1
|
Seroprevalence and risk factors of Newcastle disease virus in local chickens in Njombe and Bahi districts in Tanzania. Trop Anim Health Prod 2022; 54:53. [PMID: 35024961 DOI: 10.1007/s11250-022-03052-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 01/04/2022] [Indexed: 10/19/2022]
Abstract
Newcastle disease virus (NDV) causes significant losses of poultry in Tanzania. Like in many African countries, the regular surveillance of NDV is important for the control of disease. The objective of this study was to determine seroprevalence of NDV in unvaccinated backyard poultry in Bahi and Njombe districts of Tanzania over the rainy (May) and dry (November) seasons in 2016. Using hemaglutination inhibition test, the overall seroprevalence was determined to be 26.8%. The significant differences in seroprevalence were between seasons (higher (34.9%) in dry season, p < 0.0001) and age (higher (30.3%), p < 0.0001 in adult birds). There were no significant differences in seroprevalence between the districts or sex. The higher levels of "protective" antibody titers were significantly associated with location: Njombe (RR 1.15), dry season (RR 1.08), and age: adult birds (RR 1.16); however, the prevalence of these titers was not high enough to conclude any herd immunity among these flocks. This study therefore concludes that local chickens are naturally exposed to NDV and the birds in highlands, dry season, and adults are more protected. Future studies focusing on transmission, strain type, and monthly dynamics of NDV in backyard flocks will provide greater insight into the disease dynamics and allow new practical strategies to alleviate the effects of NDV for the smallholder farmers.
Collapse
|
2
|
Saravi AN, Jafari RA, Boroomand Z, Rezaie A, Mayahi M. A histopathological and immunohistochemical study of experimental infected turkeys with a virulent Newcastle disease virus. Braz J Microbiol 2021; 52:1677-1685. [PMID: 34558031 DOI: 10.1007/s42770-021-00623-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 09/19/2021] [Indexed: 10/20/2022] Open
Abstract
Newcastle disease (ND) is a highly contagious infection of many avian species, mainly chickens and turkeys, with a devastating impact on worldwide poultry production. This study was designed to examine the effect of virulent ND infection in turkey's tissues and the tissue tropism of the virus. During the previous study period, poults were inoculated at 32 days of age with 105 EID50 virulent Newcastle disease virus. Three poults on days 0, 1, 2, 3, 4, 6, 7, and 14 postinoculations (PI) were selected from each group. They were euthanized by intravenous sodium pentobarbital injection. After macroscopic observation, to histopathological and immunohistochemical studies, the spleen, bursa, cecal tonsils, intestine, proventriculus, lung, kidney, and brain were sampled. Clinically, the infected turkeys exhibited loss of appetite, severe depression, down on hock joint, white to greenish (sometimes bloody) diarrhea, nervous signs, and mild respiratory problems. Out of 45 birds inoculated, 9 (20%) died. Histopathological effects in lymphoid tissues included necrosis and penetration of mononuclear cells on day 4 PI, and subsequent follicular lymphoid depletion on days 6 and 8 PI was observed. Based on the immunohistochemical test, on day 3 in cecal tonsils and spleen, and on day 8 PI, all of them were positive for virus antigen. In conclusion, the NDV circulating in Iranian chicken flocks has the potential to cause severe illness in commercial turkeys.
