English: Beak and feather disease (BFD), caused by Beak and feather disease virus (BFDV) is a dermatological condition afflicting parrot species. It is becoming increasingly difficult to ignore not only the significant negative economic impact that the virus has on the parrot breeding industry but also the detrimental effect it has on the survival of the endemic Cape parrot (Poicephalus robustus). The virus, a member of the Circoviridae, is known to possess a non-enveloped, circular, single-stranded DNA genome. Two major open reading frames (ORFs) encode the replication associated protein (Rep) and the coat protein (CP). The study was set out to evaluate and improve the current diagnostic strategy for BFDV, with both molecular and serological techniques. The following objectives were attempted: 1. To evaluate polymerase chain reaction (PCR) and quantitative real-time polymerase chain reaction (qPCR) as diagnostic tools for BFDV. Detection of BFDV with conventional PCR is not always sensitive, especially in birds without clinical symptoms. Furthermore, genetic variance was suggested to have a detrimental effect on primer hybridisation. A real-time assay was designed to address these problems. It amplified a 115 bp fragment of ORF V1 and was able to quantify viral load. 2. To recombinantly express BFDV coat protein. A sustainable source of the main immunogen, coat protein, was needed for use in serological test development. Bacterial expression of BFDV CP was unsuccessful; however, BFDV CP from an alternative expression study was used as a serological diagnostic antigen. 3. To develop serological diagnostic tests for BFDV. A novel slide agglutination test was developed and will serve as an initial screening tool in serological diagnosis. Steps were made in the development of a competitive Enzyme Linked Immunosorbent Assay (ELISA) for a quantitative indication of immune response to BFDV. A significant proportion of asymptomatic BFDV infections exist. Using a combination approach of both molecular and serological tests increases the capacity to detect infections or exposure to virus. New techniques described should be used in conjunction with existing tests and should not completely replace conventional techniques for diagnosis of BFDV infection or detection of exposure to the virus.
Afrikaans: Beak and feather disease (BFD), wat veroorsaak word deur Beak and feather disease virus (BFDV) is 'n dermatologiese toestand wat papegaai spesies versmag. Dit word toenemend moeilik om nie net die beduidende negatiewe ekonomiese impak wat die virus het op die papegaai teling bedryf nie, maar ook die nadelige uitwerking wat dit op die voortbestaan van die endemiese Kaapse papegaai (Poicephalus robustus) te ignoreer. Die virus, 'n lid van die Circoviridae, is bekend as 'n nie-omvou, sirkulêre, enkelstring DNA genoom in besit te neem. Twee groot oop lees rame (OLRe) enkodeer die replikasie verwante proteïene (Rep) en die kapsied proteïen (KP). Die studie was uiteengesit om die huidige diagnostiese strategie vir BFDV te evalueer en te verbeter, met beide molekulêre en serologiese tegnieke. Die volgende doelwitte is gepoog: 1. Om polimerase kettingreaksie (PKR) en kwantitatiewe werklike tyd polimerase kettingreaksie (qPCR) as diagnostiese instrumente vir BFDV te vergelyk. Opsporing van BFDV met konvensionele PCR is nie altyd sensitief nie, veral in voëls sonder kliniese simptome. Verder is genetiese afwyking voorgestel om 'n nadelige uitwerking op primer verbastering te hê. 'n qPCR toets is ontwerp om hierdie probleme aan te spreek. Dit versterk 'n 115 bp fragment van OLR V1 en was in staat om virale lading te kwantifiseer. 2. Om die BFDV kapsied proteïen in 'n bakteriële gasheer uit te druk. 'n Volhoubare bron van die hoof immunogeen, kapsied proteïen, is wat nodig is vir die gebruik in serologiese toets ontwikkeling. Bakteriële uitdrukking van BFDV KP was onsuksesvol, maar BFDV KP van 'n alternatiewe uitdrukking studie is gebruik as 'n serologiese diagnose antigeen. 3. Om serologiese diagnostiese toetse vir BFDV te ontwikkel. 'n Plaat agglutinasie toets is ontwikkel en sal as 'n aanvanklike keuring instrument in serologiese diagnose dien. Stappe is gedoen in die ontwikkeling van 'n mededingende Ensiem-Gekoppelde Immunosorbent toets (ELISA) vir 'n kwantitatiewe aanduiding van immuun reaksie op BFDV. 'n Beduidende hoeveelheid van asimptomatiese BFDV infeksies kom voor. 'n Kombinasie van beide molekulêre en serologiese toetse verhoog die kapasiteit om infeksies of die blootstelling aan die virus op te spoor. Nuwe tegnieke wat beskryf is moet in samewerking met bestaande toetse gebruik moet word en nie konvensionele tegnieke heeltemal vervang.
Establishment of serological and molecular techiques to investigate diversity of psittacine beak and feather disease virus in different psittacine birds in South Africa ﻿
Kondiah, Kulsum (University of the Free State, 2004)
Psittacine beak and feather disease (PBFD) is a readily recognizable disease of wild and captive psittacines in Australia but it is also a problem worldwide wherever captive species are bred. The disease caused by beak and ...
Development of a DNA vaccine for the prevention of Psittacine beak and feather disease ﻿
Kondiah, Kulsum (University of the Free State, 2008-05)
Psittacine beak and feather disease (PBFD) is a readily recognisable dermatologic condition in wild and captive psittacines worldwide. It is caused by Beak and feather disease virus (BFDV) which is classified in the family ...