The main symptoms and methods of treating leukemia in cats

Feline leukemia is one of the most dangerous incurable retroviral diseases of cats, which is dormant (hidden, sluggish) and does not manifest itself until the beginning of the terminal phase. Together with infectious peritonitis and immunodeficiency in cats, leukemia is included in the ominous list of “tri-fatal” infections, characterized by high contagiousness and lethality.

Other names for leukemia in cats are VLK, FeLV, blood cancer, leukemia, viral leukemia, Leucaemia viralis, lymphosarcoma, hemoblastosis.

What is leukemia (FeLV)

Viral malignant disease of the circulatory system of the cat family - FeLV. Otherwise it is referred to as cancer or a malignant tumor that can be transmitted to other species and destroy the weakest animals with immunity.

Feline leukemia virus (FLV) belongs to the same group as HIV. Causes serious complications and exposes the body to weak protection against other diseases due to weakened immunity:

• viral, bacterial, fungal, parasitic infections;
• tumors;
• bone marrow diseases.

A cell infected with a retrovirus.
The dangerous effect of the virus awakens long after infection, cannot be treated, but can be prevented through vaccination.

In the external environment, the virus loses resistance and dies after two days. It is vulnerable to sunlight, low or high temperatures, ultraviolet rays, and is defenseless against disinfectants and substances containing alcohol.

FeLV provokes the appearance of malignant tumors, which leads to death

Why is it dangerous to neglect treatment for leukemia?

Lack of treatment is fraught with the development of the disease and its accompanying pathologies, which lead to death. An animal that does not receive veterinary care develops:

• anemia;
• spontaneous bleeding;
• chronic cystitis;
• constant low-grade fever;
• bacterial infections;
• viral respiratory diseases;
• peritonitis;
• ascites;
• toxoplasmosis;
• autoimmune glomerulonephritis;
• stillbirth;
• damage to the mammary glands in females;
• miscarriages;
• fetal resorption and fading kitten syndrome;
• sarcoma of the lymphatic system.

A pregnant cat with leukemia will give birth to already infected kittens, which usually do not survive due to the body’s lack of strength to fight the virus. Therefore, cattery owners should definitely examine their cats.

Which cats can get leukemia?

Any representatives of cats are susceptible to infection with FeLV: domestic, stray, purebred, domestic, young, elderly, mestizos.

The virus is easily transmitted from an infected individual to a healthy one in the following cases:

• games, fights, bites with each other - simple contact or fights, bites, scratches;
• sexually;
• through eating, drinking from the same bowl, using the same toys or beds;
• in utero - from mother to kittens;
• through flea bites;
• in the clinic after doctors saw a leukemic cat without further treatment of the table.

Fights and contacts with other cats on the street
There are a lot of ways to transmit a dangerous virus. This incident can occur even if the owner had contact with an infectious cat, for example, in a shelter or at an exhibition.

Infection is transmitted through any contact of a cat with saliva, blood, urine, discharge from the nose or eyes, or feces of a sick animal, even if any of the above gets on the fur of a healthy pet.

Pathogen

Virions are excreted in feces, and infection occurs orally during prolonged contact between healthy people and carriers of the pathogen. The duration of the latent phase is 3 months. Among animals in which clinical signs are recorded, the following age groups are most at risk:

• Kittens less than a year old.
• Elderly animals.
• Having suffered stress.

The pathogen poses the greatest threat to kittens. Most diseases end in death. The coronavirus is characterized by high species specificity: cats are affected. This is due to the fact that the conditions for the mutation of a harmless form of the virus into a dangerous one are present only in the bodies of representatives of the Felidae family.

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Mammals are protected from the invasion of an infectious agent by immunocompetent blood cells - macrophages. If the defense mechanism is imperfect, the stranger penetrates inside the defender, settles there, multiplies and spreads through the blood throughout the body.

Macrophages accumulate around the vessels, under the serous membranes, causing the wet (exudative) form of the disease - peritonitis. The animal dies within a few weeks. If the cat is able to defend itself, but the immunity level is low, a dry form of the disease develops, which lasts up to six months with periods of weakening of clinical symptoms and exacerbations.

Feline immunodeficiency or leukemia viruses weaken the immune system, making it vulnerable to FIPY.

Dropsy with coronavirus peritonitis

Symptoms

Signs of the disease differ in cats of different ages and depend on the strength of the animal’s immune response and the pathogenicity of the pathogen. Characteristic symptoms of peritonitis in kittens include anorexia, hyperthermia, and pleurisy. In adults, the disease occurs in the following forms:

• Exudative.
• Granulomatous.

