My cat has viral peritonitis, what should I do? Infectious or viral peritonitis in cats: symptoms and treatment
There are many dangers to the health of pets. Peritonitis in cats is considered one of the most serious diseases. Every owner must know the symptoms of this disease in order to prevent its development in time if the animal becomes infected.
Peritonitis is a disease in which inflammation of the membrane covering the internal organs occurs. The pathology is extremely dangerous because it is difficult to diagnose, and the survival rate even with timely diagnosis is extremely low.
The disease has been known to veterinary medicine for fifty years. To date, it has been sufficiently studied, however, an effective treatment method has not yet been created.
The virus that causes peritonitis - coronavirus - is localized in the tissues of the thyroid gland, as well as in kidney cells. The pathogen is resistant to external conditions, however, it dies when exposed to direct sunlight and high temperatures.
Animals aged from five months to two years are at risk. Individuals living in large numbers in a small area, as well as stray animals, are most susceptible to the disease. Young and elderly pets are most likely to contract the disease.
There are three types of peritonitis in cats:
- Bacterial species. The disease develops as a result of foreign pathogenic organisms entering the abdominal cavity. This can happen when the integrity of the digestive organs is violated, injuries, or tumor diseases in the digestive tract of the animal. Trauma to the mucous membranes, which subsequently provokes the occurrence of peritonitis, can be caused by microtrauma during the movement of hairballs and solid particles through the intestines.
- Viral. Occurs when the Coronavirus virus enters the body. The infectious agent is capable of mutation, coming into contact with the cells of the body, after which it spreads to all tissues and organs. The disease is extremely dangerous, since even with high-quality treatment, only one cat out of ten survives.
- Postoperative. May occur as a result of surgery. The development of pathology is provoked not only by the mistake of the operating doctor, but also by the weakened condition of the animal at the time of the intervention.
There are two forms of the disease in cats:
- wet,
- dry.
The wet form occurs as a result of the accumulation of fluid in the soft tissues of the peritoneum and its subsequent infection. 70% of cases are recorded in wet form. In the wet form, the inflammatory process involves many blood vessels, the elasticity of which decreases as a result of the disease. Due to the ingress of fluid (exudate) into tissues and organs, this form becomes acute.
The dry type is characterized by an accumulation of inflamed tissue in the abdominal cavity. In this form, fewer blood vessels are involved. The pathology is localized in small neoplasms - pyogranulomas - nodules resulting from inflammation.
Transfer methods
There are several routes of infection. Animals generally become infected through contact with each other. A cat can also catch the infection from waste products of an infected animal. Another way of infection is from a pregnant cat to a kitten.
That is, the disease is transmitted:
- By airborne droplets;
- Oral;
- Orally;
- Transplacental.
In large concentrations of animals in close areas, the risk of infection is greatest. Such places include nurseries, shelters and places where stray cats gather.
The postoperative type can occur after an incorrectly performed operation, including after sterilization. In case of violation of antiseptic and sanitary standards, as well as as a result of an error during the operation - violation of the integrity of the digestive organs or opening of abscesses.
Also, postoperative peritonitis can occur after a properly performed operation. The disease develops during infection of internal organs through an unhealed suture, and can also be caused by weakened immunity and low body resistance.
A cat carrying the peritonitis virus is a carrier for a long time. The incubation period ranges from three days to several weeks. All this time, the animal may not show symptoms of the disease, but infect others.
It has been noted that purebred animals are more likely to become victims of coronavirus. Pets who have recently encountered stressful situations are also at risk.
The least likely to get sick are pets who do not have free access to walks, as well as those who do not come into contact with unfamiliar animals.
However, even those animals that are kept at home and do not meet their relatives need to comply with sanitary standards. This especially applies to feeding areas and toilets.
Symptoms of peritonitis
Peritonitis develops rapidly, so the symptoms are pronounced. Depending on the form of the disease, the signs of the disease differ.
In the wet form, or exudative, the animal exhibits the following symptoms:
- Increased body temperature. Fever does not subside with antibiotics;
- Exhaustion of the body due to a complete lack of appetite;
- Enlargement of the peritoneum, the animal becomes pot-bellied;
- The accumulation of fluid may be localized in the chest area. In this case, the animal will breathe heavily and wheezing is possible;
- There is an increase in the size of the liver and lymph nodes;
- Digestion is disrupted, disorders are possible;
- With a long incubation period, kittens stop growing.
- The dry form of peritonitis has the following symptoms:
- The animal loses weight, it is apathetic and lethargic;
- Lymph nodes enlarge. Upon palpation, the doctor may detect an enlarged liver;
- Violation of the organs of vision - the eyes become cloudy, inflammation is possible;
- If the nervous system is damaged, the cat experiences convulsions, urinary incontinence, and the vestibular apparatus does not work properly.
Differences between enteritis and peritonitis
For a long time in medicine, these two concepts were synonymous. However, today it is reliably known: Enteritis and peritonitis are different diseases.
With enteritis, the intestinal mucous membranes are affected, which provokes their inflammation. In peritonitis, the virus enters the animal's immune cells. The principle of action of peritonitis is similar to the HIV virus in humans. It is for this reason that it is not yet possible to completely cure viral peritonitis in cats.
Diagnostics
Only a veterinarian can make or refute a diagnosis. However, if even a few symptoms are present, it is necessary to take the cat to the clinic for examination.
When making a diagnosis, the following factors are taken into account:
- Number of animals living in one territory;
- The condition of the animal shortly before the onset of symptoms: indigestion, sneezing;
- Having contact with other cats;
- Have you had any recent surgical interventions?
A blood test may also be needed. A biopsy is performed. For diagnostic purposes, ultrasound examination, laparoscopy and X-ray examination are also performed.
Treatment of the disease
The prognosis for a cat with a viral type of disease is unfavorable. Almost all animals that fall victim to the virus die. Only strong individuals whose organs have been partially affected by the infection can be treated. 
For minor tissue damage, maintenance therapy and a course of antibiotics are prescribed. In some cases, a blood transfusion may be needed.
The severe form of the disease is incurable.
