Vaccines are to prevent a disease, they do not cure a disease. This is a 1000 doses of a wing web stab type vaccine, which is recommended for birds 4 weeks or older, and normally gives lifetime immunity.
Avian Encephalomyelitis is:
a viral disease which affects the central nervous system of chickens, pheasants, turkeys, and quail. It is found worldwide. Morbidity 5-60%. Mortality can be high. The route of infection can be through the egg; lateral transmission (from bird to bird) is probably by the oral route, incubation >10 days. Virus in droppings may survive 4 weeks or more.