Tumors

Rats over 2 years of age have an 87 percent chance of developing tumors. Tumors may be external or internal. Leukemia (cancer involving the white blood cells) is also quite common. 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.

Rats have mammary tissue in locations beneath the skin other than along the underside of the belly, so 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 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 by the veterinarian and biopsied to determine its exact identity issue type, benign vs. malignant, etc) which, in turn, helps to determine the long-term outlook for the patient.

Tumors tend to grow continuously larger and may ulcerate and become infected if they reach very large size.  For this reason, it is always preferable to remove them when they are small. A qualified vet will also tell you if it is a tumor or an abscess. Abscesses can come up fast and also need immediate attention and care.

Benign tumors normally are not attached to any organs; they are most often just under the skin and don't grow very fast, so the tumor can be very large before removing it. BUT... it's best to have any tumor removed while it's small because it will require a smaller incision, less time under anesthesia, and the tumor itself will have had less time to sap its host
of precious nutrients and energy.

Malignant (cancerous) tumors normally grow very rapidly and most often are attached to an organ, bone, etc. The sooner you remove these types of tumors, the better, because they spread to other parts of the body very quickly.

So, every tumor situation is different. There is no set pattern, but a tumor that is attached to something (you can't get your fingers all the way around it) should be considered suspicious, as it may well be cancer.

Surgery is worth it - no matter what the price. osteosarcoma: a malignant (cancerous) bone tumor. Secondary growths
(metastases) are common. The symptoms are usually pain and swelling at the site of the tumor and there is often a history of preceding trauma, although it is doubtful whether this contributes to the cause.

Sometimes you will have to make your decision based on the age of your rat. If the rat is rather old or not in the best of shape it could be hard on it to have surgery. This you will have to discuss and decide with your vet.

Mycoplasmosis

Chronic murine pneumonia (CMP), or murine mycoplasmosis is the most significant and serious bacterial infection of rats. It is caused by the rather unusual bacterium, Mycoplasma Pulmonis. This organism is relatively difficult to isolate because it cannot be grown in the laboratory using ordinary culture methods. This makes diagnosis of CMP more difficult except for the fact that the disease is so very common and well recognized. For this reason, CMP is usually diagnosed by signs of illness, without attempts to isolate the causative bacterium.
 
Signs of CMP include sniffling, sneezing, squinting, red-brown tears, rough hair coat, and labored breathing and audible respiration. If the inner ear becomes involved, a severe, often incapacitating, head tilt usually develops. In colony situations, this disease can seriously affect the reproductive capacity of female rodents, resulting in infertility and reduced litter sizes. Because this disease tends to have a very chronic (long-lasting) course, afflicted individuals should receive antibiotic treatment as soon as the first signs are recognized. Antibiotics can be added to the 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. It is not necessary to separate the cage mates unless very ill.

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, Mycoplasma pulmonis, 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, and 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 Mycoplasma pulmonis organism without showing obvious signs of illness. This is especially true of newly acquired 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. Furthermore, 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 rat exhibiting respiratory signs (no matter how mild) should never be housed with or near a healthy pet rat.


Wounds

Wounds can occur for different reasons. It could be from a fight trying to introduce a new cage mate or from some unexpected accident.  The wounds could be on the face, back, and especially the genital areas in males. 

All rats have a pecking order to establish when a new rat arrives or even when one leaves. Occasionally serious damage can be done in minutes, more so with males who seem to want to attack another males genital parts to damage them. This can happen fast without so much as a squeak. They must be separated immediately but be careful you don't get bit yourself while trying to break up a fight. The wounds may become infected and could develop into abscesses.

A deep wound exposing muscle tissue needs suturing within 6 hours or the skin begins to die and treatment can become difficult. Shallow wounds must be attended to immediately and well cleaned out. Try not to panic and if you can carefully rinse the wounds with a clean cloth and warm water to make sure there is no debris in the wound. If you have it apply some iodine. Repeat this twice a day for 2 or 3 days until a scab forms and new skin develops. Equal amounts of hydrogen peroxide and water can be used to disinfect the wound. The peroxide will make it bubble and fizz and kill any bacteria in the wound. This will also prevent any abscesses from developing.

