Video: Polycystic Kidney Disease In Long-haired Cats
Recently, the problem of polycystic kidney disease (PKD) in long-haired, mainly Persian, cats has attracted much attention of US veterinarians and breeders. A lot of articles are devoted to this disease in the medical and popular scientific periodicals of the USA and Europe, concerning cats of this breed.
The disease has been known since 1967 and reported at Ohio State University in a six-year-old Persian cat presented with symptoms of renal failure due to PEP. However, this disease began to attract close attention from specialists in the 90s and has reached its apogee at the present time. In June 1998, a CFA Health Committee seminar was held in Philadelphia, Pennsylvania entirely dedicated to this serious feline condition. Leading doctors and veterinarians dealing with this problem, geneticists, representatives of the CFA breed committee and leadership, as well as Persian cat breeders were invited to this seminar. Questions were raised on genetics, diagnosis, early detection and treatment of PEP, as well as breeding prospects for Persian cats.
What is this pathology? The name - polycystic kidney disease - gives an idea of its essence and literally translates as the presence of multiple cavities in the structure of the kidneys. PCP is an autosomal dominant inherited disorder. This means that the manifestation of the disease occurs in all cats that have received an affective dominant gene, even from only one of the parents. In other words, a cat that does not suffer from PEP does not have an affective gene in its gene pool, i.e. is pure from this disease genetically and cannot be inherited. If a cat with PEP is positive, then it may be heterozygous (has this gene from one of the parents) or homozygous (has this gene from both parents) for PEP. In any of these options, the cat will definitely develop a disease.
PEP tends to appear in adult and mature cats, 3 to 10 years of age, more commonly at 7 years of age.Until this age, the disease may not manifest itself or be detected in any way during a routine examination by a doctor (external examination and palpation), since the size of the kidneys remains normal. Disorders in the structure of the kidneys are present in affected cats already at birth, but these changes are minimal and cysts are very small in kittens and young animals. Cysts can vary in size from 1 mm to 1 cm or more. With age, their size and number increases up to the complete replacement of the normal structure of the kidney with cavities of different sizes. Quite often, similar cysts can be detected in an animal affected by PCP and in other organs - the pancreas, liver, uterus. As the disease progresses and the normal structure of the kidneys is disrupted, their function cannot but decrease. Decreased renal function is characterized by chronic renal failure,which is usually the first alarming symptom of this disease. Chronic renal failure (CRF) is clinically characterized by symptoms of intoxication (poisoning of the body with slags), loss of appetite, depression of the animal, progressive weight loss, and urinary retention. Vomiting may occur. These symptoms can manifest themselves in varying degrees of severity and intensify as the disease progresses.
Currently, thanks to the capabilities of ultrasound examination (US) of organs, the diagnosis of PEP is possible at the earliest stages of the development of the disease, literally, at the age of eight weeks of kitten's age. Of course, such a study should be carried out by a specialist in this field, since the cysts at this time are very small - 1-3 mm. At a later age (several months), they are much easier to detect with ultrasound. Based on the studies performed, veterinarians concluded that the most reliable and highly effective (98% of cases of correct detection of PEP) is the diagnosis of PEP at the age of 10 months. The dimensions of the animal and its organs practically correspond to adult norms, which makes it easier to identify all possible deviations.
The following question arises. Can a cat with PEP be helped if it is diagnosed early? Unfortunately, there is currently no specific treatment for this genetically determined disease. The disease will progress progressively in any case and will lead to the death of the animal from chronic renal failure. However, it is possible to somewhat slow down the malignancy of the course of PEP by adhering to a special diet aimed at constant replenishment of proteins, electrolytes and fluids washed out by the affected kidneys. Symptomatic detoxification therapy of chronic renal failure and associated anemia is carried out with medication. In addition to the medical problems associated with PEP, there are also problems in designing a breeding program for purebred Persian cats.
How to avoid the appearance of animals infected with PCP in the nursery or to effectively eliminate the PCP gene in nurseries with an existing problem? These questions are of concern to many breeders. Currently, breeders in the United States have a general "PCP-fear", similar to mass hysteria, which, in general, prevents them from calmly and consistently examining cats in the cattery in order to correct their breeder programs.
Most US breeders have screened all of their cats for PCP-affected animals.The results were very different. We recently received an email from Pam Norton, a professional breeder based in Southern Mississippi. She examined 19 cats in her cattery, of which 11 were PCP-positive, the rest - affected, with minimal signs of damage. Noel Newton, President of CFA's Atlantic Himalayan Club, also examined all of her cats and published the results of the diagnosis in the Club's journal. They turned out to be quite encouraging, as most cats were found to be free of the PKP gene. The concern of breeders with this problem is understandable, however, as in all cases of genetic diseases caused by dominant genes, this problem can be solved in a fairly short time with a correct and systematic approach to it.Veterinarians and breeders offer various ways and means of ridding their catteries and the population of Persian cats as a whole from this genetic ailment. For example, Paula T.Beall, a breeder from Texas, offers several solutions to this problem in a cattery with PEP cats.
1. Do not undertake anything, do not change your breeding program, since the dominant PEP gene has been present until now in more than one generation of these cats, which did not interfere with their breeding. In this case, as the disease manifests itself in maturing cats, exclude them and their offspring from the breeding program.
2. Check all the cats in the cattery without exception, castrate and distribute as pets to all those who have even the slightest changes in the structure of the kidneys. However, it should be remembered that not all kidney problems are associated with PEP, so valuable producers can be lost if PEP is overdiagnosed. The most highly effective in the diagnosis of PCP is genetic testing of blood DNA. However, this research is not available to all veterinary hospitals and is very expensive.
3. Check only those cats and cats that are planned for breeding. Allow only PCP negative cats to breed. If there are minimal changes in the kidneys of producers, postpone their breeding for a year for follow-up. In the absence of negative dynamics, include them in the breeding plan next year.
4. Check only adult breeders and only breed PEP negative cats. Their offspring must be free of the EPP gene. Leave these kittens. Cats that do not have cysts in their kidneys at 4 years of age will be genetically pure PEP. It is worth working with them further.
So, our main recommendations are as follows. Обследование почек всех производителей с помощью УЗИ с целью выявления больных и аффектированных кошек в питомнике. При наличии позитивных результатов необходимо обследовать родителей пораженных ПКП животных. Самый быстрый способ элиминации гена ПКП - исключение пораженных и аффектированных ПКП кошек из бридинг-программы (кастрация). В случае, когда пораженное животное представляет большую ценность в программе разведения (имеет интересные бридеру кровные линии или передает перспективный тип, хороший темперамент) и является гетерозиготным по гену ПКП (т.е. только половина котят унаследуют от данного родителя ген ПКП), допустимо использование его в разведении. Однако в данном случае необходимо раннее обследование полученных котят с целью отбраковки пораженных животных. При получении достаточного количества здоровых котят желаемого типа и качества от такого производителя следует все же исключить его из программы разведения. При приобретении нового животного в питомник следует удостовериться в ПКП-негативности его самого (если животное взрослое) и/или его родителей (в случае приобретения котенка до 10 месяцев). Бридеры США со всей серьезностью подошли к проблеме ПКП у персидских кошек, что позволяет надеяться на быстрое ее разрешение. В заключение всем разведенцам персидских кошек хочется пожелать удачи в составлении ПКП-негативных бридинг-программ, а вашим питомцам - крепкого здоровья.
Source: Larisa Voronina, Candidate of Medical Sciences, "Friend" magazine (cats) 1999 - 4