The effusion (wet) form leads to the accumulation of fluid in the abdominal and pleural cavities. The following symptoms are typical:

• dyspnea,
• lethargy,
• anorexia,
• bloating,
• moderate hyperthermia,
• gradual weight loss.

The granulomatous (dry) form is characterized by conjunctivitis, inflammation of the retina, runny nose, glomerulonephritis, bronchopneumonia, pyogranulomatosis, nervous phenomena - paralysis and convulsions. Loss of coordination, attempts to hide in a dark place, a state of panic, and fungal diseases are recorded.

A sick cat dies within a few weeks, but with proper care and symptomatic treatment it can live for years.

Pyogranuloma

Diagnostics

The cause of the disease is determined based on clinical signs, results of serological studies and PCR (polymerase chain reaction). This allows us to exclude peritonitis of bacterial etiology, toxoplasmosis, hepatitis and cardiovascular pathologies, lymphosarcoma.

Treatment

To alleviate the cat’s condition, the effusion accumulated in the cavity is removed using a puncture. At the same time, diuretics are prescribed. Antibiotics are used to suppress secondary microflora. With the help of prednisolone and other antiphlogistic steroids, inflammation is eliminated.

Multivitamin preparations and the following medications are used as immunocorrectors and detoxifiers:

• Polyferrin-A.
• Roncoleukin.
• Glycopene.
• Lycopid.
• Globcan-5
• Interferon

The duration of therapeutic measures is determined by the veterinarian. A sick cat is fed prepared food for weakened animals. You cannot pamper your cat with raw meat trimmings and leftovers.

Carrying out PCR

What causes the development of leukemia and what is its danger

Infection of vertebrates with a retrovirus occurs in the cytoplasm of the cell (a viscous internal environment bounded by a membrane), where the synthesis of the viral DNA genome begins. Retroviruses, after introducing their genome into the host's chromatin, remain there forever and are transmitted genetically to offspring.

The correct transmission of information in a cell has the sequence: DNA → RNA → protein (transcription process). The protein cannot change genetic information. Retroviruses have an enzyme that changes this sequence, where genetic information is encoded in RNA.

When it enters a healthy body, this virus synthesizes host DNA into viral RNA, which then becomes normal DNA and is new genetic material for the subsequent development of the virus inside the cell.

Viral RNA, viral enzymes

The effect of the virus begins with activity in the lymphatic tissues, tonsils, nasopharynx, then spreads to the circulatory system and affects brain cells.

FeLV infection routes

The pathogen is excreted in milk, feces, saliva, mucus, and urine. In warm conditions with moderate humidity, it lasts up to 2 days. The virus is not afraid of sunlight, but dies from disinfectants and when heated above 60C.

How can you become infected:

• when mating;
• airborne;
• through secretions;
• in utero.

Less commonly, you can introduce the leukemia virus to a cat during surgical manipulations with poorly sterilized instruments or through blood transfusions. FeLV can be spread by fleas.

There is a high probability of mass infection in shelters, nurseries, and in a flock of stray animals. The leukemia virus feels free in places where there is a concentration of animals and there is no hygiene.

Fact! There have been no documented cases of cats transmitting the leukemia virus to other animals or humans. But the possibility of FeLV reproduction in human cells has been laboratory confirmed.

Symptoms of leukemia

VLK disease manifests itself in the later stages, when the number of leukocytes in the blood is exceeded, and there is no longer a chance of saving the pet. Death occurs due to concomitant diseases that arise due to dysfunction of body systems.

Symptoms may suggest that a cat has a disease, but it does not confirm its presence. To avoid any problems with your pet’s health, you need to show it to the doctor at least twice a year, without neglecting tests.

If you have any of the following symptoms, you should contact your veterinarian and consult with your doctor:

• drowsiness, lethargy, apathy;
• frequent loss of appetite or refusal of favorite foods;
• low activity, lack of interest in games;
• runny eyes and nose, drooling;
• digestive problems;
• frequent colds, cystitis, increased temperature;
• enlarged lymph nodes.

Isolation of leukemia virus in cats

A complex and lengthy process is not practical. Can be used in case of questionable and complex results of other tests. Detection of antibodies It is possible to detect antibodies in cats with abortive, regressive, progressive infection or after vaccination. The majority of all cats have anti-VLK antibodies. With advanced infection, there may be no detectable antibodies. The presence of antibodies to FLV does not always indicate the presence of immunity; even vaccinated cats, if protected, do not always have detectable antibodies to the virus. Can be used to study VLK status in a population.

