Post by Admin on Aug 15, 2008 14:35:12 GMT 10
The following has been used by permission. Please remember that Debbie is in America so some things may be different here, such as medications.
Respiratory & Heart Disease in Rats
by Debbie "The Rat Lady" Ducommun
This article is from her booklet Rat Health Care. Which can be purchase through The Dapper Rat
Respiratory disease is the most common health problem and cause of death in pet rats. The most common organism causing this disease in rats is the bacteria Mycoplasma pulmonis. Mycoplasma is very contagious and incurable. There are different strains of mycoplasma that are more or less virulent and so can cause more or less severe disease. Different rats also seem to have differing resistance to the disease. The severity of a mycoplasma infection can be increased by cigarette smoke, ammonia from a dirty cage, vitamin A or E deficiency, pine or cedar shavings, and a concurrent respiratory infection of another type, as well as genetic susceptibility.
A mycoplasma infection makes a rat more susceptible to secondary respiratory bacterial infections as well. The respiratory symptoms that are common in rats can be caused either by the primary mycoplasma infection, secondary infections, or both as well as heart disease. In young rats, symptoms are more likely to be caused by secondary infection, so they need to be treated accordingly.
Most respiratory symptoms in rats are caused by respiratory infections or heart disease. It is very rare to find a lung tumor in rats. Since 1985 I have done gross autopsies on more than 200 rats and I have only seen one possible lung tumor.
Mycoplasma typically causes a “blister” effect on the surface of the lungs, lung abscesses, and emphysema. It also causes inflammation and infection of the uterus. There is a special blood test, called a serology ELISA test, that can detect mycoplasma. (However, the disease is so common, you should just assume your rats have it.)
Common Symptoms
Often, the first symptoms of respiratory disease seen in a rat, especially in young rats, will be caused by a secondary infection. For any symptoms, I recommend first trying an antibiotic that works well for secondary infections. Secondary infections can become more serious more quickly than mycoplasma, so treat for them first. If you treat for mycoplasma first, and it turns out to be a secondary infection, the rat may get so sick he dies before you can try the treatment for secondary infections. Usually a mycoplasma infection is chronic, that is, it starts out slowly with mild symptoms that gradually get worse over a period of weeks or months, so quick treatment is not as critical as it is for a secondary infection.
In my experience, amoxicillin tends to work best for secondary infections. If the symptoms do not improve within 3 days of treatment, then you should switch to another antibiotic, probably one that is good for mycoplasma. The first symptom of mycoplasmosis is usually frequent sneezing (healthy rats rarely sneeze), but then this often goes away and there can be a long period of time without symptoms. However, mycoplasma can cause lung damage even if there haven’t been any overt symptoms.
A respiratory infection, whether caused by mycoplasma or a secondary infection or both, can begin in the upper respiratory passages and then progress into the lungs causing pneumonia, or it cause pneumonia right away. It can invade the inner ear and affect balance, causing a head tilt which can progress to rolling behavior. An infection can also cause damage to the nasal cavity and nasal bones resulting in fatal bleeding. Any noise made while breathing can be a symptom of an infection and/or heart disease.
Because mycoplasma is a chronic, progressive, incurable disease, older rats tend to have more problem with respiratory problems, but even symptoms in older rats can be caused by a secondary infection, and not mycoplasma itself. If a rat’s immunity is weakened due to stress, old age, or another disease, they can be more susceptible to secondary infections.
Without treatment, mycoplasma and secondary infections will usually cause major lung damage and in most cases the rat will eventually exhibit labored breathing. The heart may also be damaged. The rat may lose weight as his poor respiration makes it hard to eat or heart disease causes lack of appetite. The toes and tail tip may turn blue from lack of oxygen. The rat may experience respiratory distress, which causes a rat to gasp through her mouth, or dash about in panic when she can't get enough air. If treatment cannot prevent such attacks, euthanasia is the kindest action.
A rat infected with mycoplasma is usually active and eats normally until the disease is quite advanced. If a rat has a rapid onset of symptoms such as loss of appetite, lethargy, rough coat, hunched posture, runny eyes and nose, and difficulty breathing, these are symptoms of an acute secondary bacterial infection, not mycoplasma. Immediate antibiotic treatment, preferably with amoxicillin, or amoxicillin together with Baytril, will be necessary to save a rat this ill. A rat that is extremely lethargic and refuses to eat or drink must receive antibiotics by injection. Gentamicin with one of the penicillins is recommended.
