Testudinid herpesvirus 3 ( TeHV-3) is a herpes virus causing high mortality rates in several protected species of tortoises (including Hermann’s tortoise).

Until now, the 250 or so herpes viruses studied – these are found in oysters as well as in humans – are divided into six distinct genomic structures. All of them, that is, except Testudinid herpesvirus 3. Frédéric Gandar and Alain Vanderplasschen could not believe their eyes, but they had discovered a new herpesvirus genome structure. This would be the seventh. Virology reference books will need to be updated! And this does not even take into account immune evasion or phylogeny-related discoveries. The researchers are currently working on a vaccine against this disease that is decimating tortoise species many of which are endangered.

The researchers hope to perfect a vaccine that will be capable of immunizing tortoises against the plague that is killing them in such great numbers. The plague in question is Testudinid herpesvirus 3, TeHV-3.

If a group of young tortoises comes into contact with the virus, the result will be fatal for 80% to 100% of them. At first, there will be no visible signs to show that they are infected. After an incubation period of around twenty days the first symptoms will appear: nasal discharge, weakness, white spots in the mouth. Secondary infections will then appear. Then the nervous system is affected avoiding tortoises from eating and moving around. Finally, the infection affects all the organs, the spleen, the kidneys and the brain. Death is inevitable after around ten days.

Those that survive become “asymptomatic carriers”. Without any visible warning, the virus will be carried by them all their lives and will spread to other tortoises they meet.

Citation: "The Genome of a Tortoise Herpesvirus (Testudinid Herpesvirus 3) Has a Novel Structure and Contains a Large Region That Is Not Required for Replication In Vitro or Virulence In Vivo", Frédéric Gandara,b, Gavin S. Wilkiec, Derek Gathererd, Karen Kerrc, Didier Marlierb, Marianne Dieze, Rachel E. Marschangf, Jan Mastg, Benjamin G. Dewalsa, Andrew J. Davisonc and Alain F. C. Vanderplasschen. Journal of Virology, 23rd October 2015