Types and forms of leukemia

An animal can become infected with one or more strains of a retrovirus, which occurs in various forms depending on the animal's immunity.

Depending on the location of the virus and its progressive development, leukemia is noted according to the type of location:

• chest - fluid accumulates in the chest area, causing suffocation;
• abdominal - due to damage to the gastrointestinal tract, upset, jaundice, constipation, dehydration, cachexia appear;
• spinal cord - paralysis of limbs, impaired coordination, unsteady gait;
• kidneys - dehydration, uremia, general poor condition due to intoxication;
• multifocal - affects several organs, enlarged lymph nodes, severe exhaustion, internal bleeding occur.

Blood in a cat's feces
If a pregnant cat has leukemia, her kittens will be stillborn or die within the first days or weeks of life.

Treatment of viral leukemia

It is not yet possible to completely cure a cat from leukemia. But timely symptomatic therapy will significantly alleviate the pet’s condition and prolong its life. The selection of drugs is carried out by a veterinarian strictly individually, depending on the condition, tests and symptoms of the patient.

Modern veterinary science suggests acting in two directions in cases of deteriorating health:

1. Stimulation and strengthening of the animal's immunity . The following proven drugs are used:

• Raltegravir.
• Feliferon.
• Interferon.
• AZT.

Antibiotics and vitamin complexes are also used.

1. Symptomatic therapy:

• with the help of medications, symptoms of diseases developing due to decreased immunity and inhibition of hematopoiesis are relieved;
• a good but temporary effect is achieved by blood transfusion , this procedure will have to be repeated every 2 weeks; if oncology is diagnosed, chemotherapy (in particular, Vincristine), usually in this way it is possible to stop the pathological process.

In addition, owners will have to reconsider their approach to feeding their pet. Food must be complete and of high quality, heat-treated to prevent germs, bacteria and other pathogens from entering the weakened body of a pet.

A cat diagnosed with viral leukemia will have to be kept in quarantine for life , contact with other cats must be prevented, and its bed, dishes, toys, and litter tray must be kept clean. If there are other cats in the house, then after contact with the carrier you need to thoroughly wash your hands and, if possible, change clothes. It is useful to regularly quartz the room in which the carrier cat lives (during quartzing, the animal must be removed from the room).

Important! Remember that euthanizing a cat is a last resort. Never give up in the fight against the disease, even without resorting to treatment.

Diagnostics

If leukemia is suspected, the doctor prescribes a series of tests that should not only detect the presence or absence of the virus, but also determine its strain and form.

1. Blood test - to determine the level of white blood cells in the blood and the erythrocyte sedimentation rate, as well as the presence of anemia.
2. Polymerase chain reaction (PCR) is a study of peripheral blood and its elements that helps identify the pathogen in the body.
3. Immunofluorescence blood test - to detect antibodies to viruses and determine its type.
4. Enzyme immunoassay - detects antibodies and antigens to the virus in the blood.

A PCR test with a positive result shows two colored stripes, one indicates a negative result. After taking blood, you wait 15 minutes and the doctor makes the diagnosis.

If a pet suffers from a malfunction of one organ, he is prescribed an ultrasound or x-ray in order to see tumors or changes in the shape of internal organs. Additionally, a biopsy, gastroscopy, colonoscopy, or laparoscopy may be prescribed.

If the virus is not detected, the disease is not diagnosed, but signs are still present, the doctor prescribes an MRI, which makes it possible to notice the development of the tumor at the initial stage.

The examination must be comprehensive to accurately determine the cause of the disease and make a diagnosis for subsequent treatment.

Secondary diseases caused by the virus

Persistent feline leukemia is the most dangerous, as it is characterized by active progression of the disease. Against the background of this stage, the animal’s condition quickly deteriorates. There are a number of secondary diseases that arise as a result of the action of the virus in the body. Each is caused by one of four strains of the virus (A, B, C or T).

