Modelling the spatial risk of malaria through probability distribution of Anopheles maculipennis s.l. and imported cases

Malaria remains one of the most important infectious diseases globally due to its high incidence and mortality rates. The influx of infected cases from endemic to non-endemic malaria regions like Europe has resulted in a public health concern over sporadic local outbreaks. This is facilitated by the continued presence of competent Anopheles vectors in non-endemic countries.We modelled the potential distribution of the main malaria vector across Spain using the ensemble of eight modelling techniques based on environmental parameters and the Anopheles maculipennis s.l. presence/absence data collected from 2000 to 2020. We then combined this map with the number of imported malaria cases in each municipality to detect the geographic hot spots with a higher risk of local malaria transmission.The malaria vector occurred preferentially in irrigated lands characterized by warm climate conditions and moderate annual precipitation. Some areas surrounding irrigated lands in northern Spain (e.g. Zaragoza, Logroño), mainland areas (e.g. Madrid, Toledo) and in the South (e.g. Huelva), presented a significant likelihood of A. maculipennis s.l. occurrence, with a large overlap with the presence of imported cases of malaria.While the risk of malaria re-emergence in Spain is low, it is not evenly distributed throughout the country. The four recorded local cases of mosquito-borne transmission occurred in areas with a high overlap of imported cases and mosquito presence. Integrating mosquito distribution with human incidence cases provides an effective tool for the quantification of large-scale geographic variation in transmission risk and pinpointing priority areas for targeted surveillance and prevention.

Surveillance and screening of Stomoxyinae flies from Mallorca Island (Spain) reveal the absence of selected pathogens but confirm the presence of the endosymbiotic bacterium Wolbachia pipientis

Adult brachycera biting flies can significantly impact livestock through both direct effects (reduction of food intake, disturbance, painful bites, and blood loss) and indirect effects (pathogen transmission), leading to substantial economic losses and production damage. This study aimed to assess the presence of blood-sucking flies in six mixed-animal farm environments on the island of Mallorca (Balearic Islands, Spain) by employing multiple trapping methods. Additionally, distribution maps of brachycera biting fly species recorded in Spain were created, based on data extracted thorough review of scientific literature and citizen digital databases. Investigation of several pathogens, including equine infectious anemia virus (EIAV), Anaplasmataceae bacteria, and piroplasm protozoa, was carried out using different PCR targets (18S rRNA, 16S rRNA, groESL, and tat genes). Citizen science databases and literature review corroborated the consistent distribution trend for two Stomoxyinae species, underscoring the importance of citizen collaboration as a complement to traditional entomological surveillance. Our study confirmed the presence of two biting Stomoxyinae species: the prevalent stable fly Stomoxys calcitrans across all sampled farms, and the horn fly Haematobia irritans, which turned out to be less abundant. DNA barcoding techniques validated the identification of the two species. Neither EIAV nor bacterial/protozoan pathogens were detected using the selected PCR targets in either fly species. However, Wolbachia pipientis (clustered in the supergroup A together with the only sequence of W. pipientis from the USA) was identified through PCR targeting 16S rRNA, groESL and wsp genes in all pools of H. irritans (n = 13) collected from two of the examined farms. This study represents the first attempt to investigate pathogens in Stomoxyinae biting flies in Spain. The discovery of the endosymbiotic Wolbachia organism in H. irritans represents the first record in Spain and the second from Europe. This finding holds significant implications for future research on the applications of this bacterium in biocontrol programs.

An Integrated Pest Management Strategy Approach for the Management of the Stable Fly Stomoxys calcitrans (Diptera: Muscidae)

Stable flies, Stomoxys calcitrans, stand as formidable pests with a global impact, inflicting significant economic losses on the livestock sector. Larval development occurs in diverse substrates, including decomposing plant material and manure, while emerged adults pose a threat through blood-feeding on both animals and humans. Conventional chemical control methods, predominantly reliant on insecticides, not only pose environmental risks but also face challenges of resistance among stable fly populations. To address this pressing issue, we propose an integrated pest management (IPM) strategy for stable fly control. This approach involved a combination of sanitary-cultural practices, animal protection, the release of natural enemies targeting immature stages, and a specialized trapping system for adults. The Stomoxycc® trap, designed for mass trapping of adult Stomoxys, was employed alongside the release of the predatory mite Macrocheles robustulus and two wasp parasitoids, Spalangia cameroni and Muscidifurax raptor (under the commercial brands Biomite® and Biowasp®) on animal bedding as a key component of this IPM strategy. The implementation of this initiative has been undertaken at a significant sanctuary for donkeys and mules in western Spain. In this publication, we present the application and results of the IPM strategy utilized and provide insights into its use as a sustainable and environmentally friendly option for controlling stable fly populations.