Collapse
Affiliation(s)
- Amin Nejati Saravi
- Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Ramezan Ali Jafari
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Zahra Boroomand
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
| | - Anahita Rezaie
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Mansoor Mayahi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| |
Collapse
|
3
|
|
4
|
Al-Garib S, Gielkens A, Gruys E, Kochi G. Review of Newcastle disease virus with particular references to immunity and vaccination. WORLD POULTRY SCI J 2019. [DOI: 10.1079/wps20030011] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- S.O. Al-Garib
- Central Institute Disease Control (CIDC-Lelystad), P.O. Box 2004, 8203 AA Lelystad, The Netherlands
- Department of Pathology, Faculty of Veterinary Medicine, University of Utrecht, P.O. Box 80158, 3508 TD, Utrecht, The Netherlands
- Department of Poultry Diseases, Faculty of Veterinary Medicine, Al-Fateh University, P.O. Box 13662 Tripoli, Libya
| | - A.L.J. Gielkens
- Institute for Animal Science and Health (ID-Lelystad), P.O. Box 65, 8200 AB, Lelystad, The Netherlands
| | - E. Gruys
- Department of Pathology, Faculty of Veterinary Medicine, University of Utrecht, P.O. Box 80158, 3508 TD, Utrecht, The Netherlands
| | - G. Kochi
- Central Institute Disease Control (CIDC-Lelystad), P.O. Box 2004, 8203 AA Lelystad, The Netherlands
| |
Collapse
|
5
|
Absalón AE, Cortés-Espinosa DV, Lucio E, Miller PJ, Afonso CL. Epidemiology, control, and prevention of Newcastle disease in endemic regions: Latin America. Trop Anim Health Prod 2019; 51:1033-1048. [PMID: 30877525 PMCID: PMC6520322 DOI: 10.1007/s11250-019-01843-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/07/2019] [Indexed: 12/17/2022]
Abstract
Newcastle disease (ND) infects wild birds and poultry species worldwide, severely impacting the economics of the poultry industry. ND is especially problematic in Latin America (Mexico, Colombia, Venezuela, and Peru) where it is either endemic or re-emerging. The disease is caused by infections with one of the different strains of virulent avian Newcastle disease virus (NDV), recently renamed Avian avulavirus 1. Here, we describe the molecular epidemiology of Latin American NDVs, current control and prevention methods, including vaccines and vaccination protocols, as well as future strategies for control of ND. Because the productive, cultural, economic, social, and ecological conditions that facilitate poultry endemicity in South America are similar to those in the developing world, most of the problems and control strategies described here are applicable to other continents.
Collapse
Affiliation(s)
- A E Absalón
- Vaxbiotek, S.C. San Lorenzo 122-7, 72700, Cuautlancingo, Puebla, Mexico.
- Instituto Politécnico Nacional, CIBA-Tlaxcala, Carr. Est. Santa Ines Tecuexcomac-Tepetitla Km. 1.5, 90700, Tepetitla, Tlaxcala, Mexico.
| | | | - E Lucio
- Boehringer Ingelheim Animal Health, PO Drawer 2497, Gainesville, GA, 30503-2497, USA
| | - P J Miller
- Department of Population Health, College of Veterinary Medicine, The University of Georgia, 953 College Station Road, Athens, GA, 30602, USA
| | - C L Afonso
- Exotic and Emerging Avian Viral Disease Research Unit, Southeast Poultry Research Laboratory, United States National Poultry Research Center, USDA/ARS, Athens, GA, 30605, USA.
| |
Collapse
|
6
|
Al-Karagoly H, Nikbakht G, Hassanzadeh M, Tolouei T. Turkey humoral and cell-mediated immune responses to a Newcastle viscerotropic vaccine and its association with major histocompatibility complex. BULGARIAN JOURNAL OF VETERINARY MEDICINE 2019. [DOI: 10.15547/bjvm.2031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Immune responses to vaccines are mainly influenced by the nature of vaccines and host variation in response to vaccination. In this study we aimed to investigate turkey humoral and cell-mediated immune responses to a Newcastle viscerotropic vaccine and its association with major histocompatibility complex (MHC). Turkeys were vaccinated with Villegas–Glisson/University of Georgia (VG/GA) attenuated vaccine against Newcastle disease. The stimulation index of lymphocyte proliferation and antigen-specific local secretory IgA responses in bile, duodenum, ileum, as well as serum IgY and IgA responses were analysed by enzyme-linked immunosorbent assay. The turkey MHC class II B locus was selected as candidate gene for detection of associations with cellular and humoral immune responses. Significant differences were observed between both cellular and humoral responses of vaccinated and unvaccinated groups. A significant positive correlation was also found between ND specific IgY and ND specific IgA titres in serum, intestine (duodenum and ileum) and trachea. Moreover, the correlation between specific IgA titres in ileum and specific bile, duodenum and trachea was positively significant. High resolution melting analysis (HRM) was used to genotype MHC class II B exon 2. Eight melting profiles (A-G) were identified, among which, profile G showed a significant association with cellular response. The profile B revealed significant association with total IgA titres in serum and ileum. These findings help our understanding of the association of turkey MHC types with immune responses. Further correlation analysis between serum and mucosal antibody titres demonstrated that the levels of IgY and IgA in serum can give an impression about the levels of secretory IgA and situation of mucosal immunity. Based on the significant effects, ND specific IgY in serum appears to be a promising indirect marker for specific IgA in serum and trachea.
