Seroprevalence of Antibodies against Seal Influenza A(H10N7) Virus in Harbor Seals and Gray Seals from the Netherlands.

Rogier Bodewes,Ana Rubio García,Guillermo J Sanchez Conteras,Sophie M Brasseur,Marion P G Koopmans,Thijs Kuiken,Marco W G Van De Bildt,Albert D M E Osterhaus

doi:10.1371/journal.pone.0144899

Abstract

In the spring and summer 2014, an outbreak of seal influenza A(H10N7) virus infection occurred among harbor seals (Phoca vitulina) off the coasts of Sweden and Denmark. This virus subsequently spread to harbor seals off the coasts of Germany and the Netherlands. While thousands of seals were reported dead in Sweden, Denmark and Germany, only a limited number of seals were found dead in the Netherlands. To determine the extent of exposure of seals in the Netherlands to influenza A/H10N7 virus, we measured specific antibody titers in serum samples from live-captured seals and seals admitted for rehabilitation in the Netherlands by use of a hemagglutination inhibition assay and an ELISA. In harbor seals in 2015, antibodies against seal influenza A(H10N7) virus were detected in 41% (32 out of 78) pups, 10% (5 out of 52) weaners, and 58% (7 out of 12) subadults or adults. In gray seals (Halichoerus grypus) in 2015, specific antibodies were not found in the pups (n = 26), but in 26% (5 out of 19) of the older animals. These findings indicate that, despite apparent low mortality, infection with seal influenza A(H10N7) virus was geographically widespread and also occurred in grey seals.

Highlights

In the past few decades, various outbreaks of mortality among harbor seals (Phoca vitulina) caused by influenza A viruses have been reported along the east coast of North America [1,2,3,4], but not in European waters
In 2014, NP-specific antibodies were detected in 2 out of 22 gray seal pups (9%) from which serum was collected in December of that year
In serum samples collected from harbor seals in 2015, NPspecific antibodies were detected in 12 out of 78 stranded pups (15%), 5 out of 52 stranded weaners (10%) and 7 out of 12 live-capturedadult seals (58%)

Summary

Introduction

In the past few decades, various outbreaks of mortality among harbor seals (Phoca vitulina) caused by influenza A viruses have been reported along the east coast of North America [1,2,3,4], but not in European waters. Seroprevalence of Antibodies against Influenza A(H10N7) in Seals from the Netherlands

Methods

Results

Conclusion