Modeling horizontal transmission of microsporidia infecting gypsy moth, Lymantria dispar (L.), larvae

We developed a simulation model that describes the horizontal transmission of three different microsporidia, Endoreticulatus schubergi, Nosemalymantriae and Vairimorpha disparis and their insect host, the gypsy moth, Lymantria dispar. The model describes the stage specific development and mortality of uninfected, latently infected or infectious hosts, the food consumption, the infection by spore-laden feces of E. schubergi and N. lymantriae and by spore-laden cadaver of N. lymantriae and V. disparis. Model results were compared to percent infection of L. dispar test larvae published in earlier studies using caged oak trees and potted oak-plants. When feces were selected as the source of spores for transmission of E. schubergi or N. lymantriae, the model estimated a percent infection in susceptible larvae that was in the range of the experimental studies. When spore-laden cadavers were the source of spores of N. lymantriae or V. disparis, the model did not correctly predict the experimentally measured percent infection in susceptible larvae. The most critical points of the simulation model are exact calculation of spore release, mortality and exact determination of the transmission coefficients when cadavers were included as a source for microsporidian infection.

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► Development of a simulation model for description of microsporidia horizontal transmission.
► Modeled horizontal transmission pathways are spore containing feces and cadavers.
► Verification of simulation results by experimental studies.
► Model predicted experimental results correctly when feces were source of spores.
► Model underestimated experimental results when cadavers were source of spores.