Management Plan for Aedes albopictus in Greece and Italy
In the framework of LIFE CONOPS project a detailed design of management plan to control the Invasive Mosquito Species (IMS) Aedes albopictus which is already established in Greece and Italy. The document has been structured as a comprehensive practical technical guideline to assist local authorities in organizing the field activities in the best possible way. Others IMS not present yet in the two countries or present in a limited areas may deserve specific and different approaches.
Aedes(Stegomyia) albopictus (Skuse 1894) (Diptera: Culicidae), also known as “Asian Tiger Mosquito) is an IMS already well established both in Greece and in Italy, causing high concern in public health for its vectorial capacity of pathogens causing human diseases such as Dengue, Chikungunya and Zika viruses. It is therefore necessary that the responsible authorities implement specific vector control plan aimed at the reduction of the mosquito population density, possibly below the epidemiological and the noxious thresholds. This objective results difficult to achieve because of the capacity of the species to develop in urban areas exploiting a number of artificial breeding sites especially present in private properties.
Therefore this document has been structured as a comprehensive practical technical guideline to assist local authorities in organizing the vector control activities in the best possible way.
The management plan to control Aedes albopictus is a complex system that includes coordinated actions to adequately face the most important aspects involved into the problem such as:
- standardized quantitative monitoring by specific ovitraps
- the mosquito population density data
- the local community should be involved in the control campaign in private areas
- standard control measures in public areas should be organized regularly using larvicides in the road drains to cover the whole breeding season
- an emergence vector control plan should be prepared and responsibilities clearly assigned to the stakeholders to face the epidemic risk in case of importation of infected persons
- attention is also devoted in a pilot doo-to-door control strategy to be adopted locally in case the regular control campaign does not achieve sufficient results
Aedes albopictus (Skuse) is an invasive mosquito species originating from the East Asian regions, which due to its ecological plasticity and because of the human-mediated transport, it has spread in the last few decades across the world. This is a species of public health concern because vector of arboviruses such as chikungunya (CHIKV) dengue (DENV) and Zika. In Europe Ae. albopictus has been responsible in the outbreak of CHIKV which took place in Northern Italy in 2007 and in local transmissions of DENV which were detected in Southern France and Croatia in 2010 and in Southern France in 2014. In 2015-2016, there was an outbreak of Zika virus in many regions of South America which is spread to people primarily through the bite of an infected Aedes species mosquito. In the framework of LIFE CONOPS project, Benaki Phytopathological Institute (BPI) in collaboration with the Istituto Zooprofilattico Sperimentale Della Lombardia Edell’ Emilia Romagna (IZSLER-Reggio Emilia Romagna), the Centro di Riferimento Regionale per le Emergenze Microbiologiche – CRREM (Bologna) and the Medical & Veterinary Entomology Departement of Centro Agricoltura Ambiente “G. Nicoli” conducted a laboratory study on the vector competence of a Greek strain Aedes albopictus or the mutated chikungunya virus (CHIKV E1A226V) and for the dengue 2 virus (DENV 2).The presence of Aedes albopictus in Greece was confirmed for the first time in the northwestern Greece in 2003-2004. Since then the Asian tiger mosquito has been also found in other parts of the country, such as Central Macedonia, the Peloponnese and Attica. In the section “Distribution map of Aedes albopictus (Asian tiger mosquito) in Greece “ the presence of Aedes albopictus in Greece is presented via thematic map.
The management plan to control Ae. albopictus is a complex system of components that includes:
▶Please see the Distribution of Aedes albopictus in Greece
Please see the Distribution of Aedes albopictus in Europe (ECDC)
Surveillance of Aedes invasive species can be conducted with the use of ovitraps that attract females which lay their eggs on the provided oviposition supports.
Ovitraps consisted of:
1) a black plastic container with a total volume of 1 liter with an overflow hole, filled with water to two thirds. The trap-checking frequency is every 7 days but can be adjusted in order to prevent the trap from drying out during the summer months.
2) an oviposition support, usually a wooden stick such as a strip of masonite, 15 × 2.5 cm or a tongue depressor (needs to be marked) fixed to the platic container.
