A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo
The velogenic viscerotropic Newcastle disease virus or the Asiatic strain has been considered the most virulent strain of Newcastle disease virus. It is commonly found in Southeast Asia and it has been known to cause 100% mortality in susceptible flocks. In spite of this, very little research ha...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
1985
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/85610/1/t%20FPV%201985%201%20ir.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| id |
my-upm-ir.85610 |
|---|---|
| record_format |
uketd_dc |
| spelling |
my-upm-ir.856102021-12-09T04:18:57Z A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo 1985-04 Lai, Chooi May The velogenic viscerotropic Newcastle disease virus or the Asiatic strain has been considered the most virulent strain of Newcastle disease virus. It is commonly found in Southeast Asia and it has been known to cause 100% mortality in susceptible flocks. In spite of this, very little research has been conducted on it as many countries prohibit the handling of this strain of virus. In view of this, a project has been undertaken at Universiti Pertanian Malaysia to study the biological properties, cytopathogenicity and morphogenesis of a locally isolated velogenic viscerotropic Newcastle disease virus and to determine its effects on the trachea of nonvaccinated and vaccinated chickens. The in vitro study has shown that this virus has a mean death time of 66 hours, and an intracerebral pathogenicity index of 1.90. Polykaryocytosis is the principal form of cytopathic effect it produces in chick embryo fibroblasts and cells infected by it haemadsorp red blood cells. This virus plaques in cell culture. Negatively stained virus particles have diameters ranging from 100 to 600 nanometers. Electron microscopy demonstrated that the virus replicates in the cytoplasm of infected cells and aggregates of nucleocapsids are found in the cytoplasm. The virus matures at the cell membrane and is released by budding. The effects of the virus on the tracheal epithelium was evaluated by virus isolation and scanning and transmission electron microscopy. This virus causes severe ultrastructural alterations in the nonvaccinated chickens and it could be isolated from the tracheas of all the infected chickens from day 4 postinfection. None of these chickens survived past day 10 postinfection. In the vaccinated chickens, differences were observed. Besides a delay in the onset and a decrease in severity of the damages, the vaccinated chickens were apparently normal throughout the experiment with no death recorded and virus could only be isolated from some of the chickens from day 6 to 9 postinfection. Complete regeneration of the damaged epithelium was accomplished by day 13 postinfection. This study presents for the first time detailed information on the in vitro properties of a locally isolated velogenic viscerotropic Newcastle disease virus. Such information is useful in differentiating the virus from the vaccine strains present, thereby assisting in the diagnosis of the disease. It also provides a basis for understanding the behaviour of the virus in the host. Information on its replication at the site of entry as well as on the response of the vaccinated and nonvaccinated chickens to the virus suggest not only the importance of vaccination but also the call for a good vaccination programme in the control of the disease. The study has also thrown light on the possible epidemiology of the virus in relation to the poultry industry in Malaysia. 1985-04 Thesis http://psasir.upm.edu.my/id/eprint/85610/ http://psasir.upm.edu.my/id/eprint/85610/1/t%20FPV%201985%201%20ir.pdf text en public doctoral Universiti Putra Malaysia Ibrahim, Abdul Latif |
| institution |
Universiti Putra Malaysia |
| collection |
PSAS Institutional Repository |
| language |
English |
| advisor |
Ibrahim, Abdul Latif |
| topic |
|
| spellingShingle |
Lai, Chooi May A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| description |
The velogenic viscerotropic Newcastle disease virus or the
Asiatic strain has been considered the most virulent strain of
Newcastle disease virus. It is commonly found in Southeast Asia
and it has been known to cause 100% mortality in susceptible
flocks. In spite of this, very little research has been conducted
on it as many countries prohibit the handling of this strain of
virus. In view of this, a project has been undertaken at Universiti
Pertanian Malaysia to study the biological properties, cytopathogenicity
and morphogenesis of a locally isolated velogenic
viscerotropic Newcastle disease virus and to determine its
effects on the trachea of nonvaccinated and vaccinated chickens.
The in vitro study has shown that this virus has a mean
death time of 66 hours, and an intracerebral pathogenicity index
of 1.90. Polykaryocytosis is the principal form of cytopathic
effect it produces in chick embryo fibroblasts and cells infected
by it haemadsorp red blood cells. This virus plaques in cell
culture. Negatively stained virus particles have diameters ranging from 100 to 600 nanometers. Electron microscopy demonstrated
that the virus replicates in the cytoplasm of infected
cells and aggregates of nucleocapsids are found in the cytoplasm.
The virus matures at the cell membrane and is released by
budding.
The effects of the virus on the tracheal epithelium was
evaluated by virus isolation and scanning and transmission electron
microscopy. This virus causes severe ultrastructural alterations
in the nonvaccinated chickens and it could be isolated
from the tracheas of all the infected chickens from day 4 postinfection. None of these chickens survived past day 10 postinfection. In the vaccinated chickens, differences were observed. Besides a delay in the onset and a decrease in severity of the damages, the vaccinated chickens were apparently normal throughout
the experiment with no death recorded and virus could only be
isolated from some of the chickens from day 6 to 9 postinfection.
Complete regeneration of the damaged epithelium was accomplished by day 13 postinfection.
This study presents for the first time detailed information
on the in vitro properties of a locally isolated velogenic
viscerotropic Newcastle disease virus. Such information is useful
in differentiating the virus from the vaccine strains present,
thereby assisting in the diagnosis of the disease. It also provides
a basis for understanding the behaviour of the virus in the
host. Information on its replication at the site of entry as well
as on the response of the vaccinated and nonvaccinated chickens
to the virus suggest not only the importance of vaccination but
also the call for a good vaccination programme in the control of
the disease. The study has also thrown light on the possible epidemiology of the virus in relation to the poultry industry in
Malaysia. |
| format |
Thesis |
| qualification_level |
Doctorate |
| author |
Lai, Chooi May |
| author_facet |
Lai, Chooi May |
| author_sort |
Lai, Chooi May |
| title |
A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| title_short |
A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| title_full |
A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| title_fullStr |
A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| title_full_unstemmed |
A study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| title_sort |
study on a velogenic viscerotropic newcastle disease virus in vitro and in vivo |
| granting_institution |
Universiti Putra Malaysia |
| publishDate |
1985 |
| url |
http://psasir.upm.edu.my/id/eprint/85610/1/t%20FPV%201985%201%20ir.pdf |
| _version_ |
1747813567889932288 |