China, a nation that faced significant challenges with the coronavirus pandemic in 2019, has now identified a new and potentially dangerous virus, known as Wetland Virus (WELV). First detected in Jinzhou province in June 2019, this virus has recently garnered attention due to its potential to cause serious brain diseases.
According to a report published by The New England Journal of Medicine on September 4, the Wetland Virus was initially discovered in a patient from Inner Mongolia who presented with persistent fever and multiple organ dysfunction following a tick bite at Wetland Park. The report highlights that next-generation sequencing revealed the presence of an unknown Orthonairovirus, which was subsequently named Wetland Virus (WELV).
Following the discovery, researchers conducted extensive sampling of individuals who had either visited the park or exhibited similar symptoms. The findings revealed that 17 patients from Inner Mongolia, Heilongjiang, Jilin, and Liaoning tested positive for acute WELV infection through reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assays.
Symptoms among the infected varied, but common issues included fever, dizziness, headache, malaise, myalgia, arthritis, and back pain. Notably, some patients displayed petechiae—small, red or purple spots on the skin or mucous membranes—and localized lymphadenopathy, where swollen lymph nodes were confined to specific body areas.
In a particularly concerning case, one patient presented with neurologic symptoms. Laboratory results showed common findings of leukopenia (low white blood cell count), thrombocytopenia (low platelet count), and elevated levels of d-dimer and lactate dehydrogenase. The study also noted that WELV-specific antibody titers in convalescent-stage samples were significantly higher than in acute-phase samples.
Further investigation revealed that WELV RNA was present in five tick species, as well as in sheep, horses, pigs, and Transbaikal zokors (Myospalax psilurus). These samples were collected from the northeastern region of China. The virus isolated from the index patient and ticks exhibited cytopathic effects in human umbilical vein endothelial cells. In animal models, the virus caused lethal infections in BALB/c, C57BL/6, and Kunming mice, and the Haemaphysalis concinna tick was identified as a possible vector capable of transmitting WELV transovarially.
The emergence of Wetland Virus raises new concerns about vector-borne diseases and underscores the need for continued surveillance and research to understand and mitigate its impact.
