Evaluating the ability of specific-pathogen-free embryonated chicken eggs of different age to support the propagation of lentogenic Newcastle disease virus strain lasota /
Newcastle Disease (ND) is a viral disease of poultry caused by Newcastle Disease Virus (NDV ND is a major worldwide concern due to its persistent existence despite intense vaccination programmes. There are 3 pathotypes of NDV, which are velogenic, mesogenic and lentogenic. Numerous diagnostic tests...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Newcastle Disease (ND) is a viral disease of poultry caused by Newcastle Disease Virus (NDV ND is a major worldwide concern due to its persistent existence despite intense vaccination programmes. There are 3 pathotypes of NDV, which are velogenic, mesogenic and lentogenic. Numerous diagnostic tests are available to detect NDV, yet the most convenient method to detect and propagate NDV is by inoculation of allantoic cavity of embryonated chicken eggs (ECE). Many studies indicated the use of 9-11 days of ECE to propagate NDV, but there are limited studies indicating the use of young ECE to grow viruses since they have incomplete development of innate immunity compared to older ECE. Propagation of NDV in young ECE has been used for research and development in rescuing novel and reverse genetic ND viruses. This study is part of a bigger study in understanding the development immune system of ECE influencing virus growth for vaccine development. Hence, this study aimed to determine the viability of specific-pathogen-free (SPF) ECE of different ages following inoculation with lentogenic NDV strain LaSota of different inoculation doses and to detect the presence of NDV using rapid hemagglutination (HA) spot test and HA titration test. ECE of 3, 5 and 10 days were inoculated with NDV LaSota strain via allantoic cavity in three different doses; 10³, 10⁴, 10⁵. Sterile saline inoculated ECE were used as controls. The ECE were incubated at 37C incubator and embryonic viability was observed via egg candling and recorded daily post-inoculation for 3 days. The allantoic fluid of all ECE was harvested for HA spot test and HA titration test. On day 3 post-inoculation, inoculated ECE of 3 and 5-days old had 15/15 ECE (100%) mortality in all dilution doses while 10-days old inoculated ECE had 5/15 ECE (33%) mortality with 1/5 ECE mortality in dose 10³, 3/5 ECE in dose 10⁴, and 1/5 ECE in dose 10⁵. Based on statistical analysis, HA titer between 3, 5 and 10-days old ECE are significantly different where day 10 ECE had the highest NDV titer followed by day 5, and day 3 ECE. In conclusion, all ECE of irrespective age are able to support propagation of NDV LaSota strain but day 10 ECE had a lower mortality rate (33%) compared to 3 and 5-days old ECE and had the highest NDV titer. ECE of 10-days old is the most suitable age to support the propagation of NDV LaSota strain. The expression of innate immunity related genes of ECE of different age in modulating the propagation of NDV LaSota is currently under study. |
|---|---|
| Physical Description: | 38 leaves : illustrations ; 30 cm. |