated from the person's environment through the removal of nests and appropriate disinfestation of infested areas by a

pest control Pest control is the regulation or management of a species defined as a pest; any animal, plant or fungus that impacts adversely on human activities or environment. The human response depends on the importance of the damage done and will range ...

professional. Total eradication can be difficult to achieve as ''D. gallinae'' can survive for longer than nine months without a blood meal and is capable of both digesting and completing its life cycle on human blood alone. Additionally, populations can expand rapidly, with a single female capable of laying up to "30 eggs in their lifetime"; prolonged darkness has been found to significantly promote mite population growth. Columba livia nest 2 eggs

Patients are advised to: * Shower frequently to remove mites from their skin and hair. * Washing clothes and bedding at temperatures, at or above 60 °C. * Remove the source of the mites, such as infested animal shelters, cages and nests. * Perform regular intensive vacuum cleaning and steam cleaning — the vacuum bag should be placed in a sealed bag and thrown away outside in a contained bin. * Disinfect infested household items and areas with effective

acaricide Acaricides are pesticides that kill members of the arachnid subclass ''Acari'', which includes ticks and mites. Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields. Termino ...

s such as

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. ...

s. * Washing of textiles or steam cleaning (cushions, carpets, curtains) at or above 60 °C, and drying them using an automated laundry drier. * Dust infested areas with amorphous silica gels such as CimeXa. * Heat treat their residence — raising the temperature of their living space above 55 °C for a sustained period. * Reduce the relative humidity of their home below 55%.

Fluralaner Fluralaner (International nonproprietary name, 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 ...

, an effective acaricide, available commercially as Bravecto may be administered to cats and dogs after consulting a vet.

Antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

s and topical

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are inv ...

s can be used for temporary relief of symptoms. Certain essential oils are known to have an acaricide effect on avian mites. Cardboard traps impregnated with

neem ''Azadirachta indica'', commonly known as neem, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of two species in the genus '' Azadirachta'', and is native to the Indian subcontinent and most of the countries in Afr ...

extracts or other acaricides can be used to reduce avian mite populations. In the case of scalp infestation, treatments with 1%

permethrin Permethrin is a medication and an insecticide. As a medication, it is used to treat scabies and lice. It is applied to the skin as a cream or lotion. As an insecticide, it can be sprayed onto clothing or mosquito nets to kill the insects th ...

shampoo can be used to remove the mites. For ear canal infestation, aural toilet is recommended with a course of 1% permethrin to be used as ear drops and for infected wax to be removed by a professional. Ineffective and often prolonged attempts to eradicate infestations commonly result in economic issues, due to a significant financial outlay when patients relocate or attempt to control these infestations.

Epidemiology

''D. gallinae'' poses a significant threat to public health as the mite may be a vector/reservoir of several

zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. ...

pathogens, such as '' Chlamydia psittaci'', ''

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 dise ...

'', ''Salmonella spp''., ''

Lyme disease Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the '' Borrelia'' bacterium, which is spread by ticks in the genus '' Ixodes''. The most common sign of infection is an expanding red rash, known as erythema ...

'', ''Mycobacterium spp''., ''

Coxiella burnetii ''Coxiella burnetii'' is an obligate intracellular bacterial pathogen, and is the causative agent of Q fever. The genus ''Coxiella'' is morphologically similar to ''Rickettsia'', but with a variety of genetic and physiological differences. ''C. ...

'', ''Bartonella spp''., ''

Borrelia burgdorferi ''Borrelia burgdorferi'' is a bacterial species of the spirochete class in the genus '' Borrelia'', and is one of the causative agents of Lyme disease in humans. Along with a few similar genospecies, some of which also cause Lyme disease, it mak ...

'', ''

Venezuelan equine encephalitis virus Venezuelan equine encephalitis virus is a mosquito-borne viral pathogen that causes Venezuelan equine encephalitis or encephalomyelitis (VEE). VEE can affect all equine species, such as horses, donkeys, and zebras. After infection, equines m ...

'', ''Eastern equine encephalitis virus'', and '' Fowlpox virus''. An association has not been found with gamasoidosis and

alpha-gal allergy Alpha-gal allergy — or mammalian meat allergy (MMA) — is a type of meat allergy characterized by a delayed onset of symptoms (3–8 hours) after ingesting mammalian meat and resulting from past exposure to tick bites. It was first reported in ...

Clinical signs

Diagnosis

Treatment

Epidemiology

See also

References

Further reading