Mange

Eradication programme

Control programme

 

Causal agent

Sarcoptes scabiei  var. suis

Age group

Affects all age groups, although sows and growing pigs most often exhibit the characteristic clinical signs

World wide distribution with some 70% or more herds infected

Life cycle

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.

The eggs hatch out in about 5 days

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

Clinical signs

Scratching

Piglets may be uncomfortable and have intermittent body scratching

A few weeks later the weaned and growing pig demonstrate persistent itching and rubbing

Ear wax increases, sometimes forming plaques

Chronic lesions may occur with thickened skin, hair loss and abrasions, especially behind the ear and tail head.

Mange mite microscopic view

Itchy pig

Examination of the ear reveals lots of wax

Mange face 4

SM5

Areas of hair rubbed off around the face

Chronically infested thickened skin


 

Infectivity

The disease is spread through pig to pig contact and through pigs coming into contact with infested buildings

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.

The pig mange mite does not live in or on other hosts

Economic Importance

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

Diagnosis

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

An ELISA test is being developed

Examination of the skin of finishing pigs in the slaughterhouse

The problem may be more apparent in the cooler months

Skin score 1

Skin score 2

Skin  score 3

Treatment

Control

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)

Eradication

Where possible mange should be eradicated from units.  Need to purchase animals from mange free farms (Link to eradication)

Common differentials

Sows may scratch when exposed to cigarette smoke or perfumes including after shaves

Forage mites in straw/bedding

Other causes of skin hypersensitivity / allergy

Skin may be thickened with parakeratosis or dry and scaly with deficiencies of essential fatty acids

Zoonotic Implications

There are no significant zoonotic implications