Porcine sarcoptic mange
This disease is also known as pig mange or scabies. It is widespread in Australia but can be treated and controlled. Porcine sarcoptic mange substantially reduces the performance of infected pigs. Growth rates can be reduced by up to 12%. Feed conversion is reduced and mange can predispose the pig to other skin disorders. The disease can be treated and controlled, and herds can be free of mange at establishment or through eradication.
|Cause and signs||
The disease is caused by the mite Sarcoptic scabies var suis, which burrows under the skin. The female mite lays eggs as she burrows under the skin. The eggs hatch and mature mites develop in 10 to 15 days. Adult mites and eggs can survive for a short period (a few days) outside the pig and contaminate the pig's environment. Mange is usually more severe in the cooler months and the mite spreads rapidly with close contact. Mange-infested sows infect their suckling piglets in the farrowing house.
Skin lesions usually start around the head but can progressively spread over the whole body. The mite causes intense irritation with results in itching, rubbing and an allergic response in young pigs. The early lesions appear as small red patches on the skin. Chronic mange can develop, with rubbing and thickening of the skin and crusts in the ears; it is most commonly seen in boars and sows.
A significant feature of this disease is that pork producers are often unaware of the severity of the problem.
It has been shown that sarcoptic mange reduces the growth rate and feed efficiency of affected pigs, this is of special significance in weaner and grower pigs. The damage to the skin from rubbing and scratching can predispose the pig to other skin diseases, notably bacterial infections.
Chronic mange in breeding pigs can affect the body condition due to continual skin irritation, which may adversely affect the reproductive efficiency of breeders.
The clinical signs of the disease are evidence of mange infestation. Sarcoptic mange 'scoring' can be conducted on pigs after they have been slaughtered (minor dermatitis may be from other causes besides mange). This is carried out routinely on marketed grower pigs as part of the Pig Health Monitoring Scheme. The mite can be shown microscopically from deep skin scrapings and crust material from the ear canal of affected live animals. A number of skin scrapings may be needed to find the mange mite.
|Treatment and control||
A range of chemicals are available for the treatment and control of sarcoptic mange. Whichever chemical is used, it is important to follow the manufacturer's directions for use and the withholding period instructions.
When spray chemicals are used it is necessary to ensure the pig's body is thoroughly wet, with particular attention to the inside of the ears and legs, around the head, under the belly and areas covered by crusts. Small pigs, for example at weaning, may be dipped in a drum containing the chemical.
In an infested herd, the whole herd should be sprayed twice initially, 7-10 days apart. This is necessary to kill the mites that have hatched since the first treatment. Eggs are not killed by the chemical. Further sprayings may be required in severely affected herds. Chronically affected animals may need to be culled as they do not always respond to treatment.
If a pour-on product is used, it is applied to the pigs backline. However, a small part of the measured dose must be applied in the ears and onto body crusts.
Injectable treatments are now registered for treating sarcoptic mange in pigs. They are also effective against internal parasites such as worms.
To control sarcoptic mange a treatment program needs to be followed in a piggery:
With chemicals it is possible to control porcine sarcoptic mange and prevent reduced performance in the pig herd. It is also possible with a planned treatment program to eradicate the mange mite from the herd or establish a mange-free herd and maintain it as such. For the most effective program, consult your veterinarian.
View a list of chemicals that may be used to treat and control sarcoptic mange.