1990 Fiscal Year Final Research Report Summary
Studies on Control of Avian Infectious Bronchitis (IB), Specially Reference to Antigenic Variation of IB Virus Occurs Persistant Infection
| Project/Area Number |
01560321
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
基礎獣医学
|
|---|
| Research Institution | Tottori University |
|---|
Principal Investigator |
OTSUKI Koichi Tottori University Faculty of Agriculture Associate Professor, 農学部, 助教授 (00032293)
|
|---|
| Project Period (FY) |
1989 – 1990
|
| Keywords | Avian infectious bronchitis / Avian infectious bronchitis virus / Persistant infection / Antigenicity / Antigenic variation / Nephrosis |
|---|
| Research Abstract |
Antigenicity of avian infectious bronchitis virus (IBV) is thought to be very complexwd. Although several workers have tryed to type IBV serologically, reasonable serotyping of IBV is not established. Effective control of avian infectious bronchitis (IB) is also fard although various live and inactivated vaccines have been commonly used for more than 20 years. I have a hypothesis that IBV can change its antigenicity with ease. Thus in this investigation I prepared 2-, 4- and 6-week-old SPF chicks individually and infected them with nephrosis causing IBV Kagoshima-34 (K) strain. I tryed to demonstrate to occur persistant infection in these chicks and to appear antigenic variants from K strain during replication in the tissues. The results obtained are as follows :
1. The 2-week-old chicks infected IBV K strain showed more severe clinical signs than the elder ones and diarrhoea lasted for 15 weeks postinoculation (p. i.) whilst elder chiks had diarrhoea only several days p. i..
2. All infected chicks excreted IBV on and off from the faeces for 16 weeks p. i.. However I must pass each specimen in 5 or 6 occasions to confirm recovery IBV from them.
3. A lower titre of virus-neutralising antibody against only IBV K strain produced in the serum of 2-week-old chicks. On the other hand considerable titre of its antibody was produced in elder chicks and its titre was always higher than that against other strains of IBV.
4. These results were confirmed by repeated investigation.
The results obtained in this investigation suggest that antigenic variation of this IBV strain hardly occurs during successive replication in the tissues of such young chicks. Another IBV strains should be tested. Neveretheless it is of interest that 2-week-old chicks, those showed the most severe respiratory signs with IBV infection, did not produce high titre of virus-neutra-lising antibody in at least their serum.
|
Research Products
(2 results)
