Mange
Causal agent |
Sarcoptes
scabiei var. suis |
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Age group |
Affects all age groups, although sows and
growing pigs most often exhibit the characteristic clinical signs |
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World wide distribution with some 70% or
more herds infected |
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Life cycle |
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Eggs are laid in the skin of the pig. The female lays about 1 to 3 eggs a day and
the adult female lives for about a month, therefore some 30 to 40 eggs are
laid per female. Most of the eggs are
laid in the soft tissues of the inside of the ear. There may be as many as
18,000 mites per gram of ear skin. |
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The eggs hatch out in about 5 days |
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The larvae molt to the nymph, which molt
to the adult in 10 to 15 days. The
life cycle remains on the pig at all times |
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Clinical signs |
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Scratching
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Piglets may be uncomfortable and have
intermittent body scratching |
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A few weeks later the weaned and growing
pig demonstrate persistent itching and rubbing |
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Ear wax increases, sometimes forming
plaques |
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Chronic lesions may occur with thickened
skin, hair loss and abrasions, especially behind the ear and tail head. |
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Mange mite microscopic view |
Itchy pig |
Examination of the ear reveals lots of wax |
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Areas of hair rubbed off around the face |
Chronically infested
thickened skin |
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Infectivity
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The disease is spread through pig to pig
contact and through pigs coming into contact with infested buildings |
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The mite is able to survive 21 days off
the host in ideal situations. The warmer and drier the conditions the
shorter the survival time. |
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The pig mange mite does not live in or on
other hosts |
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Economic Importance
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Economic importance varies depending on
infestation, but a loss of 10% growth rates is not unusual in moderate to
severe infestations. Mange will weaken
the pig and is an added stress. Note
the constant rubbing causes damage to buildings |
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Diagnosis
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Examination of ear wax and scrapes from
the skin of the inner ear. However, individuals may be necessary to
examine to find evidence of the mite to confirm the diagnosis. Absence is very difficult to ascertain |
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An ELISA test is being developed |
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Examination of the skin of finishing pigs
in the slaughterhouse |
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The problem may be more apparent in the
cooler months |
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Skin score 1 |
Skin score 2 |
Skin score 3 |
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Treatment
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Control
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Use avermectins via various routes. Note failure
to adequately treat large boars is a common reason for failure to provide adequate control (Link to control) |
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Eradication |
Where possible mange should be eradicated
from units. Need to purchase animals
from mange free farms (Link
to eradication) |
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Common differentials
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Sows may scratch when exposed to cigarette
smoke or perfumes including after shaves |
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Forage mites in straw/bedding |
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Other causes of skin hypersensitivity /
allergy |
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Skin may be thickened with parakeratosis
or dry and scaly with deficiencies of essential fatty acids |
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Zoonotic Implications |
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There are no significant zoonotic
implications |
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