• Obesity


• Overgrown Incisors


• Tumors


• Chronic Murine Pneumonia (Murine Mycoplasmosis)


• Tyzzer's Disease


• Miscellaneous Bacterial Infections


• Viral Infections


• Parasitic Infections


• Miscellaneous Conditions


• Human Allergies to Pet Mice and Rats

Mice frequently develop tumors representing a wide variety of tissue types. The tumors may be external or internal. Leukemia (cancer involving the white blood cells) is quite common in mice as well.

Both male and female rats develop benign mammary (breast) tumors, and females develop benign tumors of the uterine and vaginal linings. These are the most common tumors of pet rats. Because rats have mammary tissue in locations beneath the skin other than along the underside of the belly, it is not uncommon to find lumps and bumps representing mammary tumors over the shoulders, flanks and base of the tail. These tumors are relatively easy to surgically remove under general anesthesia.

Owners of pet mice and rats should seek veterinary attention at once after discovering a lump, bump, or unusual mass protruding from a body opening. The mass can be surgically removed and biopsied to determine its identity (tissue type, benign vs. malignant, etc.) which, in turn, helps determine the long-term outlook for the patient. Tumors tend to grow continuously larger and may ulcerate and become infected if they reach a large size. For this reason, it is always preferable to remove them when small.
[Top of Page]

Signs of CMP include sniffling, sneezing, squinting, red-brown tears, rough haircoat, and labored and audible respiration. If the inner ear becomes involved, a severe, often incapacitating, head tilt usually develops. In colony situations, this disease can affect the reproductive capacity of females, causing infertility and reduced litter sizes.

Because this disease tends to have a chronic (long-lasting) course, afflicted individuals should receive antibiotic treatment as soon as the first sighs are seen. Antibiotics can be added to drinking water for long periods. Individuals exhibiting serious, life-threatening signs must be treated aggressively with injectable antibiotics if there is any hope of helping them. Frequently, other harmful bacteria complicate CMP. This often necessitates use of multiple antibiotics.

Elimination of the Mycoplasma pulmonis organism from infected individuals is regarded by most experts as a practical impossibility. However, early treatment reduces the severity of the disease in affected rodents.

The outcome of treatment is always unpredictable because there are so many factors that can have an influence on it: individual susceptibility and resistance to the causative agent; age, physical condition and nutritional status of the individual; and the presence of complicating factors (other bacterial and/or viral infections, high levels of ammonia within the enclosure, etc.).

The bacterium responsible for CMP is highly contagious. It may be transmitted between mother and offspring in the womb during embryonic life and by direct contact after birth. Transmission among infected and uninfected older rodents results from exchange of respiratory aerosols and sexual activity.

Rabbits, guinea pigs, other rodents may carry the causative agent but do not manifest signs of disease. Caution must, therefore, be exercised when allowing contact between murine rodents and these potential "carriers". Mice and rats, too may carry the organism without showing obvious signs of illness. This is especially true of newly acquired mice and rats. This fact underscores the importance of restricting contact between mice and rats of unknown health status and those whose health status has been proven by remaining disease-free for relatively long periods. Further, all newly acquired rats and mice should be quarantined (strictly confined from other pet rodents) for at least 4-6 weeks before contact with them is permitted. Any mouse or rat exhibiting respiratory signs (no matter how mild) should never be housed with or near a healthy pet mouse or rat.

The severity of CMP can be increased substantially by any agent that harms the respiratory linings. Other bacterial and/or viral infections and exposure to the irritation chemical effects of ammonia from urine within poorly maintained enclosures can complicate CMP, making the disease far more deadly.
[Top of Page]

Signs of infection are often unapparent but may include lethargy, rough haircoat and sudden death. Another form of the disease results in chronic wasting and death. Diarrhea may or may not be noted.

The disease is difficult to diagnose in individuals before death. It is considerably easier to diagnose during an autopsy. Sacrificing 1-2 individuals of a large group and performing autopsies on them are recommended to successfully treat and perhaps spare the majority of the group. Specific antibiotics must be used early in the course of the disease. Some evidence indicates that this disease can be transmitted to pregnant women. Therefore, all necessary precautions should be taken to prevent this possibility.
[Top of Page]

Wounds (from fighting and other forms of trauma) are commonly infected with bacteria that already exist within the living quarters. Abscesses commonly result from wounds when they have gone unnoticed and untreated. Successful treatment of certain wounds (especially long and deep cuts) and abscesses required veterinary intervention. Abscesses usually must be surgically opened because the relatively sold nature of rodent pus precludes lancing and draining them.
[Top of Page]

Sendai Virus Infection: In many mouse colonies, Sendai virus infection is the most significant and serious respiratory disease. It often complicates chronic murine pneumonia, increasing the death rate. This virus is very unlikely to infect pet mice unless they were acquired from a colony with this infection already established within its members.

