Molecular-based monitoring of live vaccines in dust samples from experimental and commercial chicken flocks and its potential use as a screening test. (March 2022)

• Record Type: Journal Article
• Authors: Assen, Awol M.; Yegoraw, Addisu A.; Walkden-Brown, Stephen W.; Gerber, Priscilla F.
• Is Part Of: Research in veterinary science. Volume 143(2022)
• Page Start: 50
• Page End: 57
• Publication Date: 2022-03
• Subjects: Live vaccine -- Monitoring -- PCR -- Poultry dust; Veterinary medicine -- Periodicals; Veterinary Medicine -- Periodicals; Médecine vétérinaire -- Périodiques; Médecine vétérinaire -- Recherche -- Périodiques; Diergeneeskunde; 636.089
• DOI: 10.1016/j.rvsc.2021.12.015
• Languages: English
• ISSNs: 0034-5288

Abstract

Abstract: Despite the high cost of vaccination programmes, conventional methods to evaluate vaccine uptake are often impractical and costly. More recently, molecular-based testing of poultry dust has been used to monitor the "take" of Marek's disease virus and infectious laryngotracheitis virus (ILTV) live vaccines. This study aimed to provide proof-of-concept for detecting other poultry pathogens by using molecular detection of vaccine microorganisms in poultry dust of vaccinated flocks. Dust and choanal cleft and cloacal swabs were collected from chickens vaccinated against avian encephalomyelitis virus (AEV), fowlpox virus (FPV), Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) using live vaccines in an experimental flock. Dust samples were collected weekly from 5 commercial breeder or layer flocks from day-old up to 25 weeks of age. These flocks were vaccinated against Newcastle disease virus (NDV), infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), ILTV, fowl adenovirus (FAdV), MG and MS . Samples were tested for nucleic acids of these microorganisms by PCR or reverse transcriptase PCR. Genomes of all targeted vaccines were detected in dust samples from the experimental and commercial flocks except for FPV, which was detected only in the experimental flock. FAdV was detected in unvaccinated commercial flocks. These findings suggest that PCR detection of target organisms in dust samples has potential as a relatively simple and inexpensive population-level test to monitor vaccine take and/or pathogen status in chicken flocks. Further studies comparing the detection of each of these microorganisms in poultry dust with individual birds samples are required to validate this approach. Highlights: Vaccine take of individual birds was reflected by vaccine genome detection in poultry dust under experimental conditions. PCR-based dust testing could be used as a screening test for microorganisms or to assess failure in vaccine administration. PCR-dust testing could be potentially used to detect AEV, IBDV, IBV, ILTV, FAdV and mycoplasma.