It is important to understand that the wet form of peritonitis inevitably leads to the death of the animal. With a favorable prognosis, it is only possible to maintain the animal’s condition through intensive therapy. However, cats whose bodies are weakened and cannot resist the virus must be euthanized.
Prevention
Since the disease peritonitis in cats is incurable, prevention of this disease is the most important measure.
With any medical intervention, it is necessary to minimize the possibility of inflammation. It is inflammatory processes that are the “breeding ground” of the peritonitis virus.
There is a vaccine, the effect of which is aimed at strengthening the cat’s immunity and resistance to coronavirus, however, the effectiveness of such a measure has not been proven.
Peritonitis is a dangerous disease, so every attentive owner should know the causes of its occurrence and become familiar with the symptoms of the disease.
If you have questions on the topic, ask us in the comments section.
An attentive owner will definitely notice changes in the behavior of his pet. Owners of young cats and those whose age limit has crossed the 11-year-old line should be on their guard. Viral peritonitis is a dangerous disease.
Viral peritonitis in cats - what is the danger
When a person decides to have a pet, he is well aware that this is a huge responsibility. When bringing an animal into your home, you need to clearly understand that now the life and health of this furry creature depends entirely on your care. Feeling this, the cat or dog will repay with devotion and love, giving a lot of unforgettable moments.
Most often, a pet becomes a full-fledged member of the family, and in the event of its illness, they worry about it as a loved one. The loss of a four-legged friend is especially painful for children and lonely people. To protect your family pet from diseases and loved ones from shocks, it is better to find out in advance about possible diseases in cats to prevent their development.
Viral peritonitis primarily affects young cats under two years of age and individuals after eleven. This does not mean that the disease is not scary for those who do not fall into this group. Infectious peritonitis in cats is caused by a virus of the coronavirus genus. But if, according to scientists, coronavirus is present in the body of every cat, then peritonitis is caused by its mutating forms. It is believed that the mutation occurs after the animal has suffered stress. This disease is rare - about 10% of animals become infected with this disease, but, unfortunately, the number of deaths is 100%. A natural question arises: why such a high mortality rate? The fact is that this disease is relatively young. It has been known to science only since the 80s, so very little has been studied. To date, there are only assumptions about the origin of this disease. A cure has not yet been found. Doctors can only alleviate the animal's suffering. In addition, there is no vaccination, which makes the situation worse.
As mentioned above, cats under two and after eleven years of age suffer first of all. It was found that the infection occurs orally. Sources of infectious peritonitis can be:
- contaminated food, if it was previously eaten by a cat who is a carrier of the disease;
- feces containing the virus accidentally entered the animal’s mouth;
- cats licking each other;
- mating of animals in nurseries;
- infection of the kitten by the mother.
Another version of the development of the disease is a mutation of the coronavirus. That is, it is known that this virus is present in every pet, but until a certain point it does not make itself felt. After an animal experiences stress or illness, the virus mutates and viral peritonitis occurs.
Symptoms of viral peritonitis
Every loving owner will notice the slightest change in the condition of their beloved four-legged friend. You should be alert to the following unusual phenomena:
- lack of appetite;
- weight loss;
- increase in abdominal volume;
- depression;
- shortness of breath;
- dryness of the upper eyelid;
- change in the shape of the pupil.
How does infectious peritonitis occur in cats?
Viral peritonitis has two forms of manifestation:
- Exudative form of the disease. Also called “wet”. It is characterized by sweating (accumulation) of fluid in the stomach, which leads to inflammatory processes. Fluid can also form in the heart, disrupting the functioning of this organ.
- Non-exudative form or dry, accompanied by damage to the eyes, internal organs, and nervous system.
Unfortunately, after 2-5 weeks the affected animal dies.
The first thing you need to pay attention to is a sharp decrease in the pet’s weight, with an increase in the abdomen. The cat may behave strangely, for example, change its mood quickly. Paralysis of the limbs, most often the hind limbs, is observed.
If you notice these symptoms, you should immediately go to the veterinarian. To make a diagnosis, a puncture of the abdomen is performed. But only after autopsy of an already deceased animal can it be confirmed.
Treatment for peritonitis
Due to insufficient research into this disease, there is currently no way to cure the affected pet. The disease irreversibly affects the internal organs, and they stop functioning. Doctors administer antimicrobial and antiviral drugs. Fluid is pumped out from the abdominal cavity. But this does not give positive results, and the animal still dies.
It should be remembered that this disease is not transmitted to humans. That is, you can care for your pet without fear of being infected.
Disease prevention
If infectious peritonitis cannot be cured, you can try to protect your cat from the possibility of acquiring it. To do this, you need to follow the following recommendations of leading veterinarians:
- protect the cat from communicating with other cats;
- if you have several animals, you need to constantly keep the toilet clean and wash the trays with disinfectants;
- prevent stress in your pet;
- provide adequate nutrition;
- Avoid visiting places where there are a large number of cats.
Viral peritonitis causes pathomorphological changes in the animal's body. There is no cure for it, only relief of the symptoms. In order not to encounter this terrible disease, you need to remember all the recommendations of specialists and take care of your pets.
Infectious peritonitis is a viral disease of cats characterized by peritonitis, fever, tissue dehydration, abdominal edema and anorexia (refusal to feed).
The disease in cats occurs in three forms - exudative (wet), proliferative (dry) and in most cats the disease is asymptomatic.
Cats aged 6 months to 5 years are more often affected.
Pathogen– RNA – containing a virus belonging to the genus Coronavirus, family Coronaviridae. Virions are polymorphic, 80-120 nm in size. On the surface of the virion there are characteristic club-shaped protrusions in the form of a solar corona. The virus is antigenically homogeneous and serologically identical. The virus multiplies in the culture of kidney and thyroid cells, is well preserved at low temperatures, but is very sensitive to heat and light.
Epizootological data. The source of the infectious agent is sick and recovered cats. The virus is shed in cats starting from the second half of the incubation period and for 2-3 months after recovery through nasal discharge, urine and feces. Infection with infectious peritonitis in cats mainly occurs through the nutritional route, through the mouth; it is also possible for a cat to become infected by airborne droplets.
