Common Hamster Ailments

Hamsters are normally hardy, healthy little creatures who will enjoy a good two years of active life. Get to know your hamster because it is then much easier to see if all is well. Open his mouth from time to time to check his teeth. Look after his toe nails and his fur. Make sure he is eating and drinking normally and that his droppings are firm. Even the best kept hamsters sometimes become ill. You can help a lot with the nursing and treatment of a sick hamster, but don’t hesitate to consult your vet if you are worried.


These are soft, closed swellings filled with pus. They appear after the hamster has been bitten or injured. Bathing with a warm salt solution helps. Mix one teaspoon of salt with a pint of water. Clip the fur around the abscesses and keep it exposed until the pus has drained away. You need to consult your vet for antibiotics if the abscess does not heal in a few days.


Falls, encounters with cats and mishandling by young children are the most common cause of injury. Fractures of the limbs or pelvis should be seen by your vet, but treatment is difficult. Hamsters will not tolerate splints or dressings! Simple fractures will heal on their own.


Not a common ailment, but a potentially serious one. The hamster may suffer some discomfort from a swollen abdomen. A good supply of clean drinking water, fresh greens and safe bedding will usually cure (and prevent) this condition.


A sudden change of diet or too many greens can cause an attack of diarrhoea. Beware of raisins and citrus fruit. The hamster will have staining around his bottom and may be off colour. Dehydration is a serious result of this condition and needs urgent veterinary treatment. Pinch a fold of your hamster’s skin. If it slips back into place he is well hydrated. If the skin stays up in a ridge the hamster needs fluid. Feed only dried food and water for a day or two. A pinch of salt and a pinch of glucose may be added to the water.


Hamsters that are too hot collapse and become disorientated. Moving them to a cool, shady place may help, but it is better to immerse him gently in a bowl of cool water (but not the head). He will gradually regain consciousness as his body temperature return to normal.


A sudden drop in temperature or even a series of dull days when daylight is depleted can cause your hamster to hibernate. A cool, stiff immobile hamster is not necessarily dead. Warm him in your hands or near a radiator, but do not over do the heat.

Lumps & Bumps (also see Hamster Polyoma Virus)

These should be investigated by a vet. Small external lumps can usually be removed. Don’t wait until the lump is large or untreatable. Lumps are not necessarily cancerous.

Respiratory Problems

Hamsters can develop “snuffles” especially after a period of damp weather. Humans may transmit “cold” to hamsters (imagine a poor hamster kept in a classroom of five year olds, he must be permanently sneezing)! Put some Vicks or menthol crystals on a tissue near the cage. Keep him comfortable and warm, treat him to hot mash and hope for the best.

Skin Diseases

Hamsters can be affected by Demodectic and sarcoptic mange. Hair loss and irritated, scaly patches are the first signs. Mites from both these manges are easily identifiable. Your vet can take a skin scraping and examine it under a microscope. Sarcoptic mange causes scabies in humans, an unpleasant, but not serious, itchy rash on the forearms. Mites found in hay can also cause intense itching in hamsters. Ringworm is relatively rare, but can be detected by an ultra violet light. The affected patches glow! Rings of dry, scaly skin are an indication of this condition. Hip spots are often mistaken for ringworm. All hamsters have two scent glands on their flanks. Sometimes they appear to be sore and wet and the hamster may rub them along the floor of his cage. This is quite normal.


Hamsters that suffer from misaligned jaws, or are given insufficient hard food, often develop overgrown teeth. Your vet can show you how to clip them Don’t worry, it’s quite painless!

Tyzzer’s Disease

This is a serious disease usually carried by wild mice. The hamster rapidly looses condition and dies. Mice can contaminate food, cages, shavings and bedding, even before you buy these products. You should be suspicious if you have a number of sudden deaths in your hamstery.

Wet Tail

This condition should not be confused with diarrhoea, although the symptoms are similar. The animal quickly becomes vary ill indeed with severe diarrhoea caused by a bacterium which is thought to attack mainly young hamsters. Ulcers form in the bowel and death usually follows. Stress, over breeding and weaning too early leave hamster hamsters susceptible to this nasty disease. Treatment by your vet is possible, but rarely successful. This is a highly infectious disease and sufferers should be isolated.

