Treating Lice and Mites in Pet Rats

Christy's picture

Lice and Mites in Pet Rats

This information should not be taken as veterinary advice. All information here is based on personal experience. It is advised that you check with a rat friendly vet before beginning any treatment.

Lice and/or mites are something that rat owners must deal with frequently. This does not mean you are not properly caring for your furry friends, it's just something that happens just as dogs get fleas.

Often your rats will come in contact with lice or mites from the bedding or litter you buy at the store. Bags of bedding and litter often sit in warehouses after production and this is where lice and mites yield their presence. Lice and mites can also be transferred from other rats that you may bring into your home.

A common symptom of lice or mites are scabs appearing on the rat, particularly on the shoulder and neck areas. Often the scabs will be the first indication of a problem as mites are not visible to the human eye and lice are hard to see unless you are looking for them.

If you suspect that your rats have lice or mites you should get them to a vet as soon as possible to be treated. Most vets will do a skin scraping to verify that there are parasites present, however these tests often result in a false negative.

Your vet will most likely prescribe ivermectin (or ivermec) to rid of the parasites. Do not let the ivermectin be injected. This can often lead to an overdose which can cause permanent nerve damage or kill your rat. All ivermectin should be dosed topically or orally. Injectable ivermectin may be used topically by placing the correct dosage on neck of the rat and allowing the rat to groom itself, hereby ingesting the medication.

Dosages per weight for injectable ivermectin 1mg/ml dilution used topically are as follows (as a precautionary measure, PLEASE double check these dosages with your vet before using):

50g - 0.02cc
100g - 0.04cc
150g - 0.06cc
200g - 0.08cc
250g - 0.1cc
300g - 0.12cc
350g - 0.14cc
400g - 0.16cc
500g - 0.2cc

Do not dose babies or pregnant/nursing mom's without first consenting with a vet.

Dosages should be given once every 10 - 14 days for a total of three treatments. Injectable ivermectin should be kept out of direct light while in storage.

If a vet trip is not possible or if your vet refuses to treat without injecting, another solution is available. However you must use great caution in using this method to ensure the dosage is given properly. Ivermec can be purchased in the form of an oral paste used for de-worming horses. A common name is Zimecterin.

To dose with this paste you must empty the entire contents of the tube into a plastic, coverable container. You will not use the entire amount, but it must all be dispensed at once. Once in the container mix the paste up very, very, very thoroughly. And then mix it again. It is very important to mix the entire tube in order to make sure the medication is not concentrated in one area, thus overdosing your rat. A horse gets the entire contents of the tube, therefore it doesn't matter if it is mixed. However a rat is getting a tiny portion so it must be mixed evenly before dosing.

Once you are certain the paste is mixed completely, you will dose each rat in your colony with a bit of paste the size of an uncooked grain of rice. Some rats will take the paste directly from the end of a toothpick, others will need it hidden in food as a treat. Dose a total of three times - one dose every 7 days and then stop treatment.

Do not dose babies or pregnant/nursing mom's without first consenting with a vet.

You will need to treat all rats in your colony, even if others are not showing symptoms. Some rats itch and scab while others do not, but this does not mean that some should go untreated. In addition to treating the rats you will need to thoroughly scrub the cage (1 part bleach to 10 parts water is recommended), throw out all litter, wash any cloth material in the cage and throw out any wooden toys that are not sealed. If you have unused bedding or litter you should freeze the bag up to 24 hours before using to kill off any lice or mites that may be living in the bag.

You should notice less scratching and fewer scabs within 2 - 3 days of the first treatment. Often a bath will help to sooth the skin of the rat while waiting for the medication to kick in. Trimming the nails of the itchy rat may also help the scabs to heal faster.

This information should not be taken as veterinary advice. All information here is based on personal experience. It is advised that you check with a rat friendly vet before beginning any treatment.


Sam's picture

We've recently had a mite

We've recently had a mite outbreak, and I'm kicking myself.
I put down the bald patches on one rat to heavy barbering from another newly introduced, and very dominant, female.

None of the others showed any signs of mites, so I assumed this is what it was.

However, when one developed an ear infection (thankfully clearing up now) and i saw signs on her I whisked them to the vet and got treatment.

I now realise how miserable they all were - my rats are all frolicking and playing again, they're like kittens, and before they were GRUMPY!

Mites can creep up on you and show no signs - if your rats are generally a bit bad tempered, get them to the vet for mite treatement is my advice!

Nicole's picture

rats with mites


I hope you get this since I see you posted in 09...

Do you remember what your vet told you to do?

Mine said get a fine toothed comb and kitten shampoo with less than .15 pyrethrins.  I have 9 rats and they all hate baths, not to mention pyrethrins are poisonous.  We were treating an adopted girl with a myco infection + lice and she died because the pyrethrins irritated her infection so badly (we had leftover from the first infection and started treating her again but she died anyway!)  

Do you have any suggestions?  Ideas?  I would use ivermectin but they are all different weights and I don't have any kind of conversion formula... when people say to use a drop the size of an uncooked grain of rice, I can only assume you can't use that for all of them.

I would go back to the vet, but it is expensive and I'm afraid to get the same answer as before.  Also, I don't want to admit that I failed with our girl-I feel bad enough already that she died.

If you get this and can help, that would make for some very happy rats =)

Thank you for your time,


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