“Illumination of anguillid herpesvirus 1 transmission reveals the importance of host developmental stage and social interactions (7072)”

Illumination of anguillid herpesvirus 1 transmission reveals the importance of host developmental stage and social interactions

The European eel (EE) is an important farmed fish and a flagship species for conservation efforts. Its life cycle involves different stages and extended migration through both marine and freshwater environments. EE is critically endangered. Among the pathogens thought to cause its decline is anguillid herpesvirus 1 (AngHV‑1). Epidemiological surveys in natural habitats have indicated that glass eels reach European coasts free from AngHV‑1 and are then contaminated to reach a high prevalence as they mature to the yellow eel stage. Here, we took advantage of in vivo bioluminescent imaging to illuminate how AngHV‑1 is transmitted to its natural host. Our results highlight that EE become sensitive to AngHV-1 only when they reach the yellow stage. Remarkably, our results highlight two modes of virus transmission: indirect transmission by water, only compatible with the high density of fish typical of aquaculture; and direct transmission by agonistic interactions between fish, specifically biting, which is compatible with the low density of fish in natural habitats. Moreover, in line with these findings, we established that one of the earliest sites of viral replication after contamination is the periodontal mucosa. These aspects of AngHV‑1 pathogenesis act to optimise viral transmission specifically through biting and represents a remarkable viral adaptation to solitary and territorial behaviour of its host and the instability of the virus in water and fish mucus. This study challenges the current paradigm that fish viruses are transmitted mainly via water acting as an abiotic and protective vector. It demonstrates that as in air so in water, social interactions matter.

1. Vanderpla, Alain, University of Liège, Presenter
2. Delrez, Natacha, University of Liège, Author
3. Denoel, Mathieu, University of Liège, Author
4. Ovidio, Michael, University of Liège, Author
5. Nzau Matondo, Billy, University of Liège, Author
6. Larbanoix, Lionel, University of Mons, Author
7. Davison, Andrew, University of Glasgow, Author
8. Donohoe, Owen, University of Liège, Author
9. Zhang, Haiyan, University of Liège, Author