Category Archives: 11 th March

Enrih Merdic

Spreading of Aedes albopictus on Croatian islands by boats and yachts

Enrih Merdi─ç1, Toni ┼Żitko2, ┼Żeljka Jeli─Źi─ç1, Ana Klobu─Źar3
1University of Osijek, Department of biology, Osijek, Croatia
2Institute of public Health of Split-dalmatia County, Split
3Institute of public Health dr Andrija Štampar, Zagreb

The vector Aedes albopictus has been introduced in several European countries since 1975. The vector was introduced in Europe through different ways. Unlike other mosquitoes their eggs can withstand desiccation, which allows them to travel around the world in a variety of containers. The international trade in used tyres has played a major role in such spread because tires make good
breeding sites likewise the importation of Dracanea plants, known as ÔÇśLucky BambooÔÇÖ.
Furthermore, public or private transport from infested areas-whether by highway, ferry or air- can contribute to the passive dispersion of Aedes albopictus. Spreading of Ae. albopictus on Croatian islands in last 3 years shows that antropochorne spreading of this species is very fast. Since 2006 the following islands were inhabit with Ae. albopictus: Vis, Hvar, Bra─Ź, Kor─Źula, Mljet, Cres,
Lošinj, Krk. All findings on islands were close to marinas or area around them. Approximately 80.000 of yachts have been in Croatian part of Adriatic sea. In this paper reasons and models of such fast spreading were presented. Special attention was given on yachts and their value in Ae. albopictus spreading from Italy.

Davorka Jaric

Comparison of insecticide toxicity research results performed using induct-test and microcosm

1Josip Milas, 2Branimir K- Hackenberger, 2Davorka Jari─ç, 2Enrih Merdi─ç
1Public Health Institute of the Osijek-Baranja County, Osijek, Croatia
2Josip Juraj Strossmayer University, Department of Biology, Osijek, Croatia

Abstract:
Induct-test is a standard procedure for testing toxicity of various chemicals for experimental organisms after intraperitoneal (i.p.) administration of tested compound and ÔÇťincubationÔÇŁ period of 4-12 days, while a microcosm as a procedure for toxicity testing
relies on imitating natural conditions and routes of exposure. Tested insecticides were malathion, temephos and carbofuran. Experimental organisms used were common carp (Cyprinus carpio) in both experiments and, additionally, prussian carp (Carrasius
auratus gibelio) in the induct-test.
Measured enzyme biomarkers in both experiments were: Ethoxyresorufin-O-deethylase (EROD), Total Glutathione (GT), Glutathione-S-transferase (GST), Thiobarbituric Acid
Reactive Substances (TBARS), Acetylcholinesterase activity (AChE) and Catalase activity (CAT). The microcosms contained 150 L of water, 35 specimens of common carp, artificial soil as sediment and 10 specimens of swan mussel (Anodonta cygnea) as a
filter-feeding organism. The pollutants were administered in realistically expected concentrations and 7 fish were sampled every 5 days, with a total of 5 samplings.
The results showed expected differences in biomarker change between induct-test and microcosm experiment (40- to 100-fold). The concentrations used in the induct-test are hardly expected in the environment even if species bioaccumulation potential is taken
into account. On the other hand, the microcosm experiment showed that all biomarkers used in the experiment can detect changes obtained by environmentally realistic concentrations and, therefore, microcosm test has a far more realistic and significant role
in ecological risk assessment of insecticides.

Luigi Avella

F─▒eld evaluation of the IGRs, Diflubenzuron, s-methprene, and bactierally-deprived insecticide, spinosad, against Culex pipiens molestus and Aedes albopictus mosquitoes in North-eastern Italy

Dalla Pozza G.1, Avella L. 2,Ceretti G.1 , Baldazzi L.3, Tagliapietra P.1, Ali A.4.

