On September 4, a team of Chinese researchers led by Dr. Wei Liu and Dr. Hao Li from the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, along with Ningyi Jin’s team from the Changchun Institute of Veterinary Medicine, published a groundbreaking study in the New England Journal of Medicine (NEJM). The report details the discovery of a new tick-borne RNA virus, named the Wetland Virus (WELV), found in a wetland park in Nei Mongol. This discovery enhances our understanding of tick-borne diseases and provides new insights into the research and prevention of emerging infectious diseases globally.
In June 2019, a patient in an Nei Mongol wetland park developed symptoms of persistent fever and multi-organ dysfunction after being bitten by a tick. Using next-generation sequencing technology, researchers identified a previously unknown orthonairovirus in the patient’s system, which they named the Wetland Virus (WELV). To further investigate, the research team conducted active surveillance in hospitals across northern China, including Nei Mongol, Heilongjiang, Jilin, and Liaoning, focusing on fever patients with a history of tick bites to determine the prevalence of WELV infections.
The study revealed that WELV belongs to the genus Orthnairovirus in the Nairoviridae family, closely related to the Hazara orthonairovirus. Using reverse transcription polymerase chain reaction (RT-PCR), researchers identified acute WELV infections in 17 patients. The main symptoms included fever, dizziness, headache, fatigue, muscle pain, arthritis, and back pain, with a few patients displaying petechiae and swollen lymph nodes. Only one patient experienced neurological symptoms, and no deaths were reported.
Laboratory tests showed common abnormalities, including leukopenia, thrombocytopenia, and elevated levels of D-dimer and lactate dehydrogenase. During the recovery phase, antibody titers specific to WELV were significantly higher in eight patients compared to the acute phase. Additionally, WELV RNA was detected in five tick species and animals such as sheep, horses, pigs, and marmots in northeastern China, indicating that WELV may be transmitted from ticks to both humans and animals.
To further investigate the pathogenicity of WELV, researchers conducted viral isolation and infection studies using animal models. They observed cytopathic effects in human umbilical vein endothelial cells infected with the virus isolated from the index patient and ticks. Additionally, lethal infections were induced in BALB/c, C57BL/6, and Kunming mice through intraperitoneal injection of the virus, confirming the significant pathogenic potential of WELV.
The research team highlighted that the tick species Haemaphysalis concinna could be an important vector for WELV transmission and may spread the virus through transovarial transmission. This discovery is crucial for understanding the ecological characteristics of WELV and its natural circulation. The identification of the Wetland Virus not only expands our knowledge of tick-borne diseases but also emphasizes the need for enhanced global surveillance and prevention efforts. It underscores the importance of strengthening global infectious disease monitoring networks and raising awareness among healthcare professionals about emerging infectious diseases and their response measures.
