Dr. R.P.Singh,Dear Colleagues,I do not think that there is a need of species specific vaccine. I my opinion, the difference in sero-conversion also suggests that sheep is relatively more resistant (poor seroconversion) to PPR than goat, as live vaccine induces immunity by limited viirus replication within the body. It is also possible that a low level of antibody in sheep may provide equivalent level of protection with higher level of antibody in goat.regards,R.P.Singh
----- Original Message -----
From: Paul Rossiter
Sent: 02/07/14 09:28 PM
Subject: From Dr Srinivasan on the possible need for species specific vaccines
Dear Colleagues,
When we first developed PPR Sungri/96 vaccine, during the initial field
evaluation of vaccine we observed goats were better sero-converters than
Sheep. In a study involving more than 500 post-vaccinate sera samples in
each of the species, we observed 98% sero-conversion in goats and 83% in
sheep. Even the VN titer was lesser in sheep than goats (eg., most of the
goats had 1:64 to 1:128 and sheep it was 1:32 to 1:64).
PPR Sungri/96 virus which was used to develop attenuated vaccine was
originally rescued from post-mortem samples from a goat died in the PPR
outbreak.
Does this suggests that we should have separate vaccine candidates for
sheep and goat? I must confess I am not keeping abreast of PPR literature
as I have moved away from PPR research almost 11 years back.
Regards
SrinivasI hope that several of you will give us your views on this radical idea - moderator
________________________________
Dr.B.P.Srinivas
Principal Scientist
Indian Veterinary Research Institute (IVRI)
Hebbal, Bangalore-560024
India
Tel: 91-80-23410729 (Work)
Fax: 91-80-23412509
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