Abstract:Psittacine beak and feather disease (PBFD), the most prevalent viral disease affecting psittacines, is caused by beak and feather disease virus (BFDV). This study assessed viral load using qPCR in a wild Cape parrot population affected by PBFD and compared it to overall physical condition based on clinical signs attributable to PBFD. A significant inverse correlation between viral load and overall physical condition was found, which confirmed that clinical signs may confidently be used to diagnose the relative… Show more
“…Techniques include light and electron microscopy 28 [ 57 , 114 ] Immunohistochemical tests Immunohistochemistry (IHC) is a technique used to observe the physical characteristics of antibodies and their concentration and distribution within host tissue. In screening for BFDV, specimens are stained using the avidin-biotin complex (ABC) immunoperoxidase technique and then exposed to a primary antibody 5 [ 19 , 91 ] Quantitative (real-time) PCR Quantitative (or real-time) polymerase chain reaction (qPCR) is a technique used to both amplify and quantify target DNA through the use of either nonspecific fluorescent dyes that intercalate with double-stranded DNA or a sequence-specific fluorescent probe that hybridizes with the target 6 [ 37 , 54 ] Standard PCR Polymerase chain reaction (PCR) is a technology used to amplify a piece of DNA across several orders of magnitude through a process of thermal cycling in combination with oligonucleotide probes synthesised to bind to the target region and a DNA polymerase enzyme 41 [ 48 , 102 ] Virus purification Virus purification allows the careful study of viral synthesis within cells by combining ultracentrifugation, adsorption chromatography, electrophoresis, and partition in liquid phases to separate virions from incomplete protein fragments and cell debris 3 [ 26 , 75 ] Whole-genome sequencing Whole-genome sequencing is a laboratory process that determines the complete DNA sequence of an organism’s genome at a single time and can be used for multiple tissue types and when only very small quantities of a full DNA copy are present 23 [ 115 , 116 ] Fig. 3 Changes in the frequency of use of the five most common screening and diagnostic methods used for detecting BFDV and PBFD between 1984 and July 2015 …”
Section: Resultsmentioning
confidence: 99%
“…More-thorough scoring systems for the classification of clinical symptoms were applied in eight studies. The most descriptive of these systems was by Regnard et al [ 37 ], consisting of six different clinical symptoms, with each broken down into five different scores of overall physical condition, and these scores were then compared to individual viral load. Other scales, such as that applied by Ritchie et al [ 9 , 17 ], descriptively scored only clinical feather and beak lesions.…”
Section: Resultsmentioning
confidence: 99%
“…The most frequently used method was mist netting, reported in 11 of the 16 publications (e.g. [ 37 , 40 , 46 ]). The second most preferred method was trapping, either whilst individuals were in nests [ 44 , 53 ] or with walk-in traps [ 53 , 54 ].…”
Section: Resultsmentioning
confidence: 99%
“…Where a study used specimens from both captive and wild individuals from the same country, the country of origin for each specimen was recorded once per category for each publication. For example: Regnard et al [ 37 ] screened specimens from both captive and wild populations of Poicephalus robustus , and this information was recorded by adding South Africa once to each category. Maps were produced using ArcGIS 10.2.1 [ 38 ], displaying the results of captive and wild specimens independently.…”
Psittacine beak and feather disease (PBFD) has emerged in recent years as a major threat to wild parrot populations and is an increasing concern to aviculturists and managers of captive populations. Pathological and serological tests for screening for the presence of beak and feather disease virus (BFDV) are a critical component of efforts to manage the disease and of epidemiological studies. Since the disease was first reported in the mid-1970s, screening for BFDV has been conducted in numerous wild and captive populations. However, at present, there is no current and readily accessible synthesis of screening efforts and their results. Here, we consolidate information collected from 83 PBFD- and BFDV-based publications on the primary screening methods being used and identify important knowledge gaps regarding potential global disease hotspots. We present trends in research intensity in this field and critically discuss advances in screening techniques and their applications to both aviculture and to the management of threatened wild populations. Finally, we provide an overview of estimates of BFDV prevalence in captive and wild flocks alongside a complete list of all psittacine species in which the virus has been confirmed. Our evaluation highlights the need for standardised diagnostic tests and more emphasis on studies of wild populations, particularly in view of the intrinsic connection between global trade in companion birds and the spread of novel BFDV strains into wild populations. Increased emphasis should be placed on the screening of captive and wild parrot populations within their countries of origin across the Americas, Africa and Asia.