Integrated taxonomy of black flies (Diptera: Simuliidae) reveals unexpected diversity in the most arid ecosystem of Europe

The family Simuliidae includes more than 2000 species of black flies worldwide. Their morphological uniformity creates difficulty for species identification, which limits our knowledge of their ecology and vectorial role. We investigated the systematics of black flies in a semi-arid area of the Iberian Peninsula, an ecologically harsh environment for these organisms. Sampling adult black flies in three different habitats (by means of CDC traps) and in avian nest boxes and collecting immature stages in high-salinity rills provided a representative sample of the component species. A combination of approaches, including morphological, chromosomal, and molecular (based on the mitochondrial cytochrome C oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) genes) revealed five species: four common species (Simulium intermedium, S. petricolum, S. pseudequinum, and S. rubzovianum) and the first European record for S. mellah. Barcoding gap and phylogenetic analyses revealed that ITS2 is a key marker to identify the species, whereas the COI marker does not provide enough resolution to identify some species or infer their phylogenetic relationships. Morphological and chromosomal features are also provided to identify S. mellah unequivocally. Our study highlights the need for integrated studies of black flies in ecologically extreme habitats to increase our knowledge of their distribution, ecology, and potential risks for public health.

Severe skin lesions caused by persistent bites of the stable fly Stomoxys calcitrans (Diptera: Muscidae) in a donkey sanctuary of western Spain

Animal sanctuaries are important organisations that promote animal welfare and health as well as social awareness. Following the appearance of several donkeys with severe and distinctive skin lesions in a sanctuary from western Spain in 2021, a multicomponent study was performed to rule out the possible causes. The lesions were mainly concentrated on the extremities and, to a lesser extent, on the face and/or chest. The use of cotton leggings on their extremities as an external barrier to prevent them from bites and treatments with antiparasitic, antiseptic washes and dermatitis lotion showed to be effective measures to improve the donkey lesions. Skin scraping was negative for any relevant causative agents. Histopathological examination of the lesions showed an inflammatory infiltrate at the superficial dermal level, compatible with diffuse chronic dermatitis. A field entomological study was conducted from May to October 2021 to ascertain if any Diptera was responsible for these lesions. Considerable numbers of the stable fly Stomoxys calcitrans were recorded in both sticky traps and decomposing straw bedding. Several species of haematophagous Diptera were also recorded in lower numbers in other traps placed on the farm facilities. According to the entomological data, the location of the bites and clinical signs, it was concluded that S. calcitrans was the main cause of the skin lesions in the donkeys. To our best knowledge, this is the first clinical case of donkeys affected by the stable fly in Spain. For differential diagnosis, a brief discussion of the evidence caused by other biting Diptera groups is provided.

Phlebotomine sand flies (Diptera, Psychodidae) from Spain: an updated checklist and extended distributions

Phlebotomine sand flies (Diptera: Psychodidae) are the natural vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae) and phleboviruses (Bunyavirales: Phenuiviridae). In Spain, these vectors appear to be increasing their geographical distribution and have serious repercussions on public and veterinary health, encouraging studies of sand flies and their associated pathogens. An up-to-date and easily accessible compendium of current and historical data on their presence and detailed distribution is a crucial step towards the development and implementation of appropriate preventive strategies. A checklist on the presence and distribution of sand flies in Spain is compiled from data extracted from a comprehensive review of scientific literature published between 1909 and 2021 and our new records on the presence of sand flies specimens collected under the entomological surveillance of bluetongue vectors from the Spanish Ministry of Agriculture, Fishery and Food (MAPA) during the period 2004-2021. In total, 13 Spanish species of sand flies (two of them with controversial status) belonging to two genera and six subgenera are presented in this updated checklist, including new distribution data for seven species, among which several stand out as confirmed or suspected vectors of Leishmaniainfantum: Phlebotomusariasi, Ph.langeroni, Ph.mascittii, and Ph.perniciosus.

AIMSurv: First pan-European harmonized surveillance of Aedes invasive mosquito species of relevance for human vector-borne diseases

Human and animal vector-borne diseases, particularly mosquito-borne diseases, are emerging or re-emerging worldwide. Six Aedes invasive mosquito (AIM) species were introduced to Europe since the 1970s: Aedes aegypti, Ae. albopictus, Ae. japonicus, Ae. koreicus, Ae. atropalpus and Ae. triseriatus. Here, we report the results of AIMSurv2020, the first pan-European surveillance effort for AIMs. Implemented by 42 volunteer teams from 24 countries. And presented in the form of a dataset named "AIMSurv Aedes Invasive Mosquito species harmonized surveillance in Europe. AIM-COST Action. Project ID: CA17108". AIMSurv2020 harmonizes field surveillance methodologies for sampling different AIMs life stages, frequency and minimum length of sampling period, and data reporting. Data include minimum requirements for sample types and recommended requirements for those teams with more resources. Data are published as a Darwin Core archive in the Global Biodiversity Information Facility- Spain, comprising a core file with 19,130 records (EventID) and an occurrences file with 19,743 records (OccurrenceID). AIM species recorded in AIMSurv2020 were Ae. albopictus, Ae. japonicus and Ae. koreicus, as well as native mosquito species.