Only cats, sometimes kittens, are sensitive to the pathogen.
Pathogenesis. The coronavirus that causes infectious peritonitis has little affinity for intestinal epithelial cells. Initially, the virus multiplies in macrophages, which spread it throughout the cat’s body. As a result, the infection becomes generalized.
Once the coronavirus enters the cat’s body, it first multiplies in the tonsils or intestines and only then enters the regional lymph nodes. As a result, primary viremia occurs. Through the bloodstream, the virus is introduced into many organs and tissues, especially those that contain a large number of blood vessels and have many macrophages.
Subsequently, the sick cat develops secondary viremia due to the spread of the virus in macrophages.
In the case when the cat has good resistance and is capable of a full immune response, the multiplication of the coronavirus in macrophages will not occur and the disease will not develop in the cat.
If the cat does not have an adequate immune response, despite the presence of specific antibodies, the coronavirus will continue to multiply in macrophages. Macrophages will accumulate around blood vessels, mainly under the serous membranes and interstitium of various organs, leading to the development of an exudative form of infectious peritonitis. This form of peritonitis in cats develops quickly and causes death of the cat within a few weeks.
When the immune response is weak, the cat develops a proliferative form of the disease. The infection process lasts up to 6 months.
Symptoms. Symptoms of the disease in cats depend on the age, number and virulence of the pathogen and the strength of the immune response.
In kittens, the disease is accompanied by a complete loss of appetite (anorexia), body temperature rises to 40° C or more, peritonitis, and in some animals, pleurisy.
In adult cats, viral peritonitis occurs in two forms: exudative and non-exudative.
Exudative form viral peritonitis is accompanied by accumulation of exudate in the abdominal or thoracic cavity. During a clinical examination, the veterinarian notes shortness of breath, upon auscultation, an irregular heart rhythm due to the accumulation of fluid in the cardiac membrane, and murmurs in the lungs. As a result of the accumulation of fluid in the abdominal cavity (ascites), we note an increase in the volume of the abdomen and its sagging.
Non-exudative form viral peritonitis occurs with damage to the eyes (conjunctivitis, damage to the retina and iris), liver (enlarged liver, visible mucous membranes are anemic and icteric), kidneys (glomerulonephritis), lungs (), central nervous system (paresis of the limbs, manege movements, increased skin sensitivity). This form of viral peritonitis ends in the death of the animal after a few weeks or months.
With conjunctivitis, owners note purulent discharge from the eyes. An ultrasound examination reveals granulomas on the surface of the kidneys; the liver is enlarged, lumpy, with foci of necrosis.
Diagnosis A diagnosis of infectious peritonitis in a veterinary clinic is made based on the symptoms of the disease, the results of ultrasound and hematological examinations, in the case of an exudative form, examination of ascites fluid, and the results of an X-ray examination of the chest and abdominal cavities. Blood and ascites fluid are examined in a veterinary laboratory using PCR.
Differential diagnosis. When conducting a differential diagnosis of the exudative form of infectious peritonitis, veterinary specialists must exclude bacterial peritonitis, ascites of cardiac and renal origin, tumors, trauma and heart failure; in the non-exudative form of the disease - toxoplasmosis, tuberculosis, lymphosarcomatosis.
Treatment. Treatment of the disease must be comprehensive. A sick cat is prescribed a diet consisting of easily digestible and fortified foods. A course of antibiotic therapy from the group of cephalosporins and sulfonamide drugs is prescribed, which must be administered intramuscularly, subcutaneously and intravenously, taking into account the severity of the animal. If ascites is present, a puncture of the abdominal cavity is performed to evacuate the exudate. Prescribe tylosin (160 mg/kg) for two days, prednisolone (2 mg/kg), diuretics (hexamethylenetetramine, Lasix, veroshpiron, etc.). Symptomatic treatment is carried out - taking painkillers, to maintain the cardiovascular system - cardiac drugs (sulfacamphocaine, caffeine). Sometimes a sick cat is given a blood transfusion. If a cat develops acute peritonitis, apply cold to the abdominal area in the first hours. Sometimes veterinary clinics prescribe chemotherapy and hormonal drugs.
Prevention. Prevention of infectious peritonitis consists of general preventive measures - complete, balanced feeding. Periodic treatment against and ticks. While walking, avoid contact with stray animals. Avoid the use of hormonal drugs. Based on the fact that the virus is weakly resistant and is easily destroyed by simple disinfectants, it is recommended to use ammonia or bleach diluted with water (1:32), owners should regularly disinfect the premises for cats.
Feline infectious peritonitis is a subacute or chronic viral disease of wild and domestic cats, caused by one of the feline coronaviruses. The disease manifests itself in three forms - exudative (wet), proliferative (dry), and in 75% of cats in a latent (asymptomatic) form.
Most often, infectious peritonitis affects animals aged 6 months to 5 years.
Pathogen- An RNA virus belonging to the genus Coronavirus, family Coronaviridae. Virions are polymorphic, 80-120 nm in size. On the surface of the virion there are characteristic club-shaped protrusions in the form of a solar corona. The virus is antigenically homogeneous and serologically identical. It multiplies in cultured kidney and thyroid cells of kittens, is well preserved at low temperatures, but is very sensitive to heat and light.
Epizootology. The source of the infectious agent is sick and recovered cats. A sick animal, starting from the second half of the incubation period and for 2-3 months after illness, excretes the virus in feces, urine and nasal discharge. Animals are mainly infected orally, but airborne transmission cannot be ruled out. Other epizootological aspects of the disease have not been studied.
Only cats are susceptible to the pathogen, and kittens are much more sensitive than adult animals.
Mechanism of disease development. Strains of coronavirus that cause infectious peritonitis have little affinity for intestinal epithelial cells (enterocytes). Initially, the virus multiplies in macrophages, and they spread it throughout the body. This is the main link in the pathogenesis of infection, which explains the generalized nature of the manifestation of the disease in cats.
