RESUMO
In the last decades, the colonization of Mediterranean Europe and of other temperate regions by Aedes albopictus created an unprecedented nuisance problem in highly infested areas and new public health threats due to the vector competence of the species. The Sterile Insect Technique (SIT) and the Incompatible Insect Technique (IIT) are insecticide-free mosquito-control methods, relying on mass release of irradiated/manipulated males, able to complement existing and only partially effective control tools. The validation of these approaches in the field requires appropriate experimental settings, possibly isolated to avoid mosquito immigration from other infested areas, and preliminary ecological and entomological data. We carried out a 4-year study in the island of Procida (Gulf of Naples, Italy) in strict collaboration with local administrators and citizens to estimate the temporal dynamics, spatial distribution, and population size of Ae. albopictus and the dispersal and survival of irradiated males. We applied ovitrap monitoring, geo-spatial analyses, mark-release-recapture technique, and a citizen-science approach. Results allow to predict the seasonal (from April to October, with peaks of 928-9,757 males/ha) and spatial distribution of the species, highlighting the capacity of Ae. albopictus population of Procida to colonize and maintain high frequencies in urban as well as in sylvatic inhabited environments. Irradiated males shown limited ability to disperse (mean daily distance travelled <60m) and daily survival estimates ranging between 0.80 and 0.95. Overall, the ecological characteristics of the island, the acquired knowledge on Ae. albopictus spatial and temporal distribution, the high human and Ae. albopictus densities and the positive attitude of the resident population in being active parts in innovative mosquito control projects provide the ground for evidence-based planning of the interventions and for the assessment of their effectiveness. In addition, the results highlight the value of creating synergies between research groups, local administrators, and citizens for affordable monitoring (and, in the future, control) of mosquito populations.
Assuntos
Aedes/fisiologia , Controle de Mosquitos/métodos , Aedes/crescimento & desenvolvimento , Distribuição Animal , Animais , Ecologia , Meio Ambiente , Feminino , Humanos , Ilhas , Itália , Masculino , Densidade Demográfica , Características de Residência , Estações do AnoRESUMO
KEY RESULTS: Both outbreaks started in small towns, but cases were also detected in nearby larger cities where transmission was limited to small clusters. The time spans between the first and the last symptom onsets were similar between the 2 outbreaks, and the delay from the symptom onset of the index case and the first case notified was considerable. Comparable infection and transmission rates were observed in laboratory. The basic reproductive number (R0) was estimated in the range of 1.8-6 (2007) and 1.5-2.6 (2017). Clinical characteristics were similar between outbreaks, and no acute complications were reported, though a higher frequency of ocular symptoms, myalgia, and rash was observed in 2017. Very little is known about the immune mediator profile of CHIKV-infected patients during the 2 outbreaks. Regarding public health responses, after the 2007 outbreak, the Italian Ministry of Health developed national guidelines to implement surveillance and good practices to prevent and control autochthonous transmission. However, only a few regional authorities implemented it, and the perception of outbreak risk and knowledge of clinical symptoms and transmission dynamics by general practitioners remained low. MAJOR CONCLUSIONS: Efforts should be devoted to developing suitable procedures for early detection of virus circulation in the population, possibly through the analysis of medical records in near real time. Increasing the awareness of CHIKV of general practitioners and public health officials through tailored education may be effective, especially in small coastal towns where the outbreak risk may be higher. A key element is also the shift of citizen awareness from considering Aedes mosquitoes not only as a nuisance problem but also as a public health one. We advocate the need of strengthening the surveillance and of promoting the active participation of the communities to prevent and contain future outbreaks.
Assuntos
Febre de Chikungunya/epidemiologia , Febre de Chikungunya/transmissão , Surtos de Doenças , Transmissão de Doença Infecciosa/prevenção & controle , Doenças Transmitidas por Vetores/epidemiologia , Doenças Transmitidas por Vetores/transmissão , Animais , Número Básico de Reprodução , Febre de Chikungunya/patologia , Febre de Chikungunya/virologia , Controle de Doenças Transmissíveis/organização & administração , Monitoramento Epidemiológico , Educação em Saúde/organização & administração , Política de Saúde , Humanos , Itália/epidemiologia , Resultado do Tratamento , Doenças Transmitidas por Vetores/patologia , Doenças Transmitidas por Vetores/virologiaRESUMO
Seasonal-long larvicide treatments and/or outdoor space-spray applications of insecticides are frequently applied to reduce Aedes albopictus nuisance in urban areas of temperate regions, where the species has become a permanent pest affecting people's quality of life and health. However, assessments of the effectiveness of sequential interventions is a difficult task, as it requires to take into account the cumulative and combined effect of multiple treatments, as well as the mosquito seasonal dynamics (rather than mosquito abundance before and after single treatments). We here present the results of the effectiveness assessment of a seasonal-long calendar-based control intervention integrating larvicide treatments of street catch basins and night-time adulticide ground spraying in the main University hospital in Rome (Italy). Cage-experiments and an intensive monitoring of wild mosquito abundance in treated and untreated sites were carried out along an entire season. Sticky traps were used to monitor adult abundance and site-specific eco-climatic variations (by recording water left over in each trap), in order to disentangle the effect of insecticide treatments from eco-climatic drivers on mosquito seasonal dynamics. Despite the apparent limited impact of single adulticide sprayings assessed based on mortality in caged and wild mosquitoes, the results of the temporal analysis showed that mosquito seasonal patterns were initially comparable in the two sites, diverged in the absence of diverging eco-climatic conditions and remained stable afterwards. This allowed to attribute the lack of the expected Ae. albopictus population expansion in the treated site to the combined effect of multiple adulticide sprayings and larvicide treatments carried out during the whole season. The approach proposed was proved to be successful to assess effects of seasonal-long control treatments on adult mosquito population dynamics and could represent a valuable instrument to assess the effectiveness of other control interventions, to evaluate their actual cost-benefits and to possibly minimize space-spraying applications to reduce mosquito nuisance.
Assuntos
Aedes/efeitos dos fármacos , Aedes/crescimento & desenvolvimento , Pesquisa sobre Serviços de Saúde , Inseticidas/administração & dosagem , Controle de Mosquitos/métodos , Animais , Análise Custo-Benefício , Feminino , Inseticidas/economia , Masculino , Controle de Mosquitos/economia , Cidade de Roma , Estações do AnoRESUMO
Several kinds of traps are available for the collection of Culicidae species creating nuisance problems and/or a potential risk of pathogen transmission. The choice of the most appropriate sampling device should take into consideration the objective of the monitoring activity (e.g., faunistic research, vector control evaluation, arbovirus surveillance, etc.), the ecological and behavioral characteristics of the target mosquito species, and the ecology of the sampling areas. However, there are few factual criteria technical personnel can rely on to choose the most suitable sampling method, particularly when the targets are represented by mosquito species in temperate areas. We carried out a Latin square experiment in three ecologically different settings in Mantua municipality (northern Italy) to compare the performance of four different traps targeting host-seeking mosquitoes: two traps specifically designed for mosquito monitoring purposes (Centers for Disease Control and Prevention CO(2) trap and Biogents BG Eisenhans de Luxe trap) and two designed to reduce mosquito densities in outdoor domestic settings (Activa Acti Power Trap PV 440 and Activa Acti Power Trap MT 250 Plus). Overall, 1,930 specimens belonging to nine species were collected and differences in the performance of the four traps with reference to their ability to detect overall species diversity, as well as to collect single species, were highlighted. These observations, coupled with an analysis of the costs associated with the trap's purchase, operation, and servicing, provide useful indications for the implementation of mosquito monitoring in temperate areas.