Passive smoking is a well-known health risk for humans; it causes lung cancer and is also associated with an increased likelihood of developing heart disease, stroke, and respiratory illnesses (such as asthma, bronchitis, and pneumonia).
There is no risk-free level of passive (second-hand) smoke exposure. Pets are also susceptible to the damaging effects of second-hand smoke.
Exposure of dogs to second-hand smoke has been associated with a greater occurrence of allergies, eye problems, and respiratory problems (including lung tumours). Dogs with long noses are prone to developing nasal cancers when exposed to cigarette smoke, whereas dogs with medium to short noses are more likely to develop lung cancers.
Cats are also at risk of suffering significant adverse health effects from inhaling second-hand smoke. Studies have found that cats exposed to smoke have a greater risk of developing lymphoma (a serious cancer of the white blood cells) and respiratory illnesses such as asthma and bronchitis, all of which can be life threatening. Cats are also at risk from the toxic residues of smoke that collect on their coat and is then ingested as they self-groom. This is associated with the development of oral tumours.
Birds are extremely sensitive to the volatile toxins found in cigarette smoke due to their small size and well developed respiratory system that is very efficient at absorbing oxygen from the air (and any toxins inhaled with it). Furthermore, birds also ingest toxins from cigarette smoke by preening themselves, similar to a cat grooming. Birds have been shown to develop respiratory illness, feather plucking, allergies, sinus, skin, eye, and fertility problems, cancers, and heart disease from exposure to cigarette smoke.
Mice, guinea pigs, and other small pets are also affected by second hand smoke. They have been documented to suffer from respiratory problems, such as emphysema, and vascular disease as a result of exposure to smoke.
Fish are also susceptible to the damaging effects of cigarettes. Nicotine is very toxic to most fish kept domestically. Nicotine and other toxins from second-hand smoke easily dissolve in water and even small amounts can be very harmful and even deadly to fish.
Pets (of all kinds, not just cats and dogs, including birds) can also suffer nicotine poisoning by consuming cigarettes, cigarette butts, nicotine patches, or parts of electronic nicotine delivery systems like e-cigarettes (for example, the nicotine refill canisters, the device itself or nicotine refill liquid).
Common signs of nicotine poisoning include vomiting, drooling, lethargy, wobbliness, fast heart rate, weakness, shaking, and seizures. Even small amounts of nicotine can be harmful, even fatal. Therefore, if your pet eats even a small amount (for example, a cigarette, cigar or nicotine refill capsule) you should take immediate action. Nicotine poisoning is an emergency and requires immediate veterinary treatment.