Lagovirus infections of hares and rabbits: review of literature and epizootic situation in the World and Russia

Abstract

Rabbit viral hemorrhagic disease (RHD) and European hare brown liver syndrome (EBHS) are two similar diseases affecting animals of the hare family, caused by closely related lagoviruses and manifesting as an acute and fatal form of hepatitis and thrombohemorrhagic syndrome in all organs, especially the lungs and liver. The two viruses are closely related genetically and antigenically and share approximately 76% identity. The causative agent of EBHS is a virus of genotype GII.1. Various species of hares and Florida rabbits are susceptible to it. VGBV is caused by viruses of two genotypes: RHDV-GI.1 and RHDV-GI.2. The first genotype (RHDV-GI.1) is strictly specific for rabbits. In contrast, the second (RHDV-GI.2) has a broader range of susceptible animals and affects not only hares but also common badgers and red-bellied musk deer. In addition, due to the lack of crossimmunity between RHDV-GI.1 and RHDV-GI.2 and a wide range of hosts, the second genotype displaces the first of the susceptible populations, which makes it more dangerous in epidemiological terms. The diseases have high morbidity and high mortality - up to 90%. Given the high persistence of the virus in the environment, the disease can cause severe economic damage. Disease control is effectively achieved through vaccination, general quarantine, and preventive measures. However, this only applies to VGBV types 1 and 2, for which vaccines exist. Currently, no vaccines are developed against brown liver syndrome in the European hare.