Experimental and natural infections of severe acute respiratory syndrome-related coronavirus 2 in pets and wild and farm animals

The severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has spread globally and has led to extremely high mortality rates. In addition to infecting humans, this virus also has infected animals. Experimental studies and natural infections showed that dogs have a low susceptibility to SARS-CoV-2 infection, whereas domesticated cats and other animals in the family Felidae, such as lions, tigers, snow leopards, and cougars, have a high susceptibility to viral infections. In addition, wild white-tailed deer, gorillas, and otters have been found to be infected by SARS-CoV-2. Furry farm animals, such as minks, have a high susceptibility to SARS-CoV-2 infection. The virus appears to spread among minks and generate several new mutations, resulting in increased viral virulence. Furthermore, livestock animals, such as cattle, sheep, and pigs, were found to have low susceptibility to the virus, whereas chicken, ducks, turkeys, quail, and geese did not show susceptibility to SARS-CoV-2 infection. This knowledge can provide insights for the development of SARS-CoV-2 mitigation strategies in animals and humans. Therefore, this review focuses on experimental (both replication and transmission) in vitro, ex vivo, and in vivo studies of SARS-CoV-2 infections in pets and in wild and farm animals, and to provide details on the mechanism associated with natural infection.

DNA Barcoding of Mosquitoes from the Pantanos de Centla Biosphere Reserve, Southeastern Mexico

Accurate identification of mosquito species is essential to support programs that involve the study of distribution and mosquito control. Numerous mosquito species are difficult to identify based only on morphological characteristics, due to the morphological similarities in different life stages and large numbers of some species that are members of morphologically similar species complexes. In the present study, the mosquitoes collected in the Pantanos de Centla Biosphere Reserve, southeastern Mexico, were evaluated using a combination of morphological and molecular approaches (mitochondrial cytochrome c oxidase subunit I [COI] DNA barcode). A total of 1,576 specimens of 10 genera and 35 species, mostly adult stages, were collected. A total of 225 COI DNA barcode sequences were analyzed; most species formed well-supported groups in the neighbor joining, maximum likelihood, and Bayesian inference trees. The intraspecific Kimura 2-parameter (K2P) genetic distance averaged 1.52%. An intraspecific K2P distance of 6.20% was observed in Anopheles crucians s.l., while a deep split was identified in Culex erraticus and Cx. conspirator. This study showed that COI DNA barcodes offer a reliable approach to support mosquito species identification in Mexico.

At the tip of an iceberg: citizen science and active surveillance collaborating to broaden the known distribution of Aedes japonicus in Spain

BACKGROUND

Active surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths. In a number of cases, however, the first detections of colonizing populations are made by citizens, either because the species has already moved beyond the implemented active surveillance sites or because there is no surveillance in place. This was the case of the first detection in 2018 of the Asian bush mosquito, Aedes japonicus, in Asturias (northern Spain) by the citizen science platform Mosquito Alert.

METHODS

The collaboration between Mosquito Alert, the Ministry of Health, local authorities and academic researchers resulted in a multi-source surveillance combining active field sampling with broader temporal and spatial citizen-sourced data, resulting in a more flexible and efficient surveillance strategy.

RESULTS

Between 2018 and 2020, the joint efforts of administrative bodies, academic teams and citizen-sourced data led to the discovery of this species in northern regions of Spain such as Cantabria and the Basque Country. This raised the estimated area of occurrence of Ae. japonicus from < 900 km2 in 2018 to > 7000 km2 in 2020.

CONCLUSIONS

This population cluster is geographically isolated from any other population in Europe, which raises questions about its origin, path of introduction and dispersal means, while also highlighting the need to enhance surveillance systems by closely combining crowd-sourced surveillance with public health and mosquito control agencies' efforts, from local to continental scales. This multi-actor approach for surveillance (either passive and active) shows high potential efficiency in the surveillance of other invasive mosquito species, and specifically the major vector Aedes aegypti which is already present in some parts of Europe.

