Coevolution   

At the same time, the researchers made another discovery with regard to the phylogeny of virus species. A long time ago (something in the order of 156 million years), tortoises and sea turtles had a common ancestor. They then evolved into two branches, one on land and the other in the sea. While they still resemble each other physically, in reality they have become more genetically distinct from each other than a horse from a whale.

If we compare the herpesvirus that affects tortoises and another herpesvirus (chelonid herpesvirus 5) which affects their sea cousins, we can see that they are as distinct from each other as the tortoises they infect. This phenomenon is known as cospeciation. This shows that the herpesvirus of terrestrial and sea turtles probably have a common ancestor and evolved with each species. This was the last secret revealed by TeHV-3.

“When taken together, all these discoveries explain why this virus affecting tortoises made the front page of Journal of Virology”, says a smiling Alain Vanderplasschen. And yet this research almost didn’t go ahead. Indeed, this research programme which aimed to find a solution to one of the main causes of the decline of several species of endangered tortoises required the performance of animal experiments. These were only allowed to go ahead after many long discussions with the bioethics committee, the only organ which has the authority to authorise animal experiments. It is deplorable to observe that the pressure exerted by a small proportion of the society which is against the performance of animal experiments could have the consequence of preventing the development of solutions against a plague that threatens several species of endangered tortoises.

The interest shown by the international scientific community following the publication in the Journal of Virology and the common sense approach adopted by the bioethics committee succeeded in unblocking the situation. Frédéric Gandar will be able to continue to develop a vaccine. In the next year, the researchers will be able to determine whether they have produced a vaccine that will be capable to protect several endangered species of tortoise. This vaccine will be supplied by the University of Liege to any foundation wishing to contribute to the survival of species threatened by the TeHV-3 virus.