A number of secondary bacteria can be associated with mycoplasma infections including the Cilia-Associated Respiratory (CAR) bacillus, Pasteurella pneumotropica, and Corynebacterium kutsheri. Another common bacteria that can cause respiratory disease in rats is Streptococcus pneumoniae. This is not the same organism that causes strep throat in humans (which is Streptococcus pyogenes) however, there have been some suspicious cases that suggest that rats might be able to get a strep infection from a person with strep throat, so people with strep throat should stay away from rats, and rats in the same house should be watched carefully for strep symptoms. Strep infections in rats are usually fatal within three days without vigorous antibiotic treatment. Rats cannot get human colds or flu.
Viral Infections
There are also viruses that can cause respiratory symptoms in rats. They cause sneezing and sometimes a stuffy nose, especially in babies which can prevent nursing and cause death.
In lab rats, which are all mycoplasma-free, these viruses are not usually fatal to post-weaning rats and the rats recover in a week or two. Both viruses will die out in a population if breeding and new introductions are discontinued for at least two months. However, if a rat is already infected with mycoplasma, which most pet rats are these days, a viral infection on top of it makes the rat extremely susceptible to dangerous secondary infections. Aggressive antibiotic treatment for secondary bacterial infections will be necessary. Either amoxicillin together with Baytril, or gentomicin with one of the penicillins is recommended. Supportive therapy, including fluids, may also be necessary. An injection of dexamethasone or dexamethasone sodium phosphate at 1 mg/lb can be extremely helpful in reducing the inflammation of the glands and respiratory tract and ease the symptoms.
Most rat respiratory diseases, especially mycoplasma and the viruses, are infectious and can be spread both through direct contact (rat to rat) and through the air. Viruses can also be transmitted on hands, clothing, and other inanimate objects. Mycoplasma is not known to be transmitted in this way. To protect your rats from the viruses, it is always a good idea for new rats or rats returning from a show to be quarantined for at least 2 weeks before exposing them to your other rats. Ideally there should be no air-flow between your rats' room and the quarantine area. Wash thoroughly and change your clothes after being with the quarantined rats.
(None of the organisms causing respiratory infections in rats are infectious to humans.)
Antibiotic Treatment
Although mycoplasmosis in rats is basically incurable, treatment with antibiotics can help control the damage. Antibiotics are also vital in treating secondary bacterial infections.
A head tilt caused by an inner ear infection requires early and aggressive treatment if the symptoms are to be reversed. Since this can also be caused by a secondary bacterial infection, Baytril, chloramphenicol, or gentamicin (always with a penicillin antibiotic) which tend to be effective against most other bacteria as well as mycoplasma, are recommended. Treatment with an anti-inflammatory such as prednisone at 1 mg/lb twice a day or ibuprofen at 60 mg/lb twice a day, along with the antibiotics, is also vital to help reduce inflammation in the inner ear.
A head tilt can also be caused by a pituitary tumor or stroke, and in this case the primary treatment is with steroids. But an antibiotic should also be given since steroids depress the immune system, and can also help shrink a tumor.
In my experience, the best antibiotics to use against mycoplasma are doxycycline and/or Baytril.
*doxycycline is more commonly known as Vibravet paste or Pssitavet podwer. The paste is given to cats and dogs and the powder is normally given to birds. Both can be used on rats. The powder is 1/2 teaspoon to 100ml water and should be crushed up in a little water first so it doesnt form hard lumps.*
Amoxicillin is available as fish capsules in some pet shops and feed stores. Amoxicillin is recommended for an acute infection, a secondary infection, or a possible strep infection. Other antibiotics that have been successful at treating secondary infections are trimethoprim-sulpha, cefadroxil, and chloramphenicol.
If a particular antibiotic is effective against the infectious organism, you should see an improvement in acute symptoms within 2-3 days, or in chronic symptoms within a week. If you don’t see any improvement within this time, you must try a different antibiotic. When treating a secondary respiratory infection, antibiotics should be continued for at least 2 weeks, or at least a week after all the symptoms disappear to prevent an immediate relapse. Treatment should be reinstated if the symptoms come back. If one antibiotic is no longer effective, try another one.
When treating mycoplasma, the minimum length of treatment should be 3 weeks, and 5-6 weeks is probably better in most cases. For some rats, those that have frequent reoccurances of symptoms, it is best to continue treatment for several months, or maybe even the rest of the rat’s life. Remember, mycoplasma is incurable and must be treated aggressively and persistently. Doxycycline and Baytril can be used for long periods of time without any ill effects in most rats.