1 Department of Public Health, Azienda ULSS 12 Veneziana, P.le S.L. Giustiniani, 11/D. 30174 Venice, Italy.
2 R&D Department Chemtura Italy Srl, Latina, Italy
3 Via De Carolis, 27. 47900 Rimini, Italy.
4 Mid-Florida Research and Education Center and Department of Entomology and Nematology, University of Florida, 2725
Binion Road, Apopka, Florida 32703, USA

Initially effectiveness and residual activity of three insect growth regulator (IGR) commercial products, Device® SC 15 (15% AI diflubenzuron, flowable), Altosid® SR-10 (5% AI s-methoprene,
microencapsulated), and Proxilar® (4% AI pyriproxyfen, emulsifiable concentrate), and a bacterially-derived insecticide, Laser® (48% AI spinosad, emulsifiable concentrate), were evaluated
against mixed populations of Culex pipiens molestus and Aedes albopictus inhabiting manholes in north-eastern Italy. The test products were applied at recommended field-use rates (label) to the
manholes in Venice-Mestre (Venezia Province) and Riccione (Rimini Province). The post-treatment efficacy of the IGRs and spinosad was judged by monitoring inhibition of adult mosquito emergence (IE) weekly up to 11 weeks post-treatment, compared to the corresponding untreated manholes serving as controls in each study area. Device® SC 15 at 0.75 ppm AI, induced >90% IE of Cx. p. molestus for 8 and 7 weeks post-treatment at Venice-Mestre and Riccione, respectively, while simultaneously yielding similar (>90% IE) control of Ae. albopictus for 9 weeks (Venice-Mestre) and 7 weeks (Riccione) post-treatment. Altosid® SR-10 at 0.75 ppm AI resulted in good control (>90% IE) of both mosquito species for 4-5 weeks post-treatment in the two study areas.
Proxilar® applied at 0.2 ppm caused >90% IE of Cx. p. molestus for 5 weeks (Venice-Mestre) and 4 weeks (Riccione) post-treatment; this IGR gave >90% IE control of Ae. albopictus for 3 and 4 weeks post-treatment at Venice-Mestre and Riccione, respectively. Laser® at 1 ppm AI induced >90% IE of Cx. p. molestus for 8 weeks post-treatment at Venice-Mestre, and for 7 weeks at Riccione,
whereas Ae. albopictus emergence was reduced >90% IE for 6 weeks and 7 weeks posttreatment at the former and latter study area, respectively. Two-way ANOVA and Tuckey test revealed
significantly (P < 0.001) longer post-treatment persistence of Device® SC 15 and Laser® over Altosid® SR-10 and Proxilar® at the treatment rates employed in this study, providing superior
control of the two mosquito species in terms of magnitude and post-treatment time duration.

Roger Eritja

Assessing larvicidal ground-based applications on Aedes albopictus by misting BTI

Roger Eritja
Servei de Control de Mosquits,Consell Comarcal del Baix Llobregat, Parc Torreblanca s/n, 08980Sant Feliu de Llobregat, Spain

Mosquito control in urban environment is a complex topic. Adulticiding applications are restricted by legal issues and larviciding applications using Bacillus thuringiensis israelensis are not cost effective for container-breeding species, because larvae are scattered in many small breeding places in private ground that
cannot be individually sprayed.
The presence of Aedes albopictus in Spain since 2004 has challenged the urban mosquito control in the Baix Llobregat region, performed since 1983 by the Mosquito Control Service of the Baix Llobregat Regional Council in 19 municipalities totalling a population of 879,000 over a surface of 250 sq km. Operations
include larviciding and adulticiding in public areas, education at primary schools, raising concern by spreading information, and promoting suppression of breeding places.
There are strong evidences that the majority of the breeding sites are found in private areas. However, larviciding operators either cannot legally enter the area where the breeding containers are found, or there are too many containers to individually apply Bti by hand. Though such situations can only be managed by
chemical adulticiding, they would be obvious candidates for distance larviciding by misting or cold fogging, provided the availability of suitable Bti formulations.
In cooperation with the manufacturer Valent Biosciences Inc. it was decided to set a test on the performance of misting their Vectobac WDG formulation via a low-volume misting Martignani 748 machine, at a dose of 1 kg of powder per hectare, using adequate dilution rates to accommodate outputs of 200 to 500 liter per
hour.
An array of five single-floor holiday cabins were used to simulate urban conditions in an abandoned camping ground. Small plastic containers ca. 250 ml each were placed in several locations of the housings up to 31 meter from the application path. All tests were duplicated and controls were used. After spraying, they were
brought to the laboratory and populated with Aedes albopictus larvae to assess the mortality rates at 24 and 48 h.
The tested output rates behave slightly differently but a mortality near to 100% could be obtained up to a distance of 20 meter. These promising results will be discussed along to the environmental factors to be considered, as well as further test planning.

