The global production of insects as mini-livestock is estimated at 100.000 tons for 2023 and a further tenfold increase is foreseen for 2030. Insects are used for a wide range of purposes: they can be used as a protein source in human diets and also are an important factor in integrated pest management. To be able to farm insects successfully, it is necessary to culture large colonies of a single insect species. However, the conditions under which this takes place easily trigger viral disease outbreaks. As a result, producers suffer extensive economic losses. How can this be solved? Researchers from Wageningen University & Research (WUR) – together with other authors – address this and other questions in the newly published book Invertebrate Pathology.
In the book chapter ‘Viral diseases of insects’, WUR researchers Vera Ros, Monique van Oers and Delphine Panziera first provide the reader with an overview of the main virus families causing disease in wild and cultured insect species. Also, they describe the current knowledge on how viral disease outbreaks can be managed or prevented in apiculture and insect mass rearing. Spoiler: this is not an easy thing to do!
In-depth knowledge still lacking
This has everything to do with the fact that in-depth knowledge on many insect viruses is still lacking. Our current knowledge of insect viruses comes from viruses that cause major disease symptoms in well-known insects. For many taxonomic groups of insects in a variety of geographical ranges, we have hardly paid any attention to the virome, let alone to the transmission and pathology of potential viruses. It is therefore not surprising that outbreaks of previously unknown viruses are frequently seen when novel insect species are reared on a large scale, for example to serve as food and feed or for waste management purposes.
Also, we face a rapidly growing gap between the fast-expanding information in viral genome sequence databases and the relatively slowly progressing build-up of knowledge on virus biology and virus-host interactions. These data are essential in understanding the role that insect viruses play in ecosystems: whether these viruses are a potential risk due to their pathogenic features, whether they co-exist in a neutral relationship with the insect hosts or even may provide the host with additional traits that increase the fitness of the insect under certain circumstances. This kind of information is of broad interest for the protection of natural ecosystems and for the establishing of resilient agricultural settings. In addition, it is of growing importance to obtain such knowledge for viruses of cultures insects in order to mitigate or prevent viral disease outbreaks in the insect mass-rearing industry.