Latest way to stop mosquitoes: Attack their egg production

24 Feb 2017

Image: Chansom Pantip/Shutterstock

Mosquitos are the annoying carriers of numerous diseases such as Zika fever. To stop them, we need to attack how they reproduce.

Mosquitoes bite into humans and other animals, extracting blood from our bodies and consuming it, for one simple reason: to help develop their eggs.

We play a key role in how they reproduce and, therefore, we can actively help to tackle the spread of dengue fever, chikungunya, the Zika virus and yellow fever.

Blood meal

A team of scientists at the University of California, Riverside has explored ways to to tamper with the reproductive events that follow a mosquito’s blood meal, looking at the process from a molecular level.

The researchers focused on small regulatory RNA molecules, called miRNAs, which play a critical role in mosquito egg maturation. Investigating mosquitoes before, during and after the blood meal, significant markers were visible.

“What we observed is that the levels of many miRNAs change significantly throughout the 48-hour period following a blood meal, indicating that these miRNAs, in turn, may be establishing significant changes in expression of key genes during this time in the fat body,” said Fedor Karginov, who co-led the study with Alexander Raikhel.

“Our work has given us a much-needed picture of which miRNAs are abundant in the fat body tissue, how each miRNA subgroup changes over time; and we have confirmation that specific upregulation and downregulation of miRNA levels takes place during egg development.”

The discovery means that the team have filled in several blanks regarding mosquito reproduction, providing an avenue for scientists to control the spread of disease by disrupting a key process in the reproductive cycle: egg production.

Modified attack

There are actually several approaches being taken towards combating the mosquito problem.

Last year, the US Food and Drug Administration (FDA) approved the trial of a new, mutant, genetically engineered mosquito.

The plan is to introduce these newly designed mosquitoes into the Florida Keys to eliminate the Zika-carrying mosquitoes, thus halting the further spread of the virus into the US.

Oxitec is the company behind the mosquitoes, which are armed with extra genes to make reproduction unlikely. If released in sufficient numbers, the thinking is that they will halt widespread reproduction, reducing the number of Zika-bearing insects.

Of course, killing off mosquitoes is probably not the most ideal scenario either, as several species of bird dine on both the insect and its egg larvae to survive.

These include purple martins, swallows, geese, ducks and migratory songbirds. Goldfish, guppies, bass, bluegill and catfish all prey on mosquito larvae.

Gordon Hunt was a journalist with Silicon Republic