1. Immune suppression is a consequence of all diseases leading to damage to the immune system. The animal becomes susceptible to a variety of viral, bacterial and fungal infections. This condition occurs in almost all infected cats.
2. Anemia or a decrease in the number of red blood cells in the blood. By affecting the bone marrow, the virus damages the precursor cells that produce red blood cells. This disrupts the normal process of hematopoiesis in the body.
3. Neoplasia is a pathological process leading to the development of tumors. The cause of these disorders is the integration of the leukemia virus into the genetic code of bone marrow cells. Sick animals become very susceptible to cancer. Their probability increases 50 times. But this does not always happen, but only in 15 percent of cases.
4. Other diseases. The animal's reproductive system and skin are most susceptible to the consequences of a viral attack.

Life expectancy of a cat after infection

The duration and quality of life of an infected cat depends on the conditions under which it is kept.
The incubation period of the virus after infection ranges from 4 days to 8 months. The lifespan of an infected cat depends on its immunity. With sufficient care, she can live from 3 to 10 years, if she does not suffer other diseases and does not show clinical symptoms of the virus. At the same time, she is a carrier and puts other cats at risk.

High mortality occurs in the 3-4th year of the disease, when the symptoms become quite obvious and the disease progresses, causing disruptions in the functioning of the body. This outcome is observed in 90% of cases of infection.

Treatment and prognosis for the future

Regardless of the symptoms, treatment of viral leukemia in cats is aimed at strengthening the immune system. There is no specific therapy for the infection, so the main emphasis is on improving the animal’s condition and prolonging its life.

For this purpose, drugs are used that increase resistance to the pathogen and disrupt its reproduction. They reduce the viral load and the risk of infecting others. Despite this, complete recovery is only possible with a latent form.

To normalize the general blood count and eliminate anemia, transfusions are used. It is important to understand that it only provides temporary improvement, so one procedure will not be enough.

Concomitant tumors are treated surgically or with chemotherapy, and respiratory diseases are treated with bronchodilators and the administration of infusion solutions. For problems with the gastrointestinal tract and kidneys, a therapeutic diet is also prescribed.

With a persistent form of the course, the diagnosis is not removed for life. Until the end of its life, the pet must remain in quarantine without the possibility of contact with other cats. In 90% of cases, death occurs 3-4 years after infection.

After the death of the patient, all his personal belongings must be disposed of, and the house itself must be disinfected and silicified. Only after this will it be possible to adopt a new pet into the family.

Is the virus transmitted to humans?

For humans, feline leukemia is not dangerous, as it has a completely different nature.

Feline leukemia is not transmitted to dogs or other animals and is only dangerous for cats.

When caring for a sick cat with FLV, it is worth protecting cats from contact with the infected person. It is acceptable to keep a cat with leukemia together with carriers of the same virus or in solitary confinement, subject to quarantine measures.

The virus of this form is not active in the human body and is not transmitted through scratches.

Pathogenic effect of the FeLV virus

The leukemia virus belongs to the family of retroviruses (RNA viruses) that attack vertebrate cells. Having penetrated the body, it penetrates into the bone marrow tissue and disrupts the genetic code of immune cells - leukocytes. As a result, they can no longer fully perform their protective function. The disease has another name - leukemia, since the number of immature white blood cells in the patient's blood increases pathologically.

The main results of the destructive effect of a viral infection are as follows:

1. A blow to the immune system leads to a sharp decrease in resistance. Animals often get sick. Any interaction with pathogens can cause unpredictable complications, including death.
2. Immune cells with a disrupted genetic code are carried throughout the body by blood. This dramatically increases the likelihood of cancer.
3. There is a difficulty in making a diagnosis. The disease begins almost asymptomatically. Immune deficiency increases gradually. Serious disorders appear when the disease is already advanced. When examining sick animals, doctors cannot always associate the presence of malignant tumors with the effect of the virus.
4. With leukemia, the death of a cat usually occurs from a secondary infection that develops in conditions of weakened immunity. At the same time, there were cases when, even without the introduction of a vaccine, the initially strong immune system destroyed the invading virus, and the animal recovered.

Prevention

It is worth preventing cohabitation or communication with other cats (domestic or street), placing pets in hotels where a previously infectious cat could be located. For the animal’s personal use, use only individual items: tray, drinking bowl, feeder, bed, grooming products. When going on vacation and leaving your pet for foster care, keep in mind that she can easily become infected with leukemia.

A foster cat can easily become infected from other animals.

After the death of a sick cat, it is not recommended to allow other cats into the room where he lived. It is necessary to wait more than two days and thoroughly treat everything with disinfectants, quartz treatment and purchase new bowls, drinking bowls and even food.

Cats living in stressful conditions are most often susceptible to disease and a decrease in their immune resistance to viruses.

How does it manifest?

