Christian Engelbrecht

Continuous trapping of adult Asian tiger mosquitoes (Aedes albopictus) with BGSentinel traps reduced the human landing rate and density indices in an urban environment in Cesena, Italy.

Ch. Engelbrecht1, C. Venturelli2, A. Rose3,1, M.Geier3,1
1 University of Regensburg, Regensburg, Germany
2 Dipartimento di Sanità Pubblica, Cesena, Italy
3 Biogents AG, Regensburg, Germany

Background and Objectives:
Mosquito density, longevity and the daily survival probability of mosquitoes are important factors for diseas transmission in vector-borne diseases such as Chikungunya or Dengue fever.
Conventional strategies to control the main vectors of these diseases (Aedes aegypti, syn. Stegomyia aegypti and Ae. albopictus, syn. St. albopicta) and thus to reduce the risk of disease transmission are the reduction of breeding sites and the application of insecticides.
Additional methods that are currently being tested include the release of sterile males and the continuous application of highly efficient mosquito traps. This strategy seems to be especially promising for Aedes aegypti and Ae. albopicus because of their strong adaptation to the urban environment and their limited flight
The objectives of the study presented here was (1) to measure the impact of BG-Sentinel mosquito traps on local Ae. albopictus populations in an urban environment and (2) to compare the standard surveillance method using ovitraps to an adult mosquito monitoring using the BG-Sentinel mosquito traps.
Material and Methods:
The study was conducted during the summer of 2008 in Cesena, Province Forli-Cesena, Emilia Romagna,
Italy. Six clusters with similar urban, geographic and climatic conditions, and population densities for Ae.
albopictus were selected.
Three clusters received treatment with eight BG-Sentinel traps each (intervention), three clusters served as acontrol without adult mosquito traps.
Monitoring was conducted in each cluster by (1) using two ovitraps per cluster, (2) placing one (additional) BG-Sentinel as an adult monitoring trap in intervals of two to five days in every cluster, and (3) by the determination of the human landing rates once per week at the beginning of the study and twice per week later, when mosquito density increased. Captured mosquitoes were collected for later examination.
Eggs in ovitraps were counted in weekly intervals. Mosquitoes collected in the BG-Sentinel traps and in the human bait collections were all determined to species, sexed and counted. Females were dissected to determine their parity by the Detinovas tracheolation method.
In all parameters measured (human landing rate, parous rate, eggs per week), a clear difference between treatment and control areas was observed. In the clusters with the BG-Sentinel traps, the biting rate of Aedes albopictus was reduced by up to 80%, the density of adult Asian tiger mosquitoes was reduced up to 70%.
The daily survival probability, indirectly measured by the parous rate, was reduced in the treatment areas and the amount of eggs per ovitrap and week was lower in the treatment areas, compared to the control areas (reduction by up to 60%).

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