Parasitoid - Parasitoidal Microbial Diseases

Parasitoidal Microbial Diseases

As mentioned, some microbial parasitoids waste most of the host's resources when it dies, but there are other parasitoidal strategies among microbes as well. One more conceptually economical form of parasitoidy is exemplified by microbial pathogens of various invertebrates such as many insects. The most notorious might well be Microsporidiosis in the form of nosema in silkworms. This infection is highly virulent and the tissues of the victims contain huge numbers of infectious spores. In effect the pathogen in its role of parasitoid has used up most of the resources of the host to propagate and spread its offspring. Similarly, many viruses, bacterial and other, continue to propagate inside a host cell until it physically ruptures. In doing so they too consume effectively the whole of the host's resources.

Parasitoidal fungi such as Entomophthora species carry this principle as far as is possible. Having infected and killed an insect, they continue to grow on the carcase and release spores for as long as any resources remain. In this such microbes resemble the aforementioned propagation of some Nematoda in snails and insects.