EXTERNAL PARASITES
by Mette Lybeck Ruelokke (Mette the Vette)
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Running Lice
These are very often found on cavies. Three different species are known to live on cavies, but Gliricola porcelli is the most common. It is about one millimetre long and yellowish. It can be found on the skin and moves around by wriggling like a worm. They can be located anywhere on the body, but are often seen on the back and around the eyes. None of the species are blood suckers, but live from skin debns. Therefore itching is only mild to moderate, al though weak animals can be heavily infested which causes more severe itching and scratching with loss of coat density. Lice eggs are attached to the hairs and can occasionally be found on the coat behind the ears. As lice can only live on one animal species, there is no need to fear that they'll be transferred to other animals or humans. Running lice are a disqualification at cavy shows.
Static Lice
These are not lice at all, but tiny mites called Chirodiscoides cavia It's uncertain where they come from, but hay seems to be a major source. Some people even call them hay mites. They are very small and firmly attached to the coat, especially on the rump. They are grey and look dark on pale coloured pigs, whilst on darker colours they seem white. As they prefer to sit on the outer half of the hair, they never get in contact with the skin and never cause itching, even when found in huge numbers all over the body. Static lice are only found on cavies and don't necessitate disqualification at shows but are regarded as a fault if they affect the appearance of the pig.
Walking Dandruff
This is another mite called Cheyletiella parasitovorax. It can live on several other animal species such as dogs, cats and rabbits. The mites live mainly on the back of the cavy, but are so small that they can hardly be seen with the naked eye. When they are seen they look like tiny bits of dandruff crawling around, hence the name. Cheyletiella lives off the skin. To dissolve the skin they excrete digesting enzymes on the skin surface which digests a small part of it, hereafter the mite eats the dissolved skin. As one can imagine this activity causes skin irritation and subsequent scratching, which may cause hair loss, scabs and wounds. The mite cannot live on humans, but skin irritation can be seen if it gets in contact with the digestive enzymes especially where the skin is thin, e.g. on the neck. Many pet owners have experienced itching and red skin eruptions on the neck after being in contact with their cavies, and this is very often due to Cheyletiella mites. Symptoms may be confused with Sellnick.
Sellnick Mange
This is a very serious disease caused by the mite Trixacarus cavia, and is fully described in the March 1993 issue of CAVI ES. It causes severe itching and scratching as the mite lives within the skin. The cavy will emaciate and die if not treated.
Fleas
Frankly, I've never found fleas on a cavy, but as dog and cat fleas can live on rabbits and hedgehogs, they may be able to survive on cavies as well.
Treatment
Treatment involves the pigs as well as their surroundings. Lice, walking dandruff and fleas can be easily eradicated on the animal by using flea powder, shampoo or dip. Use a preparation which is suitable for cats. If non-toxic to cats it can be used safely on cavies as well. Ask your vet or the local chemist. All stock must be treated. In cases of lice, treatment must be repeated after one week, whilst treatment against fleas and walking dandruff must be carried out twice a week for two weeks. Static lice are more hardy and can be difficult to remove as they will stick to the coat, even when they are dead. But an antiparasitic dip or shampoo usually solves the problem. As statics come from the hay, it is a waste of time to try to eradicate them completeley, and as they don't bother the pigs I prefer to let them stay on breeding animals and treat only the pigs which I intend to show. I'm convinced that it is more gentle to the pigs than treating them with poison every now and then. Sellnick must be treated with Ivomec. There are different opinions whether Ivomec helps against static and running lice, but my experience is that it generally does. Hutches can be washed thoroughly with an antiparasitic dip in case of flea infestation. In case of other para sites, treatment of the surroundings are less important as they are unable to survive outside the cavy for more than a few hours.
How to avoid external parasites
If you are a fancier and your cavies are in contact with others, you can forget everything about avoiding external parasites. Infection can be introduced through shows, new stock, borrowing of breed ing boars etc. Only if have a very strict quarantine at home and treat all stock which is introduced to the shed or returns from a show, can you be almost sure not to introduce parasites. And even so, you may be unlucky. I've had lice as well as Sellnick a couple of times and I've never found out where the infection came from. The most important thing is to examine the pigs regularly and treat them as any parasites are found and before the cavies get too heavily infested.
Mette Lybek Ruelokke