Klaus Hoffmann

Using Internet GIS to support the management of helicopter applications in a decentralized organizational structure

Klaus Hoffmann (KABS), Thomas Schorr (Thomas Schorr IT consulting), Norbert Becker (KABS)

Fast flow of indisputable information is a crucial task for mosquito control organisations in executing helicopter application of larvicides with dense daily schedules.
In a decentral organization structure like the German Mosquito Control Association (KABS) a webbased GIS-application warrants optimal performance in an economical manner.
Principal aim of the application is to ensure clear information between all involved parties in a reliable workflow, furthermore documentation and transparency of all up to date and past helicopter treatments in a central database is guaranteed.
The user defined system is entirely based on open source software. Main components are the web application server Zope and the web mapping platform UMN Mapserver.
Key features are:

  • Unified, easy to use web interface for all involved actors
  • Editing, upload and download function for treatments orders (ESRI-shape file)
  • Obligatory workflow for all orders
  • Up- and download function for documentation files and tabular summaries
  • Download to Google-Earth KML-files of order and documentation files
  • Modular contract based development gives a clear overview on costs
  • It is open to future enhancements

The presentation will show how a distinct workflow with a huge number of involved parties (32 field officers spread over the upper Rhine valley in Germany and France (Alsace), flight operations
contractor (2 pilots), larvicide supply and workflow management) acting at different locations with different tasks is guaranteed by use of the system.

Panagiotis Pergantas

Mosquito surveillance in Rice fields and Wetlands of Greece – Focus on Evros River in Greek-Turkish Borders.

P. Pergantas, J. Moraitis, M. Botzaki
1: Bioapplications Ltd.

We performed a longitudinal survey of mosquitoes abundance in more than 40 sampling areas in 14 prefectures in Greece with ricefields (approximetly 24.000 ha) and wetlands. Analysis of selected samples showed great differences in abundance in Evros River compared to other areas in Greece with similar enviroments. The hypothesis was that differences were due to Turkish ricefields
(approximately 39.000 ha), situated across the river on the Turkish side, and not to the Evros delta (4.600 ha). We implemented different technologies(GIS, COÔéé traps ,Species Analysis) in order to
monitor the population abundance in three sampling areas consisting of eleven sampling stations.
Each sampling area was a vertical sections across the river with different geomorphological structure. Data analysis of over 135.000 trapped mosquitoes showed differences in species composition and relative decrease in abundance as we move away from the river. Those findings and seasonal distribution, support the hypothesis that mosquitoes nuisance in Evros area is due to Turkish ricefields.

Spiros Mourelatos

Integrated Mosquito Control in Comporta, Portugal

Mourelatos Spiros1, Sandra Gewehr2 and Antonio Moreira3
1Ecodevelopment (Greece)
2Herdade da Comporta (Portugal)

A three-year mosquito control project is carried out by Ecodevelopment at Portugal (a coastal zone, 100 Km south of Lisbon): 2007 (implementation study), 2008 (pilot project), 2009 (foreseen control project). The predominant mosquito species in the region are: Culex theileri (mainly coming from the 1.000 ha of rice fields), Aedes caspius (originating from the coastal wetlands and partially from the rice fields) and Anopheles spp. (exclusively from the rice fields).
A detailed mapping of the most significant reproduction sites of the control area was concluded in 2007: 180 ha of coastal wetlands (ecological mapping) yielded 46 sampling stations; 1076 ha of rice
fields were divided into 611 plots. A first estimation of the productivity of the rice system was made during 2007: samples were taken from the 40% of the total plots of the rice fields on 3 occasions (mid June, July, August).
In 2008, the rice fields, the wetlands and the peri-urban system were monitored exhaustively on a 5-day basis and were treated with Bti when needed. An evaluation of the larval productivity of the
wetlands and the rice fields between years 2007 (no treatment) and 2008 (treatments from mid May to mid September) and adult samplings were made as well. Substantial divergences were found
between the Mediterranean and Atlantic wetlands and rice agro systems in Greece and Portugal respectively and these differences lead to different control strategies.

