title: On the origin and diversity of Newcastle disease virus in Tanzania.
abstract: Free-range rural chickens (FRCs) dominate the poultry industry in developing countries and  chickens are exposed to multi-host infections, including Newcastle disease virus (NDV). The  knowledge about the characteristics of NDV from FRCs is limited. This study investigated the  persistence, spread and risks of NDV from FRCs. NDV isolates (n = 21) from unvaccinated  FRCs in Tanzania were characterised by conventional intracerebral pathogenicity index (ICPI)  and sequence analysis of a partial region of the deduced fusion protein encompassing the  cleavage site. Results showed that five isolates were screened as lentogenic, nine as mesogenic  and six as velogenic. Phylogenetic analysis of the 21 isolates compared to reference sequences  revealed three, four, nine and five isolates in genotypes 1, 2, 3c and 4a, respectively. Genotype  3c also included published sequences of Tanzanian isolates obtained from exotic birds and  chicken isolates from Uganda. The analysis showed that NDV were persistently present  among chicken populations and possibly spread through live chicken markets or migration of  wild birds. Differences in amino acid sequences detected around the cleavage site separated  the isolates in six types. However, cleavage site pattern could not fully differentiate mesogenic  isolates from velogenic isolates.
authors: Department of Veterinary Disease Biology, University of Copenhagen. hech@life.ku.dk.
authors: Mmeta G
authors: MG
authors: Yongolo
authors: Henrik
authors: H
authors: Christensen
authors: Kurt
authors: K
authors: Handberg
authors: Uswege
authors: U
authors: Minga
authors: John E
authors: JE
authors: Olsen
mesh_terms: D000818:Animals; D001483:Base Sequence; D001717:Birds; D002645:Chickens; D005838:Genotype; D009521:Newcastle Disease / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D009522:Newcastle disease virus / Q000145:classification* / Q000302:isolation & purification*; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D017422:Sequence Analysis, DNA; D013636:Tanzania