Atypical behavior of a black fly species connects cavity-nesting birds with generalist blood parasites in an arid area of Spain

BACKGROUND

The feeding behavior of bloodsucking insects determines the transmission, distribution, host spectrum and evolution of blood parasites in the wild. Conventional wisdom suggests that some vector groups (e.g. black flies, family Simuliidae) are consistently exophagous daytime biters. We aimed to understand more about the exceptions to this pattern by combining targeted trapping and molecular identification of parasites in vectors.

METHODS

In this study, we collected black flies in nest boxes used by European rollers Coracias garrulus in southeastern Spain. We molecularly analyzed 434 individual insects, identifying the black fly species caught in the nest boxes, their potential vertebrate blood meals, and the haemosporidian parasite lineages that they carried.

RESULTS

Only one black fly species, Simulium rubzovianum, appeared to enter the nest boxes of rollers. Among the trapped specimens, 15% contained vertebrate DNA, which always belonged to rollers, even though only half of those specimens were visibly engorged. Furthermore, 15% of all black flies contained Leucocytozoon lineages, indicating previous feeding on avian hosts but probably not on infected adult rollers. The known vertebrate hosts of the recorded Leucocytozoon lineages suggested that large and/or abundant birds are their hosts. Particularly represented were cavity-nesting species breeding in the vicinity, such as pigeons, corvids and owls. Open-nesting species such as thrushes and birds of prey were also represented.

CONCLUSIONS

Our data strongly suggest that S. rubzovianum bites uninfected roller nestlings and infected individuals of other species, potentially incubating adults, inside nest boxes and natural cavities. This simuliid does not appear to have a strong preference for specific host clades. Contrary to the general pattern for the group, and possibly enhanced by the harsh environmental conditions in the study area, this black fly appeared to intensively use and may even have a preference for confined spaces such as cavities for feeding and resting. Preferences of vectors for atypical microhabitat niches where hosts are less mobile may enable social and within-family transmission and parasite speciation in the long term. At the same time, a lack of host preference in concentrated multispecies communities can lead to host switches. Both processes may be underappreciated driving forces in the evolution of avian blood parasites.

Molecular Characterization of Mosquito Diversity in the Balearic Islands

Several outbreaks of mosquito-borne diseases have taken place in Europe in recent years. In Spain, both active and passive surveillance have demonstrated that dengue and West Nile viruses are currently circulating, and seven autochthonous dengue cases have been reported in the last 2 yr. The effectiveness of vector control programs largely depends on the accuracy of the taxonomic identification of the species. However, in Spain, identification almost completely relies on the use of morphological keys to characterize the mosquito fauna. This study investigates the congruence between molecular and morphological species boundaries in 13 Spanish mosquito taxa. The Cytochrome c oxidase subunit I (COI) gene region was sequenced from 60 adult specimens collected in Mallorca, plus several representatives from other Spanish regions for comparative purposes. Phylogenetic relationships were established using Bayesian and maximum-likelihood approaches. Using three species delimitation algorithms (ABGD, mPTP, and GMYC), we found strong evidence for cryptic speciation within Anopheles algeriensis Theobald, a widespread mosquito in the Mediterranean basin. We also delimited the Mallorcan rock pool mosquito Aedes mariae (Sergent & Sergent), from mainland European populations. Finally, we found difficulties in the use of wing characters in species keys to distinguish Culiseta annulata (Schrk) from Culiseta subochrea (Edwards). Given that these species are vectors of pathogens of medical relevance and have veterinary importance, their accurate taxonomic identification is essential in European vector surveillance programs.

Detection of SARS-CoV-2 in pets living with COVID-19 owners diagnosed during the COVID-19 lockdown in Spain: A case of an asymptomatic cat with SARS-CoV-2 in Europe

Pets from COVID‐19 owners were screened for SARS‐CoV‐2 (April–May 2020). From 23 pets, an asymptomatic cat showed positive RT‐qPCRs results from oropharyngeal swab (negative rectal swab). Remaining pets were negative. This suggests that cats can contract the virus from their infected owners and may act as potential hosts for SARS‐CoV‐2. Their role in carrying live or infectious viruses and disseminating them needs more investigation.