Abscesses close over very fast and must be drained if any form to prevent the infection from traveling into the blood stream. Your rat may require stitches so it is a good idea to see your vet for advise if any of these things happen. Keep in mind too that rats don't always show their pain and could be hurting a lot.


Heat Exhaustion

Rats have a limited ability to regulate body temperature with the primary thermoregulatory mechanism being tail vein dilation or constriction.  Predisposing factors to heat exhaustion are ambient temperatures above 28°C (85°F), high humidity (about 80%), poor ventilation and overcrowding. The rats salivate profusely to wet the hair coat for cooling, and water consumption increases. Death from heat exhaustion can be diagnosed from history of high temperature, lack of water (or empty water bottles), saliva soaked chins, hyperemia of lungs and mesenteric vessels, and hemorrhage in the thymus.


Urolithiasis

Uroliths occur both in the renal pelvis and the urinary bladder. Clinical signs may be absent but obstruction within the pelvis may cause hydronephrosis. Occlusion of the neck of the bladder will cause acute dilatation, uremia and death.


Ringtail

Insufficient environmental humidity (<20%), artificially increased temperature and drafts predispose this condition.  Annular constriction of the tail may be observed in weanling rats. Tails may slough. Diagnosis is made via clinical signs and history of low environmental humidity. There is no treatment for affected rats. Tail stumps usually heal without complication. Prevention of ringtail is accomplished by providing sufficient environmental humidity, reducing drafts, and maintaining room temperatures between 70° to 74°F.

Obesity

The tendency to become grossly overweight is often a problem of pet rats. Over indulgent pet owners and the use of diets rich in seeds and nuts are most often responsible for this condition.

Owners of pet rats must resist the temptation to feed "junk food," such as French fries, doughnuts, cookies and candy. Commercial diets specifically designed for rats (lab blocks) are always preferred and can be supplemented with whole-wheat bread, dry cereal, rice, pasta, fruits, vegetables and non-fat yogurt. Sugar is also bad for the rats teeth which leads us to teeth problems.
 

Ecto-parasites                             Ecto-parasites are the external parasites that infect all living creatures. Those that infect rats and mice most commonly include lice and mites. Sometimes, even though it is less common, we see infestations of fleas, flies, or ticks, but since the main ones to affect our pets are lice and mites, this article is only about those nasty critters. Once your pets are infected by external parasites, it can be difficult to treat them successfully, but it isn’t impossible. It is important to understand the life cycle of parasites in order to successfully treat your pets and keep those pesky bugs off of them. You may not even realize you have them and your rat starts to get stressed out. A vet can take a skin scraping but sometimes that can even be missed.

WHAT IS THE DIFFERENCE?

Taxonomy is the system to establish the hierarchy and classification of a given group of organisms. Mites and ticks are classified as arachnids; lice and fleas as insects. The lice are further classified into groups of blood sucking (Anoplura) and the non-blood sucking, biting lice (Mallophaga). Mites can cause mange in rodents just as they can in dogs. Lice, and some mites, can be seen without a microscope, but other mites need to be diagnosed by a vet using the skin scraping method and a microscope.
 

LICE ARE NICE

Keeping that little phrase in mind helps you to remember that lice are species specific. Infestation by lice is called pediculosis. Although rats and mice may both be infected with lice, those lice will not cross over from one species of animal to another. The lice of rats and mice are the same genus, but they are not the same species. Rat lice are Polyplax spinulosa and mouse lice are Polyplax serrata. If a mouse louse jumps onto a rat, it won’t take long for it to realize this rat is not its food source and will jump off to find a mouse, and vise versa. This also means you will not catch lice from your pets, and if you were infected with head
lice, you could not transfer them to your pets. Transmission from mouse to mouse or rat to rat is by direct contact and by fomites (objects). Both the mouse and rat lice are Anoplura (bloodsuckers), making it vital to your pet that you rid them of these pests as quickly as possible. These can cause anemia, but even more importantly for rats, they may transmit the blood parasite Hemobartonella muris, which is a rickettsial blood parasite similar to tick fever. They may also transmit Rickettsia typhi between rats. The Ricketsia typhi (not typhoid fever, but much like tick fever) may be passed to humans via rat fleas. These blood parasites can be more deadly to your pet than the lice.