For the ovitraps management the following materials are needed:
1) Sharp object for the mark of the wooden stick (e.g. fish exfoliating body, such as those sold in supermarkets)
2) Indelible color (permanent marker) for writing the ovitraps code behind the oviposition support (on the smooth side)
3) White labels to record the code on the ovitrap
4) Screwdriver to create the overflow hole on the ovitrap (diameter about 1/100)
5) Thin wire or a big paperclip in order to adjust the masonite strip in the inner wall of the ovitrap.
6) A warning waterproof label which will also have the necessary information about the project "LIFE CONOPS" as well as contact information (e.g. phone number). Suggested dimensions of the label are as follows: a length of 15.5 cm and a width of 7 cm.
7) Optionally, the operator may also place near the trap an information-warning label with the information of the company.
8) Container (e.g. tank) with water tap which will be used in the filling of the ovitraps or plastic bins with dechlorinated water and Bacillus thuringiensis var. israelensis solution* (see below depending on the method of monitoring).
9) Disposable plastic gloves for the operator
10) Plastic bags in which to put the masonite strips collected. Particularly suitable are the cartridge bags
11) Wrappers for the oviposition supports (e.g. pharmaceutical gauze)
12) Handheld GPS receiver for the record of the geographical coordinates in decimal format
13) Paper delivery form (provided database sheet in each sampling) .
14) Sponges soap (e.g. dishwashing liquid) and paper towels for the cleaning of the ovitraps after their use.
The solution in the bins must be prepared on the day of collection and can be prepared in bins that are used for the transport of water, with a concentration of 1 ml Bti per liter.
Two methods can be followed during the sampling with the use of ovitraps:
a) If the collected eggs need to be hatched the ovitraps should be filled with tap water and remain in the field for only 7 days.
b) If there is no necessity for egg hatching, the operators may fill the ovitrap with the solution of Bacillus thuringiensis var. israelensis and remain in the field for 14 days (for more details see Carrieri et al. 2009).
The plastic containers are usually small black pots (without holes in the bottom) with approximately 1lt capacity. In the internal cavity of containers, the operator will adjust the wooden and non-sterile stick (usually tongue depressor or masonite strip) with the marked side on the outside using small piece of wire or a paperclip. These wooden sticks are marked in order to facilitate the adhesion of the eggs on its surface. The last step is the filling of the ovitrap with tap water or Bacillus thuringiensis var. israelensis solution (depending on the method) until the overflow hole (approximately 2/3).
Placement in the field
Ovitraps should be placed by skilled technicians in shady and safe position (protected from easy access to humans and animals); on the ground or at a height of no more than 50 cm from the ground (it is always better to place them on the ground). The first ovitrap positioning must be performed by highly skilled technicians and the stations must be kept fixed during the season and possibly over the years. The precise description of each station must be given in a specific database. In the selected area each ovitrap should be placed at least 100m from the each other in order to cover in a greater extend the area. Furthermore, each ovitrap has a unique code which is marked on the top of the wooden stick and on the outside of the container with a permanent marker. This code (the combination of letters and numbers) indicates the selected site where this ovitrap will be placed. For example, if it is selected to place three ovitraps in the area of a hospital, the possible codes used are H1, H2 and H3 (where “H” the first letter of the word hospital). In addition, it is important to fill a small description of the site and the exact geographical coordinates of each ovitrap in the database sheet. Once selected, the final positions, the ovitraps must be placed each time exactly in the same places and not move throughout the sampling period. If ovitraps are lost systematically at the selected sites, new sites should be chosen in order to continue monitoring. Ovitraps should be placed once per month and operate for seven days or 14 days (depending on the method) but it has to be noted that this timetable should be followed every month with scheduled dates, for example every first week of the month. Small variations of 1 or 2 days are accepted. It is advisable to use disposable plastic gloves when installing and removing the ovitraps from sampling points for hygiene reasons.
At the end of the sampling (7 or 14 days after the placement depends on the method), the wooden sticks should be collected with the use of disposable plastic gloves, wrapped with a slightly wet gauze (to avoid dehydration of the eggs) and stored in a plastic sampling bags. It is advisable to mark also on these sampling bags, the sample code and the site and date of sampling. These samples should be kept at room conditions and shipped as soon as possible (1-2 days after collection) at the competent laboratory. The inner walls of the ovitraps must be cleaned thoroughly with soap and water using a sponge, rinsed with clean water and allowed to dry until the next sampling. This step is also essential because there is a high risk to have remaining eggs in the ovitrap which in the next sampling will hatch (with the addition of water) and create a new breeding site.
