ABSTRACT
Culicoides imicola is the main vector of viral diseases of livestock in Europe such as bluetongue (BT), African horse sickness and epizootic haemorrhagic disease. Climatic factors are the main drivers of C. imicola occurrence and its distribution might be subject to rapid shifts due to climate change. Entomological data, collected during BT surveillance, and climatic/environmental variables were used to analyse ecological niche and to model C. imicola distribution and possible future range shifts in Italy. An ensemble technique was used to weigh the performance of machine learning, linear and profile methods. Updated future climate projections from the latest phase of the Climate Model Intercomparison Project were used to generate future distributions for the next three 20-year periods, according to combinations of general circulation models and shared socioeconomic pathways and considering different climate change scenarios. Results indicated the minimum temperature of the coldest month (BIO 6) and precipitation of the driest-warmest months (BIO 14) as the main limiting climatic factors. Indeed, BIO 6 and BIO 14 reported the two highest values of variable importance, respectively, 9.16% (confidence interval [CI] = 7.99%-10.32%), and 2.01% (CI = 1.57%-2.44%). Under the worst-case scenario of climate change, C. imicola range is expected to expand northward and shift away from the coasts of central Italy, while in some areas of southern Italy, environmental suitability will decrease. Our results provide predictions of C. imicola distribution according to the most up-to-date future climate projections and should be of great use to surveillance management at regional and national scales.
ABSTRACT
The Asian tiger mosquito, Aedes albopictus, competent vector of several arboviruses, poses significant impact on human health worldwide. Although global warming is a driver of A . albopictus range expansion, few studies focused on its effects on homodynamicity (i.e. the ability to breed all-year-round), a key factor of vectorial capacity and a primary condition for an Aedes-borne disease to become endemic in temperate areas. Data from a 4-year monitoring network set in Central Italy and records from weather stations were used to assess winter adult activity and weekly minimum temperatures. Winter oviposition occurred in 38 localities with a seasonal mean photoperiod of 9.7 : 14.3 (L : D) h. Positive collections (87) occurred with an average minimum temperature of the two and three weeks before sampling of approximately 4°C. According to these evidences and considering the climate projections of three global climate models and three shared socio-economic pathways for the next three 20-year periods (from 2021 to 2080), the minimum temperature of January will increase enough to allow an all-year-round oviposition of A . albopictus in several areas of the Mediterranean Basin. Due to vector homodynamicity, Aedes-borne diseases could become endemic in Southern Europe by the end of the twenty-first century, worsening the burden on human health.
ABSTRACT
BACKGROUND: The Asian tiger mosquito Aedes albopictus (Skuse 1894), which is native to Southeast Asia, is among the top 100 invasive species worldwide and one of the most troubling vector species. It has become established in more than 20 European countries. Since its arrival in Italy in the 1990s, the species has colonized all the regions of the country, up to an altitude of 600 m. Nevertheless, no thorough investigation has ever been performed to confirm or extend its elevation limit (EL) in Italy. METHODS: To define the EL of Ae. albopictus and analyse its phenology along an altitudinal gradient, we carried out an investigation by means of ovitraps placed in Lazio region, central Italy. Sampling was performed on a weekly basis in 13 villages within five 200-m altitudinal ranges [0-1000 m above sea level (asl)], with the addition of higher localities to the species range whenever the species was recorded in the highest range. RESULTS: Aedes albopictus has colonized sites well beyond its known EL, with established populations at 900 m asl and positive ovitraps recorded at 1193 m asl. The relationship between egg abundance and elevation was described by an exponential decay regression, which predicted an EL for oviposition at 1015 m asl. In the active season, egg-laying started earlier at low altitude and ended earlier within the highest altitudinal range. Aedes albopictus abundance and activity period (number of days active) decreased, respectively, by 95% and 34% from the lowest to the highest altitudinal range. CONCLUSIONS: Using data from the present study, the altitudinal limit of Ae. albopictus in central Italy was updated from 600 to 900 m asl. In addition, established populations were predicted to exist up to 1015 m asl. Considering that up to 99.5% of Lazio region's inhabitants could potentially be affected by Aedes-borne virus outbreaks, the surveillance area for Ae. albopictus should be expanded accordingly. However, our results also indicate that Ae. albopictus surveillance programs need to be revised in order to harmonize the resources earmarked for these with the altitudinal changes in the phenology of this species.
Subject(s)
Aedes , Altitude , Animals , Female , Introduced Species , Mosquito Vectors , OvipositionABSTRACT
Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) play a paramount role in medical and veterinary entomology worldwide, particularly as vectors of pathogens which cause animal diseases. Biting midges are also infamous for the nuisance they provoke to people involved in outdoor activities. Nonetheless, attacks to man by midges from any Culicoides species have not been reported in Italy. An entomological investigation was performed following repeated attacks to man in a nature park near Rome (central Italy). The study area is a natural degassing zone, characterized by widespread hazardous gas emissions of CO2 and H2S, with several water bodies including permanent lakes, ponds, and pools. The biting midge C. riethi Kieffer, 1914 was very active during daytime in the period April-June. The species has been identified as responsible for attacks on people in the area. An in-depth analysis of the extreme environmental conditions revealed the ability of larvae to thrive in several water bodies, characterized by an extremely low pH and a high concentration of sulfates.