Collapse
|
7
|
Fuller C, Löndt B, Dimitrov KM, Lewis N, van Boheemen S, Fouchier R, Coven F, Goujgoulova G, Haddas R, Brown I. An Epizootiological Report of the Re-emergence and Spread of a Lineage of Virulent Newcastle Disease Virus into Eastern Europe. Transbound Emerg Dis 2015; 64:1001-1007. [PMID: 26671034 DOI: 10.1111/tbed.12455] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Indexed: 11/28/2022]
Abstract
A number of contemporary outbreaks of Newcastle disease (ND) in Israel, Turkey, Georgia and Bulgaria have all been caused by a very similar viruses related to lineage 5a (genotype VIIa). Comparison with published ND virus (NDV) sequences suggests that this virus strain originated in South-East Asia and on introduction has circulated widely in backyard poultry in the Middle East and into Eastern Europe. An intracerebral pathogenicity index of 1.9 was obtained for a representative isolate from Bulgaria. In addition, the International Reference Laboratory for ND has characterized a molecular epidemiologically linked virus that has been reported to have caused disease in well-vaccinated broiler chickens in Pakistan. In the 1990s, another strain from the 5a lineage NDV was introduced into Europe and spread across the continent causing numerous outbreaks up to 1999. Despite improved controls, including good diagnostic tests and widespread vaccination, in commercial poultry, the novel circulating NDV strains described here have been established widely in the region and represent an increased risk for similar disease outbreak events to reoccur within the EU.
Collapse
Affiliation(s)
- C Fuller
- Animal and Plant Health Agency, Weybridge, UK
| | - B Löndt
- Animal and Plant Health Agency, Weybridge, UK
| | - K M Dimitrov
- National Diagnostic Research Veterinary Medical Institute, Sofia, Bulgaria
| | - N Lewis
- Department of Zoology, University of Cambridge, Cambridge, UK
| | | | - R Fouchier
- Viroscience lab, Erasmus MC, Rotterdam, The Netherlands
| | - F Coven
- Bornova Veterinary Control Institute, Izmir, Turkey
| | - G Goujgoulova
- National Diagnostic Research Veterinary Medical Institute, Sofia, Bulgaria
| | - R Haddas
- Division of Avian Diseases, Kimron Veterinary Institute, Beit-Dagan, Israel
| | - I Brown
- Animal and Plant Health Agency, Weybridge, UK
| |
Collapse
|
8
|
Arriero E, Müller I, Juvaste R, Martínez FJ, Bertolero A. Variation in immune parameters and disease prevalence among Lesser Black-backed Gulls (Larus fuscus sp.) with different migratory strategies. PLoS One 2015; 10:e0118279. [PMID: 25679797 PMCID: PMC4334556 DOI: 10.1371/journal.pone.0118279] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 01/12/2015] [Indexed: 01/08/2023] Open
Abstract
The ability to control infections is a key trait for migrants that must be balanced against other costly features of the migratory life. In this study we explored the links between migration and disease ecology by examining natural variation in parasite exposure and immunity in several populations of Lesser Black-backed Gulls (Larus fuscus) with different migratory strategies. We found higher activity of natural antibodies in long distance migrants from the nominate subspecies L.f.fuscus. Circulating levels of IgY showed large variation at the population level, while immune parameters associated with antimicrobial activity showed extensive variation at the individual level irrespective of population or migratory strategy. Pathogen prevalence showed large geographical variation. However, the seroprevalence of one of the gull-specific subtypes of avian influenza (H16) was associated to the migratory strategy, with lower prevalence among the long-distance migrants, suggesting that migration may play a role in disease dynamics of certain pathogens at the population level.