The virus first multiplies in the tonsils or intestines and then spreads to regional lymph nodes. In this case, primary viremia occurs. The virus is carried through the blood into many organs and tissues, especially those that contain a large number of blood vessels and contain many macrophages.
Subsequently, secondary viremia occurs due to the spread of the virus in macrophages.
If the animal is capable of a full immune response, then the virus will not continue to multiply in macrophages and the disease will not develop.
In the absence of an adequate immune response, despite the presence of specific antibodies, the virus will continue to multiply in macrophages. Macrophages, in turn, will accumulate around blood vessels, mainly under the serous membranes and in the interstitium of various organs, causing the exudative form of infectious peritonitis. This form of the disease develops relatively quickly and leads to the death of the animal within a few weeks.
If the immune response is weak, then a proliferative form of the disease develops. With it, macrophages accumulate in tissues in smaller numbers. The virus multiplies in macrophages less intensively than in the exudative variant of the disease. The infectious process occurring in this form lasts up to 6 months.
In some animals, the disease may subside for a short time due to a sufficient immune response, but then reappears.
Immunity when cats are infected with the causative agent of infectious peritonitis can be significantly weakened if the infection was preceded by infection with leukemia or immunodeficiency viruses. It is known that 20-50% of cats that develop infectious peritonitis have previously been infected with the leukemia virus.
Preceding infection by the causative agent of infectious peritonitis, the presence of antibodies to coronaviruses, as well as the intensive production of defective neutralizing antibodies (which do not neutralize the antigen) leads to the formation of antigen-antibody complexes. The complexes attach to macrophages, which, while in the blood, carry them through the blood vessels. In the blood vessels, complement is added to the antigen-antibody system; the complexes thus formed are attached to the walls of blood vessels. The complexes are phagocytosed by macrophages, which stimulate the accumulation of neutrophils through the chemotaxis factor, which ultimately leads to damage to the vascular wall.
These changes, which are essentially immune, occur in the walls of small blood vessels (venules, arterioles), mainly located under the serous membranes of various organs and cavities, in the parenchyma of the liver and kidneys. Clusters of cells - macrophages, neutrophils, lymphocytes - form around the blood vessels.
Damage to the vascular wall leads to effusion of protein-rich fluid into the serous cavities - changes characteristic of the exudative form of infectious peritonitis occur.
Symptoms. The incubation period ranges from several weeks to several months. Symptoms vary depending on the age of the cat, the number and virulence of the pathogen, and the strength of the immune response.
Typical clinical signs in kittens are anorexia, increased body temperature to 40°C and above, peritonitis, and sometimes pleurisy. In older cats, the disease clinically manifests itself in two forms: exudative and non-exudative.
- Exudative form characterized by the accumulation of exudate in the abdominal or thoracic cavity, which leads to shortness of breath, the appearance of noise in the lungs and heart.
- Non-exudative form accompanied by damage to the eyes (conjunctivitis, damage to the iris and retina), kidneys (glomerulonephritis), liver (jaundice, enlarged borders, pain), lungs (catarrhal bronchopneumonia) and the central nervous system (increased skin sensitivity, manege movements, paresis of the limbs). This form of the disease ends in the death of the animal after 2-5 weeks, sometimes after several months.
With conjunctivitis, purulent masses are released from the eyes. Ultrasound detects granulomas on the surface of the kidneys. In this study, the liver is enlarged, lumpy, with foci of necrosis.
Pathological changes. Cats that die from infectious peritonitis are usually emaciated.
Peritonitis is found in most dead animals. Up to 1 liter of exudate can accumulate in the abdominal cavity. The liquid is usually almost transparent, opalescent, viscous, intensely or slightly yellow. It may contain fibrin flakes and threads.
Serous surfaces are often covered with fibrin, giving the membranes a dull, granular appearance. Fibrin often lies on the serous covers of internal organs, causing fragile adhesions between them. On the serous covers there are white foci of necrosis, as well as masses of dense exudate in the form of small plaques and nodules that penetrate the organs (liver, intestinal wall and others). Plaques and nodules range in size from 2 to 10 mm in diameter (according to A. A. Kudryashov).
The mesentery is usually thickened and dull.
The kidneys are often enlarged with the presence of several white dense nodules under the fibrous capsule, protruding into the cortex.
There are also small white lesions in the liver and pancreas.
There is usually less exudate in the pleural cavities than in the abdominal cavity. Under the pleura there are often multiple white lesions, similar to lesions in other organs. The lungs are usually compacted and dark red in color. In some cases, hydropericardium or serous pericarditis is diagnosed (according to A. A. Kudryashov).
The lymph nodes of the abdominal and thoracic cavities are usually enlarged. Their pattern is clearly visible in the section.
In animals with the proliferative form of infectious peritonitis, inflammatory foci are found in various organs of the chest and abdominal cavities, in the central nervous system, and eyes.
Diagnosis based on the results of serological and molecular genetic studies (PCR). When diagnosing infectious peritonitis, great importance is attached to the results of autopsy of dead animals and histological examination.
In the differential diagnosis of the exudative form of infectious peritonitis, bacterial peritonitis, toxoplasmosis, ascites of cardiac and renal origin, tumors, heart failure and trauma should be excluded, and in the non-exudative form of the disease - lymphosarcomatosis, tuberculosis and toxoplasmosis.
Treatment. To alleviate the general condition of the animals, punctures are performed and the exudate accumulated in the abdominal (or thoracic) cavity is removed. At the same time, diuretics are used in therapeutic doses. To suppress pathogenic microflora, antibiotics are prescribed under the supervision of a veterinarian. It is advisable to use prednisolone and other glucocorticoids in therapeutic doses.
Symptomatic treatment should include various vitamins, especially groups B and C, and multivitamin preparations. Immunostimulants are indicated, especially immunoglobulin and interferon. The dose and course of treatment should be prescribed by a veterinarian.
Prevention. A live modified vaccine is currently available. It is used only in extreme cases.
Infectious peritonitis is most dangerous when cats are kept in groups, in cat hotels and catteries. Fortunately, the virus is not resistant and is easily destroyed by simple disinfectants. To do this, you can use ammonia or bleach diluted with water (1:32). It is necessary to regularly disinfect the premises for cats.