Viral leukemia can be asymptomatic for months or even years. The disease can become active due to stress, decreased immunity, and other diseases. Symptoms are varied and nonspecific, depending on the subgroup of the virus. The most common are the following:

• frequent infections of the respiratory tract, nose, eyes, ears, skin, often difficult to treat
• viral infections in animals vaccinated against them
• lethargy
• gingivitis (inflammation of the gums)
• stomatitis (inflammation of the mouth)
• loss of appetite
• progressive weight loss
• abortions and stillbirths in cats
• enlarged lymph nodes
• frequent persistent diarrhea
• anemia (low red blood cell count)
• leukemia, often progressing to leukemia
• “fading kitten syndrome”: newborn kittens die within a few weeks
• lymphoma (benign tumor of lymphoid tissue)
• lymphosarcoma (malignant tumor of lymphoid tissue)

Risk group

Cats at risk:

• after surgery or a visit to the clinical table without treatment;
• not vaccinated and not protected from flea bites;
• those exposed to mating with cats that have not been tested for viruses;
• often on the street;
• animals in a shelter or left for foster care;
• a pregnant cat passes the virus to her kittens or through feeding.

If a pet is not at risk, this does not guarantee its complete protection from a dangerous disease. The disease begins asymptomatically, so any of the symptoms listed in this article should be noticed and verified with a special test.

Causes of the disease and ways of its transmission

The pathogen is contained in all biological secretions of the patient, so it is quite easy to guess how viral leukemia is transmitted in cats. Risks include saliva, blood, urine, feces, breast milk, tears, ejaculate, and vaginal lubricant. Their transfer is possible in the following ways:

1. Contact.

   Infection occurs through direct contact (fighting, mating, licking) and indirect (using dishes, toys and other personal belongings of a sick cat, as well as through the clothes and hands of the owner who stroked it).

2. Airborne dust.

   Occurs least often. In this case, the infection is transmitted by sniffing the marks. The rarity is explained by the weak resistance of the pathogen in the external environment.

3. Transmissible.

   Transmission of the virus is also possible through the bites of blood-sucking parasites: fleas, ticks, mosquitoes.

4. Transplacental.

   An infected mother infects her babies through the placenta and, after their birth, through breast milk.

5. Hemocontact.

   It is mainly recorded during medical procedures with violation of asepsis and antisepsis, including during surgery - that is, through blood.

It is important to note that the main cause of feline leukemia is low immunity. In some cases, the body of a healthy “mustachioer” is able to defeat the disease without additional help, but much more often the virus simply goes into hibernation until negative factors appear.

Animals at risk include those with weak immune systems:

• kittens;
• elderly pets;
• street cats and shelter residents living in large prides or crowded conditions.

There is also a relationship with gender. Due to more aggressive behavior (fighting for territory and partners), males become infected much more often than females.

Vaccination

Vaccination is the best and most effective way to protect your pet from a terrible and deadly disease. Before the vaccine, it is necessary to carry out a test for carriage of the virus. If it is negative, then vaccinations are given annually from the age of two months. This method of protection helps increase resistance to infection and has a cumulative effect.

Vaccinating a cat against FeLV

The drug is a substance containing living and dead particles of the virus - Purevax.

A timely visit to a doctor for diagnosis of the disease will not protect the cat from a full recovery, but it will prolong its life and prevent the progressive development of the disease.

Pathogenesis of leukemia in cats

The outcome of the infection depends on the immune status and age of the cat, the pathogenicity of the virus, the degree of infection pressure and the concentration of the virus. Using PCR, the range of pathogenetic groups depending on the response to infection was expanded. Cats thought to be immune to the virus were found to test positive for the provirus (viral DNA integrated into the DNA of the host cell). The provirus persists for several years. Thus, cats with a negative test and the presence of a provirus - carriers of FLV, after reactivation of the virus, can become infectious. However, integrated DNA may be necessary for robust protection and the development of long-lasting immunity.

Currently, the stages of VLV infection have been revised and are now defined as abortive infection (comparable to the term "regressor"), regressive infection (comparable to the term "transient viremia" followed by "latent infection"), progressive infection ("persistent viremia") and focal or atypical infection.

It was previously thought that about 1/3 of cats become persistently viremic and about 2/3 eventually clear the infection. New research suggests that most cats remain infected for life after exposure, but may become aviremic (regressive infection), where there is no antigen or virus in the blood, but proviral DNA can be detected in the blood by a sensitive PCR method.