Search
. Advanced search
Product Search
Information on veterinary pharmaceutical products:
For more search options

Mange Mites

Sarcoptes suis

The stationary ectoparasites of the pig with a worldwide incidence are mange mites (Sarcoptes scabiei var. suis) and hog lice (Haematopinus suis). Occasionally infestation with the mite Demodex suis is also reported; in tropical countries with extensive management systems tick infestation may also reach significant levels.

The introduction of mange mites and lice into a clean herd usually occurs as a result of purchasing infested stock. Transmission within the herd takes place by contact from pig to pig.

The service boar plays an important role in the transmission chain. Both mange and louse infestation can be described as typical factorial diseases which are favoured by malnutrition, inadequate management and high performance such as pregnancy and lactation. Under modern management systems with a high livestock density, ectoparasites can cause substantial economic losses and jeopardise the profitability of pig rearing and breeding.

Biology

Mange in pigs is caused by sarcoptic mites (Sarcoptes scabiei var. suis). The mites, which are up to 0.5 mm long, are characterised by their almost circular body shape. Viewed from above, only the anterior 2 pairs of legs are visible which end in small suckers on long, unsegmented stalks.

The development of the adults proceeds from the egg via 1 larval stage and 2 nymphal stages and takes 21 days in the female and 14 days in the male. The females burrow tunnels in the upper skin layers, into which the eggs are deposited and where the larvae and the 1st nymphal stage also live.

The 2nd nymphal stage and the males usually live on the surface of the skin. Separated from the pig, mites can survive for 8 days and, according to recent studies, at temperatures of 5-10°C they may even be able to survive for several weeks.

Clinical Findings

Ear Mange

Clinical lesions usually start at the head (inside the ears, base of the ears, around the eyes, bridge of the nose) then spread to the back and sides of the body. The secretions from the salivary glands of the mites dissolve the upper skin layers.

The tunnels burrowed by the mites are lined with horny substances from the stratum germinativum, which are again attacked by the mites and then reformed by the body. Papular skin lesions and crusts develop and eventually, as a result of the hyperkeratosis, the skin is thrown into folds and fissured scabs several centimetres thick appear.

Intense pruritus leads to chafe wounds and lacerations which give rise to secondary bacterial infections of the skin.

Economic losses

The continuous itching irritates the animals and interferes with feeding, feed conversion and weight gains. Skin lesions caused by mange mites appear as clearly visible faults in the leather after tanning. In rearing establishments piglets from clean sows achieved 22 % higher weight gains from birth to weaning; stores treated against mange showed 14 % higher weight gains than control animals over a 16-week period, and in clean fattening pigs the weight gains were 4-6 % and 12 % higher.

It has been confirmed in recent years that even subclinical mange reduces feed conversion appreciably and prolongs the finishing period.

Principles of Mange Control

  • Not only the affected animals, but the entire herd must be treated.
  • As mange mites can also survive away from the pig, reinfection can only be prevented if the premises are thoroughly cleaned and treated with an caricidal solution
  • Areas of retreat for the mange mites are the inner ducts of the ear, where they often survive a mange treatment in skin scabs and in the cerumen earwax).
  • The eggs of mange mites are not destroyed by any acaricide. Therefore, if products with a short period of action are used a repeat treatment is necessary after 14 days in accordance with the biological cycle of the parasites.
  • To rid breeding herds of mange mites, the chains of infection must be interrupted; the service boars must be treated at least every six months, breeding sows on transfer to the farrowing house and stores at the time of selection.
  • Before joining a clean herd, newly purchased stock should receive prophylactic treatment.

Copyright © Bayer HealthCare AG