Infectious peritonitis in cats treatment. Viral peritonitis in cats: how is it transmitted, can it be cured

Peritonitis in cats is a general or limited inflammation of the peritoneum (this is a thin membrane covering the surface internal organs and internal walls of the abdominal cavity), accompanied by increased secretion of fluid in abdominal cavity.

The disease occurs acutely or chronically, and is a consequence various factors. Infection can enter the peritoneum from neighboring organs affected inflammatory process, with the flow of blood, lymph, with penetrating wounds of the abdominal wall, as a result of perforation (through violation) of the intestinal wall, stomach.

In the statistics of this pathology, one of the first places is occupied by infectious peritonitis in cats. The causative agent of the disease, coronavirus FIPV, belongs to the Coronaviridae family, has an outer shell, contains RNA in its genome, and is represented by several strains.

The infectious agent arises as a result of a mutation of the intestinal coronavirus FECV, which lives exclusively in the intestines and causes mild enteritis in young individuals.

Susceptibility

According to epidemiological data, the disease develops in only 10% of animals infected with coronavirus. The risk group includes kittens from two one month old, young cats up to two years old, old animals (12 years or more), individuals with low immunity.

The virion has selective activity, which has not yet found a clear explanation. The determining factors in the development and progression of pathology are the amount of the pathogen that has entered the body, the virulence of the strain, genetic predisposition, recent stress.

The disease most often affects cats living in large groups. The disease is rare in animals kept alone.

Transmission routes

The infection is mainly transmitted through the nutritional route (through gastrointestinal tract). IN environment the virus is excreted in the feces of sick or recently recovered animals; healthy carriers play a certain role in the spread of the disease.

Cats that share the same litter box or eat contaminated food usually become infected. Another way viral peritonitis is transmitted in cats is through airborne droplets. The infection penetrates the placental barrier in extremely rare cases.

Development mechanism

The entry gates for coronavirus are the nasal or oral cavity. The virion penetrates into the epithelial cells of the respiratory tract, nasopharynx, and intestines, where it begins to actively multiply. At this stage, the disease is asymptomatic or manifests itself as a minor stool disorder.

In some cases, severe diarrhea develops, with the appearance of frequent watery bowel movements - coronavirus enteritis. The process can go into chronic stage(unstable stools are observed for several months).

Massive spread of the virus in the body occurs only in some animals. The pathogen attacks macrophages (cells immune defense), binds to antibodies, forming immune complexes (antigen-antibody) in excess. The formed complexes are deposited in the walls of small vessels, leading to their inflammation and destruction.

There are two ways to further develop the process:

Exudative viral peritonitis in cats it develops when a large number of vessels are involved in the process. Due to increased permeability of the walls, fluid penetrates and accumulates in the abdominal cavity. Sometimes the virus affects the vessels of the pleura, pericardium, and scrotum, as a result of which fluid also accumulates there.
“Dry” or non-exudative pathological process occurs when fewer vessels are affected. Foci of inflammation in this case are formed in separate small groups and do not lead to significant secretion fluids in the cavity. The disease has a long-term chronic course.

Signs and symptoms of the disease

The clinical picture of peritonitis (caused by the FIP virus) depends on its form. TO common features include lethargy, loss of appetite, weight loss, defeat nervous system, eye, unstable body temperature (can rise or fall sharply).

Exudative peritonitis of the abdominal cavity occurs in 80% of cases and is characterized by the accumulation of a large amount of fluid in the abdominal cavity. The cat's belly increases in size and becomes tense. On palpation, an enlarged liver and mesenteric tissues are felt lymph nodes.

As it spreads pathological process new symptoms appear in other organs. The accumulation of fluid in the pleural cavity causes shortness of breath. Kidney damage leads to urinary retention and edema. During the inflammatory process in the liver, yellowness of the sclera appears.

The prognosis is unfavorable, the disease quickly leads to fatal outcome. The animal can live from several days to two weeks. Sometimes, after removal of fluid from the abdominal cavity and intensive treatment, the disease turns into a “dry” form.

