- Adult females are large mites at 750μm in length
- Males identified by copulatory suckers and paired posterior lobes
- Males attach to deutonymphs (second moult after larval stage) in a process called copula
- Males remain in copula until females moult for the last time
- Copulation occurs
- Life cycle last 14 days
- Transmitted by direct contact between sheep
- Indirect transmission can also occur
Pathogenesis
- Economically important ectoparasite of sheep
- Causes sheep scab
- Wool loss, restlessness, biting, scratching of infested area and decreased productivity through decreased weight gain
- Usually seen in late autumn and early winter (although may also occur in late summer)
- Population numbers decline after shearing due to a change in the micro-climate, then build up again as the fleece grows
- Notifiable in UK
- Mites found under scabs and in skin folds
- Lesions most common on flanks, neck, back and shoulders
- Causes pruritic condition of cattle
- Active in keratin layer
- Mouthparts abrade the skin
- Antigenic material in mite faeces can lead to hypersensitivity reactions