Determinants of the current and future distribution of the West Nile virus mosquito vector Culex pipiens in Spain

Changes in environmental conditions, whether related or not to human activities, are continuously modifying the geographic distribution of vectors, which in turn affects the dynamics and distribution of vector-borne infectious diseases. Determining the main ecological drivers of vector distribution and how predicted changes in these drivers may alter their future distributions is therefore of major importance. However, the drivers of vector populations are largely specific to each vector species and region. Here, we identify the most important human-activity-related and bioclimatic predictors affecting the current distribution and habitat suitability of the mosquito Culex pipiens and potential future changes in its distribution in Spain. We determined the niche of occurrence (NOO) of the species, which considers only those areas lying within the range of suitable environmental conditions using presence data. Although almost ubiquitous, the distribution of Cx. pipiens is mostly explained by elevation and the degree of urbanization but also, to a lesser extent, by mean temperatures during the wettest season and temperature seasonality. The combination of these predictors highlights the existence of a heterogeneous pattern of habitat suitability, with most suitable areas located in the southern and northeastern coastal areas of Spain, and unsuitable areas located at higher altitude and in colder regions. Future climatic predictions indicate a net decrease in distribution of up to 29.55%, probably due to warming and greater temperature oscillations. Despite these predicted changes in vector distribution, their effects on the incidence of infectious diseases are, however, difficult to forecast since different processes such as local adaptation to temperature, vector-pathogen interactions, and human-derived changes in landscape may play important roles in shaping the future dynamics of pathogen transmission.

Integrated Approaches in Support of Taxonomic Identification of Mosquitoes (Diptera: Culicidae) in Vector Surveillance in Spain

The pandemic of Zika virus in 2016 and other arboviruses prompted La Rioja Government in Spain to implement an entomological surveillance program of mosquitoes (Diptera; Culicidae) in the region of La Rioja. The morphological identification was supported by genetic analysis using the COI (cytochrome c oxidase subunit I) and the ITS2 (internal transcribed spacer 2) genes. In total, we identified 24 species arranged in 6 genera: Aedes (7 species), Anopheles (4 species), Coquillettidia (1 species), Culex (7 species), Culiseta (4 species), and Uranotaenia (1 species). Aedes sticticus and Aedes geniculatus are newly reported for La Rioja region. In total, 465 COI sequences were analyzed for Culicinae and Anophelinae and 54 ITS2 sequences for Anophelinae; all individuals identified as the same species clustered together in the Neighbor Joining trees. The levels of sequence divergence based on COI ranged between 0% and 2.62%, while the interspecific genetic divergence ranged from 3.05% to 20.07%. Within the genus Culiseta, certain specimens of Culiseta annulata, Culiseta litorea, and Culiseta subochrea were morphologically misidentified due to variation in the main diagnostic characters. The interspecific genetic divergence based on the ITS2 ranged from 0% to 2.98%. An accurate identification of mosquito vectors is the first step to establish a vector surveillance program for preventing pathogen transmission.

Surveillance of a Pest Through a Public Health Information System: The Case of the Blackfly (Simulium erythrocephalum) in Zaragoza (Spain) during 2009-2015

Background: Animals and people in many Spanish regions are increasingly being affected by blackfly bites in the last decade. Because of blackflies, the city of Zaragoza has become in recent years a paradigm of discomfort in Europe, with thousands of citizens affected. The OMI-AP system (Stacks, Barcelona, Spain) implemented by the Government of Aragón, a software that manages the electronic medical history of all patients, has been evaluated in order to document the increase of insect bite recorded by the primary care consultations in Zaragoza after the first outbreak of blackflies occurred in 2011. Methods: An observational, ecological and longitudinal study of insect bites recorded at the primary care consultations was carried out in primary care during the period 2009–2015. Results: The incidence of medical consultations by insect bites in Basic Health Areas (BHA) near to rivers is higher than the furthest BHA. Rural BHA are more affected by insect bites than the urban ones. The increase of medical assistance due to insect bites in Zaragoza since 2011 is correlated with the blackflies bites. Conclusions: This tool was very useful to describe the initial stage of this public health problem. It could be used for guiding public health responses in terms of surveillance and management of this pest.

Genetic diversity and population structure of Culex modestus across Europe: does recent appearance in the United Kingdom reveal a tendency for geographical spread?

In mainland Europe, the mosquito species Culex modestus Ficalbi (1890) is a bridge vector for West Nile virus (WNV) from its natural bird-mosquito cycle to mammals. The present study assessed the genetic diversity of Cx. modestus, as well as related Culex species, using the mitochondrial COI DNA barcoding region and compared this with the population structure across Europe. A haplotype network was mapped to determine genealogical relationships among specimens. The intraspecific genetic diversity within individual Culex species was below 2%, whereas the interspecific genetic divergence varied from 2.99% to 13.74%. In total, 76 haplotypes were identified among 198 sequences. A median-joining network determined from 198 COI sequences identified two major lineages that were separated by at least four mutation steps. A high level of intraspecific genetic diversity was not detected in Cx. modestus in samples submitted from different European populations, which indicates that morphologically identified specimens represent a single species and not a species complex. Therefore, it is deduced that different populations of Cx. modestus will show a similar potential to transmit WNV, lending support to concerns that the population present in southeast England represents a risk of transmission to humans.