I have found that rats with advanced respiratory disease often have heart disease as well. The recommended treatment for heart failure is a low sodium diet, enalapril (dose 0.25 mg/lb once a day), which lowers the blood pressure and makes it easier for the heart to beat, and atenolol, an beta-blocker that slows the heartbeat to make it more effective. (The American Heart Association recently announced it was recommending the use of beta-blockers for most patients with congestive heart failure.) Enalapril is so safe it can be used as a diagnostic tool. If giving enalapril makes the rat feel better, then you know he has congestive heart failure. If enalapril is going to help you should see improvement in the rat’s symptoms within 5 days. A diuretic can also help in some cases.
If the symptoms include skin edema or if it can be determined by x-ray that the heart is dilated, rather than hypertrophic, digoxin, which helps the heart beat more strongly, can be added to the treatment. The dose for digoxin is 0.001-0.0025 mg/lb twice a day. As time goes on, you often have to increase the dose. I have had two rats with congestive heart failure live to 38 months with digoxin, enalapril and atenolol treatment!
Studies have also found that some supplements can help people with congestive heart failure. These include the omega-3 oils in flax oil (25 mg/day), co-enzyme Q10 (10-30 mg/day), L-carnitine (25 mg/day), and taurine (50 mg/day). The doses I've recommended here for rats are 1/10 the human doses. I have been giving these to 5 of my rats with good results. They take them eagerly in peanut butter balls.
Other Treatments
If the air in your home is dry, a humidifier will help your rats breathe more easily. If your rat’s nose seems congested, the decongestant pseudephedrine might help clear the breathing passages. Buy the non-drowsy pediatric formula. The best dose is unknown. Try 1.5 mg twice a day. The antihistamine chlorpheniramine maleate may also be beneficial. Try giving 0.2 mg/lb twice a day.
If a rat is having gasping attacks, he may swallow large quantities of air which he can’t burp up. This will cause stomach distension and discomfort. To help the air pass through the digestive tract, you can try using the product Gas-X. Try giving about 1/4 teaspoon.
The homeopathic remedy antinonium tartaricun might be of some help. It can be used in conjunction with antibiotics and other medications. Other herbal and homeopathic remedies, as well as acupuncture may be of benefit to rats with mycoplasma. We are just beginning to explore the possibilities.
Even if your rat becomes very sick, don’t give up. I know of several rats pulled back from the brink of death after receiving antibiotics, recovering their health to live for several more months. Although respiratory and heart disease are extremely common in rats and can be devastating, prompt, persistant and aggressive treatment can help keep the diseases in check in most cases, and will usually allow your rat to enjoy a fairly normal life.
Using Antibiotics
Antibiotics must be selected carefully not only according to the type of bacteria causing the infection, but also how the antibiotic works, what tissues of the body it can penetrate, the patient’s state of health, and any possible side-effects. For instance, the penicillins and sulphonamides can cause allergic reactions in sensitive individuals, and tylosin and amoxicillin sometimes cause diarrhea.
Whenever using antibiotics there is also the possibility that some of the bacteria will be resistant. Once the susceptible bacteria have been killed off, resistant bacteria can flourish. Then a different antibiotic must be used. In some cases it may be necessary to use two antibiotics at once to eliminate this problem.
Antibiotics are divided into two groups according to how they work. Bactericidal antibiotics actually kill the bacteria, but they only kill growing bacteria. Bacteriostatic antibiotics prevent the bacteria from growing, so the immune system can kill them off. A bacteriostatic antibiotic can interfere with the action of a bacteriocidal antibiotic and so in most cases the two groups of antibiotics should not be used together. Because bacteriocidal types actually kill the bacteria, they should be used for serious acute infections when possible.
In general, the length of treatment for infections affecting the skin should be about 7-10 days. Respiratory and urinary infections generally need to be treated for several weeks. An exception to this is gentamicin which should never be used longer than 14 days.
Amoxicillin, amoxicillin with clavulanate, and cefadroxil are fairly safe for use in pregnant animals, but most other antibiotics will pass through the placenta into the developing fetuses and are not recommended for use during pregnancy. However, you may have to use another antibiotic to save the mother’s life.