The main symptoms of the “dry” form are lack of appetite and weight loss. Other signs of peritonitis in cats depend on which systems and organs are involved in the process and the degree of their damage. Inflammation choroid eyes, deposits on the cornea, infiltration of retinal vessels lead to pain and redness, lacrimation, and decreased visual acuity.

Involvement of the central nervous system in the process (excessive accumulation of fluid in the ventricles of the brain, the formation of purulent granulomas) is accompanied by convulsions, involuntary rhythmic eye movements, impaired coordination of movements, paresis, and urinary incontinence. Damage to the kidneys causes renal failure, liver - hepatitis, pancreas - pancreatitis. The long-term prognosis is not comforting; recovery, as a rule, does not occur; the animal dies no later than a year from the onset of the disease.

Coronavirus enteritis (caused by the FECV virus) most often develops in kittens between 2 and 5 months of age. The first signs of the disease are short-term vomiting and upset stool. Diarrhea lasts from 3 to 5 days, after which it goes away on its own. Special treatment, as a rule, is not required. Animals that have recovered from the disease are virus carriers for a long period.

Diagnostics

When making a diagnosis, anamnesis is taken into account (the totality of information about the sick animal), the presence of contact, the main symptoms, data laboratory research. Conducted differential diagnosis with tumor formations, pregnancy, diseases of the liver, kidneys, pancreas, cardiomyopathy, infectious diseases other etiology.

One test for peritonitis caused by coronavirus will not give an accurate idea of the nature of the disease and severity infectious process. To clarify the diagnosis, several diagnostic methods:

Immunofluorescence (detects antibodies to the pathogen, taken for analysis whole blood, plasma, effusion).
Reverse PCR method (determines the presence of the virus in the body; smears from the rectum, feces, blood, effusion, saliva are taken for research).
Effusion analysis.
Immunobiochemistry, histopathology (allows a final diagnosis to be made; pieces of organs treated with formaldehyde are taken for examination).

A general blood test shows an increase in the level of leukocytes, a decrease in hemoglobin and the number of lymphocytes.

Treatment

Productive treatments have not yet been developed. Therapy is aimed at replenishing fluid losses, nutrients, vitamins, microelements, maintaining the functioning of organs and systems, combating secondary microflora. Substances that affect the state of the immune system and diet therapy are prescribed.

With pronounced exudative process The animal undergoes a puncture of the abdominal cavity, followed by suction of fluid and administration of medications.

Prevention

The vaccine against feline viral peritonitis PRIMUELL FIP contains an attenuated strain of coronavirus. The drug is prescribed for preventive immunization of healthy animals, it is administered into the nose using a pipette, medicinal properties does not have. Causes the formation of specific immunity for up to 12 months, prescribed to kittens from sixteen weeks of age.

Prevention of the disease in an infected individual consists of minimizing stressful situations. The animal is not prescribed drugs that suppress the immune system (progesterone, corticosteroids).

Danger to humans

All questions about whether peritonitis in cats is transmitted to humans or not must be resolved with a veterinarian. There is no information about cases of human infection from a sick animal. When caring for a sick individual, you should adhere to the established rules - wear special clothes, gloves, thoroughly wash your hands after all manipulations, be sure to disinfect equipment, dishes, tray and room.

In the body of a specific individual. The disease occurs subacutely or chronically. The disease in 75% of animals occurs without the manifestation of clinical symptoms, in other cases dry and wet peritonitis develops.

Virus in external environment released by sick or recovered animals through biological fluids and cal. Infection occurs through the mouth, upon contact with material contaminated with the virus. Infection through the air is possible.

