Abstract
Experiments relating to the transmission of MIV in nature are described. Intact cadavers of diseased fourth-instar larvae were found to be potent sources of infection in laboratory experiments. A field experiment showed that infection could be acquired per os by larvae exposed under natural conditions, and that when healthy fourth-instar larvae were given access to intact diseased cadavers for a short time before pupation, they became infected and produced adults that laid infected eggs. Further laboratory tests showed that the virus becomes uninfective after a few days when liberated into artesian and 10% seawater, and does nto remain active when liberated onto the surface of soil such as might be found in natural breeding grounds of Aedes taeniorhynchus. A tentative account of the natural history of the disease is given in which it is proposed that the pathogen survives through a simple cyle. Transovarial transmission of virus gives rise to diseased larvae, which die in the fourth instar. The cadavers so formed provide the source of new infection, which is acquired per os by healthy larvae just before pupation. Infected adults from these larvae complete the cycle by depositing infected eggs.
Published Version
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