than are those infected with RHDVa. In rabbitries, an epidemic with high mortality rates in adult and subadult rabbits is typical. If the outbreak is caused by RHDV2, then deaths also occur in young rabbits. RHD can vary in the rate clinical signs occur. In peracute cases, rabbits are usually found dead with no premonitory symptoms. Rabbits may be observed grazing normally immediately before death. In acute cases, rabbits are inactive and reluctant to move. They may develop a fever up to 42 °C (107.6 °F) and have increased heart and respiratory rates. Bloody discharge from the nose, mouth, or vulva is common, as is blood in the feces or urine. Lateral recumbency, coma, and convulsions may be observed before death. Rabbits with the acute form generally die within 12 to 36 hours from the onset of fever. Subacute to chronic RHD has a more protracted clinical course, and is more commonly noted with RHDV2 infections. Clinical signs include lethargy, anorexia, weight loss, and jaundice. Gastrointestinal dilation, cardiac arrhythmias, heart murmurs, and neurologic abnormalities can also occur. Death, if it occurs, usually happens 1–2 weeks after the onset of symptoms, and is due to liver failure. Not all rabbits exposed to RHDVa or RHDV2 become overtly ill. A small proportion of infected rabbits clears the virus without developing signs of disease. Asymptomatic carriers also occur, and can continue to shed virus for months, thereby infecting other animals. Surviving rabbits develop a strong immunity to the specific viral variant with which they were infected. Diagnosis A presumptive diagnosis of RHD can often be made based on clinical presentation, infection pattern within a population, and post mortem lesions. Definitive diagnosis requires detection of the virus. As most caliciviruses cannot be grown in cell culture, antibody and nucleic acid based methods of viral detection are often used. Complete blood counts from rabbits with RHD often show low levels of white blood cells and platelets, and chemistry panels show elevated liver enzymes. Evidence of liver failure may also be present, including increased bile acids and bilirubin, and decreased glucose and cholesterol. Prolonged prothrombin and activated partial thromboplastin times are typical. Urinalysis can show bilirubinuria, proteinuria, and high urinary GGT. The classic post mortem lesion seen in rabbits with RHD is extensive hepatic necrosis. Multifocal hemorrhages, splenomegaly, bronchopneumonia, pulmonary hemorrhage or edema, and myocardial necrosis may sometimes also be seen. RT-qPCR tests are a commonly