It is necessary to periodically check catteries and all cats in the house for infectious peritonitis. Kittens are tested for coronavirus at 12-16 weeks.
Feline infectious peritonitis was discovered in 1963. The causative agent, coronavirus, was originally named feline infectious peritonitis virus. It was subsequently discovered that many healthy cats had antibodies to this coronavirus in their blood, and it was suggested that these cats were infected with a non-virulent coronavirus called feline enteric coronavirus.
At the time, it was thought that enteric coronavirus resided exclusively in the intestines and would only cause mild diarrhea in kittens; however, subsequent studies showed that many clinically healthy cats were viremic, suggesting that the spread of the virus was not limited to the intestines.
Epidemiological studies have shown that up to 10% of cats with antibodies to coronavirus develop infectious peritonitis. It is now believed that the virulent infectious peritonitis virus arises as a result of mutation of feline enteric coronavirus in the body of individual animals, which can then develop peritonitis. Since infectious peritonitis virus and enteric coronavirus could no longer be considered viruses of different groups, the broader name "feline coronavirus" was adopted.
There are many strains of this virus, varying greatly in virulence; however, there is no reliable method to differentiate virulent from avirulent strains.
Spreading
Many cats, especially those kept in groups, are infected with coronavirus.
The percentage of cats that respond positively to serological testing is:
- 82% at cat shows
- 53% purebred cats
- 28% of domestic cats kept in groups
- about 15% of domestic cats are kept alone.
Up to 10% of cats infected with coronavirus and living in large groups develop infectious peritonitis, while this is rare in cats living alone or in small stable groups.
Pathogenesis
The route of transmission of coronavirus is mainly nutritional, through contaminated feces. When infected through the oral or nasal cavity, initial viral replication occurs in the epithelial cells of the pharynx, respiratory tract, or intestines. Most infections at this stage are asymptomatic. There may be signs of mild enteritis, but chronic or severe diarrhea is possible. Most cats clear the virus over time and do not develop peritonitis.
In some cats, after viral replication in epithelial cells, viremia develops, leading to infection of target cells - macrophages. Virus-specific antibodies can increase the infectivity of the virus against macrophages; cats with viral peritonitis often have high titers of antibodies against coronavirus. The virus binds to antibodies, forming immune complexes that accumulate in the walls of small blood vessels, where they activate complement and coagulation cascades, leading to immune-mediated vasculitis.
After this, two options for the development of pathology are possible.
- First, the involvement of many blood vessels in the process leads to an increase in their permeability and the accumulation of protein-rich effusion in the body cavities and other spaces, sometimes including the heart sac and scrotum. The result of this process is the development of exudative, or “wet” peritonitis.
- The second option: when a smaller number of vessels are affected, the course of peritonitis is more chronic, characterized by the formation of individual pyogranulomas in various tissues of the body. As a result, a non-exudative, or “dry” form of peritonitis develops.
Factors that determine whether a cat infected with coronavirus will develop pathology include:
- strain – different strains of coronavirus vary in virulence
- dose – infection with the virus at higher titers increases the risk of developing peritonitis
- stress – cats with peritonitis were usually stressed 3–6 weeks before developing FIP, and several months before developing dry peritonitis
- Genetically determined susceptibility – some cat breeds are likely to be more susceptible. This suggests that there is a genetic predisposition to the development of infectious peritonitis, possibly related to certain MHC gene loci.
Clinical signs
Anamnesis
Exudative (“wet”) and non-exudative (“dry”) peritonitis occur with different symptoms. Since they reflect different aspects of the same clinical process, in some cases signs of both forms are observed.
The history and clinical signs of infectious peritonitis vary widely, depending on the form of the disease.
In addition to the usual medical history, several other factors are important for the diagnosis of peritonitis:
- Was the cat adopted from a breeder, a multi-pet shelter, or an animal boarding facility in the last few weeks or months? In these situations, the likelihood of contracting coronavirus is greater.
- Has the cat been stressed in the last few weeks, such as house changes or surgery? Exudative peritonitis, an acute form of infectious peritonitis, usually develops within 3-6 weeks after a stressful situation in the cat's life
- Age of the cat? Despite the fact that cats of all ages suffer from peritonitis, 80% of sick animals are under 2 years of age. Cats of both sexes are equally susceptible
- Cat breed? Although cats of all breeds are affected, purebred cats make up a much larger percentage.
- Have you had any history of diarrhea, coughing or sneezing in the last few weeks? Diarrhea and mild respiratory symptoms may precede the development of both forms of fulminant infectious peritonitis
- Do you have a history of contact with cats, especially from the same litter, with infectious peritonitis?
Clinical examination
Exudative or “wet” infectious peritonitis:
At exudative peritonitis the following signs predominate:
- Ascites and/or pleural effusions
- Activity and preserved appetite, or lethargy and anorexia
- In some cases, mild fever; has a tendency to fluctuate
- With effusion into the pleural cavity - breathing problems
- Weight loss
- On palpation – enlarged mesenteric lymph nodes and liver
- Spread of the pathological process involving other abdominal organs (this leads to the appearance of symptoms of their dysfunction, for example, hepatopathy, renal failure, pancreatic diseases)
- Damage to the central nervous system and eyes - sometimes observed with effusion peritonitis, although they are more typical for dry peritonitis.
Non-exudative or “dry” peritonitis: clinical signs are often mild, nonspecific and varied; This condition is one of the most difficult to diagnose.