Description of a Culex pipiens Gynandromorph Captured in La Rioja (Spain)

A gynandromorph is an imago combining well-defined male and female structures, caused by different processes, and it is infrequent in wild-caught mosquitoes. A Culex pipiens gynandromorph was caught in La Grajera wetland (La Rioja, Spain) in 2016. The phenotypic sex of wings was determined using linear discriminating analysis and the training error for the model on a previous database of sex-classified wing biometry data. It is suggested that the individual had an uncommon layout categorized as a top quarter male gynandromorph.

The mosquitoes (Diptera: Culicidae) of Tabasco, Mexico

To document and update the mosquito species of Tabasco, Mexico, field collection trips were conducted in the two physiographic regions of Tabasco: the coastal plain of the southern gulf and the mountains of Chiapas and Guatemala. Mosquitoes were collected as immature and adult stages during the dry and rainy seasons from 2014 through 2015. Additionally, the Reference Collection of Arthropods of Medical Importance (CAIM-InDRE) containing mosquitoes of Tabasco was re-examined. In total, 4,913 specimens were collected and examined, which are divided into seven tribes, 18 genera, 27 subgenera, and 104 species. Of these, one genus (Shannoniana Lane and Cerqueira), two subgenera (Georgecraigius Reinert, Harbach and Kitching, and Carrollia Lutz), and 21 species are new records for the mosquito fauna of Tabasco. Culex metempsytus Dyar is a new record for Mexico and Wyeomyia jocosa (Dyar and Knab) is removed from the Mexican mosquito fauna. Seventeen species historically reported were not found in the field collections conducted here. Taxonomic notes, new distribution limits, and comments about the medical importance of species of mosquitoes of Tabasco are discussed. Tabasco is the second state in Mexico with the largest mosquito richness (104 species), followed by Veracruz with 139 species.

Evidence for infection but not transmission of Zika virus by Aedes albopictus (Diptera: Culicidae) from Spain

Background

A number of mosquito-borne viruses such as dengue virus (DENV), Usutu virus (USUV), West Nile virus (WNV) are autochthonously transmitted in Europe and six invasive mosquito species have been detected in this temperate region. This has increased the risk for the emergence of further mosquito-borne diseases. However, there is a paucity of information on whether European populations of invasive mosquito species are competent to transmit arboviruses. In this study, the susceptibility of Aedes albopictus originating from Spain and a laboratory-adapted colony of Aedes aegypti, was assessed for infection with, and transmission of Zika virus (ZIKV). Vertical transmission in both species was also assessed.

Methods

Aedes albopictus colonised from eggs collected in Spain and an existing colony of Ae. aegypti were fed infectious blood meals containing ZIKV (Polynesian strain) at 1.6 × 10⁷ PFU/ml. Blood-fed mosquitoes were separated and maintained at 20 °C or 25 °C. Legs, saliva and bodies were sampled from specimens at 7, 14 and 21 days post-infection (dpi) in order to determine infection, dissemination and transmission rates. All samples were analysed by real-time RT-PCR using primers targeting the ZIKV NS1 gene.

Results

At 14 dpi and 21 dpi, ZIKV RNA was detected in the bodies of both species at both temperatures. However, live virus only was detected in the saliva of Ae. aegypti at 25 °C with a transmission rate of 44%. No evidence for virus expectoration was obtained for Ae. albopictus under any condition. Notably, ZIKV RNA was not detectable in the saliva of Ae. aegypti at 20 °C after 21 days. No vertical transmission of ZIKV was detected in this study.

Conclusions

Experimental infection of Ae. albopictus colonized from Spain with ZIKV did not result in expectoration of virus in saliva in contrast to results for Ae. aegypti. No evidence of vertical transmission of virus was observed in this study. This suggests that this strain of Ae. albopictus is not competent for ZIKV transmission under the conditions tested.

Surveillance of Mosquitoes (Diptera, Culicidae) in a Northern Central Region of Spain: Implications for the Medical Community

