Endplate potentials, acetylcholine potentials, and electrotonic potentials were recorded from the motor endplates of isolated diaphragms from acute late septic and nonseptic rats.
In primary viremia the virus infects a part of immune system in the liver and spleen, called the reticuloendothelial system, which is made of phagocytic cells.
About two weeks after entering the body, the virus starts infecting immune cells themselves - specifically T cells - and that is considered the secondary viremia.
Birds act as a reservoir for the virus, meaning the virus can replicate at high enough levels to cause significant viremia, or elevated viral blood counts, which allows for transmission to other uninfected mosquitoes.