Characteristic features include:
- Weight loss
- Lack of appetite
Other symptoms depend on which organs are affected and the extent of the damage. These include:
- Eyes – uveitis, deposits on the cornea, vitreous opacification and aqueous humor opalescence, lymphocytic infiltration of retinal vessels, retinal pyogranuloma
- Central nervous system - formation of pyogranulomas and development of hydrocephalus, leading to nystagmus, vestibular disorders (eg, head tilt), seizures, cerebellar ataxia, cranial nerve dysfunction, paresis, loss of proprioceptive sensation, urinary incontinence, or behavioral changes. Nervous symptoms are observed in 10% of cases of dry feline infectious peritonitis
- Intestine – thickening of the colon wall
- Mesenteric lymph nodes – enlarged on palpation
- Liver – jaundice and enlargement
- Kidneys – pyogranulomas, can be palpated
Differential diagnosis
In table Table 1 lists the main differential diagnoses of exudative peritonitis and indicates the methods of differentiation. It is especially difficult to differentiate the exudative form of peritonitis from inflammatory lymphocytic cholangitis. Both diseases can present with similar symptoms: weight loss, anorexia and ascites. The pattern of ascites fluid is the same in both cases (see Fig. 9.4), and changes in serum biochemical properties and hematological properties are also similar, although cats with infectious peritonitis are more likely to develop non-regenerative anemia. Other symptoms may help differentiate these diseases, such as uveitis or pleural effusion from infectious peritonitis. Cats with lymphocytic cholangitis tend to be more active than cats with peritonitis, and polyphagia is sometimes present. If clinical differentiation is not possible, a liver biopsy may be required.
In table Table 2 lists the main differential diagnoses for dry peritonitis.
|
Pathology |
Method of differentiation from infectious peritonitis |
|
Cardiomyopathy |
Transudate with low protein content (less than 35 g/l). X-rays may reveal an enlarged or round heart. Ultrasound of the heart |
|
Liver diseases (lymphocytic cholangitis, cholangohepatitis, cirrhosis) |
If the ascites fluid resembles an altered transudate rather than an exudate, infectious peritonitis can be excluded. However, in some liver pathologies associated with vascular obstruction after hepatitis, the effusion may contain large amounts of protein, as in infectious peritonitis. Ascites fluid can be examined using the reverse CPR method; if this is not possible, exploratory laparotomy and biopsy may be required. A bile acid stimulation test is useful in diagnosing cirrhosis. |
|
Liver tumors |
As in the previous case, the tumor is diagnosed using ultrasound |
|
Purulent serositis |
Foul-smelling, opalescent exudate containing bacteria and large numbers of white blood cells with degenerative neutrophils |
|
Lymphosarcoma |
In thymic lymphosarcoma, a lateral chest x-ray may reveal a mass cranial to the heart and possibly a high location of the esophagus. With lymphosarcoma in the abdominal cavity, organ enlargement is possible. Fluid analysis usually reveals a low protein content, and the cell population consists of lymphocytes rather than neutrophils and macrophages |
|
Pregnancy |
Diagnosis by palpation of the abdomen; It is impossible to pump out the fluid with paracentesis; kittens can be seen on an x-ray or ultrasound of the uterus |
|
Obesity |
Diagnosis by palpation of the abdomen, it is impossible to pump out fluid with paracentesis, there are no signs of ascites on ultrasound and x-ray |
Table 1: differential diagnoses for feline infectious peritonitis and methods of differentiation. Conditions are listed in order: the most common misdiagnoses are at the beginning of the table, less common ones are at the end
|
Clinical sign |
Differential diagnosis |
|
Chronic weight loss, anorexia, low-grade fever |
Feline leukemia virus, feline immunodeficiency virus, neoplasms, hyperthyroidism in old cats |
|
Eye lesions |
Immunodeficiency virus (uveitis), feline leukemia virus, toxoplasmosis, fungal infections, idiopathic diseases |
|
Cholangiohepatitis, Nemobartinellafelis, biliary obstruction, autoimmune hemolytic anemia |
|
|
Nervous symptoms |
Trauma, portosystemic shunts, feline leukemia virus, feline immunodeficiency virus, toxoplasmosis, neoplasms, feline spongiform encephalopathy |
Table 2: Differential diagnoses for the variety of clinical manifestations of FIP
Diagnostics
Contrary to many claims, there are no simple methods for diagnosing infectious peritonitis in a living animal, other than biopsy and histology of the affected tissue. Many available test systems detect infection with coronavirus, and reverse CPR detects feline coronavirus (see below).
No method can distinguish a virulent strain of coronavirus from an avirulent one, although some methods can differentiate isolates obtained in the laboratory. In most cases, the diagnosis of “feline infectious peritonitis” (of any form), made on the basis of clinical signs and history, requires additional research using several diagnostic methods, the results of which, corresponding to each other, can suggest this disease.
These methods include:
- Clinical pathology for the diagnosis of organ damage
- Analysis of abdominal or thoracic effusion
- Serological tests to detect virus infection
- Reverse CPR for virus detection
- Histopathological examination of affected tissues; This is the only method to make a definitive diagnosis of infectious peritonitis.
In table 3 lists the different methods and examples of their use. In table 4 presents all the methods currently available for determining coronavirus and antibodies to it, and lists the clinical situations in which these tests are used.
Table 3: laboratory methods used to diagnose feline infectious peritonitis and materials required for testing by each method
|
The test determines |
Available test systems |
Clinical situations in which the method can be used |
|
Antibodies |
Immunofluorescence method, enzyme-linked immunosorbent assay (e.g. IDEXX Snap*) immunoimmigration rapid analysis* |
Diagnosis of feline infectious peritonitis (in combination with other methods and clinical examination) Testing cats that have been in contact with patients with peritonitis to determine whether it may be infectious Check before mating Checking before placing a cat with animals free from coronavirus |
|
Reverse CPR |
Diagnosis of exudative infectious peritonitis (exudate is taken for analysis) Examination of a cat that has been in contact with patients with peritonitis to determine whether it was infectious; repeat studies are required Checking family animals for the presence of coronavirus Check before sharing with animals free from coronavirus; repeat studies are required |
|
|
Virus in tissues |
Immunohistochemistry |
Making a final diagnosis, especially with questionable histology results |
|
Pathological changes |
histopathology |
Making a final diagnosis |
Table 4: a list of diagnostic methods to determine exposure or infection with feline coronavirus, and clinical situations for which the methods are recommended.