Maurizio Calvitti

Preliminary characterization of a new Aedes albopictus strain obtained by horizontal transfer of Wolbachia from Culex pipiens

M. Calvitti1, R. Moretti1, R. Bellini2 & S.L. Dobson3
1BAS-Biotec_Agro, C.R. ENEA Casaccia (Roma), Italy;
2CAA ÔÇŁG.NicoliÔÇŁ Crevalcore (BO), Italy;
3Dept. Entomology, University of Kentucky (Lexington), KY, USA

Wolbachia (Rickettsiales) is a maternally inherited endosymbiont present in a wide range of insects. Depending on hosts and bacterium strains, the infection may induce Cytoplasmic Incompatibility (CI), a phenomenon of non-viability of embryos resulting from mating of males carrying a specific Wolbachia strain with females that are uninfected or are infected by a different
Wolbachia strain. The release of CI males has the potential for the genetic control of insects,
following the principles of the sterile insect technique. Aedes albopictus is reported to be uniformly superinfected with two Wolbachia strains (wAlbA and wAlbB) throughout its geographical
distribution. Infected males were proved to be fully incompatible with artificially obtained aposymbiotic females.
In this work, we report on the attempt to infect an aposymbiotic strain of Ae. albopictus (RT) with a Wolbachia strain drawn from Culex pipiens embryos (wPip strain). Further experiments were
designed to study the supportive host background and the adaptation of the wPip Wolbachia strain to the new recipient host and evaluate the infection dynamics key parameters like (i) CI level and (ii) maternal inheritance in the new host-Wolbachia association.
About 7.6% of the Ae. albopictus embryos survived the microinjection procedure. About 11% of the adults developed from microinjected embryos were infected with Wolbachia wPip strain. The progeny obtained from two females were found infected and used to establish the new transinfected Ae. albopicuts line (RTP) and then perform the subsequent tests.
CI was very high in all crosses between RTP males and females characterized by a different infection status. No viable eggs (i.e. high CI) were found in the reciprocal cross between normal superinfected males and RTP females as well. Maternal inheritance was found close to 100%.
Further studies are focusing on the analysis of the potential fitness costs associated with the new infection in terms of immature and adult survival, fecundity and egg hatching rate.
Results are discussed in relation to the possibility of using the new Ae. albopictusÔÇôWolbachia symbiosis as suitable system for the study and development of CI-based strategies for the suppression of the vector population.

Alessandro Albieri

Monitoring of Aedes albopictus (skuse) in emilia-romagna: cluster  investigation and geostatistical analysis

Albieri A.1, Carrieri M. 1, Angelini P.2., Baldacchini F.2, Venturelli C.3, Mascali Zeo S.3, Bellini R. 1
1Centro Agricoltura Ambiente “G.Nicoli”, Medical & Veterinary Entomology Dept., Italy
2Emilia Romagna Region Public Health Dept., Italy
3Emilia Romagna Region Public Health Dept., Urban and Health Entomology Dept., Italy

The Emilia-Romagna Regional Aedes albopictus (Skuse) control project use ovitraps as tools for mosquito population density estimation.
2,741 ovitraps have been positioned in urban areas using standard criteria and checked weekly during the favourable season 2008. Distance between ovitraps is fixed in the range 200-800 m.
The estimation of distribution and abundance based on ovitraps or on mean eggs density for municipalities provide only point data and not a continuous spatial distribution of the target species.
Kriging interpolation was used to estimate seasonal abundance of the species at unsampled locations throughout the study area, and cluster analysis was used to identify particular areas that had consistently high or low mosquito density statistically significant.
Definition of large geographic areas with consistently high or low abundance of Ae.albopictus may provide information on environmental variables that promote species diffusion and on disease risk surveillance programs (Chikungunya and Dengue surveillance in Emilia-Romagna).