FIP is a dangerous disease only for cats; young animals and kittens are especially sensitive. To fully immerse yourself in the topic, we recommend reading the article to the end and watching this video:

Flow

In the first stages, the causative agent of viral peritonitis enters the body through organs digestive tract And respiratory system, where it settles in the tonsils, then proceeds to develop in the intestinal cells.
In the animal’s body, the virus begins to actively multiply in macrophage cells, which becomes the cause of a generalized course of the disease. Macrophages become a kind of carrier of the pathogen throughout the body.
The virus enters the blood through macrophages, resulting in viremia.
In the case of strong immunity, the body suppresses the development of the pathogen in macrophages and infectious peritonitis does not develop in the kitten.
In the absence of an immune response, feline coronavirus will actively multiply in macrophages, which spread throughout the body. Their greatest concentration occurs in places of high concentration of blood vessels, which determines their location under the serous membranes. In this case, wet or exudative peritonitis develops.
In the case where an immune response to the penetration of the virus into the body occurred, but it was not enough to prevent the disease, the level of affected macrophages spreading throughout the body is significantly lower. In this case, the cat develops proliferative or dry peritonitis.
In some cases, the development of viral peritonitis is suppressed by the immune system, but after some time the disease still spreads.
Previous infection leads to the formation of antibodies to other strains of the virus, which contributes to the formation of an antibody-antigen complex, which is carried by macrophages throughout the body; in places where blood vessels accumulate, such complexes cause damage to the vascular wall. This process is typical for exudative peritonitis, in which, through a damaged vascular wall sweats fluid containing large amounts of proteins.

How long do cats with peritonitis live?

According to statistics, the mortality rate with infectious peritonitis is about 90%. If the type of peritonitis is bacterial, then the chances of survival increase to 50%.

Symptoms

Viral peritonitis in a kitten can manifest itself in different ways, the intensity of the disease depends on the virulence of the strain, the condition of the cat’s body and its age.

The incubation period in cats can last from several weeks to several months, depending on the amount of pathogen and the state of the cat's immunity.

Depending on the course of the disease, symptoms may appear various symptoms:

In kittens. Lethargy develops, the temperature can rise to 40 degrees, signs of peritonitis are observed, and there is a possibility of developing pleurisy.
In adults. There are two forms of the disease with different symptoms:
- Wet peritonitis. Fluid accumulates in the abdominal and chest cavity. This leads to the animal having difficulty breathing, shortness of breath, and murmurs in the heart area upon auscultation.
- Disease without accumulation of exudate. In this case, the symptoms will depend on which organs were affected:
  - Eyes. The first manifestation of FIP in cats is the development of conjunctivitis, followed by lesions of the retina and iris.
  - Kidneys. Development of glomerulonephritis.
  - Liver. With liver damage, jaundice is observed skin and mucous membranes, pain in the liver area.
  - Lungs. Bronchopneumonia develops.
  - Nervous system. Extreme skin sensitivity, paresis or paralysis may occur.

Lifelong diagnosis

Peritonitis in cats has similar clinical signs with other infectious diseases, the symptoms and treatment are different for different forms, so the diagnosis should only be made by a specialist.

The final analysis is based on serological blood tests confirming the presence of antibodies to coronaviruses, PCR. Detection of a virus in the body is a weak argument for making a final diagnosis, because It is impossible to determine the strain of the virus during research.

Differentiation of the feline peritonitis virus can be reliably established through post-mortem diagnosis of dead animals.

Post-mortem diagnosis

Diagnosed based on autopsy results and histological studies affected organs.

Autopsy results

Necrotic plaques in viral peritonitis

The animal is severely emaciated.
Detection of a large amount of fluid in the abdominal and chest cavity. The nature of the exudate is transparent, straw-colored; minor impurities of fibrin threads may be observed.
Serous membranes have dull color due to the accumulation of fibrin protein on their surface, which also causes dense adhesions on the surface of the membranes.
White necrotic plaques can be seen on the surface of the internal organs.
Enlarged lymph nodes; when cut, a characteristic pattern is clearly visible.
In the proliferative form, there may be inflamed foci in the organs.

Danger to humans

Although peritonitis is practically incurable, it is not transmitted in any way from a cat and is absolutely safe for humans.

