Mosquitoes may serve a purpose other than being the source of disease and human misery, according to research by scientists at Japan’s Nagoya University.

The researchers were able to extract “identifiable DNA” from human blood in mosquito stomachs up to two days after the bug had eaten, according to their study published in the journal PLOS ONE.

In what had to be an uncomfortable experiment, volunteers were asked to allow mosquitoes to bite them, the study explained. The scientists, led by Dr. Toshimichi Yamamoto, then allowed the mosquitoes to digest the blood for varying amounts of time, after which it was extracted and subjected to a DNA analysis.

Forensic techniques

Using a process called polymerase chain reaction, or PCR, to “amplify” short, broken strands of DNA found in the tiny amount of blood extracted from the bugs, the scientists were able to genotype the DNA and match it to specific volunteers, the study said.

Although earlier research studies were able to detect human DNA in mosquitoes’ blood meals, the Nagoya University study is apparently the first in which clear identification of the human bite victim was possible. The researchers used two different species of mosquitoes found in Japan, including the disease-carrying Aedes albopictus, to determine variations in the amount of time it takes mosquitoes to digest their blood meal. In general, the study found that DNA could be successfully analyzed for up to two days after the mosquito fed, after which it becomes too degraded to be tested.

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Little criminal investigators

The researchers suggested that one application of the study’s results could be in criminal investigation. The DNA from the blood in the mosquitoes’ stomachs could help to identify people who were at a crime scene, forensic scientist Yuuji Hiroshige explained, and lead to more certain convictions. The Dna Testing technique could also help in locating missing persons, or identifying people at risk of contracting one of the many diseases carried by mosquitoes, he added.

Mosquitoes, particularly those in the Aedes genus, are notorious for their ability to carry and spread a number of infectious diseases, including malaria, yellow fever, dengue fever, Zika virus, chikungunya, Mayaro, and West Nile disease. Further refinement of the DNA testing technique, the researchers said, should allow the unpleasant flying pests to partly redeem themselves with at least one helpful purpose.