Risk Evaluation of Passive Transmission of Animal Parasites by Feeding of Black Soldier Fly (Hermetia illucens) Larvae and Prepupae

Finding sustainable feed alternatives is an emerging topic in times of depletion of potential arable land and strict land use regulations. Black soldier fly (Hermetia illucens) larvae can be reared on almost all organic matters and may be used as a source for animal feed. However, the risk of disease transmission is high when animals are fed larvae or prepupae raised on waste materials that may contain potentially infectious pathogens. We qualitatively examined the effect of larval intestine extracts on the coccidian parasites Eimeria nieschulzi and Eimeria tenella and on eggs of the nematode Ascaris suum. Furthermore, we focused on the question of whether the persistent parasite stages (oocysts and eggs) would be digested, pass through living larvae, or attach to the larval surface. Neither living black soldier fly larvae nor black soldier fly larval intestine extracts had any effect on oocysts or eggs of the studied parasites. Thus, untreated H. illucens larvae as animal feed pose a risk of disease transmission to animals and humans, and a simple larval washing step is not sufficient for total removal of parasites. HIGHLIGHTS Black soldier fly larval intestine extracts do not affect coccidian oocysts or nematode eggs. Studied parasites passed through black soldier fly larvae or attached to the larval surface. Black soldier fly larvae as animal feed may pose a risk of parasite transmission. Larval washing is not sufficient for removing parasites; further hygiene steps are needed.