A new virus, dubbed wetland virus (WELV), has been discovered in China that can spread to humans through tick bites, causing neurological disease in some cases, according to media reports.

The virus was first identified in a 61-year-old patient in Jinzhou city in June 2019, who fell ill five days after being bitten by ticks in Inner Mongolia’s wetlands. The patient experienced fever, headache and vomiting, with symptoms resistant to antibiotics, according to a report published in The New England Journal of Medicine.

WELV belongs to a group of viruses known for being transmitted by ticks, similar to the Crimean-Congo hemorrhagic fever virus, which can cause severe illness in humans. Following the initial discovery, researchers conducted a thorough investigation in northern China, where they collected nearly 14,600 ticks from various locations. About 2 per cent of these tested positive for WELV genetic material, primarily from the species Haemaphysalis concinna.

WELV RNA was also found in sheep, horses, pigs and rodents called Transbaikal zokor. The virus showed cytopathic effects in human umbilical-vein endothelial cells and caused lethal infections in animal models.

The researchers also analysed blood samples from forest rangers in the region, finding antibodies to WELV in 12 out of 640 individuals. Further tests on patients with tick bites revealed that 20 individuals tested positive for the virus, with symptoms ranging from fever, dizziness and headache to nausea and diarrhoea. One patient even fell into a coma due to high white blood cell counts in the brain and spinal fluid.

Although all patients recovered after treatment, lab experiments on mice showed that WELV can cause lethal infections and potentially affect the nervous system. This suggests that while WELV can be mild in some cases, it has the potential to cause severe health issues, particularly involving the brain.