Nanopore sequencing identifies both blood-feeding insects and their food sources

A recent study led by CVM researchers established a proof of concept for an improved approach to identifying blood-feeding insects, offering insights into their genetics, and clarifying the transmission pathways of the diseases they can carry.

Blood-feeding insects spread many diseases among animals and people alike. Scientists have historically selected insect species for study based on whether they spread key diseases such as malaria or West Nile virus. But efforts to research the many species of blood-feeding insects more broadly have been limited. 

However, technological advancements have opened the door for targeted genetic sequencing of insect genomes. For blood-feeding insects, such technologies can help clarify not only the insects’ genome but the genetic makeup of their blood-meal source animals as well. With this increase in information, scientists could better pinpoint emerging disease vectors of concern and better trace how established key diseases move through the environment. Armed with that information, they could help stop outbreaks before they even happen.

The researchers used nanopore adaptive sampling (NAS) to sequence genomic DNA from four species of field-collected, blood-engorged mosquitoes and one species of deer fly. Their goal for this study was to establish a proof of concept for using NAS to analyze the genetics of blood-meal source animals. The team suspected that NAS holds great promise for a variety of research projects aimed at clarifying blood-feeding insect diversity and how they help transmit disease.

Compared to the data non-NAS control experiment data the team generated, NAS yielded a substantially higher proportion of usable readings of the genetic material. The researchers were also able to identify the blood-meal sources for three of the mosquito species and found that they were human, house sparrow, and eastern cottontail rabbit. The findings show that NAS has the ability to simultaneously identify blood-feeding insects and their blood-meal hosts. 

“Our approach opens the door to a variety of exciting applications that can be leveraged to fight vector-borne disease in new ways,” says Dr. Peter Larsen, who led the study. “Next steps will focus on deploying this technology in hot-spots of emerging mosquito-borne disease to help identify new transmission pathways.” 

Read more in Parasites and Vectors.