Sane and sound: a serologic and molecular survey for selected infectious agents in neozootic Egyptian geese (Alopochen aegyptiacus) in Germany

Abstract

Aquatic birds can act as vectors and reservoir hosts for pathogens relevant for wild birds and poultry as well as human health. In this study, we address the questions (1) if the Egyptian goose (Alopochen aegyptiacus), as one of the most successful neozootic bird species in Europe, carry infectious agents that are relevant for poultry and wild birds and (2) if seasonal prevalences of these infectious agents differ from those of native geese species. In 2015 and 2016, up to 190 Egyptian geese from Western Germany were investigated serologically for antibodies (Ab) against influenza A viruses (IAV), Avian avulavirus 1 (AAvV-1), aviadenoviruses, Duck atadenovirus A (syn.: egg drop syndrome 1976 virus) (EDSV), and West Nile virus (WNV). Ab were detected against IAV in 6.1% (10/164), against AAvV-1 in 2.4% (4/165), against EDSV in 15.2% (16/105), and against aviadenoviruses in 0.86% (1/116) of the geese blood samples, respectively. None of the birds had Ab against WNV (0/84). PCR-based techniques (cloacal and/or pharyngeal swabs) were applied for the presence of IAV, AAvV-1, Mycoplasma spp., and Riemerella anatipestifer. Riemerella DNA was detected in the pharyngeal swabs with an overall prevalence of 70.3% (104/148). Neither Mycoplasma DNA nor IAV or AAvV-1 RNA could be detected in the pharynx or cloaca of the examined birds. Our study shows that Egyptian geese are frequent carriers of Riemerella anatipestifer and furthermore provides serological evidence of exposure to IAV, AAvV-1, and EDSV. It is one of very few studies on infectious agents of neozootic bird species. Comparing our results from a neozootic non-migratory goose species with published results from native migratory geese species (bean goose (Anser fabalis) and white-fronted goose (A. albifrons)) and another neozootic non-migratory goose species (Canada goose (Branta canadensis)), we found differences in the seroprevalence of viral pathogens. Native goose species show higher seroprevalences of IAV and AAvV-1, whereas neozootic non-migratory geese reveal higher seroprevalences for EDSV. The findings are discussed in the frame of seasonal variations in selected infectious agents, differences in sampling periods, and contrasting movement ecology of the different geese species.

Increased immune marker variance in a population of invasive birds

“…Twenty-one Egyptian geese (9 male, 12 female) were live trapped in Namibia (22.35° S, 17.05° E) (native range) in February 2016. Additionally, data from a subset of 110 adult Egyptian geese from Germany (65 male, 45 female) investigated by Prüter et al 32 were included. German geese were sampled in the Rhine and Mosel areas (50.4° N, 7.6° E) (invasive range) in 2015 ( n = 78) and 2016 ( n = 32) in different months (supplementary data Table S1 ).…”

“…To compare with previously determined bacterial prevalence of adult German Egyptian geese 32 (Table 2 ), the Namibian birds were screened for Mycoplasma spp. and Riemerella (R.) anatipestifer using conventional 16S rRNA-based PCR assays as described by Prüter et al 32 .…”

“…To compare with previously determined bacterial prevalence of adult German Egyptian geese 32 (Table 2 ), the Namibian birds were screened for Mycoplasma spp. and Riemerella (R.) anatipestifer using conventional 16S rRNA-based PCR assays as described by Prüter et al 32 . To verify the specificity of the Mycoplasma PCR assay, products with a clear band were further investigated by sequence analysis, following the procedure described by Prüter et al 32 .…”

“…and Riemerella (R.) anatipestifer using conventional 16S rRNA-based PCR assays as described by Prüter et al 32 . To verify the specificity of the Mycoplasma PCR assay, products with a clear band were further investigated by sequence analysis, following the procedure described by Prüter et al 32 . Only samples with a clear sequencing result were designated positive.…”

“…The seroprevalence of antibodies (Ab) against Influenza A virus (IAV), Avian avulavirus 1 (AAvV-1) and West Nile virus (WNV) were determined 32 . For the detection of Abs against IAV, a commercial competitive enzyme linked immunosorbent assay (ELISA) was used following the manufacturer instructions (ID.vet, Grabels, France, Influenza A Antibody competition, FLUACA ver 0917DE).…”