Treatment

In most cases, the animal does not recover from feline infectious peritonitis. The animal must be treated comprehensively under the supervision of a veterinary specialist. There is no specific therapy for infectious peritonitis, so maintenance therapy is carried out until stable immunity to the pathogen is formed.

Puncture. It is carried out to remove exudate that has accumulated in the abdominal cavity. After surgery, re-development is possible

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 the feline enteric coronavirus in the body of individual animals, which can then develop peritonitis. Since FPV and enteric coronavirus could no longer be considered viruses 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.

Percentage of cats reacting positively to serological study, 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 FIP, 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. If infected through the mouth or nasal cavity initial replication of the virus occurs in epithelial cells pharynx, respiratory tract or intestines. Most infections at this stage are asymptomatic. May be observed signs of lung 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 occurs with different symptoms. Since they display different sides one 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 a change of home or surgical interventions? Exudative peritonitis, an acute form of infectious peritonitis, usually develops within 3–6 weeks after stressful situation in the life of a cat
Age of the cat? Despite the fact that peritonitis affects cats of all ages, 80% of sick animals are under 2 years of age. Cats of both sexes are equally susceptible
Cat breed? Although cats of all breeds get sick, 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 lungs 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 effusions in pleural cavity
Activity and preserved appetite, or lethargy and anorexia
In some mild cases 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.

TO 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, corneal deposits, clouding vitreous and opalescence of aqueous humor, 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, dysfunction cranial nerves, paresis, loss of proprioceptive sensation, urinary incontinence or changes in behavior. Nervous symptoms observed in 10% of cases of dry infectious peritonitis in cats
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 exudative form peritonitis from inflammatory lymphocytic cholangitis. Both diseases can occur 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	For thymic lymphosarcoma, radiography chest in the lateral projection may reveal a neoplasm 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 low content protein, 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 a variety of clinical manifestations for dry infectious peritonitis of cats

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 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 methods available on at the moment to determine coronavirus and antibodies to it, and lists the clinical situations in which these tests are used.

Table 3: laboratory methods, used for the diagnosis of feline infectious peritonitis, and materials necessary for research by each method

The test determines	Available test systems	Clinical situations in which the method can be used
Antibodies	Immunofluorescence method, solid phase enzyme immunoassay(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 definitive diagnosis, especially when questionable results histology
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 disease duration. Hyperglobulinemia (sometimes monoclonal gammopathy) and increased concentrations of α1-acid glycoprotein are consistently observed (see below). Nonspecific changes in the blood may include neutrophilia (often with a shift to the left), lymphopenia and non-regenerative 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 inadvertently give positive reaction, especially thoroughbreds; 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. Results expressed in titer are convenient for monitoring individual cats or a group of cats of the same owner to get rid of 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 it would be unwise to get another cat (unless new cat has antibodies indicating that she was exposed to 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 chance of this happening 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 6–12 months will help determine when this occurs as antibody titres fall and more cats begins to react negatively. To avoid re-infection It is recommended to separate negatively reacting cats from positive ones.

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
Next method diagnosis 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 the 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 a few 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 does not usually 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. 9.15 provides detailed step by step diagram isolation and early weaning (Eddie and Jarrett, 1992)

Destruction of coronavirus in places where cats are kept
When keeping 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 are no ways to identify such carrier cats, except for isolation and examination of feces using the reverse CPR method every month. If virus 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 scheme for ridding animals in the house from coronavirus and maintaining their cleanliness.

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
There is no specific way to prevent an infected cat from developing peritonitis, but the following may help:

Reducing stress in a cat: do not move a positively reacting cat to another home, put aside non-essential surgical operations Until the time the cat begins to react negatively, avoid giving the cat for foster care; During the holidays, it is better for owners to ask someone to look after the cat in their home
If possible, do not mate cats that react positively: as genetics play a role important role Whether or not an infected cat develops peritonitis, it is best not to breed cats whose offspring have already had cases of peritonitis. Ideally, cats whose kittens develop peritonitis should never be used for breeding again.
Avoid drugs that suppress the immune system, such as corticosteroids, progestogens.