Collapse
Affiliation(s)
- Elena Arriero
- Department of Migration and Immunoecology, Max Planck Institute for Ornithology, Radolfzell,Germany
- Department of Zoology and Anthropology, University Complutense of Madrid, Madrid, Spain
- * E-mail:
| | - Inge Müller
- Department of Migration and Immunoecology, Max Planck Institute for Ornithology, Radolfzell,Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Risto Juvaste
- Department of Biology, University of Turku, Turun yliopisto, Finland
| | | | - Albert Bertolero
- Institute of Aquatic Ecosystems (IRTA), Sant Carles de la Ràpita, Spain
| |
Collapse
|
9
|
Prevalence of avian paramyxovirus 1 and avian influenza virus in double-crested Cormorants (Phalacrocorax auritus) in eastern North America. J Wildl Dis 2014; 49:965-77. [PMID: 24502724 DOI: 10.7589/2012-06-164] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although it is well established that wild birds, such as cormorants, carry virulent avian paramyxovirus serotype 1 (APMV-1; causative agent of Newcastle disease) and avian influenza virus (AIV), the prevalence of these viruses among Double-crested Cormorants (Phalacrocorax auritus) in the Great Lakes region of North America has not been rigorously studied. We determined the prevalences of APMV-1 and AIV in Double-crested Cormorants from the interior population of eastern North America. From 2009 to 2011, oropharyngeal and cloacal swabs and serum samples were collected from 1,957 individual Double-crested Cormorants, ranging from chicks to breeding adults, on breeding colony sites in Michigan, Wisconsin, and Mississippi, USA, and Ontario, Canada, as well as on the wintering grounds of migratory populations in Mississippi, USA. Prevalence of antibodies to APMV-1 in after-hatch year birds was consistently high across all three years, ranging from 86.3% to 91.6%. Antibody prevalences in chicks were much lower: 1.7, 15.3, and 16.4% in 2009, 2010, and 2011, respectively. Virulent APMV-1 was detected in six chicks sampled in 2010 in Ontario, Canada. Only one adult was positive for AIV-specific antibodies and five individuals were positive for AIV matrix protein, but the latter were negative for H5 and H7 AIV subtypes. We provide further evidence that Double-crested Cormorants play an important role in the maintenance and circulation of APMV-1 in the wild, but are unlikely to be involved in the circulation of AIV.
Collapse
|
10
|
Abstract
Newcastle disease (ND) is a devastating disease of poultry that has to some extent been neglected by those working in the field in the past 10 to 15 years while attention has been focused on the emergence and spread of highly pathogenic avian influenza caused by a H5N1 subtype virus. During 2000 to 2009 in the European Union (EU) member states, ND viruses virulent for chickens have been detected in wild birds, domesticated pigeons and poultry. Based on these isolations it appears that the epizootic in racing pigeons caused by the variant viruses termed pigeon avian paramyxovirus type 1, which form the genetic group 4b(VIb) first seen in Europe in 1981, continued during 2000 to 2009, and the virus is probably enzootic in racing pigeons in some EU countries. This virus appears to have spread regularly to wild birds, especially those of the Columbidae family, and has been the cause of significant outbreaks in poultry. Other avian paramyxovirus type 1 viruses responsible for ND outbreaks in the EU during 2000 to 2009 have been those from genetic groups 5b(VIIb) and 5d(VIId). There is evidence that the former may well represent spread from a wild bird source and these viruses have also been isolated from wild birds, while the latter represents continuing spread from the East. Future legislation or recommendations aimed at the control and eradication of ND will need to encompass these three sources of virulent ND viruses.
Collapse
Affiliation(s)
- Dennis J Alexander
- Virology Department, Animal Health and Veterinary Laboratories Agency Weybridge, Addlestone, Surrey, UK.
| |
Collapse
|
11
|
Development of a real-time reverse-transcription PCR for the detection and simultaneous pathotyping of Newcastle disease virus isolates using a novel probe. Arch Virol 2009; 154:929-37. [DOI: 10.1007/s00705-009-0391-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 04/23/2009] [Indexed: 11/30/2022]
|
12
|
Gabal MA, Azzam AH. Interaction of aflatoxin in the feed and immunization against selected infectious diseases in poultry. II. Effect on one‐day‐old layer chicks simultaneously vaccinated against Newcastle disease, infectious bronchitis and infectious bursal disease. Avian Pathol 2007; 27:290-5. [DOI: 10.1080/03079459808419338] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
13
|
|
14
|
Fuller CM, Collins MS, Easton AJ, Alexander DJ. Partial characterisation of five cloned viruses differing in pathogenicity, obtained from a single isolate of pigeon paramyxovirus type 1 (PPMV-1) following passage in fowls' eggs. Arch Virol 2007; 152:1575-82. [PMID: 17514489 DOI: 10.1007/s00705-007-0963-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Accepted: 02/23/2007] [Indexed: 11/26/2022]
Abstract
Viruses with intracerebral pathogenicity indices (ICPIs) of 0.025, 0.55, 1.013 and 1.3. were cloned from a PPMV-1 isolate with an ICPI of 0.32 by passage in embryonated fowls' eggs. Deduced amino acid sequences of the haemagglutinin-neuraminidase (HN) and precursor fusion proteins (F0) showed them to have only a single amino acid difference: those with an ICPI value <0.7 had proline at amino acid position 453 of the F0 protein, and those with an ICPI value >0.7 contained a serine. The virus with an ICPI of 0.025 was further passaged, and the ICPI of non-cloned virus increased to 0.76/0.79, which was then reduced to 0.49 on cloning. The proline at residue 453 was retained, but there were two nucleotide changes in the virus of ICPI 0.49, T --> C at position 1769 in the untranslated region of the fusion gene and G --> A at position 437 of the HN gene, resulting in the amino acid change G --> R at position 116 in the HN protein.
