Viral emergence in marine mammals in the North Pacific may be linked to Arctic sea ice reduction

Elizabeth Vanwormer ,S L Cosby,John A Hammond ,Mark Henstock ,Verena A Gill ,Tom Gelatt ,Ailsa J Hall ,Brian S Fadely ,A Jeffers,Michelle E Lander ,Lorrie D Rea ,Rolf R Ream ,Josh M London ,Kathleen A Burek‐Huntington ,Michael J Rehberg ,Patrick M Brock ,Brett Smith ,Vladimir N Burkanov ,Jonna A K Mazet ,Peter L Boveng ,Jeremy T Sterling ,Tracey Goldstein

doi:10.1038/s41598-019-51699-4

Abstract

Climate change-driven alterations in Arctic environments can influence habitat availability, species distributions and interactions, and the breeding, foraging, and health of marine mammals. Phocine distemper virus (PDV), which has caused extensive mortality in Atlantic seals, was confirmed in sea otters in the North Pacific Ocean in 2004, raising the question of whether reductions in sea ice could increase contact between Arctic and sub-Arctic marine mammals and lead to viral transmission across the Arctic Ocean. Using data on PDV exposure and infection and animal movement in sympatric seal, sea lion, and sea otter species sampled in the North Pacific Ocean from 2001–2016, we investigated the timing of PDV introduction, risk factors associated with PDV emergence, and patterns of transmission following introduction. We identified widespread exposure to and infection with PDV across the North Pacific Ocean beginning in 2003 with a second peak of PDV exposure and infection in 2009; viral transmission across sympatric marine mammal species; and association of PDV exposure and infection with reductions in Arctic sea ice extent. Peaks of PDV exposure and infection following 2003 may reflect additional viral introductions among the diverse marine mammals in the North Pacific Ocean linked to change in Arctic sea ice extent.

Highlights

Climate change-driven alterations in Arctic environments can influence habitat availability, species distributions and interactions, and the breeding, foraging, and health of marine mammals
Samples were collected from 2,530 live and 165 dead ice-associated seals, Steller sea lions, northern fur seals, and northern sea otters in the North Pacific Ocean between 2001 and 2016; not all species were sampled in all years (Supplementary Table 1)
Open water along most of northern Russia linked the North Pacific Ocean to the eastern North Atlantic Ocean (Fig. 1), where European harbour seals were dying in an epidemic of Phocine distemper virus (PDV) that began in May 2002

Summary

Introduction

Climate change-driven alterations in Arctic environments can influence habitat availability, species distributions and interactions, and the breeding, foraging, and health of marine mammals. Phocine distemper virus (PDV), which has caused extensive mortality in Atlantic seals, was confirmed in sea otters in the North Pacific Ocean in 2004, raising the question of whether reductions in sea ice could increase contact between Arctic and sub-Arctic marine mammals and lead to viral transmission across the Arctic Ocean. Www.nature.com/scientificreports responsible for extensive mortality in European harbour seals (Phoca vitulina vitulina) in the North Atlantic, was identified in northern sea otters (Enhydra lutris kenyoni) in Alaska[8] This finding raised the possibility that increased contact between Arctic and sub-Arctic marine mammals could result from climate change-associated reductions in Arctic sea ice extent which could alter animal movement allowing for disease transmission across the Arctic Ocean. PDV was not confirmed in the North Pacific Ocean until virus was detected in northern sea otters sampled in 2004, which raised a number of questions regarding the timeline of introduction into the North Pacific, how the virus reached sea otters, and what role the virus may play in North Pacific marine mammal illness and mortality

Methods

Results

Conclusion