Vaccination
At the time of writing, there was only one coronavirus vaccine available in Europe. This is a modified live vaccine that is sensitive to temperature changes; contains a coronavirus that replicates only in the nasopharynx at low temperatures, but not at body temperature. The principle of action of the vaccine is that it induces immunity at the first point of impact of the virus, that is, the oropharynx, thus preventing the spread of coronavirus throughout the body. Induces local (IgA), general humoral (cats begin to react positively in serological tests) and cellular immunity. The vaccine is not effective in cases where the cat has already become infected and has begun to develop infectious peritonitis. The effectiveness of the vaccine is 50-75% (that is, out of 100 cats infected with coronavirus, you can expect that 10 will develop peritonitis, but if all 100 animals are vaccinated, only 2-5 will get sick). The vaccine is only licensed for kittens over 16 weeks of age; however, many purebred kittens may be infected with coronavirus by this time. It is very important to protect young kittens from infection by keeping them in isolation and early weaning, as well as by using the least susceptible cats for breeding.

"A practical guide to infectious diseases of dogs and cats",
British Small Animal Veterinary Association,
Editors:
Ian Ramsey and Bryn Tennant

Viral diseases in pets can manifest themselves various forms. One of the dangerous diseases is viral peritonitis in cats. It causes severe damage to internal organs and in most cases can lead to death.

What is the danger for cats?

Viral peritonitis in cats is an inflammation of the abdominal walls caused by a coronavirus. In an animal’s body, it is capable of mutations, resulting in a changed intestinal form Coronavirus causes the development of infectious peritonitis.

A cat suffering from peritonitis also suffers from serious disturbances in the functioning of the immune system. Instead of fighting the virus, the animal’s own antibodies become carriers of the disease, spreading it throughout all organs and systems.

Peritonitis in cats often causes the death of the animal, especially if its symptoms are not immediately noticed. The virus poses a greater threat in crowded areas, so it is recommended to vaccinate cats when the kitten reaches sixteen weeks of age.

Vaccination does not provide complete protection, but it can reduce the destructive effects of the infection. The cat has the opportunity to overcome the disease and get rid of it completely. Owners must not forget that even after full recovery the animal remains infectious for several months.

The disease spreads through the oral-fecal route or through contact with an infected animal. The virus is especially dangerous for cats living in nurseries, in foster care, in shelters or when keeping several cats in the house, as well as at exhibitions.

To prevent the spread of infection, feces must be covered with bleach, trays must be disinfected, and their locations must be treated with special preparations.

Even if the disease is cured and there are no signs, the animal may remain a source of infection for some time. Some cats recover and then become ill again through contact with carriers or due to the presence of contaminated feces.

A small kitten can become infected from its mother, and a cat can become infected from her sick baby, as she licks it, removing traces of discharge. In this case, in a weak baby, symptoms appear very quickly, and it is extremely rare to save him. If you miss the first signs, not only the entire litter will die, but also the mother, as well as the cats that came into contact with them.

Viruses cause in cats various diseases. One of the most dangerous and mysterious viruses is coronavirus. It provokes the occurrence of various kinds of diseases in animals, including viral peritonitis in cats, kittens are especially susceptible to it. The article describes the features of the disease, causes, symptoms and treatment methods.

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Features of the disease

The coronavirus has a spherical shape with a diameter equal to one ten-thousandth of a millimeter. The virus got its name because of the club-shaped protrusions that resemble a crown. The disease is characterized by an inflammatory process serous membranes, which line the inside surface of the internal organs and the abdominal cavity. In cats, this virus causes two types of disease: coronavirus enteritis and feline viral peritonitis.

Causes of infection

The most common form of the virus is the intestinal form of the virus (feline enteric coronavirus, FECV); this virus is easily transmitted from one individual to another through the oral-fecal route. In other words, the virus is transmitted through contaminated food or from one cat's feces to another. Airborne infection is possible, but extremely rare. Once inside, the virus multiplies in the cells of the gastrointestinal tract. Cats infected with this virus show no obvious clinical signs. There is short-term diarrhea caused by damaged intestinal cells, which gradually goes away on its own.

