Late summer/early autumn-associated epidemic disease of northern temperate areas
large numbers of mosquitoes feed on Ardeid birds (spring season)
Ardeid birds migrate between rural and urban ecosystems introducing JE virus
(spring season); these birds also amplify virus
increased vector activity leads to spill-over and infection of swine by mosquito
vectors shared by birds and pigs
infection of pigs produces additional amplification of virus; also large
populations of vector-accessible swine with rapid generational overturn
facilitate JE virus infection (summer)
with profusion of JE virus circulating, mosquitoes of horses and humans also
transmit agent to these hosts; usually sporadic and localised
epizootics/epidemics (late summer or early autumn