Guinea Pigs - Problems

By Rick Axelson, DVM

Care & Wellness, Emergency Situations, Medical Conditions, Nutrition, Parasites

Guinea pigs are easy to care for and, if handled frequently and gently, make great family pets. They are generally hardy, healthy animals but are susceptible to certain problems and diseases. The following is a brief description of some of the more common problems of guinea pigs, which include respiratory infections, diarrhea,scurvy (vitamin C deficiency), tumors, abscesses due to infection, urinary problems and infestations by lice, mites or fungus.

Respiratory Infections

guinea_pigs_-_problems-1Pneumonia is one of the most significant diseases of pet guinea pigs and can be caused by a number of bacteria, including Bordetella and Streptococcus. Guinea pigs can naturally harbor these bacteria and may be asymptomatic (apparently healthy) carriers. These bacteria tend to be "opportunistic", meaning that they infect susceptible animals, multiply and cause disease if the opportunity presents itself.

"Pneumonia is one of the most significant diseases of pet guinea pigs."

Stresses increase the chance that disease will develop, and young animals are most often affected. The bacteria are spread by direct contact, aerosolized (airborne) particles, and on contaminated hands or other objects. Infected guinea pigs may be off food, have discharge from the eyes or nose, sneeze or have troubles breathing. Cultures can be taken to confirm the causative organism so that the appropriate antibiotics can be prescribed. Some guinea pigs may need to be hospitalized for additional supportive care.


Guinea pigs have a sensitive gastrointestinal tract (as do rabbits). They have a very specific natural population of "good" bacteria (flora) critical to normal bowel function. If this normal bacterial flora becomes upset or unbalanced, then the "bad" bacteria can overgrow, damage the intestinal tissues, release toxins and cause severe diarrhea; in severe cases, death may occur. In addition to bacterial infections, some intestinal parasites like cryptosporidia and coccidia can cause diarrhea.

Other clinical signs that may occur with diarrhea include anorexia (not eating), depression, dehydration, and a low body temperature. These sick guinea pigs need immediate veterinary attention and supportive care.

Certain antibiotics should never be used in guinea pigs. Only use antibiotics on the advice of a veterinarian familiar with guinea pigs. Never use antibiotics that you can purchase over the counter in a pet store, since they are often inappropriate.

Scurvy (Vitamin C deficiency)

Every animal has certain nutritional requirements, some of which are "essential" nutrients and some of which are "non-essential" nutrients. Animals need a regular dietary supply of essential ingredients, while they can produce their own supply of the non-essential nutrients. These essential elements differ between species. In guinea pigs and primates, including man, one key essential nutrient is vitamin C. The vast majority of other animals can produce their own vitamin C through their intestinal bacterial flora but guinea pigs and primates are unable to do this. (This is why sailors historically developed scurvy when not able to eat fresh fruit.) Vitamin C is vital in the normal development and maintenance of skin, joints and mucosal surfaces like gums. It is also important in the healing of wounds. As well as predisposing to skin problems, a lack of vitamin C seems to make the body more prone to other diseases, infections and conditions. A guinea pig that has a rough hair coat, is off food, has diarrhea, is reluctant to walk, perhaps seems painful, has swollen feet or joints, or has hemorrhages and ulcers on its gums or skin is likely to be deficient in vitamin C.

"In guinea pigs and primates, including man, one key essential nutrient is vitamin C."

Guinea pigs need 10 - 50 mg of vitamin C per day, depending on the condition of the animal (young, old, stressed, normal, pregnant). Vitamin C is readily available from fresh fruit and green or colored vegetables, but it is a relatively unstable compound. Ensure your fresh guinea pig pellets contain added vitamin C; however, because this vitamin breaks down or oxidizes so fast, the pellets should be used up or must be replaced within 90 days of the date of manufacture. If your guinea pig develops a deficiency, it is much better to give a crushed vitamin C tablet or liquid by mouth rather than in the drinking water, since the vitamin also breaks down rapidly in water and loses its potency. However, mixing about 100 mg of ascorbic acid twice daily in fresh water will meet the vitamin C requirement.


Guinea pigs can get various tumors but skin tumors and mammary tumors are the most common. They are often benign. Any mass should be brought to the attention of your veterinarian. In most cases surgical removal is curative.

"But skin tumors and mammary tumors are the most common."


Abscesses (an infected swelling within a body tissue, containing an accumulation of pus) can affect lymph nodes, the skin, the muscles, the teeth, the jaws, or other areas of the face. They may be treated medically and/or surgically, depending on veterinary assessment. Some (like those involving the jaw and teeth) are more challenging to treat.

Urinary Problems

Guinea pigs are very prone to urinary calculi (stones). These stones most often form in the bladder but some may form in the kidney itself. Stones may become lodged in the ureter (the tube carrying urine from the kidney to the bladder) or the urethra (the tube carrying urine from the bladder to the outside), causing a life-threatening obstruction. Female pigs are more prone to cystitis (bladder infection) then are male guinea pigs and often stones develop in association with a bladder infection. The signs of urinary problems include anorexia (off food), blood in the urine, straining to urinate, a hunched posture (with straining); if an obstruction has occurred, the guinea pig will be unable to produce urine.

Urinary problems are diagnosed with a thorough history and physical examination, including abdominal palpation (examination by feel), blood tests, urinalysis and x-rays. Depending on the findings, antibiotics may be prescribed. Sick guinea pigs may require hospitalization, supportive care and therapy and in the case of stones, will likely need surgery to remove the calculi.

Parasites and Skin problems

Guinea pigs (especially young ones) are prone to ringworm, which is a fungal infection, not an actual worm. Certain animals may be carriers of the fungus without showing any signs of illness. They can spread the disease to susceptible animals or develop disease themselves if stressed by overcrowding, poor nutrition, inadequate husbandry or other environmental stresses. The areas affected by ringworm can be itchy, usually lose hair, and may have crusty scabs on them. Ringworm lesions are found most commonly around the face, head and ears, but will spread to the back and legs. After proper diagnosis by your veterinarian, they are treated topically and/or orally with anti-fungal medications.

Guinea pigs can get fleas and lice; fleas usually diagnosed by finding the adults or their feces on the skin or in the fur; lice are often diagnosed microscopically by observing either the adults or eggs (nits) on a sample of hair and skin debris. Lice eggs are laid on the shafts of the hairs, often around the face, behind the ears or over the shoulders. A mite that can cause itching (pruritus) so intense as to occasionally cause seizures can infest guinea pigs. With a mite infestation, the skin is crusty, often is scraped or raw from scratching so much, has visible hair loss and may have secondary infections. These parasites are best treated with very effective anti-parasite medications available from your veterinarian.

"Lice eggs are laid on the shafts of the hairs."

Primary or secondary skin infections due to bacteria will be treated with antibiotics as indicated.

Other problems

Barbering is a problem, usually associated with boredom, in which the guinea pig chews or barbers its own hair so that it looks like it has been given a "brush cut". Providing the guinea pig with more stimulation, guinea_pigs_-_problems-2redirecting its attention to other chewing activities by providing more hay or chew toys; if the barbering was done by another guinea pig, separation of the two may be necessary.

Pododermatitis or bumblefoot is reasonably common in guinea pigs. It occurs most often in overweight animals housed on wire-bottomed cages or in filthy cages that abrade the feet, making them susceptible to a chronic, deep infection that causes lameness and pain. Treatment is challenging, but with appropriate veterinary care the problem can be alleviated.

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