IMPORTANT: Do not forget to fill the provided database sheet in each sampling
Quantitative standardized monitoring system for Aedes albopictus based on mean egg density provides detailed and reliable information on the biting females population, and can be used to develop prevention models in the view of Aedes albopictus transmitted disease epidemics.
To inform the local community on how to prevent and control Ae. albopictus in private areas and communicate what the Public stakeholders have put in place to contain the problem is necessary to conduct information campaigns using the most appropriate channels and methods.
These regulations should include the following points:
- remediation of micro dumps in suburban and peripheral areas
- the deletion, emptying water and indoor storage of containers and handworks of potential risk
- Indoor storage of unused tires (alternatively the cover with sheets without creating depressions that can maintain rainy water)
- the treatment of cavities in the trunks
- avoid where possible the use of saucers
- hermetic coverage (with mosquito netting, with caps or lids) of drums, bins, tanks used in orchards and gardens
- the weekly emptying and cleaning the bottom of the troughs for birds and pets
- larval treatment of the catch basins of the courtyard areas
Tools of disclosure:
- brochure on the biology of mosquitoes and methods of their control
- posters and flyers to be posted in the public health units, pharmacies, garden shops, in the waiting rooms of public places, bus stops, etc.
- specific web page within the websites of public administrations involved
- TV spots to be transmitted on local stations themed public meetings held by experts
Common mosquitoes breeding sites in private areas
Larval control is the main activity to be organized accurately by targeting as much as possible all the breeding sites. To achieve this aim it is fundamental to develop and continuously update the breeding sites mapping. Breeding sites in public areas must be censed and reported in a database, preferably in digital form with a GIS software (es. QGIS 2.x). Another data base including the "most sensible sites" must also be organized and updated continuously. "Most sensible sites" are locations where the presence of high vector densities can create particular impact: examples are nurseries, kindergartens, nursing homes for the elderly and hospitals. Most larval breeding sites of Aedes albopictus in the urban environment are concentrated in the private properties. These larval breeding sites should be considered under the responsibility of the owners (see community participation). Larvicide treatments are necessary in breeding sites that can’t be removed, as typically is the case of catch basins.
Determination of treated area
- For single case detection the area to be disinfested correspond to a buffer with a radius of 100 meters from the residence of the suspected subject.
- In case of cluster cases (two or more cases) identified and defined by the DPH, the area to be submitted to mosquito control will be extended up to 300 meters buffer from the more peripheral cases of the outbreak itself, as well as of interest to the entire outbreak area.
Mosquito control activities
Αn entomological investigation in the treated area should should be performed in order to confirm the presence of Aedes albopictus and decide for the necessity of applying control activities. Mosquito control activities are divided into three stages that must be conducted in a synergistic way: adulticide treatments, larvicide treatments and larval breeding sites removal. The optimal sequence in which these processes should be conducted is:
- adults treatments in public areas during the night
- adults and larval treatments and source removal in private areas (door-to-door)
- contextual larval treatment in public catch basins
It is important to use only biocides with marketing authorization in your country and in accordance with the instructions of use.
The treatments in public and private areas should be applied in the foliage (bushes, fences) up to a certain high, approximately 3-4 meters. In addition, the treatments which are applied on the roads should be ensured that the application is spread consistently on both sides of the road.
- five door-to-door larval treatments during the season in all private properties with treatment of permanent and occasional breeding sites and direct information of the citizen (minimum access threshold: ≥95% of premises)
- reporting to the authority of any citizens who refuse the treatment and management of critical cases
- quality controls on the efficacy of interventions in the public and private areas
- monitoring with ovitraps for measuring the lowering of population density in the treated areas
- adulticide treatments targeted at specific sites and only in case of real necessity
- introduction of copepods, predators of mosquito larvae, collected in permanent water (eg. cans of vegetable gardens); monitoring with ovitraps for measuring the lowering of population density in the treated areas
- release of sterile males of Ae. albopictus in inaccessible areas
- management of an information channel open to the public via Internet and local press
- direct telephone number for to citizens who request assistance