American Fancy Rat & Mouse Association

This article is from the WSSF 2009 AFRMA Rat & Mouse Tales news-magazine.


Rats & Lyme Disease; Draining Tumors

By Carmen Jane Booth, D.V.M., Ph.D.

Editor, Karen Robbins
Q My mom has been corresponding with a new member in Maine the last few months and this person had a question we thought would be good for the newsletter (my mom told her to see a vet about this question initially). Laura (new member) lives in a rural area (woods around her) and puts her rats in an outside cage during the summer days. Well, when she brought the rats in, apparently they brought a tick with them and Laura was wondering if a rat can get lyme disease by eating a tick. Her one rat wasn’t doing well.

Also, another question Laura had was “can you drain a tumor.” She has a rat with a tumor and someone told her it could be drained. Are there any tumors that are fluid and not tissue?

Answers by Carmen Jane Booth, D.V.M., Ph.D.

Re: Rats and Sunlight

Rats are nocturnal animals and as a species tend to avoid light. Their eyes are very sensitive to light and retinal degeneration and blindness can occur with prolonged exposure to high intensity light. Albino rats are even more sensitive and marked retinal degeneration can occur subsequent to light intensities that would be relatively harmless to pigmented rats. Retinal changes are reported to occur with a light intensity of 130 lux or higher at the cage level¹. The amount of lux on a sunny day is ~4000 lux and for an office building it is ~ 150 lux².


  1. Adapted from Pathology of the Rodents and Rabbits, (2001), Percy and Barthold.

Re: Rats and Lyme Disease

Lyme disease is caused by the spirochete bacteria, Borrelia burgdorferi, which lives in the mid-gut of infected black-legged tick, Ixodes scapularis. The natural host is believed to be the white-footed mouse. Ticks become infected after feeding on an infected. animal and then transmit bacteria to other warm- blooded animals during their 3–8 days of attachment and feeding. In humans, dogs, and many other animals, infection with Borrelia burgdorferi results in the pathology of Lyme disease. The most common symptoms in mice are arthritis and cardiac inflammation. I. scapularis is also a vector of other tick-born diseases (anaplasmosis, and babesiosis). Rats can become infected with Borrelia burgdorferi if a tick attaches for a blood meal. However, there are no reports of infection in rodents through eating infected ticks. The low pH in the stomach would likely kill the bacteria. However, there are no studies on this. The good news is that Lyme disease can be treated with antibiotics.


  1. Narasimhan S, Deponte K, Marcantonio N, Liang X, Royce TE, Nelson KF, Booth CJ, Koski B, Anderson JF, Kantor F, Fikrig E. Immunity against Ixodes scapularis salivary proteins expressed within 24 hours of attachment thwarts tick feeding and impairs Borrelia transmission. PLoS ONE. 2007 May 16;2(5):e451

Re: Draining Tumors

All tumors are composed of cells. Benign tumors tend to be more organized and resemble the normal tissue that they are derived from. Malignant tumors by definition are invasive and tend to be more disorganized. Some types of tumors secrete copious amounts of fluid or other glandular material. Some tumors are composed of single or multiple fluid-filled cystic spaces where the tumor cells line the cavity. Theoretically the fluid could be removed, but the fluid would recur since the tumor cells would still be present. In human medicine, in cases of inoperable terminal cancer where there is massive fluid accumulation in the thorax or abdomen, clinicians will do a pleural or abdominal tap to reduce the amount of fluid to provide palliative (alleviate pain and suffering) care until the patient dies. *

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Updated April 3, 2014