Hamsters can suffer colds and are able to catch colds and flu from humans. Therefore if you have a cold or flu you should keep handling of your hamster to a minimum until you are recovered to avoid spreading your cold to the hamster. Hamsters can also catch a cold if the cage is exposed to draughts or are bathed.
Signs that a hamster has a cold are normally sneezing and runny nose. In more severe cases the hamster may have runny eyes, lethargy, weight loss, refusal to eat and drink or laboured breathing/wheeziness.
If the hamster exhibits signs of sneezing and running nose only and it continues to eat and drink and is active it should be kept in a warm room (not hot) of constant temperature and away from draughts. Some extra paper bedding should be placed in the cage and the hamster should recover within a couple of days. If the hamster does not recover after a couple of days or worsens veterinary advice should be sought as antibiotic treatment may be required.
If the hamster exhibits any signs of a severe cold (runny eyes, lethargy, weight loss, refusal to eat/drink or laboured breathing/wheeziness) veterinary advice should be sought immediately as antibiotic treatment is likely to be needed and failure to treat quickly could lead to bronchitis or pneumonia from which the hamster may have trouble recovering.
Giving a mixture of lukewarm water, milk and honey will also help with the hamster's recovery.
Provided colds are treated early before severe symptoms occur the hamster should make a full recovery within a few days.