Wild birds of the ordersAvian influenza (AI) viruses have been reported from a wide diversity of free-living birds representing over 100 species in 12 taxonomic orders (11). All of the known hemagglutinin (H1 to H16) and neuraminidase (N1 to N9) subtypes of AI viruses have been isolated from wild birds (8, 9, 11), and currently, species in the orders Anseriformes (ducks, geese, and swans) and Charadriiformes (gulls, terns, and shorebirds) are believed to be the natural reservoirs. Surveillance for AI virus in wildbird populations is predominately dependent on diagnostic assays that identify the virus, including reverse transcriptase PCR and virus isolation. Virus isolation from oropharyngeal or cloacal swabs of embryonating chicken eggs currently represents the preferred method of AI virus diagnosis and surveillance in wild-bird populations. However, agent-specific identification assays, such as virus isolation and reverse transcriptase PCR, are expensive, labor-intensive, and dependent on the host actively excreting virus. Consequently, a limitation of the agent identification-based approach to AI virus surveillance in wild birds relates to the relatively short duration of viral shedding and the high degree of spatial and temporal variations in viral prevalence within different wild avian populations. These limitations and uncertainties often necessitate large sample sizes to identify positives and repeat sampling at different times and locations. Additionally, the variability creates difficulty when interpreting negative test results, i.e., in determining whether a negative result is indicative of inappropriate sampling (wrong location or time) or a species that is resistant to or rarely infected with AI virus.Serologic assays are commonly utilized for surveillance and diagnostics with domestic poultry to detect whether a population of birds has previously been exposed to an AI virus. Serologic tests utilized for AI virus antibody detection in domestic poultry include the agar gel immunodiffusion (AGID) test, the enzyme-linked immunosorbent assay (ELISA), the hemagglutination inhibition test, and the neuraminidase inhibition test (17). The AGID test and the ELISA detect antibodies against all type A influenza viruses and consequently are the preferred assays for use as a screening tool. The hemagglutination inhibition and the neuraminidase inhibition tests are hemagglutinin and neuraminidase specific, respectively, and typically are performed to identify antibodies to specific subtypes or to confirm AGID test-or ELISA-positive samples when information on the subtype is available.The AGID test is the most commonly utilized serologic assay for AI virus surveillance in domestic poultry and detects antibodies directed against the AI virus internal proteins nucleoprotein (NP) and matrix 1 (M1) protein (20). While the AGID test is inexpensive and simple to perform, the primary disadvantage is that it is only moderately sensitive for gallina-* Corresponding author. Mailing address: Southeastern Cooperative Wildlife D...

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.

Worldwide, Salmonella spp. is a significant cause of disease for both humans and wildlife, with wild birds adapted to urban environments having different opportunities for pathogen exposure, infection, and transmission compared to their natural conspecifics. Food provisioning by people may influence these factors, especially when high-density mixed species flocks aggregate. White Ibises (Eudocimus albus), an iconic Everglades species in decline in Florida, are becoming increasingly common in urbanized areas of south Florida where most are hand-fed. We examined the prevalence of Salmonella shedding by ibises to determine the role of landscape characteristics where ibis forage and their behavior, on shedding rates. We also compared Salmonella isolated from ibises to human isolates to better understand non-foodborne human salmonellosis. From 2010–2013, 13% (n = 261) adult/subadult ibises and 35% (n = 72) nestlings sampled were shedding Salmonella. The prevalence of Salmonella shedding by ibises significantly decreased as the percent of Palustrine emergent wetlands and herbaceous grasslands increased, and increased as the proportion of open-developed land types (e.g. parks, lawns, golf courses) increased, suggesting that natural ecosystem land cover types supported birds with a lower prevalence of infection. A high diversity of Salmonella serotypes (n = 24) and strain types (43 PFGE types) were shed by ibises, of which 33% of the serotypes ranked in the top 20 of high significance for people in the years of the study. Importantly, 44% of the Salmonella Pulsed-Field Gel Electrophoresis patterns for ibis isolates (n = 43) matched profiles in the CDC PulseNet USA database. Of these, 20% came from Florida in the same three years we sampled ibis. Importantly, there was a negative relationship between the amount of Palustrine emergent wetland and the number of Salmonella isolates from ibises that matched human cases in the PulseNet database (p = 0.056). Together, our results indicate that ibises are good indicators of salmonellae strains circulating in their environment and they have both the potential and opportunity to transmit salmonellae to people. Finally, they may act as salmonellae carriers to natural environments where other more highly-susceptible groups (nestlings) may be detrimentally affected.

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SUMMARYOxyspirura petrowiis a heteroxenous parasitic nematode that has been reported in high prevalences from birds in the Order Galliformes experiencing population declines in the USA. There is a paucity of information regarding the natural historyO. petrowi, including the life cycle and effects of infection on wild bird populations. In order to study the life cycle of this parasite, we collected plains lubber grasshoppers (Brachystola magna) from a field location in Mitchell County, Texas. We found third-stage larvae (L3) in 37.9% (66/174)B. magna. We determined that they wereO. petrowithrough morphological comparison of L3 from experimentally infectedAcheta domesticusand by sequence analysis. Then, we showed thatB. magnaare a potential intermediate hosts forO. petrowiinfections in northern bobwhites (Colinus virginianus) in a laboratory setting by experimental infection. We first detected shedding of eggs in feces using a fecal float technique 52 days post infection. In addition, we recovered 87O. petrowifrom experimentally infected northern bobwhites. Although we detected shedding in feces, recovery of eggs was low (>5 eggs/g). Future work is needed to understand shedding routes and shedding patterns of northern bobwhites infected withO. petrowi.

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Northern bobwhite (quail) (Colinus virginianus) and scaled quail (Callipepla squamata) populations have declined dramatically in the Rolling Plains ecoregion of Texas and Oklahoma (USA). There is rising concern about potential toxicity of neonicotinoids to birds. To investigate this concern, the authors examined crops of 81 northern bobwhite and 17 scaled quail to determine the presence or absence of seeds treated with 3 neonicotinoids (clothianidin, imidacloprid, and thiamethoxam). No treated seeds were found in the 98 crops examined. Liver samples from all 98 quail were collected and analyzed for neonicotinoid residues. Analysis revealed very low concentrations of neonicotinoids within the quail liver samples. The results suggest there is little to no risk of direct toxicity to quail from neonicotinoids. Environ Toxicol Chem 2016;35:1511-1515. © 2015 SETAC.

Oxyspirura petrowi is a parasitic nematode that infects wild birds. This parasite has a broad host range, but has recently been reported in high prevalences from native Galliformes species in the United States. In order to better understand the impact O. petrowi has on wild bird populations, we developed a quantitative PCR protocol to detect infections in wild northern bobwhites (Colinus virginianus). We used paired fecal and cloacal swab samples from wild caught and experimentally infected northern bobwhites and matching fecal float data from experimentally infected birds to validate our assay. Overall we detected more positive birds from fecal samples than the paired cloacal swabs and there was strong agreement between the qPCR results from fecal samples and from fecal flotation (84%; κ = 0.69 [0.53–0.84 95% CI]). We also detected O. petrowi DNA in ten replicates of samples spiked with one O. petrowi egg. This qPCR assay is an effective assay to detect O. petrowi infections in wild birds. Our results suggest that fecal samples are the most appropriate sample for detecting infections; although, cloacal swabs can be useful for determining if O. petrowi is circulating in a population.