Chinese scientists are developing an unusual way to protect people from dangerous viruses transmitted from animals. In the new study, they described a strategy in which are trying to vaccinate bats using mosquitoes that carry the rabies vaccine. The aim is to reduce the risk of virus transmission from animals to humans.
Bats are known to be natural hosts of several viruses, such as rabies virus or Nipah virus. It is from these animals that pathogens can sometimes be transferred to humans. According to scientists, vaccinating bats could prevent such transmission, but the problem so far has been how to effectively immunize large populations of these wild animals.
Researchers from the Wuhan Institute of Virology have therefore developed a method in which mosquitoes carry the vaccine and deliver it to bats by sucking blood. At the same time, the scientists also used traps with a saline solution containing the vaccine. According to the authors of the study, it is a form of so-called ecological vaccination, which is safer and more effective, because there is no need to catch or handle animals.
Experiments show that after contact with mosquitoes carrying the vaccine – either after biting them or after eating them – the bats developed a strong immune response against the antigens of the rabies and Nipah viruses. “Under simulated natural conditions, cohabitation with vaccine-carrying mosquitoes elicited a strong immune response in bats, supporting feasibility outside the laboratory environment.” the authors state.
As part of the experiment, bats were placed in rooms where there were mosquitoes with the vaccine. Both species fed each other. The vaccine was created based on the vesicular stomatitis virus (VSV), which can infect both insects and mammals, allowing it to be transmitted by mosquitoes. Scientists have engineered this virus to make the proteins of the rabies virus or Nipah virus.
The mosquitoes were then infected with the vaccine virus by feeding on blood containing the virus. To prevent further spread of the vaccine between mosquitoes, they were sterilized using X-rays. After exposure to these mosquitoes, the bats developed a strong immune response against both viruses. According to the study, four out of six bats that came into contact with mosquitoes developed detectable antibodies against both rabies and the Nipah virus.
Authors also tested the effectiveness of saline traps containing the vaccine. Bats naturally look for minerals and quickly absorb these liquids. This method also produced a similarly strong immune response. According to the scientists, such traps could be placed, for example, in caves with wild populations of bats.
The authors of the study emphasize that the vaccine is not transmitted between bats. “Transportable vaccines offer the possibility of high population coverage with minimal effort, but at the same time increase evolutionary and ecological risks. Our strategy, in contrast, deliberately prioritizes biosecurity through a limited-diffusion approach.” At the same time, they warn that any technology using genetically modified viruses must be subject to careful supervision and a thorough biosafety assessment.
