Abstract Title
A serological and virological avian influenza survey in African Penguins during the 2021-2022 clade 2.3.4.4b high pathogenicity avian influenza (H5N1) outbreak in South African seabirds
Abstract
Clade 2.3.4.4b high pathogenicity avian influenza (HPAI) H5N1 virus was first detected in South Africa (SA) in April 2021, six months before significant outbreaks in the Northern Hemisphere. Nearly 25 000 coastal seabirds were reported as affected between September 2021 and November 2022, including over 24 000 Cape Cormorants (Phalacrocorax capensis) and more than 300 African Penguins (Spheniscus demersus). This study aimed to investigate prevalence of and risk factors for HPAI virus infection in African Penguins.
Avian influenza serology was performed on samples from 389 adult penguins from SA breeding colonies and two tested avian influenza H5Nx seropositive. However, no virus was detected in 535 penguins sampled in SA and Namibian colonies. In contrast, HPAI (H5N1) virus was detected in twelve of 382 penguins, of various ages, sampled at a seabird rehabilitation centre. Most positive birds were sampled in late 2022, from one site. Positive tests were more likely from adults and those displaying neurological clinical signs and congestion and petechiation of the bare skin above the eyes, though there were mild infections. Next generation sequencing of two of the viruses assigned them to the seabird sub-genotype that emerged in the second half of 2021 and was detected exclusively in that group into 2024.
This study highlights the value of clinical surveillance for HPAI in African Penguins and the relative susceptibility of adults compared to young birds. This work also indicates that African Penguins are unlikely to be an HPAI virus reservoir and to maintain virus between outbreaks.
Avian influenza serology was performed on samples from 389 adult penguins from SA breeding colonies and two tested avian influenza H5Nx seropositive. However, no virus was detected in 535 penguins sampled in SA and Namibian colonies. In contrast, HPAI (H5N1) virus was detected in twelve of 382 penguins, of various ages, sampled at a seabird rehabilitation centre. Most positive birds were sampled in late 2022, from one site. Positive tests were more likely from adults and those displaying neurological clinical signs and congestion and petechiation of the bare skin above the eyes, though there were mild infections. Next generation sequencing of two of the viruses assigned them to the seabird sub-genotype that emerged in the second half of 2021 and was detected exclusively in that group into 2024.
This study highlights the value of clinical surveillance for HPAI in African Penguins and the relative susceptibility of adults compared to young birds. This work also indicates that African Penguins are unlikely to be an HPAI virus reservoir and to maintain virus between outbreaks.
Co-Author(s)
Laura Christl Roberts (Department of Production Animal Studies and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Pretoria, Gauteng, South Africa; Department of Agriculture, Western Cape Government, Elsenburg, Western Cape, South Africa), Celia Abolnik (Department of Production Animal Studies and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Pretoria, Gauteng, South Africa), David Gordon Roberts (Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town, Western Cape, South Africa), Darrell Abernethy (Department of Life Sciences, Aberystwyth School of Veterinary Science, Aberystwyth University, Aberystwyth, Ceredigion, UK; Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Pretoria, Gauteng, South Africa)
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds