For today's slightly late a-z post(sorry!) I am going to cover some of the main illnesses that affect hamsters.
Cancers are quite common as a disease in hamsters - anything that has such a short lifespan is prone to cancers. There seems to be a higher prevalence of cancers in female hamsters than male hamsters - but this is only because the female reproductive tract is often a site for cancers hence the skewed results. As with most cancers, they can be benign or malignant. Malignant cancers are fast growing and inevitably kill the affected hamsters with great rapidity. Benign cancers as their name implies are often slow growing and is not a death sentence per se. Hamsters seem to be quite prone to getting many different types of benign cancers. The most common cancers in hamsters are ones involving they thyroid and adrenal glands. Signs include hair loss and alterations in their behaviour. Skin tumors are also common in hamsters. Whilst surgery is an option, most hamster owners will opt for euthanasia when the word 'cancer' surfaces whether the condition is benign or not.
Lumps and bumps - if you discover a lump on your hamster don't just leap to the conclusion that it's cancer (it could be), more often than not, it could be an abscess. Abscesses are usually caused by bite wounds from fighting. These often form hard painful lumps under the skin where the puncture wound has closed up. Hamsters can also get abscesses in their cheek pouches - these would've resulted from puncture wounds from food or bedding materials. If you suspect an abscess in your hamster, you will need to take it into the vet to have it drained and antibiotic therapy started.
Hamsters can suffer from what is known as cage paralysis - this is generalized weakness that results due to lack of exercise and a small cage is usually the problem. Choose the largest cage you can afford because your little friend deserves to be in spacious surrounds. Generally providing them with adequate exercise and a larger cage would solve the problem. Sometimes a lack of Vitamin E and D could contribute to weakness and paralysis, if this is the case then vitamin supplementation helps. Some Syrian hamsters also have a hereditary defect which often starts as a progressive hind limb paralysis from 6 months of age. There is no cure for this hereditary disease condition.
Being sick is horrible for any human, so imagine what it is like being a hamster, unable to tell anyone how you feel. Make sure you check your little friend at least once a week for illnesses :).