Experimental infection of calves with epizootic hemorrhagic disease virus.

OBJECTIVE: To determine whether experimental inoculation with a field strain of epizootic hemorrhagic disease virus serotype-2 (EHDV-2) suspected of causing clinical disease in naturally infected cattle would cause clinical disease in calves. ANIMALS: 8 calves. PROCEDURE: A strain of EHDV-2 isolated from a white-tailed deer that died of hemorrhagic disease was passaged twice in deer and used to inoculate 6 calves SC and ID; the other 2 calves were used as controls. Physical examinations, CBC, lymphocyte blastogenesis assays, and coagulation assays were performed; rectal temperature, interferon production, and serum neutralizing antibody responses were measured; and virus isolation was attempted every other day for 21 days after inoculation and then every fourth day for another 30 days. Calves were euthanatized on postinoculation day 51, and necropsy was performed. RESULTS: Calves inoculated with EHDV-2 became infected, as evidenced by development of viremia and seroconversion. However, the virus did not cause detectable clinical disease, clinicopathologic abnormalities, or gross lesions. Viremia was prolonged despite development of a serum neutralizing antibody response. A white-tailed deer inoculated with the same EHDV-2 strain developed clinical signs of epizootic hemorrhagic disease, demonstrating that the inoculum was virulent. CONCLUSION: Calves experimentally infected with EHDV-2 developed viremia and seroconverted but did not develop detectable clinical disease.

Liver lobe torsion and liver abscess in a dog.

A 4-year-old Rhodesian Ridgeback had acute onset of vomiting, lethargy, and discolored urine. Physical examination revealed lethargy, pyrexia, weak femoral pulses, cardiac arrhythmia, distended abdomen, and signs of pain on abdominal palpation. Abdominal radiography and ultrasonography revealed a gas-containing lesion in the cranial portion of the abdomen. Preoperative care included administration of fluids, antibiotics, and antiarrhythmic medication. Exploratory laparotomy revealed hemobilia and a 360 degrees clockwise torsion of the papillary process of the caudate lobe of the liver. Clinical signs resolved completely after liver lobectomy, and the dog was alive 2 years after surgery. Torsion of a liver lobe is rare in dogs. Necrosis of the involved liver lobe can result in acute weakness, shock, and death. Hemodynamic stabilization, antibiotic treatment, and surgical intervention have been successful in treating this condition. Liver lobe torsion should be considered on the differential diagnoses list of acute abdominal pain.