A New Orthonairovirus Associated with Human Febrile Illness

In June 2019, a tick-bitten patient in Inner Mongolia presented with fever and multiorgan dysfunction, leading to the discovery of a novel orthonairovirus Wetland virus (WELV), via next-generation sequencing. Active hospital surveillance in northeastern China identified 17 additional WELV infections. Patients exhibited nonspecific febrile symptoms with frequent leukopenia, thrombocytopenia, and elevated D-dimer. WELV RNA was also found in five tick species and in sheep, horses, pigs, and Transbaikal zokors, with viral strains showing cytopathic effects in human umbilical vein endothelial cells and lethality in immunocompetent mice. Haemaphysalis concinna ticks demonstrated transovarial transmission capacity. Phylogenetic analysis positioned WELV closest to the Hazara orthonairovirus genogroup but as a distinct species within Nairoviridae. Findings highlight WELV’s pathogenic potential and the need for enhanced surveillance.

In June 2019, a tick-bitten patient in Inner Mongolia presented with fever and multiorgan dysfunction, leading to the discovery of a novel orthonairovirus Wetland virus (WELV), via next-generation sequencing. Active hospital surveillance in northeastern China identified 17 additional WELV infections. Patients exhibited nonspecific febrile symptoms with frequent leukopenia, thrombocytopenia, and elevated D-dimer. WELV RNA was also found in five tick species and in sheep, horses, pigs, and Transbaikal zokors, with viral strains showing cytopathic effects in human umbilical vein endothelial cells and lethality in immunocompetent mice. Haemaphysalis concinna ticks demonstrated transovarial transmission capacity. Phylogenetic analysis positioned WELV closest to the Hazara orthonairovirus genogroup but as a distinct species within Nairoviridae. Findings highlight WELV’s pathogenic potential and the need for enhanced surveillance.