Clinical pathology
Changes in serum biochemistry depend on organ damage and duration of the disease. Hyperglobulinemia (sometimes monoclonal gammopathy) and increased concentrations of α1-acid glycoprotein are consistently observed (see below). Nonspecific blood changes may include neutrophilia (often with a left shift), lymphopenia, and nonregenerative anemia. Such changes are more typical for dry peritonitis. Coagulopathies are possible.
Nature of peritoneal fluid
Fluid analysis can reveal changes characteristic of infectious peritonitis or exclude it.
Effusion from infectious peritonitis is usually characterized by the following properties:
- Usually straw colored and always sterile
- High protein content (more than 35 g/l), foams when shaken, may form clots when standing for several hours at room temperature
- If the albumin/globulin ratio is less than 0.4, the likelihood that this is infectious peritonitis is high; more than 0.8 is unlikely; with a value between 0.4 and 0.8 it is possible but uncertain
- An α1-acid glycoprotein concentration of more than 1500 mg/ml (Dutee et al., 1997) is characteristic of infectious peritonitis
- Total nucleated cell count less than 5000 cells/ml (mainly neutrophils and macrophages)
- When tested using the reverse CPR method, the reaction is positive (see below)
Serological methods
Serological methods are used:
- for the study of cats with suspected infectious peritonitis
- for the study of cats that have been in contact with cats possibly suffering from infectious peritonitis
- at the request of the cat breeder
- to check cats living in the house for the presence of coronavirus
- to check cats before sharing them with others who are free from coronavirus
Interpreting the results of serological methods can be difficult because:
- Cats with similar clinical signs may occasionally test positive, especially pedigree cats; therefore, although high titers of antibodies in cats in combination with clinical signs are characteristic of peritonitis, this has no diagnostic value
- Some cats with exudative peritonitis have low antibody titres or react negatively, possibly due to the sheer volume of viral particles in the body, causing all antibodies to be bound and therefore unable to bind to the test antigens
- Some serological tests detect the presence of antibodies without measuring titers (eg, rapid immunoimmigration test, Snap), while others (Immunocomb®, immunofluorescence test) measure titers. The results, expressed in titres, are useful for monitoring individual cats or a group of cats from the same owner for freedom from coronavirus.
Interpretation of serological test results in all cats
Exudative infectious peritonitis: Although serological methods are used to diagnose exudative infectious peritonitis, they should be used only in cases where the clinical signs, albumin/globulin ratio, α1-acid glycoprotein content and cytological properties of the effusion are characteristic of peritonitis. Cats with exudative peritonitis may react negatively, but may also have antibodies, including high titers. Cats with other medical conditions can sometimes have antibodies to the coronavirus, especially if there are other cats in the household or if they were adopted from a shelter or breeder in the last 6 to 12 months.
Dry infectious peritonitis: Coronavirus antibody titers determined by immunofluorescence are usually 640 or higher. Titers less than 160 almost always exclude dry peritonitis. The detection of antibodies in a healthy cat is mistakenly mistaken for the early stage of dry peritonitis.
Interpretation of serological test results in healthy cats
Testing of healthy cats that have been in contact with cases: Healthy cats that have been in contact with cases of infectious peritonitis or sources of infection are tested for one of two reasons described below. In any case, it is necessary to explain to the owner that the cat is likely to be seropositive.
Almost all cats that come into contact with the source of infection become infected. This does not indicate a poor prognosis, as less than 10% of infected cats develop peritonitis; most often the body is freed from the virus and the animals begin to react negatively.
In a situation where the owner is going to get another cat to replace the one that died from infectious peritonitis and wants to know whether a cat that has been in contact with a sick person is spreading the virus:
- If a cat that has been in contact with a sick cat reacts negatively to a serological test, it is unlikely to be infected and therefore not spreading the virus; Is it safe to get a new cat?
- If a cat reacts positively (that is, has an antibody titer of 1:10 or more), there is a 1 in 3 chance that it will spread the coronavirus, so getting another cat would not be wise (unless the new cat has antibodies indicating that she was in contact with a source of infection). The cat should be retested after 3–6 months to determine whether the antibody titer has decreased. In most cats that are cleared of the virus, antibodies disappear within 3 months to several years. Ideally, cats that react positively should be separated from negatively reacting indoor cats. As soon as a cat begins to react negatively, it should be moved to an appropriate group to avoid reinfection from other cats.
If the owner wants to know the prognosis for a cat that has been exposed to a source of infection:
- If your cat reacts negatively, she most likely is not infected and will not develop FIP.
- If the cat reacts positively, it may develop peritonitis, but the likelihood of this is small (less than 1:10)
Checking breeding cats
Breeders often ask for animals to be examined before mating. In this case:
- A cat that reacts negatively is most likely not infected and is not shedding the virus and can therefore mate with animals that react negatively.
- If the cat reacts positively, it would be wise to find a partner who also reacts positively to reduce the risk of introducing the disease into the virus-free group. Isolation and early weaning are necessary to prevent kitten infection.
Testing a group of cats for coronavirus: A random sample of 3 or 4 cats living together for a study will show whether the coronavirus is endemic as it is highly contagious.
Homes that have fewer than 10 cats, or where cats live in isolated groups of 3 or fewer animals, often eventually clear the infection. Testing every 6 to 12 months will help determine when this occurs as antibody titers drop and more cats begin to react negatively. To avoid re-infection, it is recommended to separate negatively reacting cats from positive reactors.
Checking a cat being placed in a coronavirus-free group: Only cats that react negatively should be introduced into infection-free groups. Cats that have antibodies can be isolated and retested every 3 to 6 months until the result is negative.
Reverse CPR
The reverse polymerase chain reaction amplifies a selected portion of the viral nucleic acid to concentrations that allow it to be detected.
The method is sensitive but requires strict precautions to avoid contamination leading to false positive results. Some laboratories claim to have reverse CPR tests for diagnosing FIP and can even predict the likelihood of a healthy cat developing peritonitis; however, at the time of writing, when analyzing the gene sequences of several strains of infectious peritonitis virus and feline enteric coronavirus, the mutation responsible for virulence was not found. Due to the variability of the coronavirus genome, it is unlikely that a test system will ever be available that can distinguish between virulent and non-virulent strains (Horzinek, 1997). Feces, blood, saliva, or effusion can be collected for testing, although monitoring viral shedding in saliva is not useful because it stops long before fecal shedding stops.