Notes on Administration
One of the trickiest parts of medicating rats is getting the medicine inside them! Oral medications can be administered to rats in four forms: liquid, paste, chewable, or in the drinking water. If tablets or capsules are prescribed, the only way to get the medicine down your rat is to mix it in one of these forms. For tablets, you can grind them up into a fine powder on a small plate with a spoon, or let them soften in a liquid. For capsules, pull the halves of the capsule apart and dump out the powder. You can then mix them in liquid or food. To mix in food, mix the powder well and divide into little piles, each containing the proper dose. Then you can scrape a pile into the food.
Some medicines, like tetracycline and tylosin, can be added to the drinking water. This can be a handy way to give medicine to a large number of rats. However, there are a few special precautions. First, if the medicine tastes bad, some rats refuse to drink, resulting in both no medication ingested and dehydration. Adding the medication to a flavored drink will usually solve this problem.
Light will destroy tetracycline, so cover the water bottle with a tin can, aluminum foil, or a dark sock. You can put tylosin in apple juice, Tang, Hawaiian Punch or Kool-Aid. However, do not use Tang for tetracycline. Calcium and magnesium, present in this drink, can bind to the tetracycline and deactivate it. For the same reason it's a good idea to use distilled water (available in grocery stores) for tetracycline because some tap water also contains calcium and magnesium. You should also avoid giving dairy products within 2 hours of tetracycline.
Medications in the water must be mixed up fresh and replaced often, so don’t make up too much at one time. Rats only drink about 1-2 oz. per day. In hot weather, keep most of the mixture in the refrigerator to prevent fermentation, and replenish the water bottle 2-3 times a day.
Giving medications in water is a handy way to dose lots of rats at one time, but it’s better to dose individual rats with medications in food. They are more likely to get the correct dose this way and you won’t be dosing cagemates who don’t need the medication. You can mix medications in foods such as baby food, mashed avocado, pasta sauce, margarine, butterscotch syrup, brown sugar and carob powder, graham crackers and Kool-Aid, Nutri-Cal, and even as a last resort, frosting or chocolate syrup. Antibiotics other than tetracycline can be mixed in yogurt, pudding, non-fat cream cheese, or ice cream.
Use only enough food to mask the taste of the medicine so your rat will eat it all immediately. Adding a bit of salt will help counter bitterness. If your rat refuses to eat the doctored food, you can mix it in a dab of margarine and smear it on the back of his ear. Most rats will clean the margarine off their ear and eat it, no matter how bad it tastes.
You can also mix either powders or liquids in liquids such as Hawaiian Punch Concentrate, VAL syrup (ask your vet), or strawberry sundae syrup. Liquid medications are easy to give if they taste good to your rat. Just place a drop in the side of his mouth with an eyedropper or syringe (without a needle) and he’ll probably start to lick it right from the tip. However, if a rat dislikes the taste (or the aftertaste) of a liquid, it can be impossible to get it down, because he’ll simply refuse to swallow.
Powders can also be mixed into my famous peanut butter balls. To make 20 doses, mix 1/2 tablespoon smooth peanut butter with 20 doses of the medication. Add 1/2 teaspoon sugar (more if the medication is very bitter) and enough flour to form a stiff dough and mix well. Roll into a snake on wax paper and cut into20 equal pieces. Form each piece into a ball and roll in flour and keep in the refrigerator. You can also use non-fat cream cheese instead of peanut butter. Most rats love these balls, but try making just one first before mixing up a whole recipe and possibly wasting the medication.
If you have to medicate a rat who looks similar to another rat, you can use a non-toxic felt pen to mark one of the rats on his fur or the base of the tail. Or, if they have dark fur, you can try using peroxide to make a lighter mark on one of them. Food colour can be used but it may be cleaned away quickly by the rat itself or by other rats.
Special Warnings
Tetracycline should not be given to pregnant rats because it can be toxic to the liver and interfere with bone and tooth development in the fetuses.
The kidney toxicity that gentamicin sometimes causes in other animals is not a big problem in rats, but it is still a good idea to encourage the patient to drink plenty of water by offering sugar water or juice to drink. Gentamicin can’t be given orally because it can’t be absorbed so it must be injected. Or, another method of giving gentamicin is with a nebulizer which creates tiny droplets which can be inhaled into the lungs. The antibiotic is mixed in a 10% saline solution and administered for 15 minutes twice daily. Baytril can also be nebulized.
Baytril should be given by injection only when absolutely necessary as it is extremely caustic and can cause severe skin ulcers which take a long time to heal. I know of 2 rats who bled to death after scratching the ulcers caused by Baytril injections. Diluting the Baytril 30:1 with sterile saline might help prevent this. It should be given by subQ injection only and never in the muscle.
