Live Avian Metapneumovirus Vaccines
Live vaccine strains
Several commercial live attenuated vaccines are now available. The vaccines stimulate both local and systemic immunity, some even in the presence of maternal immunity.
Although it is well known that different subtypes exist, studies have shown that in general there is good cross protection between the subtypes. Live attenuated subtype A or subtype B vaccines (chicken or turkey origin) protect against challenge with subtypes A, B or C. Live cell culture attenuated vaccines and inactivated vaccines are currently being used in Europe and other parts of the world to control disease caused by subtypes A and B. Protection provided by type C against challenge with types A or B is less solid.
Application
- Oculo-nasal method -In general gives the best response but it is labour intensive and time consuming.
- Spray vaccination – A good alternative to the oculo-nasal method.
- Drinking water- Vaccination through the drinking water is the least reliable application method.
chicks in the hatchery
Live vaccines:
- are usually applied by mass vaccination (e.g. coarse spray)
- are usually cheap
- induce local as well as systemic immunity
- some vaccination reaction is usually observed for a few days after application