Prevalence of beak and feather disease virus in wild Platycercus elegans: comparison of three tissue types using a probe-based real-time qPCR test

Abstract

The detection of avian viruses in wild populations has considerable conservation implications. For DNAbased studies, feathers may be a convenient sample type for virus screening and are, therefore, an increasingly common technique. This is despite recent concerns about DNA quality, ethics, and a paucity of data comparing the reliability and sensitivity of feather sampling to other common sample types such as blood. Alternatively, skeletal muscle tissue may offer a convenient sample to collect from dead birds, which may reveal viraemia. Here, we describe a probe-based quantitative real-time PCR for the relative quantification of beak and feather disease virus (BFDV), a pathogen of serious conservation concern for parrots globally. We used this method to test for BFDV in wild crimson rosellas (Platycercus elegans), and compared three different sample types. We detected BFDV in samples from 29 out of 84 individuals (34.5%). However, feather samples provided discordant results concerning virus presence when compared with muscle tissue and blood, and estimates of viral load varied somewhat between different sample types. This study provides evidence for widespread infection of BFDV in wild crimson rosellas, but highlights the importance of sample type when generating and interpreting qualitative and quantitative avian virus data.

A high prevalence of beak and feather disease virus in non-psittacine Australian birds

“…Although the 210 liver samples tested in our study form a biased sample population, as all of these birds either had died or were euthanized due to the severity of their injuries or illness, the prevalence of BFDV infection was comparable to that seen in previous studies. We detected BFDV DNA in 30 % of 20 Victorian crimson rosellas, while another recent study detected BFDV DNA in 34.5 % of 84 wild crimson rosellas in southeastern Australia [9]. Likewise Raidal et al [5]reported a seroprevalence of 41-94 % within wild cockatoo flocks in New South Wales in the early 1990s using a haemagglutination inhibition assay [5], while we detected BFDV DNA in 67.7 % of 31 Victorian cacatuids.…”

“…It has been implicated as a cause of wild parrot declines in Australia and Mauritius [9,11,22]. Host-switching occurs at a high rate across divergent Psittaciformes, with rare spillovers into distantly related non-psittacine bird species also reported [6,10,11,16].…”

“…BFDV had its origins in and has coevolved with psittacine birds [2]. Even though neotropical, African and New Zealand parrots are susceptible to BFDV infection, there is strong phylogeographic genetic evidence of a post-Gondwanan origin of the ancestral virus in psittacine birds in Australia, with anthropogenic global spread of BFDV to a wide variety of free-ranging and captive psittacines over the past 150 years as a result of the live pet bird trade [2,6,9,17].…”

“…Circoviruses are the smallest and simplest autonomously replicating pathogens known to infect vertebrates [1,6,11,12]. Psittacine birds are the natural host of BFDV [16], and while the virus is thought to be capable of infecting all psittacines, different species vary in their susceptibility to infection and development of disease [6,9,11,12]. There is currently no treatment or vaccine available for PBFD.…”

“…Infection with BFDV is endemic in Australia, with wild psittacine populations across the continent carrying a rich viral genetic diversity [2,6]. Infection with BFDV can cause severe feather and beak deformities and is potentially fatal, being an important cause of morbidity and mortality in wild and captive psittacine birds in Australia and in other countries [1][2][3][4][5][6][7][8][9]. BFDV is a small, non-enveloped virus with an icosahedral capsid that belongs to the genus Circovirus within the family Circoviridae [1,[10][11][12][13][14][15].…”