Respiratory & Heart Disease in Rats
by Debbie "The Rat Lady" Ducommun
This article is from her booklet Rat Health Care. Which can be purchase through The Dapper Rat
Respiratory disease is the most common health problem and cause of death in pet rats. The most common organism causing this disease in rats is the bacteria Mycoplasma pulmonis. Mycoplasma is very contagious and incurable. There are different strains of mycoplasma that are more or less virulent and so can cause more or less severe disease. Different rats also seem to have differing resistance to the disease. The severity of a mycoplasma infection can be increased by cigarette smoke, ammonia from a dirty cage, vitamin A or E deficiency, pine or cedar shavings, and a concurrent respiratory infection of another type, as well as genetic susceptibility.
A mycoplasma infection makes a rat more susceptible to secondary respiratory bacterial infections as well. The respiratory symptoms that are common in rats can be caused either by the primary mycoplasma infection, secondary infections, or both as well as heart disease. In young rats, symptoms are more likely to be caused by secondary infection, so they need to be treated accordingly.
Most respiratory symptoms in rats are caused by respiratory infections or heart disease. It is very rare to find a lung tumor in rats. Since 1985 I have done gross autopsies on more than 200 rats and I have only seen one possible lung tumor.
Mycoplasma typically causes a “blister” effect on the surface of the lungs, lung abscesses, and emphysema. It also causes inflammation and infection of the uterus. There is a special blood test, called a serology ELISA test, that can detect mycoplasma. (However, the disease is so common, you should just assume your rats have it.)
Common Symptoms
Often, the first symptoms of respiratory disease seen in a rat, especially in young rats, will be caused by a secondary infection. For any symptoms, I recommend first trying an antibiotic that works well for secondary infections. Secondary infections can become more serious more quickly than mycoplasma, so treat for them first. If you treat for mycoplasma first, and it turns out to be a secondary infection, the rat may get so sick he dies before you can try the treatment for secondary infections. Usually a mycoplasma infection is chronic, that is, it starts out slowly with mild symptoms that gradually get worse over a period of weeks or months, so quick treatment is not as critical as it is for a secondary infection.
In my experience, amoxicillin tends to work best for secondary infections. If the symptoms do not improve within 3 days of treatment, then you should switch to another antibiotic, probably one that is good for mycoplasma. The first symptom of mycoplasmosis is usually frequent sneezing (healthy rats rarely sneeze), but then this often goes away and there can be a long period of time without symptoms. However, mycoplasma can cause lung damage even if there haven’t been any overt symptoms.
A respiratory infection, whether caused by mycoplasma or a secondary infection or both, can begin in the upper respiratory passages and then progress into the lungs causing pneumonia, or it cause pneumonia right away. It can invade the inner ear and affect balance, causing a head tilt which can progress to rolling behavior. An infection can also cause damage to the nasal cavity and nasal bones resulting in fatal bleeding. Any noise made while breathing can be a symptom of an infection and/or heart disease.
Because mycoplasma is a chronic, progressive, incurable disease, older rats tend to have more problem with respiratory problems, but even symptoms in older rats can be caused by a secondary infection, and not mycoplasma itself. If a rat’s immunity is weakened due to stress, old age, or another disease, they can be more susceptible to secondary infections.
Without treatment, mycoplasma and secondary infections will usually cause major lung damage and in most cases the rat will eventually exhibit labored breathing. The heart may also be damaged. The rat may lose weight as his poor respiration makes it hard to eat or heart disease causes lack of appetite. The toes and tail tip may turn blue from lack of oxygen. The rat may experience respiratory distress, which causes a rat to gasp through her mouth, or dash about in panic when she can't get enough air. If treatment cannot prevent such attacks, euthanasia is the kindest action.
A rat infected with mycoplasma is usually active and eats normally until the disease is quite advanced. If a rat has a rapid onset of symptoms such as loss of appetite, lethargy, rough coat, hunched posture, runny eyes and nose, and difficulty breathing, these are symptoms of an acute secondary bacterial infection, not mycoplasma. Immediate antibiotic treatment, preferably with amoxicillin, or amoxicillin together with Baytril, will be necessary to save a rat this ill. A rat that is extremely lethargic and refuses to eat or drink must receive antibiotics by injection. Gentamicin with one of the penicillins is recommended.
