A fatal viral disease appears suddenly, spreads quickly, and can lead to the death of the entire livestock. With hemorrhagic disease of rabbits, also called hemorrhagic pneumonia and hepatitis with necrosis, severe structural changes in internal organs occur, as a result of which the vital functions of the body become impossible. The only way to prevent infection is vaccination.
Description and history of VGBK
For the first time, viral hemorrhagic disease of rabbits appeared in one of the Chinese provinces at the beginning of the 20th century, although the pathogen was discovered in the 19th century by the French microbiologist Louis Pasteur. The scientist identified the virus in poultry, but experimentally learned that the infection affects different species of animals.
In 1984, the infection spread from China to a Far Eastern state farm, causing the death of the entire rabbit population. Viral distemper began to rapidly spread throughout Russia and Europe, and by 1986 it had captured most European rabbit farms.
The disease flared up especially strongly in Italy after the import of Chinese contaminated rabbit meat.
The causative agent of the disease, containing the RNA gene, affects the entire body of the animal, is extremely tenacious, and is not afraid of high temperature, frost, or even household chemicals containing chlorine and ethers. It freezes at -50°C, but comes back to life when thawed. It remains viable in the animal's body for about 100 days. Capable of causing epidemics all year round.
A viral infection is not dangerous for the human body. Once in the rabbit's body, she:
- begins to actively reproduce;
- transported through the blood vessels to the lymph nodes;
- releases toxic waste products;
- this leads to the destruction of cellular structures and vascular walls;
- the result is hemorrhagic disease.
There are two forms of hemorrhagic disease:
- Spicy. Has severe symptoms. Most often it occurs after stress, relocation or transportation, when sick rabbits are placed together with healthy ones. The infected individual dies within 2-3 days.
- Chronic. May be asymptomatic. Usually associated with poor quality animal care.The sick individual survives if immunity has time to develop. But the surviving rabbit remains a carrier of the virus forever.
Routes of infection
The route of transmission of a fatal hemorrhagic infection is predominantly airborne. But a rabbit can also become infected by contact with a sick animal, its feces, saliva, or contaminated objects. The worker himself can spread the infection by transferring it on the skin of his hands and clothes, touching cages, bedding, feeders, equipment, and touching the skins and meat of infected animals.
The hemorrhagic virus remains viable on wooden cages for 2 months, on metal instruments, in food, water and feces - for one month, in the natural environment - up to 3 months.
Sources of the virus can be heaps of waste, sewage and premises where meat and rabbit skins are processed if sanitary safety standards are not followed and disinfection is not carried out. Hemorrhoids can even spread from veterinary institutions if the rules of epidemiological prevention are violated there. That is, in many cases, people themselves are to blame for the spread of the disease.
Symptoms of the disease
The incubation period of hemorrhagic disease lasts 2-3 days. The infected animal appears healthy and eats well. The development of hemorrhagic disease is rapid, symptoms appear abruptly and too late, when the pet is on the verge between life and death. In most cases, only a few hours pass between the first symptoms and the death of the rabbit.
Manifestation of an acute form of hemorrhagic disease:
- fever, body temperature 40-42 °C (normal 38-39 °C);
- weakness, lethargy;
- lack of appetite;
- heavy breathing, shortness of breath;
- diarrhea with copious release of liquid stool.
Sometimes the acute form of the disease occurs as hyperacute. This means the incubation period takes only a few hours. There are no symptoms, they just don’t have time to appear. A seemingly healthy rabbit suddenly begins to convulse, gasps for air, and then falls dead.
The only symptom that indicates imminent death in the hyperacute form of the disease is lack of appetite. A healthy rabbit always chews food. If he stops eating, then he begins to bleed in his throat and spleen, the tissues of the lungs, heart, blood vessels, liver and kidneys are destroyed, which means that death throes will soon begin. Often, hemorrhagic disease occurs in conjunction with myxomatosis, another viral disease. This is due to the weakening of the body's immune defense.