MITES ARE NOT SO NICE

Mites are different than lice because they are not species specific. However, they are generally host specific, meaning they will usually attack only a certain species host, but they will sometimes cross over from one species to another. They will do this if their choice of host is not available. Infestation by mites is called acariasis. There are three categories of mites that infect mice and rats: fur mites, burrowing mites, and the most serious, bloodsucking mites.

MOUSE MITES

The three most common mites of mice are the fur mites, Myobia musculi, Myocoptes musculinus, and Radfordia affinis. These are not bloodsuckers and are often endemic to mice populations with no visible symptoms. Transmission between mice is by direct contact. These mites are not known to infect humans. These mites won’t cause harm to the mouse unless the infestation is heavy, or unless the mouse’s immune system is in some other way compromised. Symptoms you may see are patches of hair loss or skin lesions and ulcerations. That sounds as if it’s not so bad for mice, however, mice don’t get off so easily because rat mites may also attack them and cause severe problems.


RAT MITES

Rats may be infected with three types of mites. Radfordia ensifera, the fur mite of rats, is very similar to the fur mites of mice. They won’t cause problems unless the infestation is heavy or the rat is ill with another disease. Symptoms will be the same as those of mice, patches of hair loss with possible skin ulceration or lesions. These also are not known to infect humans.

Burrowing mites of rats are Notoedres muris. These are the ear mange mites. A skin scraping and a microscope are needed to see these mites. They attack the ear pinnae, tail, nose, and extremities. Lesions caused by this mite are reddened, crusty, itchy areas. These mites are spread by direct contact, so it is important that you keep wild mice and rats away from your pets. They may also infect other rodents, but are not known to infect humans.

The bloodsucking mites that infect rats and may also infect mice are Ornithonyssus bacoti. They are the most dangerous to your pets. This one is closely related to ticks and is especially common in tropical and subtropical areas. This is the one that will feed on rodent blood, then drop off to hide in wood products, cracks, and crevices in or near the cage.  O. bacoti will cause anemia, and, like the lice, it will also transmit rickettsial blood parasites. These may be seen without a microscope in the bedding or in and around the cage. This mite has a wide range of hosts that includes other rodents, and this one will attack humans. It is transmitted by direct contact with an infected animal, but also may arrive in contaminated bedding or wood products. Be careful not to buy open bags of bedding for this reason. Freezing your bedding before using may help eradicate these mites.


WHAT TO DO ABOUT EXTERNAL PARASITES

The life cycles of external parasites are fairly simple as compared to internal parasites. In order to rid your pets of external parasites you need to understand their life cycles. The adults are easily killed, but the eggs are left behind and will hatch after the first treatment. Mites are arachnids, so they have eight legs. In the mite, life cycle stage one is the egg, or nit, which hatches to stage two, the six-legged nymph (larvae). In stage three, they molt into the eight-legged nymph, and then into the final stage, the adult. It may take only a week for the mites to complete the life cycle. You have to hit them when in the nymph or adult stage of life. This is why it’s so important to disinfect your cage at least once a week, and, anything in it, as well as treat your pets more than one time to kill all the parasites. Disinfecting with bleach is the fastest and easiest way to kill any type of microorganisms in the cage, including bacteria, virus, or fungi. Throw away anything made of wood as the eggs or nits may be hidden in it, and wood is not easily disinfected. Insects such as lice are six legged creatures. Lice spend their entire
life cycle on the host in just three stages: egg, nymph, adult. Their life cycle may be as long as 14-21 days. They lay their sticky eggs (nits) on the hair shaft so you can actually see them. This is where the phrase “nit picking” comes from; you can actually pick them out of the fur yourself. The life cycle will determine how often you treat, but the type of treatment is also a factor. There are several ways to treat: oral, injectable, and topical. Each type of treatment has its advantages and disadvantages. It’s best to see your vet to get a diagnosis before initiating any treatment, although treatment for most of these creatures
is the same.