Subject(s)
Ceratopogonidae , Animals , Breeding , Humans , Insect Vectors , Italy , Larva , WaterABSTRACT
Avian malaria is a parasitic disease of birds caused by protozoa belonging to the genus Plasmodium, within the order Haemosporida. Penguins are considered particularly susceptible, and outbreaks in captive populations can lead to high mortality. We used a multidisciplinary approach to investigate the death due to avian malaria, occurred between 2015 and 2019, in eight African penguins (Spheniscus demersus) kept in two Italian zoos located in central Italy, and situated about 30 km apart. We also provided information about the presence and circulation of Plasmodium spp. in mosquitoes in central Italy by sampling mosquitoes in both zoos where penguin mortalities occurred. In the eight dead penguins, gross and histopathological lesions were consistent with those previously observed by other authors in avian malaria outbreaks. Organs from dead penguins and mosquitoes collected in both zoos were tested for avian malaria parasites by using a PCR assay targeting the partial mitochondrial conserved region of the cytochrome b gene. Identification at species level was performed by sequencing analysis. Plasmodium matutinum was detected in both dead penguins and in mosquitoes (Culex pipiens), while Plasmodium vaughani in Culex pipiens only. Parasites were not found in any of the PCR tested Aedes albopictus samples. Based on our phylogenetic analysis, we detected three previously characterized lineages: Plasmodium matutinum LINN1 and AFTRU5, P. vaughani SYAT05. In Culex pipiens we also identified two novel lineages, CXPIP32 (inferred morphospecies Plasmodium matutinum) and CXPIP33 (inferred morphospecies P. vaughani). Significantly, LINN1 and AFTRU5 were found to be associated to penguin deaths, although only LINN1 was detected both in penguins (along the years of the study) and in Culex pipiens, while AFTRU5 was detected in a single penguin dead in 2017. In conclusion, in our study Plasmodium matutinum was found to cause avian malaria in captive penguins kept in Europe, with Culex pipiens being its most probable vector. Our results are in agreement with previous studies suggesting that Culex pipiens is one of the main vectors of Plasmodium spp. in Europe and the Northern Hemisphere. Zoos maintaining captive penguins in temperate areas where Culex pipiens is abundant should be well aware of the risks of avian malaria, and should put every effort to prevent outbreaks, in particular during the periods when the number of vectors is higher.
ABSTRACT
Polymerase chain reaction (PCR)-based genotyping of mutations in the voltage-sensitive sodium channel (vssc) associated with resistance to pyrethroid insecticides is widely used and represents a potential early warning and monitoring system for insecticide resistance arising in mosquito populations, which are vectors of different human pathogens. In the secondary vector Aedes albopictus-an Asian species that has invaded and colonized the whole world, including temperate regions-sequencing of domain II of the vssc gene is still needed to detect the V1016G mutation associated with pyrethroid resistance. In this study we developed and tested a novel allele-specific PCR (AS-PCR) assay to genotype the V1016G mutation in this species and applied it to the analysis of wild populations from Italy. The results confirm the high accuracy of the novel AS-PCR and highlight frequencies of the V1016G allele as >5% in most sampling sites, with peaks of 20-45% in coastal touristic sites where pyrethroid treatments are extensively implemented, mostly for mosquito nuisance reduction. The high frequency of this mutation observed in Italian Ae. albopictus populations should serve as a warning bell, advocating for increased monitoring and management of a phenomenon which risks neutralizing the only weapon today available to counteract (risks of) arbovirus outbreaks.
ABSTRACT
The Asian tiger mosquito Aedes albopictus (Skuse 1894) is assuming an ever-increasing importance as invasive species in Europe and consequently as human health and nuisance concern. In Central Italy, the species has been recently involved in a chikungunya outbreak. A 3 yr Ae. albopictus monitoring was carried out in 21 municipalities of the Lazio region (Central Italy), belonging to three provinces. Samplings were performed on a weekly basis using ovitraps, in order to investigate climatic and spatial variables driving egg abundance and Ae. albopictus period of activity. A temperature of 10.4°C was indicated as lower threshold for the onset of egg-laying activity, together with a photoperiod of 13:11 (L:D) h. The whole oviposition activity lasted 8 mo (May-December), with 95% of eggs laid between early June and mid-November and a peak at the end of August. Egg abundance was positively influenced by accumulated temperature (AT) of the 4 wk preceding sampling and negatively by precipitation during the week before. Egg-laying activity dropped with decreasing AT, increasing rainfall, and with a photoperiod below 10:14 (L:D) h. Our results pinpointed the importance of fine-scaled spatial features on egg abundance. Some of these fine-scaled characteristics have been highlighted, such as the presence of vegetation and human footprint index. Our model estimated an almost doubled maximum number of laid eggs for the maximum value of human footprint. Compelling evidence of the relevance of fine-scaled characteristics was reported, describing cases where human-made breeding sites driven the abundance of Ae. albopictus.
Subject(s)
Aedes/physiology , Introduced Species , Animals , Humans , Humidity , Italy , Oviposition , Seasons , TemperatureABSTRACT
An increasing number of people regularly eats lunch away from home, using catering services. In this context, therefore, it is extremely important to improve the meals' quality, remaining faithful to the principles of hygiene, nutritional and organoleptic quality and proper food handling. At the same time, it is necessary to promote food choices, nutritionally correct, by evaluations of appropriateness of menus. The study of food waste allows an evaluation of the nutritional habits of consumers and an important economic consideration of the costs incurred for the implementation of the service. This becomes even more important in some particularly sensitive groups, such as children and elderly. The purpose of this work is to test a model of semi-quantitative evaluation of waste to monitor food consumption in two different catering contexts (educational and business), in order to improve the service for school students and other consumers.