(p. 801) Scabies and other mite infections 

Acariasis in humans and animals is caused by a diversity of parasitic mites taxonomically grouped into the class Arachnida, subclass Acari. The zoonotic species that can transfer from birds and animals to man (e.g. Cheyletiella spp; Dermanyssus spp and Ornithonyssus spp) are important in that they often cause major skin irritation or a hypersensitivity reactions or alternatively act as vectors of diseases such as scrub typhus. Like ticks the lifecycle of mites involves four life stages of development. The female mite lays eggs on the host or in the environment; the eggs hatch into larvae and pass through two nymphal stages. All stages have eight legs except the six-legged larva. Transmission is predominantly via direct contact between hosts; however fomites have been recognised as a potential source of infestation although the importance of this is variable and dependent on the ability of the mite to survive in the environment. The geographic range of most zoonotic species is worldwide although some varieties may be rare or non-existent in some countries. No developmental change or propagation of the organism occurs during the transmission.