Prevalence of Antibodies to Type a Influenza Virus in Wild Avian Species Using Two Serologic Assays

Abstract

Serologic testing to detect antibodies to avian influenza (AI) virus has been an underused tool for the study of these viruses in wild bird populations, which traditionally has relied on virus isolation and reverse transcriptase-polymerase chain reaction (RT-PCR). In a preliminary study, a recently developed commercial blocking enzyme-linked immunosorbent assay (bELISA) had sensitivity and specificity estimates of 82% and 100%, respectively, for detection of antibodies to AI virus in multiple wild bird species after experimental infection. To further evaluate the efficacy of this commercial bELISA and the agar gel immunodiffusion (AGID) test for AI virus antibody detection in wild birds, we tested 2,249 serum samples collected from 62 wild bird species, representing 10 taxonomic orders. Overall, the bELISA detected 25.4% positive samples, whereas the AGID test detected 14.8%. At the species level, the bELISA detected as many or more positive serum samples than the AGID in all 62 avian species. The majority of positive samples, detected by both assays, were from species that use aquatic habitats, with the highest prevalence from species in the orders Anseriformes and Charadriiformes. Conversely, antibodies to AI virus were rarely detected in the terrestrial species. The serologic data yielded by both assays are consistent with the known epidemiology of AI virus in wild birds and published reports of host range based on virus isolation and RT-PCR. The results of this research are also consistent with the aforementioned study, which evaluated the performance of the bELISA and AGID test on experimental samples. Collectively, the data from these two studies indicate that the bELISA is a more sensitive serologic assay than the AGID test for detecting prior exposure to AI virus in wild birds. Based on these results, the bELISA is a reliable species-independent assay with potentially valuable applications for wild bird AI surveillance.

Wood ducks (Aix sponsa) as potential reservoirs for avian influenza and avian paramyxoviruses

“…Two studies have reported IAV antibody test results for wood ducks, and in both cases no antibodies were detected (Kocan et al, 1979;Brown et al, 2010). One of these studies only tested serum from three wood ducks using a blocking ELISA (Brown et al, 2010), and the other study did not report sample size, but sera were tested by the agar gel immunodiffusion assay, which has been shown to perform poorly in waterfowl species (Bahl et al, 1975;Brown et al, 2009).…”

“…One of these studies only tested serum from three wood ducks using a blocking ELISA (Brown et al, 2010), and the other study did not report sample size, but sera were tested by the agar gel immunodiffusion assay, which has been shown to perform poorly in waterfowl species (Bahl et al, 1975;Brown et al, 2009). Experimentally infected wood ducks have developed an antibody response that has been detected up to 21 days after exposure to IAVs (Brown et al, 2009;Costa et al, 2011).…”

Fidelity and Persistence of Ring-Billed (Larus delawarensis) and Herring (Larus argentatus) Gulls to Wintering Sites

“…Aliquots of banked gull serum were acquired from previous studies conducted at multiple locations in Massachusetts during autumn/ winter and in New Jersey during spring (Brown et al 2010). In both cases, birds were captured using a cannon net or net launcher (Clark et al 2014).…”

Avian Influenza Virus Antibodies in Pacific Coast Red Knots (Calidris canutus roselaari)

“…The high frequency of detection of antibodies in adults implies that C. c. roselaari, like C. c. rufa, is susceptible to AIV, and individuals from both populations may have some degree of immunity to specific subtypes (Brown et al 2010). The lack of positive results for chicks suggests that C. c. roselaari did not encounter AIV at natal sites, and chicks did not appear to have maternally derived AIV antibodies.…”