title: High pathogenicity and low genetic evolution of avian paramyxovirus type I (Newcastle disease virus) isolated from live bird markets in Uganda.
abstract: BACKGROUND
  Newcastle disease is still a serious disease of poultry especially in backyard free-range production systems despite the availability of cross protective vaccines. Healthy-looking poultry from live bird markets have been suspected as a major source of disease spread although limited studies have been conducted to ascertain the presence of the virulent strains in the markets and to understand how they are related to outbreak strains.
  
  
  METHODS
  This study evaluated the occurrence of Newcastle disease virus in samples collected from poultry in live bird markets across Uganda. The isolates were pathoyped using standard methods (mean death time (MDT), intracelebral pathogenicity index (ICPI), and sequencing of the fusion protein cleavage site motif) and also phylogenetically analysed after sequencing of the full fusion and hemagglutin-neuraminidase genes. The isolates were classified into genotypes and subgenotypes based on the full fusion protein gene classification system and compared with other strains in the region and world-wide.
  
  
  RESULTS
  Virulent avian paramyxovirus type I (APMV-1) (Newcastle disease virus) was isolated in healthy-looking poultry in live bird markets. The viruses belonged to a new subgenotype, Vd, in genotype V, and clustered together with Tanzania and Kenya strains. They harbored low genetic diversity.
  
  
  CONCLUSIONS
  The occurrence of virulent AMPV-1 strains in live bird markets may serve as sources of Newcastle disease outbreaks in non-commercial farms.
authors.affiliation: College of Veterinary Medicine, Makerere University, P,O, Box 7062, Kampala, Uganda. dkb@covab.mak.ac.ug.
authors.forename: Denis K
authors.initials: DK
authors.lastname: Byarugaba
authors.forename: Kizito K
authors.initials: KK
authors.lastname: Mugimba
authors.forename: John B
authors.initials: JB
authors.lastname: Omony
authors.forename: Martin
authors.initials: M
authors.lastname: Okitwi
authors.forename: Agnes
authors.initials: A
authors.lastname: Wanyana
authors.forename: Maxwell O
authors.initials: MO
authors.lastname: Otim
authors.forename: Halid
authors.initials: H
authors.lastname: Kirunda
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Nakavuma
authors.forename: Angélique
authors.initials: A
authors.lastname: Teillaud
authors.forename: Mathilde C
authors.initials: MC
authors.lastname: Paul
authors.forename: Mariette F
authors.initials: MF
authors.lastname: Ducatez
mesh_terms: D000818:Animals; D003132:Commerce; D019143:Evolution, Molecular; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009521:Newcastle Disease / Q000453:epidemiology / Q000821:virology*; D009522:Newcastle disease virus / Q000235:genetics* / Q000472:pathogenicity; D010802:Phylogeny; D011200:Poultry; D014454:Uganda / Q000453:epidemiology; D014774:Virulence