Detection of Avian Influenza Viruses From Shorebirds: Evaluation of Surveillance and Testing Approaches

Abstract

Although influenza A viruses have been isolated from numerous shorebird species (Family: Scolopacidae) worldwide, our understanding of natural history of these viruses in this diverse group is incomplete. Gaining this information can be complicated by sampling difficulties related to live-capture, the need for large sample sizes related to a potentially low prevalence of infection, and the need to maintain flexibility in diagnostic approaches related to varied capabilities and resources. To provide information relevant to improving sampling and testing of shorebirds for influenza A viruses, we retrospectively evaluated a combined data set from Delaware Bay, USA collected from 2000–2009. Our results indicate that prevalence estimates and subtype diversity, can be effectively determined by either direct sampling of birds or indirect sampling of feces. Although predominant subtypes present in the populations also can be identified by either approach, the extent of detected subtype diversity is a function of the number of viruses recovered during that year. Even in cases where a large number of viruses are identified, this likely will result in an underestimation of actual subtype diversity. Influenza A virus isolation from Ruddy Turnstones can be enhanced by testing both cloacal and tracheal samples, and matrix real-time PCR can be used as an effective screening tool. Serologic testing to target species of interest also has application to shorebird surveillance. Overall, all of the sampling and diagnostic approaches have utility as applied to shorebird surveillance, but all are associated with inherent biases that need to be considered when comparing results from independent studies.

Spread and Persistence of Influenza A Viruses in Waterfowl Hosts in the North American Mississippi Migratory Flyway

“…As a result, the sampling of AIVs within the MMF at a few sites in any given year will likely provide a snapshot of the diversity that exists within the flyway and show that movement of these viruses occurs frequently. Traditionally, this is how many very important and noteworthy North American surveillance sites operate (47,48). However, repeated annual sampling along the MMF as conducted in this study showed that, over time, the movement of these genetic lineages was often unsuccessful and resulted in a pattern of temporal structuring of the AIVs within the MMF.…”

Avian Influenza: Mixed Infections and Missing Viruses

“…Ideally, field and laboratory efforts should yield results that accurately reflect nature—screening tests should have 100% sensitivity and specificity, and virus isolation and sequencing should not alter or bias results. However, this is rarely the case, and many studies have shown that researchers must carefully consider the limitations and biases associated with different sampling strategies and diagnostic tests [5,6,7,8,9,10]. …”

Vigilância epidemiológica dos vírus da influenza aviária em aves migratórias na região costeira da Amazônia

“…Uma possível explicação é o fato de que a primeira expedição correspondeu a uma maior amostragem de Arenaria interpres, sendo que mais da metade dos exemplares desta espécie amostrados neste estudo (23/43) foram capturados nesta saída de campo. Estes dados corroboram observações anteriores de que a prevalência de AIV em uma determinada localidade pode estar intimamente correlacionada à presença de uma espécie na qual a prevalência é particularmente elevada , como é sabidamente o caso de A. interpres (KAWAOKA et al, 1988;HANSON, 2008;STALLKNECHT;BROWN, 2008;STALLKNECHT et al, 2012).…”

“…Sabe-se que inúmeros fatores podem influenciar o sucesso do isolamento viral, sendo que a ausência de partículas virais viáveis e a quantidade insuficiente de vírus para causar infecção no embrião são os mais importantes a se considerar (SPACKMAN et al, 2008;STALLKNECHT et al, 2012). A caracterização das amostras isoladas revelou pertencerem ao subtipo H11N9.…”

“…A glicoproteína H11 tem sido identificada em amostras de Charadriiformes em diferentes países com relativa frequência (HURT et al, 2006;FOUCHIER et al, 2007;KRAUSS et al, 2007;STALLKNECHT;BROWN, 2008;BORM et al, 2012;STALLKNECHT et al, 2012;LEWIS et al, 2013). Em um estudo realizado ao longo de 16…”