The signs of chronic hemorrhagic disease are somewhat different:
- rhinitis;
- conjunctivitis with hemorrhage into the mucous membranes of the eyeballs;
- pallor and bluish color of the mucous membranes, bruises under the skin;
- disruption of the digestive tract;
- bleeding from the anus;
- vomiting blood, bleeding in the gums;
- pneumonia with ordinary and purulent exudation.
Diagnosis of the disease
The diagnosis is made by a pathologist after an autopsy. If a healthy-looking rabbit dies suddenly, it should be taken to a veterinary laboratory. The veterinarian must make sure that the animal did not die due to pathologies with similar symptoms: intoxication, salmonellosis, pasteurellosis, hyperthermia.
At autopsy, the pathologist reveals the following signs of hemorrhagic disease:
- an enlarged, blood-filled liver;
- a spleen swollen by 2-3 sizes, black with blood;
- inflamed digestive tract;
- blood vessels clogged with blood clots;
- swollen and darkened lungs, covered with blood spots;
- bloodshot eyeballs;
- blood-filled nasopharynx;
- bleeding ulcers in the mouth;
- destroyed tissue of the lymph nodes.
Treatment of VGB in rabbits
There is no cure for viral hemorrhagic pathology. It is impossible to save a sick rabbit. But it is possible to prevent infection of livestock by timely vaccination. Although the effectiveness of vaccines cannot be called 100%. Rabbits are vaccinated with either an associated (two-component) or a single-component vaccine. The first includes strains of VGBV and myxomatosis, the second - only the VGBV strain.
Common drugs:
- "Rabbivak V" (Russia);
- Cunipravac RHD (Spain);
- Dervaximixo (France);
- “Tissue inactivated aluminum hydroxide vaccine” (Russia).
Experienced farmers advise using two-component vaccines. The first injection is given to a baby rabbit that has reached 1.5 months of age. The next procedure is carried out 3 months after the first. The next vaccinations should be done every 6 months.
A farmer can vaccinate his pets himself, or he can contact a veterinarian. The vaccine is injected into the thigh muscle. Dose – 0.5 cm3. Before the procedure, the needles are sterilized, and the skin of the rabbit’s thigh is disinfected with alcohol.
Disease prevention
Viral hemorrhagic pathology has no cure, but it can be prevented if you follow preventive measures:
- vaccinate rabbits in a timely manner;
- keep purchased and vaccinated animals in quarantine;
- keep rabbits in accordance with sanitary and hygienic standards;
- Clean and disinfect rabbit hutches regularly.
Actions in the event of an epizootic:
When hemorrhagic disease has already begun, do the following immediately:
- Healthy animals are moved to a safe place and vaccinated.
- Cages and equipment are disinfected from a spray device and thoroughly cleaned with a hot solution of caustic soda. What cannot be cleaned is disposed of. Formaldehyde, carbolic acid, phenol, slaked lime, Ecocide, Glutex, Virocide are used as disinfectants.
- Feeders and drinkers are immersed for 3 hours in a solution of formaldehyde or calcium hypochlorite.
- If possible, the cell walls are treated with a blowtorch.
- Carcasses of dead animals, bedding, pieces of food, feces, work clothes, and plastic equipment are burned in a pit.
- The place where the sick rabbits were located, the waste pit and the manure heap are sprinkled with lime powder.
- They destroy mice, rats, and insects living near the rabbitry that can carry hemorrhagic infections.
- Finally, the rabbitry and cages are thoroughly washed with a soda solution. The vehicle in which the animals were transported is disinfected.
After 2 weeks, it is advisable to repeat the described activities. It is strictly forbidden to eat the meat of sick rabbits or use the skins. New animals can be brought to the farm two weeks after disinfection measures. To prevent hemorrhagic disease from recurring, you should vaccinate your pets in a timely manner, take good care of them, and maintain cleanliness and order in the rabbitry.
