Chinese Virologists Pioneer Mosquito-Delivered Vaccines for Bat Immunisation
In a groundbreaking development, Chinese scientists have engineered vaccine-carrying mosquitoes to bite and immunise bats against rabies and Nipah viruses. This innovative strategy, developed at the Wuhan Institute of Virology, aims to curb the spillover of pandemic-potential pathogens from animals to humans by targeting bats, notorious reservoirs of such diseases.
Ecological Vaccination: A Safer Approach to Wildlife Immunisation
Bats are key culprits in viral transmission events, harbouring pathogens like rabies and Nipah that can jump to humans. While vaccinating bats could deter these spillovers, traditional methods are inefficient for immunising wild populations. The new approach, termed "ecological vaccination," eliminates the need to capture and handle animals, enhancing safety and efficacy.
Experiments revealed that when bats consumed or were bitten by vaccine-carrying mosquitoes, they mounted robust immune responses to antigens from both viruses. Under simulated natural conditions, cohabitation with these mosquitoes elicited strong defences, supporting the feasibility of this method beyond laboratory settings.
Proof-of-Concept Study Details and Findings
The research, published in Science Advances, demonstrated that bats quickly ingested vaccine-storing saline, providing immunity. Scientists placed bats in enclosures with Aedes aegypti mosquitoes infected with a modified vesicular stomatitis virus (VSV), engineered to produce proteins from rabies or Nipah viruses. To prevent spread, mosquitoes were sterilised using X-rays.
Results showed that four out of six bats exposed to vaccine-carrying mosquitoes developed detectable antibodies against both viruses. Similarly, saline traps, which bats naturally gravitate towards for minerals, produced strong immune responses, offering a deployable solution for wild populations in caves.
Biosafety Prioritisation and Potential Risks
Researchers emphasise that this multi-route vaccine is not transmissible from bat-to-bat, deliberately prioritising biosafety through a "limited spread" approach. They caution that while transmissible vaccines could offer high coverage with minimal input, they increase evolutionary and ecological risks. Deploying engineered viruses into wildlife requires careful oversight to avoid unintended ecosystem impacts.
The strategy confines vaccine exposure to directly targeted hosts, rather than allowing propagation through bat populations. Scientists warn that any technology involving engineered viruses must undergo rigorous biosafety evaluation to mitigate potential risks, such as the vaccine becoming virulent.
This development marks a significant step in pandemic prevention, leveraging ecological methods to address viral reservoirs while balancing innovation with safety considerations.