Spread of the virus through the tray

The virus can be excreted in excrement for several months, and then this process is interrupted. The cat begins to produce antibodies in response to infection. She may become infected with the virus again if she is in an environment where it is highly prevalent. Although over time more cats become permanent carriers of the virus and cease to be its source. The coronavirus has such a feature as a tendency to genetic changes: it can mutate into a virus that will be more pathogenic than the previous one. There is a version that peritonitis in cats occurs in this way. The mutated virus leaves the gastrointestinal tract and affects other organs and systems of the cat’s body, causing various complications.

Feline infectious peritonitis virus (FIPV) triggers the immune system. But often this does not improve, but worsens the situation. The antibodies produced cannot destroy the virus and form a complex with the virus, which begins to move through the blood and, accumulating in blood vessels, causes dangerous inflammation V various systems the cat's body, so the disease has wide range signs.

At normal reaction In the body, antibodies find the virus, attach to it, and immune system cells (macrophages) destroy the virus. In the case of an inadequate immune response during viral peritonitis in cats, macrophages cannot destroy the virus, but rather spread it throughout the body through the blood vessels.

Feline infectious peritonitis can be chronic or acute. The chronic form is divided into two subtypes: exudative (wet) and non-exudative (dry) peritonitis. In the first case, a lot of fluid is released into the animal’s abdominal cavity. With dry peritonitis, granulomatous changes occur - nodules form in the internal organs.

The disease is very dangerous for animals and can lead to the death of a cat. Therefore, it is important to identify it in time and provide appropriate treatment.

Granulomatous changes in internal organs

Most often, kittens aged 1 to 5 months become infected with viral peritonitis. The disease begins with vomiting, progressing to diarrhea, which lasts several days. The kitten then recovers, but remains a carrier of the virus for a long time. The virus present in the carrier's feces is transmitted to other kittens if they share a litter box. Elderly cats that have passed the ten-year mark are also susceptible to this disease.

Research intensively conducted by American scientists has identified factors that increase the likelihood of cats contracting infectious peritonitis:

keeping a large number of cats in one room;
kittens under the age of 5 months, as well as cats over 10 years old;
unsanitary conditions and unbalanced nutrition;
a lot of stress;
with early separation of kittens from their mother;
external contacts: transportation, exchange, mating, exhibitions, etc.;
weakened immune system, most often this applies to kittens and old cats;
some cat breeds are more susceptible to the virus;
genetic predisposition;
surgery, possibly castration.

If the animal has a strong immune system, the virus is suppressed by macrophages and the cat recovers. With an average intensity of the cellular immune response, the disease occurs in a latent form, after which the animal remains a carrier of the virus. With a weakened immune system, the disease passes into the wet form and the animal, after being ill for a short time, dies.

Symptoms

Feline viral peritonitis has various symptoms, which depend on the degree of development of the disease, the strength of the animal’s immune system and general condition cat health. The main symptoms that are characteristic of infectious peritonitis can be identified:

diarrhea and vomiting (on early stages), especially in kittens;
prolonged lack of appetite;
sudden weight loss, especially noticeable loss of subcutaneous fat in the withers and lower back;
painful sensations when pressing on the abdominal cavity;

jaundice and anemia with damage to the mucous membranes;
with the wet form of the disease, an increase in the volume of the abdomen;
kittens with peritonitis are noticeably stunted in growth;
depression;
accumulated fluid in the chest cavity causes shortness of breath, cough and the development of pleurisy;
when fluid accumulates in the heart sac, heart rhythm disturbances may occur;
enlarged lymph nodes;
slight increase in temperature;
fever;
possible disorders of the central nervous system, which manifest themselves in paralysis of the legs, convulsions, and coordination disorders of the cat, which are not typical for it;
there is clouding of the eyes;
possible conjunctivitis, damage to the iris;
depressed state of the animal, lethargy, decreased activity;
disturbances in the functioning of the intestines and digestive system;
in dry form feline peritonitis symptoms of damage to the cat’s internal organs (liver, intestines, kidneys) appear sharply;
disturbance of stool and urination.