A number of secondary bacteria can be associated with mycoplasma infections including the Cilia-Associated Respiratory (CAR) bacillus, Pasteurella pneumotropica, and Corynebacterium kutsheri. Another common bacteria that can cause respiratory disease in rats is Streptococcus pneumoniae. This is not the same organism that causes strep throat in humans (which is Streptococcus pyogenes) however, there have been some suspicious cases that suggest that rats might be able to get a strep infection from a person with strep throat, so people with strep throat should stay away from rats, and rats in the same house should be watched carefully for strep symptoms. Strep infections in rats are usually fatal within three days without vigorous antibiotic treatment. Rats cannot get human colds or flu.
Viral Infections
There are also viruses that can cause respiratory symptoms in rats. They cause sneezing and sometimes a stuffy nose, especially in babies which can prevent nursing and cause death.
In lab rats, which are all mycoplasma-free, these viruses are not usually fatal to post-weaning rats and the rats recover in a week or two. Both viruses will die out in a population if breeding and new introductions are discontinued for at least two months. However, if a rat is already infected with mycoplasma, which most pet rats are these days, a viral infection on top of it makes the rat extremely susceptible to dangerous secondary infections. Aggressive antibiotic treatment for secondary bacterial infections will be necessary. Either amoxicillin together with Baytril, or gentomicin with one of the penicillins is recommended. Supportive therapy, including fluids, may also be necessary. An injection of dexamethasone or dexamethasone sodium phosphate at 1 mg/lb can be extremely helpful in reducing the inflammation of the glands and respiratory tract and ease the symptoms.
Most rat respiratory diseases, especially mycoplasma and the viruses, are infectious and can be spread both through direct contact (rat to rat) and through the air. Viruses can also be transmitted on hands, clothing, and other inanimate objects. Mycoplasma is not known to be transmitted in this way. To protect your rats from the viruses, it is always a good idea for new rats or rats returning from a show to be quarantined for at least 2 weeks before exposing them to your other rats. Ideally there should be no air-flow between your rats' room and the quarantine area. Wash thoroughly and change your clothes after being with the quarantined rats.
(None of the organisms causing respiratory infections in rats are infectious to humans.)
Antibiotic Treatment
Although mycoplasmosis in rats is basically incurable, treatment with antibiotics can help control the damage. Antibiotics are also vital in treating secondary bacterial infections.
A head tilt caused by an inner ear infection requires early and aggressive treatment if the symptoms are to be reversed. Since this can also be caused by a secondary bacterial infection, Baytril, chloramphenicol, or gentamicin (always with a penicillin antibiotic) which tend to be effective against most other bacteria as well as mycoplasma, are recommended. Treatment with an anti-inflammatory such as prednisone at 1 mg/lb twice a day or ibuprofen at 60 mg/lb twice a day, along with the antibiotics, is also vital to help reduce inflammation in the inner ear.
A head tilt can also be caused by a pituitary tumor or stroke, and in this case the primary treatment is with steroids. But an antibiotic should also be given since steroids depress the immune system, and can also help shrink a tumor.
In my experience, the best antibiotics to use against mycoplasma are doxycycline and/or Baytril.
*doxycycline is more commonly known as Vibravet paste or Pssitavet podwer. The paste is given to cats and dogs and the powder is normally given to birds. Both can be used on rats. The powder is 1/2 teaspoon to 100ml water and should be crushed up in a little water first so it doesnt form hard lumps.*
Amoxicillin is available as fish capsules in some pet shops and feed stores. Amoxicillin is recommended for an acute infection, a secondary infection, or a possible strep infection. Other antibiotics that have been successful at treating secondary infections are trimethoprim-sulpha, cefadroxil, and chloramphenicol.
If a particular antibiotic is effective against the infectious organism, you should see an improvement in acute symptoms within 2-3 days, or in chronic symptoms within a week. If you don’t see any improvement within this time, you must try a different antibiotic. When treating a secondary respiratory infection, antibiotics should be continued for at least 2 weeks, or at least a week after all the symptoms disappear to prevent an immediate relapse. Treatment should be reinstated if the symptoms come back. If one antibiotic is no longer effective, try another one.
When treating mycoplasma, the minimum length of treatment should be 3 weeks, and 5-6 weeks is probably better in most cases. For some rats, those that have frequent reoccurances of symptoms, it is best to continue treatment for several months, or maybe even the rest of the rat’s life. Remember, mycoplasma is incurable and must be treated aggressively and persistently. Doxycycline and Baytril can be used for long periods of time without any ill effects in most rats.
