Articles on the Internet, which Google presents as the best (ranked high up) tell me that chylothorax is more common in Siamese cats than other cats (‘over represented’ is probably the terminology).
Chylothorax is the build up of a fluid in the chest cavity that puts pressure on the lungs causing breathing difficulties. It is a form of pleural effusion. The sort of fluid building up in the space around the lungs can be of various kinds but in this instance the fluid is lymph fluid containing chyle. The reason why this happens is unknown (idiopathic).
Are these internet articles correct? The reason why I ask is because when you ‘drill down’ (an internet phrase meaning search a bit more deeply) you seem to find the source, or a source, of the statement that chylothorax is more common in Siamese cats.
The source is in Google Scholar, a repository of scientific work, research documents, and studies on all manner of subjects.
In the Journal of the British Veterinary Association website ‘In Practice’, there is a scientific article entitled: Diagnosis and management of chylothorax in dogs and cats. The abstract (summary) is all you see and there is no reference to Siamese cats there but in a search under Google Scholar that relates to this article, we have “However, older cats, purebred
cats, Siamese and Himalayan cats seem to be overrepresented..”
Note that the author, Kit Sturgess PhD uses the word, ‘seem’. I don’t know if his work is the source of information for the popular articles on the Internet but it might be.
I do know that when you check well known books on cat health you do not find information on this rare condition.
The well regarded Cat Owner’s Home Veterinary Handbook has a nice section on pleural effusion but no mention of chylothorax and no reference to Siamese cats in respect of pleural effusion.
An even better book on cat breed health problems, Medical, Genetic & Behavioral Aspects of Purebred Cats has a comprehensive list of genetic diseases for the Siamese cat and other non-inherited diseases. There is no mention of chylothorax.
My conclusion is that chylothorax may not be more common in Siamese cats. I would like some sort of definitive answer on that. There is a tendency on the internet for people who are building content websites to regurgitate what someone else has written. This can turn something that ‘seems’ to be the case into a fact. Beware of the internet is the motto!
Incidentally, the Siamese cat does have the longest list of genetic diseases of all the purebred cats and the Himalayan a pointed Persian is also said to be predisposed to chylothorax.
Why is the Siamese such a relatively sickly cat? Is it over-breeding? Inbreeding for appearance while disregarding health? Not sure.
One interesting fact is that the first Siamese to be imported into the West (England) in the late 1800s were quite sickly with worms and possibly other conditions. Is it fair to say that all Siamese cats in the West come from the Siamese cats that were kept by the royal family in Siam? And if so were these cats inherently healthy!?