As a rule, feline infectious peritonitis leads to the death of the animal within a short time - no more than a few months. At strong immunity animal disease can progress to chronic form, in which the cat feels satisfactory. The process takes on a granulomatous form without the release of fluid. If the virus persists in kittens that have recovered from the disease, then with further weakening of the immune system, the disease may recur.

An accurate diagnosis of feline viral peritonitis can only be made by performing an autopsy of the sick animal based on histological and pathoanatomical changes in the internal organs. IN specialized clinics you can conduct a PCR study (polymerase chain reaction), which can be used to determine the presence of a virus in a cat’s body. Alternative way diagnostics - take a puncture of the abdominal cavity from the animal and examine it in laboratory conditions ascites fluid. Blood tests, ultrasound, and comparative characteristics symptoms and detailed study clinical picture diseases. Diagnosis is complicated by the fact that intestinal coronavirus and peritonitis virus are similar in genetic composition.

Treatment and prevention

Feline viral peritonitis is a disease that has no cure, progresses rapidly and is fatal. The disease in cats progresses very quickly from several days to several weeks. The wet form of the disease progresses faster. With this disease, symptoms are treated and supportive treatment is provided to alleviate the pet's condition. Maintenance nutrition, corticosteroids and antibiotics may provide temporary relief, but the disease will still progress. Animals are often euthanized.

In the early stages of the disease, steroid hormones can be used. Immune system cats, when the infectious peritonitis virus appears, produces antibodies and triggers the mechanism by which secondary signs– symptoms of viral peritonitis. The appearance of these signs indicates that the disease has entered active phase. Application steroid hormones makes it possible to suppress the immune system and prevent the formation of antibodies. This treatment cannot cure the disease, but it can help prolong your pet's life for some time.

Depending on the severity of the disease, your veterinarian may prescribe the following treatment:

immune correctors;
serum;
anabolic steroids;
antibiotic therapy;
vitamin therapy;
maintenance therapy.

It is currently impossible to cure the animal. Since diagnosing the disease is difficult, cases of cure of the disease cannot be confirmed, since there is no guarantee that the animal suffered from infectious peritonitis and not intestinal coronavirus.

Examination of an infected animal

You can alleviate the condition of a sick cat using a puncture, clearing the abdominal cavity of exudate. During acute attacks of peritonitis, cold can be applied to the cat's abdomen. In acute cases, blood transfusion is possible. If the kitten is sick viral hepatitis, it should be switched to light food, enriched with vitamins, to support the weakened body.

Prevention of the disease consists of preventing the kitten from becoming infected with intestinal coronavirus. To do this, it is necessary to take the following preventive measures:

Keep your pet's toilet clean, change it more often and disinfect it regularly.
Provide each cat with a separate toilet.
The number of animals in the house should not exceed 8-10.
Kittens and their mother should be isolated from others for three months.
If there is a suspicion that a mother cat has been infected with coronavirus, the kittens should be transferred to artificial feeding and isolated from others until sold.
A newly arrived cat should also be isolated from other animals for a month.

The mutated virus is not transmitted from animal to animal, and only mutates from the coronavirus of an infected cat. Peritonitis in cats is not a viral case, it is a situation where the animal's antibodies fight the virus itself.

To date, there is only one vaccine against feline infectious peritonitis - Primucell (Pfizer). But its effectiveness has not been proven, and its safety is highly questioned, so the attitude towards it is skeptical. The kitten is vaccinated at the age of 16 weeks and the drug is administered intranasally. In this case, immunity is created only for the mucous membranes, and not for the entire body. The degree of protection against the virus is only 50% and is valid only for animals positive for coronavirus enteritis. Therefore, as a reliable prophylactic this vaccine cannot be called.