Samantha JAMES

The Herpesviridae family (order Herpesvirales) is made up of DNA viruses divided into 3 subfamilies: Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae. They are found in a wide range of hosts, from mammals to reptiles and birds. These viruses have the capacity to persist throughout the host's life in latent form and to reactivate. Most of these viruses are specific to a particular host species. This specificity is thought to be the result of a long process of co-evolution. My thesis work involves studying the diversity of herpes viruses and their evolutionary relationships, using non-human primates (cytomegalovirus) and New World bats as study models.

Over the last few decades, the search for homologs of human herpes viruses in non-human primates has led to the identification of numerous viruses. Several dozen non-human primate viruses (NHP) are currently recognised by the ICTV. The availability of new molecular techniques, combined with the development of new computer tools, has led to an explosion in the number of herpesvirus sequences identified.

Research into herpes viruses in bats is more recent. It benefited from the interest shown in these mammals in the early 2000s because of their role as reservoirs of potentially zoonotic viruses. The first bat herpesvirus sequences were described in 2007. This was followed by the description of dozens of new sequences identified from different bat species in Africa, Asia, Oceania, Europe and America, including only two from Amazonian species.

In the course of our work we were able to partially characterise 12 cytomegalovirus-type viruses from 12 different species belonging to six genera and representative of the four families of New World non-human primates (NWHNP). These results demonstrate that most NTMNP species can be infected by a virus belonging to the Cytomegalovirus genus. They have also enabled us to understand the systematics of their platyrrhine hosts. The same approach, applied to 11 species of New World bats, enabled us to obtain viral sequences from all the species tested. These are divided into the Beta- and Gamma- herpesvirinae subfamilies. Although the phylogenetic analyses of beta-herpesvirus sequences show a distribution of viral sequences linked to their host species, the analysis of gamma-herpesvirus sequences is more complex. This work is the largest to date in terms of the diversity of species of non-human primates and neotropical bats tested. Nevertheless, they represent only a small proportion of this diversity. Further analyses, on a wider panel of species representative of other geographical regions, will increase our understanding of the evolutionary processes of these viruses.

Herpesviridae (order Herpesviridae) is a large family of DNA viruses, classified into three subfamilies : Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae. Members of herspesviridae family are known to infect a wide range of hosts. In addition to humans, those hosts include mammals, reptiles and birds. The ability to enter into latency provides herpesviruses with an important survival advantage to persist throughout the life of the host and to be reactivated from latency following an appropriate stimulus. Most of these viruses are host-specific. It has been suggested that this specificity would result from a long process of co-evolution during which, herpesviruses have reached a fine-tuned balance with their hosts. The Aim of my thesis project is to study the diversity of herpesviruses and their evolutionary relationships with non-human primates (cytomegalovirus) and bats of the New World.

Like humans, it has been shown that non-human primates are naturally infected with herpesviruses. During the last decades, dozen of non-human primates herpesviruses, homologs to the humans herspesviruses have been identified and recognized by the ICTV. The availability of new molecular techniques, combined with the development of new computer tools, has resulted in the explosion of the number of the herpesvirus sequences.

The search for herpesvirus in bats is more recent. It benefited from the interest in these mammals because of their role as reservoirs of potentially zoonotic viruses. The first bat herpesvirus sequences have been described in 2007, then followed by the description of dozens of new sequences in different bat species from Africa, Asia, Oceania, Europe and America. However, only two of these sequences belong to Amazonian species.

During my thesis work, we have been able to partially characterize 12 cytomegalovirus-like viruses from 12 different species belonging to six genera and representative of the four families of non-human primates of the New World (NWM). These results demonstrate that most species of NWM can be infected with a virus belonging to the genus Cytomegalovirus. They also allowed us to apprehend the systematics of their Platyrrhinian hosts. The same approach, applied to 11 species of New World bats, allowed us to obtain viral sequences in all tested bat species. These viruses are distributed within the Beta- and Gamma-herpesvirinae subfamilies. Although phylogenetic analyses of beta-herpesvirus sequences demonstrate a distribution of viral sequences in relation to their host species, the analysis of gamma-herpesvirus sequences is more complex. In conclusion, this work is the largest conducted to date in terms of the diversity of non-human primate species and Neotropical bats tested. Nevertheless, they represent only a small proportion of this diversity. Further analysis, on a broader panel of representative species from other geographic areas will increase our understanding of the evolutionary processes of these viruses.