Ivermectin, dosed orally or as an injectable, is often used safely in rodents, but it is not the be-all, end-all answer to parasite problems. You must still disinfect the cage and everything in it, or you will never stop the problem. Be aware that Ivermectin is a drug, and while it is relatively safe, as with any drug, the possibility exists that it can have adverse reactions in certain individual pets sensitive or allergic to it. Topical treatments are sometimes safe, but they, too, can cause adverse reactions, and often are not very effective. There are powders, dips, foams, sprays, shampoos, insecticide strips, and guards on the market.
Many of these are not at all safe for rodents. The dog and cat flea powders are not safe, they are too powerful and can poison your rat or mouse. The insecticide strips and mite guards for birds also are not safe. Rodents may eat them through the bars of the cage, or the odor from them may expedite respiratory problems, forcing them to be placed so far away from the mice and rats that they are not effective.

Dips, foams, sprays, and shampoos with the active ingredient pyrethrins, at no higher than 0.15%, are fairly safe, and some of them are effective. Pyrethrins are a natural substance that is extracted from chrysanthemum flowers. However, just because it is a natural substance does not mean it cannot be toxic to rodents. If a product is safe for two-week-old kittens, it is probably safe for rodents, but you should check with your vet before using one.

If your rats or mice are miserable, itchy, and developing lesions, think about these nasty bugs, but have no fear because you can get rid of them!

Skin Problems in Rats
This article was found in the Rat Health Care Booklet updated regularly by Debbie "The Rat Lady" Ducommun. Order a copy by visiting the Rat Fan Club Website.

The most common skin problem in rats is caused by itching. The rat scratches herself which creates scabs, most often on the neck and shoulders, but sometimes also on the face, chin, or forehead. These scabs are sometimes mistaken for injuries caused by other rats. The causes of itching are fur mites, an allergy, excessive dietary protein (such as fish or cat food), eczema, and a fungus infection. A bacterial infection of the skin may also be involved, but it is rarely the primary cause.

Itching also seems to be related to stress, common for eczema. It's also possible that some rats infested with mites can keep them under control until their immune system is suppressed by stress. It's also possible that some rats with mites eventually develop an allergy to them. If you have more than one rat with scabs, it's probable that mites are the cause.

Regardless of the cause of the itching, when the rat scratches, her back toenails break the skin which can allow bacteria to enter. As the scratches heal, scabs form and can themselves itch which causes more scratching, resulting in a vicious cycle. The first step to breaking the itching cycle is to clip the rat's back toenails. Trimming off the sharp tips reduces the amount of damage the nails do to the skin. You might need to clip the nails as often as once or twice a week. You can also put a brick or concrete block in your rat's cage to help her wear down her toenails.

You might also apply a vitamin E cream or an antibiotic ointment to the scabs once or twice a day. Neosporin Plus contains a topical anesthetic which can be especially helpful. This treatment may be sufficient to clear up the scabs. If they recur, you need to look for another cause.


Clipping Toenails

Trimming your rat's toenails is really quite easy to do once both you and the rat are used to it. The best tools to use are human fingernail clippers. Hold your rat on your lap facing left if you're right-handed (reverse these directions if you're left-handed). Press him against your stomach with your left forearm to hold him still and hold his foot in your left hand. Pull his foot backward and clip the nails with your right hand. You only need to clip off the sharp tip on the end of the nail. If you cut too much off, the nail will bleed. It's a good idea to have some styptic powder or silver nitrate sticks on hand to stop any bleeding, but if you're careful, bleeding rarely occurs. You can eliminate the chance of accidentally cutting a toe by holding the foot so only the nails stick out. Your fingers protect the toes.

