Not all mosquitoes are the same. In addition to the different pains that the bite of either species can cause us, it is important to know its identity for health reasons.
Mosquitoes are vectors of various diseases and controlling them can save millions of lives.
Innovative work carried out by the expert team in entomology and arboviruses from the Animal Health Research Center (CReSA) of the Institute for Food Research and Technology (IRTA) and the company Irideon SL has enabled the development of the first coupled optical sensor to a trap that automatically and reliably classifies captured mosquitoes by gender and sex.
“The results of laboratory tests, recently published in the journal Parasites and vectors, indicate that the sensor is able to classify specimens according to sex Aedes oh Culex with a reliability of 94.2%, as IRTA points out in an informative note on the results of this research. The study, which is part of the European VECTRACK project, also shows that the sensor differentiates men from women of gender. Aedes with a reliability of 99.4% and distinguishes the gender of Culex with total reliability.
The research team worked with these genera because they include two of the species of most concern currently in Europe in the field of public health and surveillance of mosquito-borne viruses. These are, on the one hand, the tiger mosquito (Aedes albopictus), an urban mosquito and potential transmitter of viruses such as dengue, Zika and chikungunya fever, and on the other hand the common mosquito (Culex pipiens), which lives in urban, rural and humid areas and can transmit diseases such as West Nile virus. “We are primarily interested in sensors that identify females because they are the ones that can bite people and transmit viruses,” says Sandra Talavera, researcher at IRTA-CReSA and head of the VECTRACK project.
For two years, the IRTA-CReSA laboratory has recorded the flight of more than 4,300 tiger mosquitoes and common mosquitoes bred in the same facilities to train the optical sensor and learn to detect the frequency with which mosquitoes beat their wings, which would be understood as the hum – measured in Hertz. In the case of mosquitoes, the flight frequency is between 300 and 900 Hz.
“We relied on this trait because it is very unique to each species and varies by sex and other aspects of mosquito biology, such as size, age, and behavior during mating, as well as other environmental factors such as temperature. , explains Maria Isabel González, predoctoral researcher at IRTA-CReSA and first author of the study. Until now, commercially available optical sensors only distinguished mosquitoes from other species and counted them, without differentiating their species, sex or other characteristics of the mosquitoes.
When a mosquito flies near the inlet funnel of the trap, it may be sucked in by the fan inside. At this moment, the sensor detects the insect thanks to an optical panel which emits light and another which receives it. When the mosquito crosses the detection area, it casts a shadow on the optical receiver. Thus, when the insect flaps its wings, the light falling on the receiver changes and causes changes in the amplitude of the light waveform recorded by the sensor. “Using the Python programming language, the sensor manages to translate these optical signals into acoustic signals”, emphasizes João Encarnação, director of the company Irideon SL
Behind the shadow biting insect
Recordings of mosquito flights last an average of 30 milliseconds and can be downloaded from the sensor as audio files for playback and viewing. This information was combined with machine learning techniques and artificial intelligence algorithms developed to train the sensor.
Knowing that each year more than 700,000 people die on the planet due to diseases transmitted by mosquitoes, it is essential to quickly identify their species when there are cases of people suffering from a disease transmitted by mosquito bites . This work is carried out by entomology professionals from the observation of the morphology of insects. “It is very laborious and urgent work, especially in emergencies where the weather marks the possible spread of a mosquito-borne virus,” Talavera points out.
Thanks to artificial intelligence, the traps should be able to identify mosquitoes in real time and immediately send the results remotely to the competent authorities to help them make decisions and thus speed up the process of monitoring and controlling virus-carrying mosquitoes. One of the advantages explained by the experts is that the personnel resources can be prioritized and it will not be necessary to travel to the place where the entomological inspection must be carried out if the species of interest is not not detected. For example, during entomological inspections where there is a suspicion of dengue fever, if the trap indicates that there is no tiger mosquito, it will not be necessary for anyone to go there expressly to take the sample . The remote connection will also be useful for analyzing the trends and risk of transmission of mosquito-borne diseases at a general level.
In recent years, many studies have been initiated to develop technologies based on identifying mosquito wing beat even with body shape, but achieving a very reliable sensor is a challenge. “So far, our study has shown that the optical sensor is reliable under controlled conditions in the laboratory, but soon we will have the results of tests carried out in the field, where environmental conditions vary and can have an influence”, concludes the searcher. Sandra Talavera.