The Maine Coon is a hardy breed,
however the breed has a genetic predisposition to several significant disorders as do many other pedigree cats.
Genetic diseases exist among all cats, pedigreed or non-pedigreed.
Hypertrophic Cardiomyopathy (HCM)
Hypertrophic cardiomyopathy (HCM) is a clinically heterogeneous myocardial disease and is the most common cardiac disease identified in domestic cats.
HCM is characterised by an increased left ventricular mass due to an increase in wall thickness of the heart, with papillary muscle hypertrophy and systolic anterior motion of the Mitral valves.
Death by HCM can occur via three mechanisms:
(i) sudden cardiac death with arrhythmia and ventricular fibrillation,
(ii) heart failure with tachycardia, increased respiration, shortness of breath, pulmonary oedema and pleural effusion or
(iii) thrombus formation. Thrombi can form either in the left atrium due to abnormal blood circulation or in the heart chamber itself due to severe hypertrophy and cardiac weakness.
Atrial thrombi can break free and reach the arterial blood circuit, thereby often causing blood congestion at the branching of pelvic and crural arteries with paralysis of the hind legs. Echocardiographic examination has so far been the only diagnostic tool for this disease. However, it can only be identify affected cats with some years of age, when they already present first symptoms of HCM.
HCM is not exclusive to the MAINE COON CAT breed. It has been diagnosed in Persians, RagDolls, and other breeds as well. It is only singled out as appearing to be prevalent to these breeds, because these are the breeders who are doing the most to try to trace, document, and prevent carrying the genes on in their lines.
Spinal Muscular Atrophy (SMA)
SMA is a disorder caused by death of spinal cord neurons that activate skeletal muscles of the trunk and limbs. Loss of neurons in the first few months of life leads to muscle weakness and atrophy that first becomes apparent at 3-4 months of age.
Affected kittens develop an odd gait with a sway of the hindquarters and stand with the hocks nearly touching. They may also stand with toes out in the front.
By 5-6 months of age they are too weak in the hindquarters to readily jump up on furniture and often have a clumsy landing when jumping down. The long hair of Maine Coon cats may hide it, but careful feeling of the limbs will reveal reduced muscle mass.
Breeders are able to test for this condition to identify cats that are carriers.
Polycystic Kidney Disease (PKD)
Maine Coon cats are also predisposed to PKD, which also affects many Persian or Persian-related felines. The disease causes cysts on the kidneys. These growths multiply and grow in size as the cat gets older.
Symptoms include weight loss, depression and increased thirst and urination. Owners might also see vomiting. Although PKD is irreversible, it generally progresses slowly.
Feline Infectious Peritonitis (FIP)
There is no known cure and no reliable test for FIP, this horrible disease claims cats of every breed, it is the greatest fear of any breeder and cat owner. There is so very little known about it, however there are many myths and stories that have become "general knowledge".
FIP is the mutation of a corona virus that brings about severe symptoms leading to death. The feline enteric coronavirus is very common and lives in the intestine of many cats that appear healthy. It mutates very readily and just occasionally this mutation enables the virus to escape from the gut, spreading throughout the body and causing FIP.
Since the symptoms can mimic so many other conditions, vets can reach a diagnose of FIP when they don't know what's really wrong with a cat, subsequently as there is no single laboratory test that can definitely diagnose FIP, likewise, no diagnostic procedure can identify which FCoV - infected cats will go on to develop FIP, serology cannot be used to differentiate between FECV and FIPV infections. Vast amounts of money continue to be spent each year by breeders on FIP testing, in almost all cases, the results are non-interpretable, even by the veterinarians. However, although infection with feline coronaviruses is clearly commonplace, (80 - some % of all felines in the world carry the corona virus in their system), the prevalence of FIP disease is low, it is estimated that only 1- 3% ever get sick.
Unfortunately, the highly infectious nature of the FECV and our lack of understanding of its evolution to FIPV make elimination of risk virtually impossible.
There is no generally agreed practical and effective scheme for achieving control as there is for other important infectious agents of cats such as respiratory viruses and FeLV.
FIP losses are thought to be higher among cats that spend their early kittenhood in large multiple cat households such as breeding catteries, and shelters. Overcrowding and intermingling of kittens, adolescent and older cats are a common feature of such environments and are obvious contributors to other infections of cats.
Some catteries isolate and early wean their kittens Prevention of Coronavirus Infection in kittens, however infection with coronavirus is almost assured once these kittens are reintroduced into the normal environment, such as relocation to new homes, visits to the vet/neutering/spaying, cat shows, etc. The advantage of a successful isolation and early weaning program results in a delay to infection to 16 weeks of age or older. This is the time when the immune system begins to attain adult levels of activity and when kittens become more resistant to clinical disease of all sorts, including FIP. Kittens in the 8-12 week age range are just starting to become immunocompetent, near adult levels of immunity are not achieved until 16 weeks and later. Most kittens are exposed to FECV, at an age when they are not fully immunocompetent. If infection to FECV were to be delayed for several more weeks or months, the likelihood of the FIPV mutant taking hold should hopefully be greatly decreased, also kittens retained by breeders for future breeding purpose have the chance for their immune systems to mature giving some of the potential stresses of early life such as vaccination the time to pass before introducing them to the rest of the colony.
Early weaning in isolation also contributes to the control of other infectious agents, cats are known to be secret carriers of many problems however healthy they appear, these problems they can pass on to their kittens.
Catteries contemplating undertaking the isolation and early weaning programme need to be highly experienced in the care of very young kittens, it is not a method for breeders to take on if they cannot dedicate 100% to the kittens care, it's exspensive and time consuming. Breeders also need to determine whether it is viable given their facilities/husbandry, whether it will work for them.
If the kittens are found to be seropositive at 16 weeks of age, the program has failed.
There is no such thing as a “FIP-negative cattery.”
It is true that there is currently no cure, or totally effective prevention, but breeders can make FIP a rare event via wise cattery management.
Interpreting Titre Results
The gold-standard test for measurement of antibodies to feline coronavirus (FCoV)