Emergence of a new genetic lineage of Newcastle disease virus in West and Central Africa--implications for diagnosis and control.
Newcastle disease (ND) is an OIE listed disease caused by virulent avian paramyxovirus type 1 (APMV-1) strains, which affect many species of birds and may cause severe economic losses in the poultry sector. The disease has been officially and unofficially reported in many African countries and still remains the main poultry disease in commercial and rural chickens of Africa. Unfortunately, virological and epidemiological information concerning ND strains circulating in the Western and Central regions of Africa is extremely scarce. In the present study, sequence analysis, pathotyping and detailed genetic characterization of virulent ND strains detected in rural poultry in West and Central Africa revealed the circulation of a new genetic lineage, distinguishable from the lineages described in the Eastern and Southern parts of the continent. Several mismatches were observed in the segment of the matrix gene targeted by the primers and probe designed for the molecular detection of APMV-1, which were responsible for the false negative results in the diagnostic test conducted. Furthermore, deduced amino acid sequences of the two major antigens eliciting a protective immune response (F and HN glycoprotein) revealed protein similarities <90% if compared to some common vaccine strains. Distinct mutations located in the neutralizing epitopes were revealed, indicating the need for detailed assessment of the efficacy of the current vaccines and vaccination practices in Africa. The present investigation provides important information on the epidemiology, diagnosis and control of NDV in Africa and highlights the importance of supporting surveillance in developing countries for transboundary animal diseases.
Cattoli
G
G
OIE/FAO Reference Laboratory for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Virology Department, Legnaro (PD), Italy. gcattoli@izsvenezie.it
Fusaro
A
A
Monne
I
I
Molia
S
S
Le Menach
A
A
Maregeya
B
B
Nchare
A
A
Bangana
I
I
Maina
A Garba
AG
Koffi
J-N N'Goran
JN
Thiam
H
H
Bezeid
O E M A
OE
Salviato
A
A
Nisi
R
R
Terregino
C
C
Capua
I
I
D000350:Africa, Central; D000354:Africa, Western; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003906:Developing Countries; D014644:Genetic Variation; D015707:HN Protein / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009521:Newcastle Disease / Q000175:diagnosis / Q000517:prevention & control / Q000821:virology; D009522:Newcastle disease virus / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D010802:Phylogeny; D011201:Poultry Diseases / Q000175:diagnosis / Q000517:prevention & control / Q000821:virology; D016415:Sequence Alignment; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics*; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000235:genetics; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000235:genetics
D015707:HN Protein; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; D014763:Viral Matrix Proteins