Collapse
Affiliation(s)
- C M Fuller
- Virology Department, Veterinary Laboratories Agency, Addlestone, Surrey, UK.
| | | | | | | |
Collapse
|
15
|
Calderón NL, Galundo-Muñiz F, Ortiz M, Lomniczi B, Fehervari T, Paasch LH. Thrombocytopenia in Newcastle disease: haematological evaluation and histological study of bone marrow. Acta Vet Hung 2006; 53:507-13. [PMID: 16363152 DOI: 10.1556/avet.53.2005.4.11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A Newcastle disease virus (NDV) isolated in Mexico and called Chimalhuacan strain was characterised by gene F restriction enzyme analysis and found to be a genotype II velogenic virus. Haematological evaluations and histological studies of bone marrow were conducted on chickens experimentally infected with the Chimalhuacan virus and on control chickens. Within 72 hours post infection (hpi), a 50% decrease in thrombocyte and monocyte counts and a complete cellular depletion in bone marrow islands were evident in the infected group. These findings suggest that the Chimalhuacan strain of NDV causes an early and severe damage of the haematopoietic cells including thrombocyte precursors, which might explain the marked thrombocytopenia detected in early stages of this disease.
Collapse
Affiliation(s)
- Norma L Calderón
- Department of Animal Production: Poultry, Faculty of Veterinary Medicine and Animal Science, National Autonomous University of Mexico.
| | | | | | | | | | | |
Collapse
|
16
|
Yeo SG, Nagy E, Krell PJ. Indirect method for prediction of hemagglutination inhibition antibody titers to Newcastle disease virus in chickens by titration of antibodies in egg yolk. J Vet Diagn Invest 2003; 15:184-7. [PMID: 12661732 DOI: 10.1177/104063870301500216] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Attempts were made to establish methods for indirect prediction of hemagglutination inhibition (HI) antibody titers to Newcastle disease virus (NDV) in sera of laying hens and day-old chicks by determining if these are correlated to HI titers in egg yolks. For this purpose, geometric means of HI antibody titers in sera from 60 hens, yolks from 60 matched eggs, and sera from 180 day-old chicks of an identical vaccination program were measured and plotted. There was a significant correlation between HI antibody titers in yolks (X) and hens (Y), with a linear regression of Y = 23.24 + 0.47X and a correlation coefficient of r = 0.65. The linear regression between HI antibody titers in yolks (X) and chicks (Y) was Y = 6.33 + 0.36X (r = 0.58). Immunity to NDV in hens and their offspring can be maintained effectively, and the proper time for the vaccination or booster can be determined by reference to HI titers predicted from the linear regression in the present study. The approach of testing egg yolk for HI titers provides a feasible alternative to determining HI titers from blood samples and eliminates stress in birds during blood sampling.
Collapse
Affiliation(s)
- Sang-Geon Yeo
- College of Veterinary Medicine, Institute of Animal Medicine, Gyeongsang National University, Chinju 660-701, Republic of Korea
| | | | | |
Collapse
|
17
|
Aldous EW, Collins MS, McGoldrick A, Alexander DJ. Rapid pathotyping of Newcastle disease virus (NDV) using fluorogenic probes in a PCR assay. Vet Microbiol 2001; 80:201-12. [PMID: 11337136 DOI: 10.1016/s0378-1135(00)00371-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hybridisation of PCR fragments with fluorogenic probes specific for pathotype allowed an estimation of pathogenicity of Newcastle disease virus (NDV) isolates using a modified TaqMan procedure. Six probes were used, designed to recognise nucleotide sequences in the fusion protein gene sequence corresponding to the precursor protein F0 cleavage site of both virulent and avirulent viruses. Forty-three of the 45 isolates tested, including 18 examined in a blind study were pathotyped successfully and rapidly, with close correlation between cleavage site nucleotide sequences, TaqMan results and intracerebral pathogenicity index (ICPI) values. One isolate, which could not be pathotyped by nucleotide sequencing, was shown using the TaqMan system to be a mixture of virulent and avirulent NDV. The results of this study suggest that using this modified TaqMan protocol, the likely virulence of most ND isolates can be determined rapidly and reproducibly.
Collapse
Affiliation(s)
- E W Aldous
- Virology Department, Central Veterinary Laboratories Agency, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
| | | | | | | |
Collapse
|