Researchers from Liverpool School of Tropical Medicine have helped uncover how ticks mount a defence against a deadly virus increasingly found in parts of East Asia, a discovery that could help disrupt disease transmission.
The study, published in Nature Communications, provides the most detailed picture yet of how cells from the tick species Rhipicephalus microplus respond to infection with severe fever with thrombocytopenia syndrome virus (SFTSV).
SFTSV can cause high fever, internal bleeding and death in humans and currently has no licensed treatment or vaccine. As climate change alters the geographic range of ticks, the risk of all tick-borne diseases is likely to rise.
By using a systems biology approach, unitizing advanced tools to analyse how genes and proteins work together, researchers mapped the molecular changes that take place in tick cells after infection. They identified two proteins, UPF1 and DHX9, that act as natural viral restriction factors, helping the tick cells restrict virus replication.
Professor Alain Kohl, Chair in virology and emerging infectious diseases at LSTM, said: “Ticks are important vectors of disease, but their biology and ability to block viruses pathogenic to humans is still relatively poorly understood.”
“Our study shows they have sophisticated ways of detecting and controlling viral infections. This matters, because understanding how ticks manage to control viruses can help us find new ways to break the chain of transmission to people.”
The discovery show that ticks’ antiviral control system is more sophisticated than previously thought and lays the foundation for future work to map antiviral mechanisms in other disease-carrying ticks. It is hoped that this could help identify weak points in the virus-vector relationship that can be targeted to block transmission.
Dr Marine Petit, the study's lead author and a Lecturer in Virology at the University of Surrey added: “Our findings demonstrate that tick cells are not passive carriers of SFTSV; they actively mount antiviral responses. Ticks even repurpose conserved proteins to act as molecular guardians, playing a key role in their antiviral defences.
“Understanding how these proteins work not only helps us decipher how ticks tolerate dangerous viruses but also opens new ways to disrupt disease transmission.”
With the help of University of Liverpool’s tick cell repository, the research team profiled genes and proteins in the Rhipicephalus microplus BME6 cell line. In doing so, they annotated nearly 400 previously unknown proteins and identified a wide range of RNA molecules.
This research was carried out by scientists from Liverpool School of Tropical Medicine, the University of Surrey, the University of Glasgow, the University of Liverpool and the University of Dundee.