Characterization of Rabensburg virus, a flavivirus closely related to West Nile virus of the Japanese encephalitis antigenic group

Abstract

Rabensburg virus (RABV), a Flavivirus with ∼76% nucleotide and 90% amino acid identity with representative members of lineage one and two West Nile virus (WNV), previously was isolated from Culex pipiens and Aedes rossicus mosquitoes in the Czech Republic, and phylogenetic and serologic analyses demonstrated that it was likely a new lineage of WNV. However, no direct link between RABV and human disease has been definitively established and the extent to which RABV utilizes the typical WNV transmission cycle is unknown. Herein, we evaluated vector competence and capacity for vertical transmission (VT) in Cx. pipiens; in vitro growth on avian, mammalian, and mosquito cells; and infectivity and viremia production in birds. RABV infection and replication only were detected on mosquito cells. Experimentally inoculated birds did not become infected. Cx. pipiens had poor peroral vector competence and a higher VT rate as compared to US-WNV in Cx. pipiens. As a result, we postulate that RABV is an intermediate between the mosquito-specific and horizontally transmitted flaviviruses.

Figure 1. Rabensburg virus growth on mosquito, human, and avian cells.

Data points represent means of three replicates at each time point +/− standard deviation. LOD, limit of detection; WNV, West Nile virus strain WN02-1956; RABV, Rabensburg virus strain 97–103; C6/36, Aedes albopictus cells; Hek293, human kidney cells; DF-1, chicken cells; pfu, plaque forming units. A.) Mosquito Cells. B.) Human Cells. C.) Avian Cells.