CO2 Mosquito Trap

Overview

A CO₂ mosquito trap is an autonomous surveillance and control device that exploits the host-seeking behavior of female mosquitoes. Mosquitoes locate blood-hosts by detecting CO₂ in the breath, combined with body heat and moisture cues. The trap simulates these attractants using a controlled CO₂ release, an electric heater, and a suction fan to draw approaching mosquitoes into a fine-mesh collection chamber.

Used in vector-control programs and epidemiological surveillance, these traps provide real-time data on mosquito species composition, infection rates (dengue, malaria, West Nile virus), and population dynamics. Unlike light traps or sticky traps, CO₂ traps are highly selective for host-seeking mosquitoes and non-toxic.

How it works

The CO2 Release System releases carbon dioxide at a steady rate of 400–600 mL/min, approximately the output of human breathing, through the CO2 Release Tube that rises through the center of the trap. CO₂ disperses into the air and creates a concentration gradient that female mosquitoes detect from 5–20 meters away.

Simultaneously, the Thermal Attraction System, powered by the Power System, generates heat on a dark-colored Heat Radiator Panel panel kept at 37–40 °C by a Temperature Limiter thermostat. This temperature mimics human skin and is highly attractive to mosquitoes.

The Suction Fan, a brushless Fan Motor driving an Fan Impeller, creates an airflow that draws in the CO₂-enriched air and any mosquitoes oriented toward it. Mosquitoes following the CO₂ plume are pulled into the trap entrance and directed into the Collection Net, a fine Mesh Netting (0.3–0.5 mm) secured by a Net Support Frame.

A Net Entry Port one-way valve or funnel allows mosquitoes to enter the net but prevents escape. Captured mosquitoes remain in the mesh until the operator collects the trap. A Desiccant Cartridge in the net chamber absorbs moisture to preserve samples for later laboratory identification.

The Control Electronics contains a Timer Module that activates the trap on a schedule, typically dusk to dawn, when most mosquitoes are actively host-seeking. The Fan Relay and Heater Relay switch the fan and heater on/off under timer control, minimizing power consumption.

The Weatherproof Housing protects electronics and batteries from rain and sun, with Intake Vents allowing CO₂ to disperse and heat to radiate while blocking water entry. Optional Solar Panel (Optional) and Charge Controller extend operational duration to weeks or months without manual recharging.

Selectivity and efficiency

CO₂ traps are highly selective for host-seeking (blood-feeding) mosquitoes, catching very few non-biting insects or males (which do not feed on blood). This selectivity is valuable for surveillance of disease vectors like Aedes aegypti (dengue, yellow fever), Culex species (West Nile virus), and Anopheles species (malaria). The capture efficiency ranges from 50–90% depending on the mosquito species, trap placement (height, proximity to breeding sites), wind conditions, and the number of competing hosts nearby.

Comparison to other methods

CO₂ traps outperform light traps and sticky traps for host-seeking mosquitoes, but are slower than CDC-style landing-net sampling for catching individual specimens. They provide objective, passive surveillance without operator bias and can run continuously for weeks, making them ideal for monitoring temporal trends and outbreak detection.

Maintenance and field operation

The CO2 Cartridge or chemical CO₂ pack is replaced every 24 hours to one week depending on the design and desired sampling duration. The Collection Net is removed weekly or monthly (depending on catch volume), sealed with the desiccant-preserved sample, labeled with a Sample Label, and sent to the laboratory. The battery is recharged monthly if solar charging is unavailable.

Regular field maintenance includes cleaning Intake Vents to prevent blockage, checking Weather Gaskets for water ingress, and verifying Power Status LED status to confirm the timer is functioning.