Symptoms and treatment of HBV in rabbits
Viral hemorrhagic disease, or HBV in rabbits, is one of the most dangerous diseases affecting livestock. HBV in rabbits is characterized by rapid development and distribution, which as a result leads to lightning-fast death of animals, it is not possible to treat the disease.
VGBK in rabbits
On the nature of HBV in rabbits
Among other names for viral hemorrhagic disease in rabbits, hemorrhagic pneumonia or necrotizing hepatitis is often found. It belongs to an infectious type of disease with an acute course. This highly contagious infection spreads rapidly among adults and is accompanied by high death rates: from 80% to 100%.
The first cases of HBV in rabbits were recorded on Chinese territory in 1984. Through imported Chinese rabbit meat, the viral haemorrhagic disease of rabbits moved to eastern European countries, engulfing farms in Italy, and further spread to Asian and American destinations. The first Russian cases of VGBK were noted in 1986 on the Far Eastern border with China.
The sources of transmission of viral hemorrhagic infection are those who have suffered from the disease and are sick rabbits and the person himself. Among the ways of spreading VGBK, there are 2 main ones: alimentary or respiratory, and the role of factors is:
- manure and soil layer,
- litter with pathogens present,
- feed and drinking water,
- fur and skins of infected rabbits, fur products from them.
The causative agent of viral hemorrhagic disease in rabbits is a virus containing RNA, which retains its activity in a frozen state for five years, and is also able to resist esters and chloroform.
At the same time, outbreaks of the occurrence and spread of VGBK do not depend on the season and can manifest themselves in any season. For other animals, as well as for the human body, this virus is not dangerous, but it cannot be treated in rabbits.
Clinical picture
The latent incubation period for the manifestation of the disease is 2-3 days, sometimes it is delayed up to 5 days. The fulminant and hyperacute course of the disease occurs without symptoms and ends in most cases fatally. Outwardly, rabbits that do not show any signs begin to make convulsive movements with their paws and die.
The acute course of VGBK manifests itself after 2-4 days with disease-specific symptoms:
- general depression of animals,
- decreased or complete lack of appetite,
- nervous manifestations in the form of irritability, fever and convulsive movements of the paws, throwing the head back,
- moans and squeaks made by rabbits.
Adults and rabbits older than three months of age are most susceptible to the influence of VGBK, while the sex and breed of animals do not matter.
Before the death of sick rabbits, some individuals have discharge from the nasal openings of a yellow color or with the presence of blood components.
Pathology of changes and diagnosis
The highest concentration of VGBA reaches in the liver, where it multiplies rapidly, leading to consequences incompatible with the life of animals. Among the main pathological changes that lead to the development of viral hemorrhagic infection in rabbits, there is:
- damage to the liver with its increase in size and becoming flabby in consistency, with hemorrhages,
- violation of the integrity of the spleen (increases by 1.5-3 times) and kidneys (enlarged and permeated with hemorrhages),
- changes in the structure of the stomach and intestines, which are subject to catarrhal inflammation,
- disruption of the heart muscle, while the ventricles in the walls are stretched, the heart itself is enlarged, speckled with many hemorrhages.
The diagnosis of HBV is based on complex analytical information, including epizootological (sudden death of unvaccinated rabbits, lightning-fast spread of infection) and clinical (nervous changes, fever, nasal discharge) symptoms. In this case, a pathomorphological laboratory study is done.
Vaccination procedure
Viral hemorrhagic disease of rabbits is not amenable to treatment. It is possible to save the rabbit population only with timely vaccination.
In order to prevent haemorrhagic disease in rabbits, the Russian veterinary service recommends the use of one of the following vaccines:
- hydroxide-based aluminum formol-graft, inactivated,
- lyophilized tissue grafting, including formol grafting, theotropin or thermovaccine,
- lyophilized injection against myxomatosis and VGBK,
- inactivated antipasterella 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 introduction of 0.5 milliliters of the vaccine intramuscularly to the animal. The duration of the active action of the vaccine is at least a year, after which revaccination is carried out.
Vaccination of pregnant rabbits is carried out at all stages. Two months after birth, the rabbits retain passive immunity from those rabbits that were vaccinated with the vaccine.
With passive immunization, serum from HBV is used with a period of active prophylactic action up to 1 month.
Quarantine measures
When making a diagnosis of viral hemorrhagic disease of rabbits, by order of the regional administration, quarantine is established in the village and restrictions are imposed:
- the import, export and sale of animals, products from them, skins and down is prohibited, the import and export of household equipment and feed mixtures is limited,
- a ban is introduced on organizing exhibitions and other events with the participation of rabbits,
- exchange of rabbits between owners and their regrouping is not allowed,
- not used for feeding grass and hay from places where quarantined.
In a region unfavorable for VGBK, quarantine measures are carried out according to the following instructions:
- the exact number of rabbits on all existing farms is calculated,
- a clinical examination of livestock is carried out to identify diseased individuals,
- sick and suspicious animals are sent for slaughter, followed by incineration of corpses,
- all livestock are immunized for prophylaxis and vaccinated.
In addition, on all farms where rabbits are kept, disinfection of premises, inventory and equipment, and walking areas is compulsory. The skins, which were harvested in the region declared for quarantine by the VGBK, are stored in isolation for the purpose of subsequent disinfection and processing at industrial enterprises.