Mosquitoes are important to public and animal health due to their capacity to transmit diseases. Since the Zika virus was declared a pandemic by the WHO in 2016, and it has been recorded in different regions of Mediterranean Area (included Spain), the Government of La Rioja (Northern Spain) through the Center of Rickettsiosis and Arthropod-Borne Diseases, implemented an entomological surveillance programme of mosquitoes in La Rioja and in a close area of Navarra. This surveillance extended to some of the pathogens that they can transmit. Here we describe the framework of the initial surveillance programme for the detection of mosquitoes and associated human pathogens. We outline the benefits and the limitation of the programme to date, and explore how greater benefits can be achieved, for example using a One Health approach. Entomological surveillance has been carried out with BG-Sentinel traps, human bait technique and other methods such as collecting adults in resting places or immature stages by dipping in several wetlands. Since Aedes albopictus, vector of arbovirus such as Dengue, Chikungunya, and Zika, has not been detected yet in the region, the entomological programme included the surveillance of this exotic species using ovitraps in the most important cities. Morphological identification was supported using the mitochondrial cytochrome C oxidase subunit I and the internal transcribed spacer 2 genes analysis. In 2016 and 2017, more than 6,000 mosquitoes were collected. The mosquito's community included 21 species associated with six genera: Anopheles (n = 4), Aedes (n = 5), Culex (n = 6), Culiseta (n = 4), Uranotaenia (n = 1) and Coquillettidia (n = 1). Eleven species represent new records for La Rioja and Navarra regions. Several species were collected biting humans and a great proportion of the sampled mosquito population are competent vectors of several pathogens, such as West Nile virus. Sequences closely related to mosquito–only flavivirus have been detected in 0.34% of analysed pools. At the same time, the epidemiological surveillance emphasis is placed in the early detection of mosquito-borne diseases in primary health and emergency services. The surveillance programme represents a relevant and necessary assessment of the risk of pathogen transmission in a region, and it allows for the establishment of the appropriate preventive measures.

First detection of Aedes japonicus in Spain: an unexpected finding triggered by citizen science

BACKGROUND

Aedes japonicus is an invasive vector mosquito from Southeast Asia which has been spreading across central Europe since the year 2000. Unlike the Asian Tiger mosquito (Aedes albopictus) present in Spain since 2004, there has been no record of Ae. japonicus in the country until now.

RESULTS

Here, we report the first detection of Ae. japonicus in Spain, at its southernmost location in Europe. This finding was triggered by the citizen science platform Mosquito Alert. In June 2018, a citizen sent a report via the Mosquito Alert app from the municipality of Siero in the Asturias region (NW Spain) containing pictures of a female mosquito compatible with Ae. japonicus. Further information was requested from the participant, who subsequently provided several larvae and adults that could be classified as Ae. japonicus. In July, a field mission confirmed its presence at the original site and in several locations up to 9 km away, suggesting a long-time establishment. The strong media impact in Asturias derived from the discovery raised local participation in the Mosquito Alert project, resulting in further evidence from surrounding areas.

CONCLUSIONS

Whilst in the laboratory Ae. japonicus is a competent vector for several mosquito-borne pathogens, to date only West Nile virus is a concern based on field evidence. Nonetheless, this virus has yet not been detected in Asturias so the vectorial risk is currently considered low. The opportunity and effectiveness of combining citizen-sourced data to traditional surveillance methods are discussed.

Arthropods as vectors of transmissible diseases in Spain

Different aspects related to globalization together with the great capacity of the arthropod vectors to adapt to a changing world favour the emergence and reemergence of numerous infectious diseases transmitted by them. Diptera (mosquitoes and sandflies), ticks, fleas and lice, among others, cause a wide spectrum of diseases with relevance in public health. Herein, arthropod-borne disease are reviewed, with special emphasis on the existing risk to contract them in Spain according to different parameters, such as the presence of arthropod and the circulation or the possible circulation of the causative agents.

Arthropods as vectors of transmisible diseases in Spain

Diferentes aspectos relacionados con la globalización junto a la gran capacidad de los artrópodos vectores para adaptarse a un mundo cambiante propician la emergencia y reemergencia de numerosos procesos infecciosos transmitidos por los mismos. Dípteros (culícidos y flebótomos), garrapatas, pulgas y piojos, entre otros, provocan un variado espectro de enfermedades con gran importancia en Salud Pública. En esta revisión se repasan las diferentes afecciones transmitidas por artrópodos vectores, haciendo un especial hincapié en el riesgo existente para contraerlas en España en función de diferentes parámetros, como la presencia del artrópodo y la circulación o posible circulación de los agentes causales.

DNA barcoding of blackflies (Diptera: Simuliidae) as a tool for species identification and detection of hidden diversity in the eastern regions of Spain

Background

Blackflies have negative impact on public and animal health due to the haematophagous habit of females. In recent times, in some regions in Spain, blackfly outbreaks are becoming more and more frequent, threatening the public health. However, there is still a paucity of data concerning the Spanish blackfly fauna. Correct identification of species is of paramount importance in order to provide correct information on species distribution, biology and behaviour, so that control measures could be implemented appropriately.

Methods

Blackflies specimens (larvae, pupae, reared adults and biting females) were collected in the period 2015–2017 in and near rivers and streams from different regions in Spain. A modified Hotshot technique was used for the DNA extraction and the cox1 DNA barcoding region of the cytochrome c oxidase subunit 1 was sequenced from the specimens collected.