I have found that rats with advanced respiratory disease often have heart disease as well. The recommended treatment for heart failure is a low sodium diet, enalapril (dose 0.25 mg/lb once a day), which lowers the blood pressure and makes it easier for the heart to beat, and atenolol, an beta-blocker that slows the heartbeat to make it more effective. (The American Heart Association recently announced it was recommending the use of beta-blockers for most patients with congestive heart failure.) Enalapril is so safe it can be used as a diagnostic tool. If giving enalapril makes the rat feel better, then you know he has congestive heart failure. If enalapril is going to help you should see improvement in the rat’s symptoms within 5 days. A diuretic can also help in some cases.
If the symptoms include skin edema or if it can be determined by x-ray that the heart is dilated, rather than hypertrophic, digoxin, which helps the heart beat more strongly, can be added to the treatment. The dose for digoxin is 0.001-0.0025 mg/lb twice a day. As time goes on, you often have to increase the dose. I have had two rats with congestive heart failure live to 38 months with digoxin, enalapril and atenolol treatment!
Studies have also found that some supplements can help people with congestive heart failure. These include the omega-3 oils in flax oil (25 mg/day), co-enzyme Q10 (10-30 mg/day), L-carnitine (25 mg/day), and taurine (50 mg/day). The doses I've recommended here for rats are 1/10 the human doses. I have been giving these to 5 of my rats with good results. They take them eagerly in peanut butter balls.
Other Treatments
If the air in your home is dry, a humidifier will help your rats breathe more easily. If your rat’s nose seems congested, the decongestant pseudephedrine might help clear the breathing passages. Buy the non-drowsy pediatric formula. The best dose is unknown. Try 1.5 mg twice a day. The antihistamine chlorpheniramine maleate may also be beneficial. Try giving 0.2 mg/lb twice a day.
If a rat is having gasping attacks, he may swallow large quantities of air which he can’t burp up. This will cause stomach distension and discomfort. To help the air pass through the digestive tract, you can try using the product Gas-X. Try giving about 1/4 teaspoon.
The homeopathic remedy antinonium tartaricun might be of some help. It can be used in conjunction with antibiotics and other medications. Other herbal and homeopathic remedies, as well as acupuncture may be of benefit to rats with mycoplasma. We are just beginning to explore the possibilities.
Even if your rat becomes very sick, don’t give up. I know of several rats pulled back from the brink of death after receiving antibiotics, recovering their health to live for several more months. Although respiratory and heart disease are extremely common in rats and can be devastating, prompt, persistant and aggressive treatment can help keep the diseases in check in most cases, and will usually allow your rat to enjoy a fairly normal life.
Using Antibiotics
Antibiotics must be selected carefully not only according to the type of bacteria causing the infection, but also how the antibiotic works, what tissues of the body it can penetrate, the patient’s state of health, and any possible side-effects. For instance, the penicillins and sulphonamides can cause allergic reactions in sensitive individuals, and tylosin and amoxicillin sometimes cause diarrhea.
Whenever using antibiotics there is also the possibility that some of the bacteria will be resistant. Once the susceptible bacteria have been killed off, resistant bacteria can flourish. Then a different antibiotic must be used. In some cases it may be necessary to use two antibiotics at once to eliminate this problem.
Antibiotics are divided into two groups according to how they work. Bactericidal antibiotics actually kill the bacteria, but they only kill growing bacteria. Bacteriostatic antibiotics prevent the bacteria from growing, so the immune system can kill them off. A bacteriostatic antibiotic can interfere with the action of a bacteriocidal antibiotic and so in most cases the two groups of antibiotics should not be used together. Because bacteriocidal types actually kill the bacteria, they should be used for serious acute infections when possible.
In general, the length of treatment for infections affecting the skin should be about 7-10 days. Respiratory and urinary infections generally need to be treated for several weeks. An exception to this is gentamicin which should never be used longer than 14 days.
Amoxicillin, amoxicillin with clavulanate, and cefadroxil are fairly safe for use in pregnant animals, but most other antibiotics will pass through the placenta into the developing fetuses and are not recommended for use during pregnancy. However, you may have to use another antibiotic to save the mother’s life.
