page_title: Mites of domestic animals
section_title: Living layer of epidermis
hierarchical_section_title: Mites of domestic animals / Diseases / Living layer of epidermis
caption_attribution_description: English: Photograph of parasitic mite infestation of sheep.
context_page_description: Mites that infest and parasitize domestic animals cause disease and loss of production. Mites are small invertebrates, most of which are free living but some are parasitic. Mites are similar to ticks and both comprise the order Acari in the phylum Arthropoda. Mites are highly varied and their classification is complex; a simple grouping is used in this introductory article. Vernacular terms to describe diseases caused by mites include scab, mange, and scabies. Mites and ticks have substantially different biology from, and are classed separately from, insects. Mites of domestic animals cause important types of skin disease, and some mites infest other organs. Diagnosis of mite infestations can be difficult because of the small size of most mites, but understanding how mites are adapted to feed within the structure of the skin is useful.
context_section_description: This is typically caused by sarcoptic mites. Sarcoptes scabiei is an example: it infests many species of mammals, including humans. Other common sarcoptic mites are in the genus Notoedres, and the genus Knemidokoptes (or Cnemidocoptes) which infest birds. Sarcoptic mites as adults are microscopic, nearly circular in outline, and their legs are short, adapted for burrowing. The females, after mating with males on the surface of their host's skin, burrow into the living layers of the epidermis (mainly the stratum spinosum). They make long tunnels horizontal to the surface of the skin. Eggs are laid in the tunnels and development of larvae and nymphs occurs in such tunnels. The feeding of the mites and their excretory products irritates and inflames the skin, causing intense pruritus. Dermal hypersensitivity reactions will develop in the host. Chronic infestations lead to thickening of the skin by overproduction of epidermal cells (acanthosis), resulting in a characteristic depilated and scaly appearance. Stress caused by the pruritus can be severe, and will result in lost productivity of most species of livestock animals. Camels are prone to severe infestation and wild animals such as foxes may die from sarcoptes infestation.
caption: Psoroptes ovis mites (white dots) infesting sheep skin
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