If your rat really struggles, only do a few nails at a time. Reward him with a treat afterward. You can also distract him during the procedure by giving him a treat in the beginning.


Parasite Treatment

If your rat is still itching, the next step should be to treat your rat for fur mites. Although you can have your vet do a skin scraping on your rat to test for mites, this often results in a false negative, so I recommend progressing right
to the treatment. The most effective treatment is with Ivermectin which paralyzes arthropods by over stimulating a neurotransmitter (GABA). Ivermectin is very safe for use in mammals because we use GABA only in the central nervous
system, which is relatively impenetrable by Ivermectin. In tests, calves showed signs of ivermectin toxicity only after receiving 20 times the normal dose. You can get a prescription for oral Ivermectin from your vet at a dose of 100-200 mcg/lb (some rats are sensitive to it by injection and can die), or you can buy a horse paste wormer containing Ivermectin at a feed store or through a mail order catalog (one brand is Zimecterin). Squeeze out all the paste into a small container such as a film canister and mix it thoroughly. Then take a tiny bit of the paste the size of an uncooked grain of white rice and put it on a tiny piece of bread for your rat to eat. This dose should be repeated in a week. If necessary, a third dose can be given after another week. You can also use dog or cat Ivermectin heart worm tablets, cutting them up into the proper dose. Improvement is usually seen within the first week. You should treat all of your rats, since if one rat has the mites they probably all do, even if they don't all have scabs. Be sure to continue the toenail trimming and ointment until the scabs are gone.

Warning: Although lots of rats have been successfully treated with the Ivermectin horse paste without problem, I know of one rat who became paralyzed the afternoon of her second dose and died 3 days later. Paralysis would be the result of an overdose. Perhaps the dose of paste she received was abnormally concentrated, as the owner did not mix up all the paste first before taking out doses. Or perhaps she was abnormally sensitive or developed an allergy to the paste. Or perhaps she had another problem. Use this method at your own risk.


Allergies

The most common foods for a rat to be allergic to are peanuts and dairy products, including yogurt drops. Eliminate these items for at least two weeks to see if this solves the problem. If the problem is another allergy, or eczema, treatment with a steroid will stop the itching. You can try a hydrocortisone cream (be sure to rub it into the skin well), or ask your vet for oral Predisone an antibiotic should be given with it because steroids depress the immune system). Sometimes the steroid treatment alone will clear up the problem, but if the itching returns after the treatment, you must try to identify what the rat
is allergic to.

It is rare for a rat to be allergic or sensitive to most litters, other than pine or cedar shavings, but you might want to try changing your rat's litter or bedding. Because I think a rat can develop an allergy to fur mites, I recommend treating for mites if you can't identify another allergen. If you know your rat's problem is an allergy, the next step is to test for further food allergies. A good testing diet is a mixture of cooked brown rice and raw millet, plus 1 teaspoon of Nutri-Cal per day. You can buy Nutri-Cal at any vet hospital. If you see an improvement in 7-10 days you then add foods one at a time to see if they cause itching. If you identify the food your rat is allergic to, then you can put her back on a normal diet, minus the offending food.

It is also possible for a rat to have eczema, which causes itching with no known cause. The treatment in this case is a topical steroid cream or shampoo, and you often have to continue the treatment for the rest of the rat's life.


Fungus

If your rat hasn't responded to the Ivermectin or the prednisone, the only thing left is to have your vet treat your rat for a fungal infection. Like the skin scraping for mites, biopsies or skin scrapings for fungus often yield a false negative. Therefore, you must try the treatment.