Hamster Polyoma Virus (2002)

Separating the Facts from the Fiction. History: In the seventies, unusual outbreaks of infectious lymphomas were first seen in Syrian hamsters. We now understand the cause of this disease, how to recognise it and how to deal with it. Hamster polyoma virus, abbreviated as HaPV, is a relatively new disease in Syrian hamsters. It probably came from European hamsters some decades ago – a short time in virus terms. HaPV is not common, but infections of colonies of both Syrian and European hamsters have been reported in Europe and the United States. It has not been seen in any other species, hamster or otherwise.

Classification: HaPV belongs to a diverse family of viruses called the Papovaviridae. It was put here because of its structure, not the disease it causes. In fact papovaviruses cause a huge range of diseases quite dissimilar to HaPV. For this reason, it is much better to use the correct name hamster polyoma virus as this immediately tells us that it causes multiple lymphomas. This is especially important when talking to your vet.

How the virus works: The likely source of virus is infected hamster urine and this is why good hygiene and husbandry are crucial. Once a hamster is infected, the virus spreads through many body systems without causing symptoms for 4-30 weeks. Sometimes, but not always, HaPV will go on to cause multiple internal lymphoma tumours, as the name “polyoma” suggests. The hamster may then develop tumours of the hair follicles called “trichoepitheliomas”. These are often seen in groups around the eyes, mouth, feet and anus.

Why does the disease sometimes seem different? When HaPV infects a new group of hamsters, it can be very virulent and infect as much as 80% of individuals. Once the virus is in the group, however, the infection rate falls as young hamsters become resistant. Eventually, only the old or sick may be susceptible. The unfortunate few are more likely to develop the trichoepitheliomas, although we are not sure why. These differences in disease and infection rate have lead to great confusion and suggestion that several viruses are involved. In fact we know definitely it is the same virus, but different hamsters respond differently for a variety of reasons such as age, health and immunity. It is a feature of viruses that with time they become less virulent. HaPV is no exception and we should be heartened by this. Remember, we have already coped with it for 30 years – at least!

What to look for: Infected hamsters lose weight and condition. Lumps may be felt within the abdomen (lymphomas). These can be in many different organs from the liver to the spleen. Wart-like nodules may be seen on the skin (trichoepitheliomas). In addition, as the hamster is weakened, it may develop Demodectic mange which will appear as hair loss, with scaliness of the skin and itching.

How can we and our vets diagnose HaPV? This is a fairly simple process, even without tests. Firstly lymphomas are extremely rare in young hamsters and should immediately raise suspicions. Secondly, trichoepitheliomas are ALWAYS caused by HaPV. If the hamster has these, it is a definite diagnosis. Tests on tissue from lymphomas and trichoepitheliomas may not reveal virus. This is common with HaPV and is a result of the way the disease works and the difficulty of the tests. This is an important point to remember. There is currently NO efficient laboratory test.

Will the vet know about HaPV? Hamsters are not as numerous as say, cats and dogs. For this reason, not all vets are hamster experts. They should, however, know the significance of a polyoma virus. If you suspect HaPV, tell your vet immediately and, if necessary, it is perfectly acceptable to describe what you know, or even show this article.

Treatment: Unfortunately there is no treatment for individual hamsters yet. Culling the entire group is advised, followed by rigorous disinfection of cages etc, by specifically ANTIVIRAL agent such as VIRKON (widely available from vets and pet shops). It is also wise to wait some months before restocking. HaPV is quite tough, with some reports of recurrence even after thorough disinfection. It is better to be cautious.

The implications for the future: On a much more encouraging note, it can safely be said that there is no need for hamster owners to panic and the Syrian population will NOT be wiped out! There are such myths floating around, which although well intentioned, are not based on fact, understanding or knowledge. Viruses become less virulent with time. To an individual owner or breeder, HaPV can cause devastating loss, which should not be underestimated. The hamster population as a whole, however, is quite safe and over the years, HaPV will become less of a problem. This is a fundamental fact of virus evolution. The key is to spread awareness of the disease, something we can all be involved in. It may be hard, but action must be taken as soon as an infection is supected. Finally, the value of good husbandry and hygiene cannot be overemphasised. We can do much to control the problem, but it is essential that EVERYBODY takes responsibility.


Please can I acknowledge main source text:


Pathology of Laboratory Rodents and Rabbits. Authors: Percy & Barthold ISBN 08138 2551-2

-containing an excellent, comprehensive chapter on hamster husbandry and pathology, which I would recommend to interested parties.

Many thanks also to friends and researchers at Glasgow Vet School, particularly Professor Os Jarrett and Dr Joyce Ferguson