Mosquito Surveillance Overview
NOMTRCB conducts year-round adult mosquito surveillance to monitor species distribution, population trends, and potential disease risks across the parish. Our surveillance program utilizes three different adult trap types. Each trap type varies in targeted mosquito species and adult life stage, fitting specific surveillance goals for our program. Our adult trapping program comprises of Gravid traps, BG-Sentinel II traps, and CDC Miniature Light traps, deployed on a seasonal schedule that reflects mosquito activity patterns. Trapping sites remain consistent over many years, allowing NOMTRCB to monitor population abundances and compare them to historical trends. NOMTRCB uses results from our surveillance traps to make targeted abatement decisions.
Mosquito traps are set at the beginning of the week and are picked up 24 hours after deployment. All mosquitoes captured in these traps are brought back to our laboratory and identified by NOMTRCB staff to the species level, when possible. There are around 45 different species of mosquitoes that can be found in Orleans Parish. Some play a major role as vectors of diseases like West Nile virus, while others are nuisance biters. Mosquitoes that are known vectors of diseases in our region are tested in our laboratory for the presence of pathogens which include West Nile virus, Eastern Equine encephalitis, and St. Louis encephalitis. Our lab has the ability to test for additional pathogens of importance when the need arises.
Gravid Traps
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The gravid trap (John Hock, Gainesville, FL) is a specialized mosquito surveillance tool designed to attract female mosquitoes that are ready to lay eggs. The lure used by NOMTRCB in these traps is particularly effective for collecting Culex mosquitoes, specially Culex quinquefasciatus, which is the primary vector of several mosquito-borne diseases that are present in our region. NOMTRCB utilizes a hay and fish emulsion infusion to bait this trap.
Most female mosquitoes take a blood meal to get the proteins, iron, and amino acids they need to produce eggs. They must take a new blood meal each time they lay a new batch of eggs. Since Gravid traps target mosquitoes that are ready to lay their eggs, mosquitoes captured in these traps have a higher likelyhood to have taken a bloodmeal, and thus may have picked up a mosquito-borne disease like West Nile virus (WNV), Eastern Equine encephalitis (EEE), and St. Louis encephalitis (SLE). This is why our Gravid traps are our primary tool for our arbovirus surviellance program. NOMTRCB conducts year-round weekly trapping at 55 consistant sites throughout the parish. Our trapping locations are strategically placed throughout the parish to give us an accurate picture of vector populations and arbovirus risk across the different neighborhoods. This representation helps us make targeted and effective mosquito‑control decisions.
BG-Sentinel II Traps
The BG Sentinel II (BioGents, Regensburg, Germany) traps attract mosquitoes that are actively seeking a host to take a bloodmeal, and are the ”gold-standard” for monitoring container species like Aedes aegypti and Aedes albopictus. This trap uses visual cues and scent attractants that mimic humans and other preferred hosts, making it highly effective at capturing mosquito species that matter most for public health.
These species are of particular concern because they are capable of transmitting diseases such as dengue, Zika, and chikungunya. BG Sentinel II traps play an essential role in our surveillance program by helping us monitor the distribution of these important mosquito species. The information collected supports our ability to assess disease risk and guide targeted mosquito control efforts.
To improve trap performance, NOMTRCB uses both the BG‑Lure (BioGents, Regensburg, Germany), which mimics human skin odors, and carbon dioxide (CO₂), a key signal mosquitoes use to locate host. At NOMTRCB, CO₂ is delivered using dry ice placed in specially designed one‑gallon canisters that release a steady plume of CO₂ as the dry ice sublimates. This combination of attractants reliably in these trageted mosquitoes. NOMTRCB deploys these traps on a seasonal schedule—monthly during the colder months and weekly during the warmer months.
CDC Miniature Light Traps
The CDC Miniature Light Trap (John Hock, Gainesville, FL) is a versatile surveillance tool used to monitor a wide range of mosquito species. These traps are hung from trees throughout the city, allowing them to operate in shaded, natural areas where many mosquito species are most active.
The trap uses a small incandescent light source and a steady airflow to draw mosquitoes into a collection chamber. To increase its effectiveness, it is also baited with carbon dioxide (CO₂) generated from dry ice placed in one-gallon canisters, which releases a steady stream of CO₂ as the dry ice sublimates. This combination of light and CO₂ attracts many different mosquito species, and it helps us monitor population densities of many permanent water and floodwater species. These traps also assist in monitoring new species that establish themselves in our parish. These traps follow the same seasonal deployment as the BG Sentinel II traps.