Nursing mice and those being weaned are the most commonly and seriously infected. Adult mice may become infected but rarely show signs. Signs of the infection include labored breathing, rough haircoat, weight loss and death. Bacterial infections complicate the picture and usually increase the death rate.

There is no specific treatment for this disease. A commercial vaccine is available but it is only of prractical use with large colonies of susceptible mice.

Sialodacryoadenitis: Sialodacryoadenitis is a highly contagious viral disease of rats and recently weaned mice. Initial signs include squinting, blinking and rubbing of the eyes. Later, sneezing and swelling in the neck region are noted. As the disease progresses, swellings below or around one or both eyes, bulging of the eyes, red-brown tears, and self-trauma to the eyes are noted. Respiratory signs also may occur.

There is no specific treatment for this viral disease. This virus us very unlikely to infect pets rats and mice unless they were acquired from a colony with this infection already established within its members.

Mousepox (Ectromelia): Mousepox is a highly contagious viral disease of mice that was only recently recognized in the US. The mouse is the only natural host of the virus.

The acute (sudden onset) form of the disease affects the entire body. Clinical signs include lethargy, hunched posture, rough haircoat, diarrhea, inflammation of the eye membranes, swelling of the face and legs, and death. Another form of the disease results in a body-wide skin rash. Soon the skin becomes swollen and ulcerated. Because of the resulting pain and discomfort, afflicted mice begin to chew on themselves. This behavior often becomes obsessive, resulting in amputation of appendages.

There is no specific treatment for this viral disease. This virus if very unlikely to infect pet mice unless they were acquired from a colony with this infection already established within its members.
[Top of Page]

A veterinarian should be consulted if mite infestation is suspected. Microscopic examination of a scraping of the skin is necessary to confirm the diagnosis. Treatment may include an injectable drug (ivermectin) that has proven very effective in treating mange in a wide range of animals.

Lice may also parasitize the haircoats of pet mice and rats. They are flattened, wingless insects that suck tissue fluids and blood from the skin of the host. Lice are larger than mites and can usually be seen without a magnifying lens. Lice are most often transmitted by direct contact with infested bedding and between infested and uninfected individuals.

The lice of mice and rats are found most often on the neck and body. They suck blood and can, therefore, cause anemia (sometimes death) and transmit blood-borne diseases to rodents. Louse infestations may also cause scratching, hair loss and skin wounds. A veterinarian should be consulted if louse infestation is suspected.

Intestinal Parasite Problems: Tapeworms and pinworms are the most common intestinal parasites of pet mice and rats. They often go undetected unless present in large numbers. Signs of infection may include weight loss, inactivity, inappetence, constipation, excessive licking and chewing of the rectal area and base of the tail.

Stoop examination should be conducted by a veterinarian to diagnose these parasitisms. Appropriate treatment will be recommended by the veterinarian. Pinworms are especially difficult (sometimes impossible) to eliminate from mice and rats.

Transmission of these parasites to people is possible but unlikely. Therefore, great care should be taken when handling and disposing of rodent feces. Further, contact between pet mice and rats, their feces, and young children should be limited and always supervised by adults.
[Top of Page]

Cannibalism: Female rats (mice mush less often) disturbed shortly after giving birth to a litter may destroy the pups and eat them. Male rats also engage in the same behavior. For theses reasons, it is important not to disturb female rodents for 2-3 days after they have given birth. Male rats must be removed from enclosures just before females deliver their litters.

Skin Disease: There are many causes of skin disease in pet mice and rats. Numerous infectious agents, including bacteria, viruses, fungi and parasites, may be involved. Cage-mates may be responsible for hair loss and/or wounds to the skin. Allergies are also a suspected cause of skin disease of pet rodents. In these cases, it is wise to replace the bedding being used with plain white, unscented paper toweling.

A Veterinarian should be consulted When pet mice and rats exhibit signs of skin disease. The doctor will need to conduct diagnostic tests. Appropriate treatment is then based on the results of these tests.
[Top of Page]

The offending allergens may be rodent skin dander and hair, or the proteins in aerosolized rodent urine. Signs among allergic people may include runny eyes and nose, sneezing, congestion, coughing. Shortness of breath, and anaphylactic shock. Some people develop a rash and/or hives, especially in areas contacted by the claws or hair of a rodent.

Allergy to a pet mouse or rat must be considered if someone in a household develops any of these signs. The medical doctor consulted about the problem must be made aware of the existence of a pet rodent with the home.
[Top of Page]





Copyright © 1996-2002 Animal Health Center. All Rights Reserved.

Webmaster @caringtogether.com
Info @caringtogether.com