“…Techniques include light and electron microscopy 28 [ 57 , 114 ] Immunohistochemical tests Immunohistochemistry (IHC) is a technique used to observe the physical characteristics of antibodies and their concentration and distribution within host tissue. In screening for BFDV, specimens are stained using the avidin-biotin complex (ABC) immunoperoxidase technique and then exposed to a primary antibody 5 [ 19 , 91 ] Quantitative (real-time) PCR Quantitative (or real-time) polymerase chain reaction (qPCR) is a technique used to both amplify and quantify target DNA through the use of either nonspecific fluorescent dyes that intercalate with double-stranded DNA or a sequence-specific fluorescent probe that hybridizes with the target 6 [ 37 , 54 ] Standard PCR Polymerase chain reaction (PCR) is a technology used to amplify a piece of DNA across several orders of magnitude through a process of thermal cycling in combination with oligonucleotide probes synthesised to bind to the target region and a DNA polymerase enzyme 41 [ 48 , 102 ] Virus purification Virus purification allows the careful study of viral synthesis within cells by combining ultracentrifugation, adsorption chromatography, electrophoresis, and partition in liquid phases to separate virions from incomplete protein fragments and cell debris 3 [ 26 , 75 ] Whole-genome sequencing Whole-genome sequencing is a laboratory process that determines the complete DNA sequence of an organism’s genome at a single time and can be used for multiple tissue types and when only very small quantities of a full DNA copy are present 23 [ 115 , 116 ] Fig. 3 Changes in the frequency of use of the five most common screening and diagnostic methods used for detecting BFDV and PBFD between 1984 and July 2015 …”
Section: Resultsmentioning
confidence: 99%
“…More-thorough scoring systems for the classification of clinical symptoms were applied in eight studies. The most descriptive of these systems was by Regnard et al [ 37 ], consisting of six different clinical symptoms, with each broken down into five different scores of overall physical condition, and these scores were then compared to individual viral load. Other scales, such as that applied by Ritchie et al [ 9 , 17 ], descriptively scored only clinical feather and beak lesions.…”
Section: Resultsmentioning
confidence: 99%
“…The most frequently used method was mist netting, reported in 11 of the 16 publications (e.g. [ 37 , 40 , 46 ]). The second most preferred method was trapping, either whilst individuals were in nests [ 44 , 53 ] or with walk-in traps [ 53 , 54 ].…”
Section: Resultsmentioning
confidence: 99%
“…Where a study used specimens from both captive and wild individuals from the same country, the country of origin for each specimen was recorded once per category for each publication. For example: Regnard et al [ 37 ] screened specimens from both captive and wild populations of Poicephalus robustus , and this information was recorded by adding South Africa once to each category. Maps were produced using ArcGIS 10.2.1 [ 38 ], displaying the results of captive and wild specimens independently.…”
Psittacine beak and feather disease (PBFD) has emerged in recent years as a major threat to wild parrot populations and is an increasing concern to aviculturists and managers of captive populations. Pathological and serological tests for screening for the presence of beak and feather disease virus (BFDV) are a critical component of efforts to manage the disease and of epidemiological studies. Since the disease was first reported in the mid-1970s, screening for BFDV has been conducted in numerous wild and captive populations. However, at present, there is no current and readily accessible synthesis of screening efforts and their results. Here, we consolidate information collected from 83 PBFD- and BFDV-based publications on the primary screening methods being used and identify important knowledge gaps regarding potential global disease hotspots. We present trends in research intensity in this field and critically discuss advances in screening techniques and their applications to both aviculture and to the management of threatened wild populations. Finally, we provide an overview of estimates of BFDV prevalence in captive and wild flocks alongside a complete list of all psittacine species in which the virus has been confirmed. Our evaluation highlights the need for standardised diagnostic tests and more emphasis on studies of wild populations, particularly in view of the intrinsic connection between global trade in companion birds and the spread of novel BFDV strains into wild populations. Increased emphasis should be placed on the screening of captive and wild parrot populations within their countries of origin across the Americas, Africa and Asia.
“…The clinical signs vary depending on the species and age of infected birds (Gerlach, 2004), but new cases show that they are strictly host related (Robino et al, 2015). The occurrence and the degree of observed clinical signs correlate strongly with viral load (Regnard et al, 2015). PBFD is potentially fatal and can manifest in the peracute, acute, or chronic form of infection, with the latter as the most frequent, known as the "classical form".…”
Psittacine beak and feather disease (PBFD) affects a large number of Psittaciformes species. In this study, five White Cockatoo parrots (Cacatua alba) with clinical signs of PBFD were examined. After euthanasia, a full necropsy of parrots was performed and organs with macroscopic changes were sampled for routine histopathological evaluation. To confirm the presence of psittacine beak and feather disease virus (PBFDv), feather samples were analyzed with the PCR method. Sequence analysis of the obtained PCR products indicated their close relationship (99%) to other PBFDv isolates. Six variable nucleotide sites were discovered, two missense and four silent mutations. This paper presents the evidence of new PBFDv sequence in Cockatoo species.
Pathogen outbreaks in the wild can contribute to a population's extinction risk. Concern over the effects of pathogen outbreaks in wildlife is amplified in small, threatened populations, where degradation of genetic diversity may hinder natural selection for enhanced immunocompetence. Beak and feather disease virus (BFDV) was detected for the first time in an island population of red-crowned parakeets (Cyanoramphus novaezelandiae) in 2008 on Little Barrier Island (Hauturu-o-Toi) of New Zealand. By 2013, the prevalence of the viral infection had significantly decreased within the population. We tested whether the population of red-crowned parakeets showed a selective response to BFDV, using neutral microsatellite and two immunity-associated genetic markers, the major histocompatibility complex (MHC) and Toll-like receptors (TLRs). We found evidence for selection at viral-associated TLR3; however, the ability of TLR3 to elicit an immune response in the presence of BFDV warrants confirmation. Alternatively, because red-crowned parakeet populations are prone to fluctuations in size, the decrease in BFDV prevalence over time may be attributed to the Little Barrier Island population dropping below the density threshold for viral maintenance. Our results highlight that natural processes such as adaptation for enhanced immunocompetence and/or density fluctuations are efficient mechanisms for reducing pathogen prevalence in a threatened, isolated population.
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