Viral hemorrhagic disease, or HBV in rabbits, is one of the most dangerous diseases affecting the livestock. The rapid development and spread of rabbit HBV is inherent, which as a result leads to fulminant death of animals; it is not possible to treat the disease.
HBVC in rabbits
About the nature of HBV in rabbits
Among other names for rabbit viral hemorrhagic disease, hemorrhagic pneumonia or necrotic hepatitis is often found. It refers to an infectious type of disease with an acute course. This highly contagious infection is spreading rapidly among adults and is accompanied by high death rates: from 80% to 100%.
The first cases of HBV in rabbits were recorded in Chinese territory in 1984. Through rabbit imported from Chinese production, rabbit viral hemorrhagic disease has moved to eastern European countries, covering Italian farms, and then spread to Asian and American directions. The first Russian cases of VGBK were noted in 1986 on the Far Eastern border with China.
Sources of transmission of viral hemorrhagic infection are the rabies and the sick rabies and the person himself who have suffered the disease. Among the ways of spreading HBVC, there are 2 main ones: alimentary or respiratory, and the following serve as factors:
- manure and soil layer,
- litter with pathogens present,
- feed products and drinking water,
- fur and skins of infected rabbits, fur products from them.
The causative agent of rabbit viral hemorrhagic disease is a virus with RNA content, which remains active in the frozen state for five years, and is also able to resist ethers and chloroform.
Moreover, outbreaks of the occurrence and spread of HBVC are independent of the time of year and can occur in any season. For other animals, as well as for the human body, this virus is not dangerous, but can not be treated in rabbits.
Clinical picture
The latent incubation period for the manifestation of the disease is 2-3 days, sometimes delayed up to 5 days. The fulminant and super-acute course of the disease occurs without symptoms and ends in most cases lethally. Outwardly not showing any signs, the rabbits begin to make jerky movements with their paws and die.
The acute course of HBVD manifests itself after 2-4 days of disease-specific symptoms:
- general depressed state of animals,
- decreased or complete lack of appetite,
- nervous manifestations in the form of irritability, fever and convulsive movements of the paws, tipping of the head,
- rabbits moaning and squeaking.
The effects of HBV are most susceptible to adults and rabbits older than three months of age, while the sex and breed of animals do not matter.
Before the death of sick rabbits, in some individuals, discharge from the nasal openings of yellow color or with the presence of blood components is observed.
Pathology of changes and diagnosis
The highest concentration of HBVC reaches in the liver, where it multiplies rapidly, leading to consequences incompatible with animal life. Among the main pathological changes that the development of viral hemorrhagic infection in rabbits leads to is observed:
- damage to the liver with its increase in size and becoming flaccid in consistency, with hemorrhages,
- violation of the integrity of the spleen (increases 1.5-3 times) and kidneys (enlarged and permeated with hemorrhages),
- changes in the structure of the stomach and intestines, which undergo catarrhal inflammation,
- disruption of the heart muscle, while the ventricles in the walls are stretched, the heart itself is enlarged, mottled with many hemorrhages.
The diagnosis of HBV is based on complex analytical information, including epizootological (sudden death of unvaccinated rabbits, fulminant infection) and clinical (nerve changes, fever, nasal discharge) symptoms. In this case, a pathomorphological laboratory study is done.
Vaccination procedure
Rabbit viral hemorrhagic disease cannot be treated. Preserving the rabbit population is possible only with timely vaccination.
In order to prevent rabbit hemorrhagic disease, the Russian Veterinary Service recommends using one of the following vaccines:
- hydroxide-based aluminum formol inoculation, inactivated,
- lyophilized tissue grafting, including formol grafting, theotropin or thermal vaccine,
- lyophilized injection against myxomatosis and HBV
- inactivated anti-pasteurellosis vaccine.
The appearance of intense immunity against viral hemorrhagic disease in rabbits occurs at the age of 1.5 months on the third day after the administration of an animal 0.5 ml of the vaccine intramuscularly. The duration of the active effect of the vaccine is at least a year, after which revaccination is carried out.
Vaccination of pregnant rabbits is carried out at all times. Two months after birth, passive immunity of rabbits from those rabbits that were vaccinated with vaccines is maintained.
With passive immunization, serum from HBV is used for a period of active prophylactic action up to 1 month.
Quarantine Activities
When making a diagnosis of rabbit viral hemorrhagic disease by the order of the regional administration, a quarantine is established in the village and restrictions are introduced:
- the import, export and sale of animals, their products, skins and fluff is prohibited, the import and export of household equipment and feed mixtures is limited,
- a ban is introduced on the organization of exhibition and other events with the participation of rabbits,
- exchange of rabbits between owners and their regrouping is not allowed,
- grass and hay from places where quarantine is applied are not used for feeding.
In the region unfavorable for VGBK, quarantine measures are carried out according to the following instructions:
- the exact number of rabbits on all available farms is calculated,
- clinical examination of livestock is carried out to identify diseased individuals,
- sick and suspicious animals are sent for slaughter, followed by burning of corpses,
- the entire population is undergoing universal immunization for the purpose of prevention and the vaccine is vaccinated.
In addition, at all farms where rabbits are kept, the disinfection of premises, equipment and equipment, and places of walking is carried out by force. The skins that were procured in the quarantined region of the VGBK region are kept in isolation for the purpose of subsequent decontamination and processing at industrial enterprises.
