The impacts of co-circulating pathogens in Pacific herring depend on interactions between viral life-cycle traits and transmission parameters, highlighting interdependencies between pathogen epizootics

Philosophical Transactions of the Royal Society, Series B
By: , and 

Links

Abstract

The average host susceptibility decreases as the epizootic progresses because easily infected hosts are first removed from the population. While host susceptibility is pathogen-specific, it is likely that host susceptibility is correlated between different pathogens, so that co-circulating pathogens may have reciprocal impacts on their epidemics. However, despite well-documented examples of concomitant infections in marine hosts, reciprocal epizootic effects have not been documented in wild marine organisms. We quantify reciprocal impacts between viral haemorrhagic septicaemia and viral erythrocytic necrosis in Pacific herring (Clupea pallasii) using field and laboratory work. We show that the causative viruses for both diseases circulate through herring populations and that infection with one pathogen has negative impacts on the epizootic and infection characteristics of the other pathogen, suggesting positive correlations in the susceptibility to infection between pathogens. We then use simulations of a two-strain pathogen model to show that the impact of the correlation is modulated by transmission parameters, such as the incubation period and the initial transmission rate. Our work shows that co-occurring epizootics pose a management challenge because single-pathogen management actions may amplify the epizootics of the non-targeted pathogen. This study provides a framework to evaluate the consequences of reciprocal epizootic impacts through field, experimental and modelling work.

Suggested Citation

Páez, D.J., Grady, C.A., Gregg, J.L., Batts, W.N., Ferreiro-Luce, S., Herron, V.L., Loeher, M.M., Williamson, S., and Hershberger, P., 2026, The impacts of co-circulating pathogens in Pacific herring depend on interactions between viral life-cycle traits and transmission parameters, highlighting interdependencies between pathogen epizootics: Philosophical Transactions of the Royal Society, Series B, v. 381, no. 1945, 20240329, 12 p., https://doi.org/10.1098/rstb.2024.0329.

Study Area

Publication type Article
Publication Subtype Journal Article
Title The impacts of co-circulating pathogens in Pacific herring depend on interactions between viral life-cycle traits and transmission parameters, highlighting interdependencies between pathogen epizootics
Series title Philosophical Transactions of the Royal Society, Series B
DOI 10.1098/rstb.2024.0329
Volume 381
Issue 1945
Publication Date March 05, 2026
Year Published 2026
Language English
Publisher The Royal Society Publishing
Contributing office(s) Western Fisheries Research Center
Description 20240329, 12 p.
Country United States
State Washington
Other Geospatial Port Angeles Harbor
Additional publication details