Notes on Administration
One of the trickiest parts of medicating rats is getting the medicine inside them! Oral medications can be administered to rats in four forms: liquid, paste, chewable, or in the drinking water. If tablets or capsules are prescribed, the only way to get the medicine down your rat is to mix it in one of these forms. For tablets, you can grind them up into a fine powder on a small plate with a spoon, or let them soften in a liquid. For capsules, pull the halves of the capsule apart and dump out the powder. You can then mix them in liquid or food. To mix in food, mix the powder well and divide into little piles, each containing the proper dose. Then you can scrape a pile into the food.
Some medicines, like tetracycline and tylosin, can be added to the drinking water. This can be a handy way to give medicine to a large number of rats. However, there are a few special precautions. First, if the medicine tastes bad, some rats refuse to drink, resulting in both no medication ingested and dehydration. Adding the medication to a flavored drink will usually solve this problem.
Light will destroy tetracycline, so cover the water bottle with a tin can, aluminum foil, or a dark sock. You can put tylosin in apple juice, Tang, Hawaiian Punch or Kool-Aid. However, do not use Tang for tetracycline. Calcium and magnesium, present in this drink, can bind to the tetracycline and deactivate it. For the same reason it's a good idea to use distilled water (available in grocery stores) for tetracycline because some tap water also contains calcium and magnesium. You should also avoid giving dairy products within 2 hours of tetracycline.
Medications in the water must be mixed up fresh and replaced often, so don’t make up too much at one time. Rats only drink about 1-2 oz. per day. In hot weather, keep most of the mixture in the refrigerator to prevent fermentation, and replenish the water bottle 2-3 times a day.
Giving medications in water is a handy way to dose lots of rats at one time, but it’s better to dose individual rats with medications in food. They are more likely to get the correct dose this way and you won’t be dosing cagemates who don’t need the medication. You can mix medications in foods such as baby food, mashed avocado, pasta sauce, margarine, butterscotch syrup, brown sugar and carob powder, graham crackers and Kool-Aid, Nutri-Cal, and even as a last resort, frosting or chocolate syrup. Antibiotics other than tetracycline can be mixed in yogurt, pudding, non-fat cream cheese, or ice cream.
Use only enough food to mask the taste of the medicine so your rat will eat it all immediately. Adding a bit of salt will help counter bitterness. If your rat refuses to eat the doctored food, you can mix it in a dab of margarine and smear it on the back of his ear. Most rats will clean the margarine off their ear and eat it, no matter how bad it tastes.
You can also mix either powders or liquids in liquids such as Hawaiian Punch Concentrate, VAL syrup (ask your vet), or strawberry sundae syrup. Liquid medications are easy to give if they taste good to your rat. Just place a drop in the side of his mouth with an eyedropper or syringe (without a needle) and he’ll probably start to lick it right from the tip. However, if a rat dislikes the taste (or the aftertaste) of a liquid, it can be impossible to get it down, because he’ll simply refuse to swallow.
Powders can also be mixed into my famous peanut butter balls. To make 20 doses, mix 1/2 tablespoon smooth peanut butter with 20 doses of the medication. Add 1/2 teaspoon sugar (more if the medication is very bitter) and enough flour to form a stiff dough and mix well. Roll into a snake on wax paper and cut into20 equal pieces. Form each piece into a ball and roll in flour and keep in the refrigerator. You can also use non-fat cream cheese instead of peanut butter. Most rats love these balls, but try making just one first before mixing up a whole recipe and possibly wasting the medication.
If you have to medicate a rat who looks similar to another rat, you can use a non-toxic felt pen to mark one of the rats on his fur or the base of the tail. Or, if they have dark fur, you can try using peroxide to make a lighter mark on one of them. Food colour can be used but it may be cleaned away quickly by the rat itself or by other rats.
Special Warnings
Tetracycline should not be given to pregnant rats because it can be toxic to the liver and interfere with bone and tooth development in the fetuses.
The kidney toxicity that gentamicin sometimes causes in other animals is not a big problem in rats, but it is still a good idea to encourage the patient to drink plenty of water by offering sugar water or juice to drink. Gentamicin can’t be given orally because it can’t be absorbed so it must be injected. Or, another method of giving gentamicin is with a nebulizer which creates tiny droplets which can be inhaled into the lungs. The antibiotic is mixed in a 10% saline solution and administered for 15 minutes twice daily. Baytril can also be nebulized.
Baytril should be given by injection only when absolutely necessary as it is extremely caustic and can cause severe skin ulcers which take a long time to heal. I know of 2 rats who bled to death after scratching the ulcers caused by Baytril injections. Diluting the Baytril 30:1 with sterile saline might help prevent this. It should be given by subQ injection only and never in the muscle.