If the infection isn't too advanced, try an over-the-counter cream such as Lotrimin. Antifungal shampoos don't seem to work. For severe infections, you may need to use an oral fungicide such as Nizoral (ketoconazole). Treatment can take several weeks up to 3 months. Because fungus thrives on sugar, a rat with a fungal infection should receive only limited amount of sugar (including fruit) in his diet.


Dry Skin

While oily dandruff is normal in intact males, dry skin and dandruff can be symptom of a poor diet. If your rat is getting an adequate diet, try giving a supplement containing essential fatty acids. Dry dandruff can also occur in rats with hindquarter paralysis since they can't groom themselves normally. If the humidity in the air is too low, it usually affects the tail rather than the skin. This can prevent the dead skin cells on the tail from shedding properly resulting in patches of scaly skin and discoloration. The solution is to run a humidifier in the room.


Ringtail

Ringtail is a skin problem caused by dehydration that is occasionally seen in baby or hairless rats, and rarely in haired adults. Dehydration can occur if baby or hairless rats are kept on litter that is too absorbent (commonly corn cob litter) or in any rat if the water bottle malfunctions. In babies ringtail causes a constriction at the base of the tail. In adults it can cause a moist oozing sore at the base of the tail. The problem usually goes away when the rats are rehydrated, although if the problem is bad enough a baby may lose part of her tail.


Hair Loss

There are two main causes of bald spots in rats. The most common is barbering, a behavior where a rat obsessively grooms itself or another rat to the point of nibbling off the hair. The result is bald patches or areas where the hair looks like it's had a bad haircut. Usually there is no damage to the skin, but sometimes there can be scabs. The most common areas for self-barbering are the front legs and stomach. The most common areas for barbering another rat are on the head, face, neck, and shoulders. These bald spots are not usually symmetrical. Because this behavior doesn't usually cause any health problems,
there is no reason to separate a barber from her roommates, unless you are showing your rats. Another cause of bald spots is fungus (see above.)

Another type of hair loss is a general thinning of the hair. This can occur in a rat infested with lice or tropical rat mites. Although in these cases the rat usually doesn't self-inflict scabs, constant scratching can cause general hair loss, most commonly on the back. Rex rats may tend to have thinning hair as they grow older or if they are stressed due to disease.

In some other animals, such as dogs and cats, a hormone problem can cause hair thinning, although I haven't seen this in rats. This type of hair loss is usually seen on the flanks, hindquarters and sometimes the stomach and is usually symmetrical.

Lice and mites treatment

 Ivermectin paste (horseworm medicine)

See your vet for a proper diagnosis.

The best treatment for almost any kind of rat parasite (except for tapeworms) is Ivermectin. People have successfully treated their rats including nursing mothers with babies OVER two weeks of age for mites and lice using this drug. You will need to treat for the life cycle of the parasite (which in most cases is for 3 weeks)

The brand names Rotectin 1, Zimecterin, Equalvan, or Equimectrin. All of these contain 1.87% Ivermectin.

Administering Ivermectin is very simple. Using the tip of a toothpick, take a small amount, the size of an uncooked grain of white rice, out of the tube and smear it on the inside of the rat’s lip. She will lick it off. Repeat this once a week for three weeks.

The Ivermectin will be passed through the mothers milk to the babies which should take care of any parasite problems they may have, but you will need to watch the offspring for a while to be sure. They may need to be treated directly, but wait until they are five or six weeks old before doing so.

Pinworms

Pinworms were basically the only worm type parasite that is transferableacross species (your rats, your dog, your cat and you.
Humans are the only host to the pinworm Enterobius vermicularis. Humans do not become infected with rat pinworms which are of a different species known as Syphacia muris and the mouse pinworm Aspicularis tetraptera that rarely affects rats unless that pinworm specific to humans has managed somehow to get to your pet rat. If you were to ingest the rat species
of pinworms they would pass through you, not requiring treatment because they would not be able to reproduce.

We are only speaking of pinworms here. The previous recommendations about good hygiene, hand washing etc, should be a part of living and caring for any animal including humans.

From The American Academy of Family Physicians

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