Reverse CPR can be used to diagnose infectious peritonitis:
- The presence of coronavirus RNA in effusion is a probable but not definitive sign of infectious peritonitis
- Positive results in a blood test using the CPR method do not allow a diagnosis of infectious peritonitis to be made, since healthy cats or cats with other diseases can also react positively.
- A negative result obtained from a blood test using reverse PCR does not exclude the possibility of infectious peritonitis, since sick cats may react negatively.
Reverse CPR can be used to monitor the spread of the virus in a home where disease control is being carried out.
Cats can be divided into 3 types:
- Most cats infected with coronavirus shed the virus for a while, have antibodies, then the shedding stops and the antibodies disappear; the cats are then re-infected and the cycle repeats
- A small group of cats carry the virus and spread it continuously
- A small group of cats show resistance to the spread of the virus
Table 5 scheme of measures to prevent coronavirus infection in kittens:
Preparing a room for kittens
1. Remove all cats and kittens a week before placing the mother
2. disinfect the room with a hypochlorite solution at a dilution of 1:32
3. allocate baskets for kittens, bowls for food and water specifically for this room and disinfect them with a hypochlorite solution
4. Indoor the cat 1-2 weeks before giving birth
Prevention of indirect spread of the virus
1. Enter the room with kittens before visiting rooms with other cats.
2. wash your hands with disinfectant before entering the kitten room
3. wear spare shoes or shoe covers when entering the room
Early weaning and isolation of kittens
1. test your cat for antibodies to coronavirus before or after lambing
2. if the mother’s titer is greater than zero, the kittens should be placed in a separate clean room until 5–6 weeks of age
3. if the mother’s antibody titer is zero, the kittens can be left with her until an older age
4. Take care to acclimate kittens 2–7 weeks of age in isolation to humans.
Kitten research
1. test kittens for coronavirus antibodies over 10 weeks of age to ensure they react negatively
General pathology/histopathology
Serous surfaces are often covered with fibrinous deposits, 1–2 mm in diameter. Large granulomas may be found in individual organs.
Multiple tumors and other infections (for example, tuberculosis) may present with similar symptoms. The liver, omentum and intestine can be examined by biopsy, while tissue from the eye and central nervous system is only available for post-mortem examination.
Histological examination allows us to make a final diagnosis.
Immunohistochemistry
The next diagnostic method in cases where infectious peritonitis cannot be clearly identified using histology
Treatment of infectious peritonitis
FIP is usually fatal, and no treatment has been shown to be reliable. Consequently, therapy is mainly symptomatic, including fluid replacement and nutrition.
Because FIP is an immune-mediated disease, treatment is often aimed at regulating the immune response to the virus.
Typically, regulation of the immune response is achieved by using immunosuppressants or immunostimulants, alone or in combination:
immunosuppressants including corticosteroids (eg prednisolone) or cyclophosphamide. Commercially available cyclophosphamide tablets (50 mg) cannot be dosed according to schedule; imported tablets of 25 g are available
Many compounds may have nonspecific immunostimulatory, anti-inflammatory or antioxidant effects that may be useful in the treatment of infectious peritonitis; however, their benefits have not been proven. Compounds that may have beneficial effects with minimal harm include: human α-interferon, aspirin (salicylic acid), vitamin C (ascorbic acid); vitamin B1 (thiamine) and anabolic steroids.
Forecast
The prognosis for feline infectious peritonitis is always unfavorable, as the outcome is almost always fatal. Cats with exudative peritonitis may survive from several days to several weeks. In some cases, after removal of fluid as a result of treatment, dry peritonitis develops. Cats with dry peritonitis can live up to a year if treated early if diagnosed early, before developing overt anorexia and nervous symptoms.
Control and prevention
Preventing infection in kittens
Coronavirus usually does not cross the placental barrier, and kittens are protected by maternal antibodies until 5–6 weeks of age. Therefore, in groups where coronavirus is endemic, pre-lambing cats should be isolated from other cats until the kittens are 5–6 weeks old. The litter is then separated and kept in isolation until sold. Antibodies in infected kittens may not be detected until 10 weeks of age, so testing before this age is not necessary. In Fig. Figure 9.15 provides a detailed step-by-step scheme for isolation and early weaning (Eddie and Jarrett 1992)
Destruction of coronavirus in places where cats are kept
If you keep fewer than 10 cats in the house, the virus disappears spontaneously in most cases. Viral shedding stops and the antibody titer eventually drops to zero; Getting rid of the infection can take from several months to several years. If owners want to rid their animals of coronavirus, all cats should be tested every 3-6 months using a reliable test system based on immunofluorescence and/or reverse CPR (feces are examined). It is necessary to divide cats into 2 or more groups: those that react negatively and those that react positively. Once the cat stops responding positively, it is moved to the “negative” group. Dividing into stable groups of 2-3 animals is preferable. In most cases, all cats will stop shedding the virus because isolating the positive reactors from the negative reactors breaks the cycle of infection-immunity-loss of immunity-re-infection.
However, chronic carriers of infection who spread the virus still exist in small numbers. At the moment, there is no way to identify such carrier cats, except for isolation and examination of feces using the reverse CPR method every month. If viral shedding continues for more than 8 months despite sources of infection being removed, the animal is likely a carrier. In Fig. 9.17 provides a step-by-step diagram for ridding animals in the house from coronavirus and maintaining their cleanliness.
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Reduce the number of cats in all premises |
|
Owners should not keep more than 6–10 cats Cats should be kept in stable groups of up to 3-4 animals In shelters, cats must be kept in isolation. Under the coronavirus exemption program, cats must be kept in small groups according to antibody titer or virus shedding: those that react negatively or do not shed virus are separated from those that react positively or shed virus. Prevention of infectious peritonitis in clinically healthy cats infected with coronavirus
Vaccination "A practical guide to infectious diseases of dogs and cats", |
