Use of a Novel Feeding System to Assess the Survival of a Very Stable Mammalian Virus, Porcine Parvovirus, Within Black Soldier Fly (Hermetia illucens) Larvae: A Comparison with Mealworm (Tenebrio molitor) Larvae

Insect larvae production offers the potential for large-scale synthesis of high-quality protein that can be used as feed or food. However, currently, there are limitations on the source of substrates for the insect larvae to use. One concern is the potential survival of animal pathogens within insect larvae if their feed is contaminated. In this study, the survival of a very stable virus, porcine parvovirus (PPV), within mealworm (<i>Tenebrio molitor</i>) and black soldier fly (BSF) (<i>Hermetia illucens</i>) larvae has been analyzed after oral ingestion of the virus. PPV genomic DNA could be readily detected by PCR in both species of larvae up until 9 days post ingestion (DPI), the end of the study period. Furthermore, infection of susceptible PK15 cells by PPV from homogenized mealworm larvae could be detected until at least 3 DPI, using an immunoperoxidase staining method and, up until 9 DPI, with a more sensitive real time PCR assay. Thus, PPV can remain infectious within mealworm larvae during their main growth phase through to their harvesting. However, it may be considered that PPV is exceptional in this respect since it displays unusual stability, e.g., to heat.