Genetic diversity of Newcastle disease virus in Pakistan: a countrywide perspective
1 Quality Operations Laboratory, University of Veterinary and Animal Sciences, Lahore, Pakistan
2 National Veterinary Institute, Uppsala, Sweden
3 Department of Microbiology, University of Veterinary and Animal Sciences, Lahore, Pakistan
4 University of Baluchistan, Quetta, Pakistan
5 Veterinary Research and Disease Investigation Center, Abbottabad, Pakistan
6 Livestock and Dairy Development Department, Punjab, Pakistan
7 Veterinary Research Institute, Lahore, Pakistan
8 Department of Biology, University of Bergen, Bergen, Norway
9 Poultry Research Institute, Rawalpindi, Pakistan
10 University Diagnostic Laboratory, University of Veterinary and Animal Sciences, Lahore, Pakistan
11 Department of Microbiology, Chittagong Veterinary and Animal Sciences University, Chittagong, Bangladesh
12 Department of Theriogenology, University of Veterinary and Animal Sciences, Lahore, Pakistan
13 Sindh Poultry Vaccine Center, Karachi, Pakistan
14 Swedish University of Agricultural Sciences, Uppsala, Sweden
15 Department of Geography, Government College University, Lahore, Pakistan
16 Government Collage University Faisalabad, Faisalabad, Pakistan
17 Department of Parasitology, University of Veterinary and Animal Sciences, Lahore, Pakistan
18 The Pirbright Institute, Compton Laboratory, Compton, Berkshire RG20 7NN, United Kingdom
Virology Journal 2013, 10:170 doi:10.1186/1743-422X-10-170Published: 30 May 2013
Newcastle disease (ND) is one of the most deadly diseases of poultry around the globe. The disease is endemic in Pakistan and recurrent outbreaks are being reported regularly in wild captive, rural and commercial poultry flocks. Though, efforts have been made to characterize the causative agent in some of parts of the country, the genetic nature of strains circulating throughout Pakistan is currently lacking.
Material and methods
To ascertain the genetics of NDV, 452 blood samples were collected from 113 flocks, originating from all the provinces of Pakistan, showing high mortality (30–80%). The samples represented domesticated poultry (broiler, layer and rural) as well as wild captive birds (pigeons, turkeys, pheasants and peacock). Samples were screened with real-time PCR for both matrix and fusion genes (1792 bp), positive samples were subjected to amplification of full fusion gene and subsequent sequencing and phylogenetic analysis.
The deduced amino acid sequence of the fusion protein cleavage site indicated the presence of motif (112RK/RQRR↓F117) typical for velogenic strains of NDV. Phylogenetic analysis of hypervariable region of the fusion gene indicated that all the isolates belong to lineage 5 of NDV except isolates collected from Khyber Pakhtunkhwa (KPK) province. A higher resolution of the phylogenetic analysis of lineage 5 showed the distribution of Pakistani NDV strains to 5b. However, the isolates from KPK belonged to lineage 4c; the first report of such lineage from this province.
Taken together, data indicated the prevalence of multiple lineages of NDV in different poultry population including wild captive birds. Such understanding is crucial to underpin the nature of circulating strains of NDV, their potential for interspecies transmission and disease diagnosis and control strategies.