A comparison of intradermal and intravenous inoculation of bluetongue virus serotype 23 in sheep for clinico-pathology, and viral and immune responses.

Abstract The pathogenesis of bluetongue (BT) could vary with route of inoculation. Using laboratory-passaged moderately virulent bluetongue virus serotype 23 (BTV-23), one of the most prevalent Indian serotype, we investigated the pathogenesis of BT in intradermally (ID) and intravenously (IV) inoculated native sheep. The ID inoculation resulted in relatively increased clinical signs and lesions in many organs as compared to IV inoculation. BTV-23 detection by real-time RT-PCR and isolation studies revealed that ID inoculation can be more efficient than IV ones in disseminating and spreading virus to systemic organs, including pre-scapular draining lymph node, spleen, lungs and pulmonary artery. Furthermore, the ID inoculation resulted in early onset and increased humoral response with significant increase ( P