Molecular epidemiology of respiratory viruses in commercial chicken flocks in Pakistan from 2014 through to 2016

Abstract

Background Viral diseases are a matter of great concern for poultry farmers in Pakistan. Multiple common viral respiratory diseases (CVRDs) cause huge economic losses in the poultry industry. The prevalence of CVRDs in many countries, including Pakistan, is not clearly understood. Results Incidences of 5 chicken respiratory viruses: avian influenza virus (AIV), Newcastle disease virus (NDV/AAVV-1), infectious bronchitis virus (IBV), avian metapneumovirus (aMPV) and infectious laryngotracheitis virus (ILTV) were assessed on commercial Pakistani farms with respiratory problems from 2014 through to 2016. While AIV and AAVV-1 were frequently detected (16 to 17% of farms), IBV and aMPV were rarely detected (in 3 to 5% of farms) and ILTV was not detected. We characterized H9 AIV of the G1 lineage, genotype VII AAVV-1, GI-13 IBV, and type B aMPV strains with very little genetic variability in the 2-year study period. Co-infections with AIV and AAVV-1 were common and wild type AAVV-1 was detected despite the use of vaccines. Control measures to limit the virus burden in chicken flocks are discussed. Conclusions Our data shows that AIV (H9), AAVV-1, IBV and aMPV are prevalent in commercial poultry in Pakistan. Further studies are necessary to assess circulating strains, economic losses caused by infections and coinfections of these pathogens, and the costs and benefits of countermeasures. Furthermore, veterinarians and farmers should be informed of the pathogens circulating in the field and hence advised on the use of vaccines.

Investigation of respiratory disease outbreaks of poultry in Bangladesh using two real-time PCR-based simultaneous detection assays

“…The death of the two turkeys examined here may not have been caused by any of the viral diseases tested here; however, one turkey was found to be positive for the LPAI subtype H9N2. These similar fundamental respiratory viral diseases have been identified previously in many other countries in Asia and Africa, including Bangladesh ( 4 , 24 , 31 – 33 , 42 , 43 ). For many years, Bangladesh has reported ~30–50% prevalence of respiratory infections in commercial poultry ( 22 , 23 , 42 , 43 ), also in line with our observation, which has led to slow growth and productivity, generating substantial economic losses in the poultry industry.…”

“…These methods are time-consuming and laborious, particularly when used separately for a single pathogen ( 25 – 27 ). Nowadays, rapid diagnostic tests have been developed for the detection of either viral nucleic acids or viral antigens, including rapid chromatographic and, molecular techniques ( 28 – 33 ). However, those techniques detect only one specific pathogen at a time.…”

Circulation of three genotypes and identification of unique mutations in neutralizing epitopes of infectious bronchitis virus in chickens in Bangladesh

“…This study did not consider further avian viral or bacterial pathogens that are likely to complicate the overall clinical picture. The prevalence of IBV in different chicken breeds and considerable frequency of mixed infection with AIV and NDV have been reported in many countries in Asia and Africa [ 18 , 19 , 30 , 36 ]. Here, in the clinical outbreaks, the respiratory form of the disease was relatively common and characterized by congested lungs, but we also detected the nephropathogenic form, indicated by the presence of severe nephritis (Fig.…”

Arachidonic acid metabolism is elevated inMycoplasma gallisepticumandEscherichia colico-infection and induces LTC4 in serum as the biomarker for detecting poultry respiratory disease

“…The primary pathogens of respiratory disease in poultry include Mycoplasma gallisepticum ( MG), Escherichia coli ( E.coli), Avian influenza virus and Infectious bronchitis virus , which have caused huge economic losses to the poultry industry worldwide [ 1 – 3 ]. Recently, outbreaks of multiple respiratory diseases with high morbidity and mortality have been frequently reported ` 4 , 5 ]. Due to the intensification of commercial poultry production, the explosive multiple respiratory infections has become an urgent problem.…”