| Autor: |
J.W. Parfitt, I.J. Sinclair |
| Rok vydání: |
1967 |
| Předmět: |
|
| Zdroj: |
Research in Veterinary Science. 8:6-13 |
| ISSN: |
0034-5288 |
| DOI: |
10.1016/s0034-5288(18)34645-9 |
| Popis: |
SUMMARY Calves which were infected with Dictyocaulus filaria were more resistant to a challenge infection of D. viviparus than previously uninfected animals. The reduction in the D. viviparus worm burden was 67% at 10 and 24 days, and 76% at 30 days after challenge. The difference appeared to be due to 3 causes: (a) fewer worms becoming established in the lungs of the vaccinated calves, (b) a slower growth rate, (c) possibly a greater loss from the lungs. One animal died of D. filaria infection and some mature worms of this species were recovered from its lungs. The D. filaria infection elevated the respiration rates in the vaccinated calves. On challenge with D. viviparus, all calves showed a similar level of respiratory distress; this was demonstrable in the vaccinated calves 7 days before a similar level was reached in the control animals. The production of precipitating antibodies was investigated using the gel-diffusion test and it was found that precipitins to D. filaria antigen were formed in the vaccinated animals. One of these precipitins was found to cross react with D. viviparus antigen. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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