Results

In total, we collected 239 specimens representing 22 species. Of these, six species are new records for the Aragón region: P. tomosvaryi, S. bertrandi, S. galloprovinciale, S. lineatum, S. rubzovianum and S. xanthinum. Cox1 DNA barcode sequences for 21 species were recovered, including four species of the genus Prosimulium and 17 species of the genus Simulium [Boophthora (1 species), Eusimulium (1 species), Nevermannia (4 species), Simulium (s.s.) (6 species), Trichodagmia (1 species) and Wilhelmia (4 species)]. For the first time the complete DNA barcodes for five species (P. tomosvaryi, S. carthusiense, S. brevidens, S. monticola and S. sergenti) were registered. Most of the specimens belonging to the same recognized species were clustered together in the neighbour-joining tree, except for S. argyreatum, S. monticola and S. variegatum. The overall genetic distance in the dataset was 0.14%. The average of the intraspecific genetic divergence within the different taxa was 1.47% (0.05–3.96%). In contrast, the interspecific divergence varied between 2.50–22.0%.

Conclusions

In this study we assessed the use of the cox1 DNA barcoding region for the identification of species of blackflies in Spain. Our results showed that combining DNA barcoding with morphology enhanced our taxonomic rationale in identifying the blackflies in the country.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3046-7) contains supplementary material, which is available to authorized users.

[New public health challenges in vector management: black flies in Murcia (Spain)]

Historically, no black fly (Diptera: Simuliidae) nuisance has been reported in the Murcia Region. Back in September 2016 the Ojós City Council has contacted the Regional Public Health General Directorate for help regarding a local insect nuisance, most probably based on mosquitoes. After sampling with a BG-sentinel 2 trap, collecting adult specimens with an entomological aspirator, and collect larvae and pupae on submerged giant cane stalks at the river, it turned out that Simulium sergenti was the insect species causing the nuisance. This species is not considered particularly anthropophilic; therefore, a low vector risk for human health was considered. However, the high fly density impaired the life quality of the people at the village. A management plan was recommended, treating the river with Bacillus thuringiensis var israelensis.

Human-landing rate, gonotrophic cycle length, survivorship, and public health importance of Simulium erythrocephalum in Zaragoza, northeastern Spain

BACKGROUND

Simulium (Boophthora) erythrocephalum (De Geer, 1776) is one of the blackfly species responsible for major public health problems in Europe. Blackfly outbreaks of this species are becoming more frequent, threatening public health in Spain. In the present study, bionomic parameters of S. erythrocephalum in northeastern Spain were estimated.

METHODS

Simulium erythrocephalum was collected from May through June 2015 in Zaragoza, Spain, using the human-landing-collection (HLC) method. Daily pattern of total and parous landing activity was estimated, as was the gonotrophic cycle (GC) length and survivorship (S) rate, using time series analysis.

RESULTS

Host-seeking females of S. erythrocephalum showed a bimodal human-landing activity pattern, with a minor and major peak at dawn and dusk, respectively; there was a significant negative association between human daily landing rate and temperature (P = 0.003) and solar radiation (P < 0.001). Overall, a daily landing rate (DLR) of 34 lands/person/day was estimated. Series of sequential data analysis on parity showed the highest significant (P < 0.001) correlation indices (r = 0.45 and r = 0.39 for raw and filtered data) for a 2-day time lag, indicating that the GC length corresponded to 2 days. Daily survivorship and parity rate were 0.85 and 0.72, respectively.

CONCLUSIONS

Simulium erythrocephalum was confirmed as a nuisance species in Zaragoza, using the HLC method for the first time in Spain. The data offer insights into the ecology of S. erythrocephalum, which can improve management strategies of this pest in Spain.

A novel spotted fever group Rickettsia infecting Amblyomma parvitarsum (Acari: Ixodidae) in highlands of Argentina and Chile

The tick Amblyomma parvitarsum (Acari: Ixodidae) has established populations in Andean and Patagonic environments of South America. For the present study, adults of A. parvitarsum were collected in highland areas (elevation >3500 m) of Argentina and Chile during 2009-2013, and tested by PCR for rickettsial infection in the laboratory, and isolation of rickettsiae in Vero cell culture by the shell vial technique. Overall, 51 (62.2%) out of 82 A. parvitarsum adult ticks were infected by spotted fever group (SFG) rickettsiae, which generated DNA sequences 100% identical to each other, and when submitted to BLAST analysis, they were 99.3% identical to corresponding sequence of the ompA gene of Rickettsia sp. strain Atlantic rainforest. Rickettsiae were successfully isolated in Vero cell culture from two ticks, one from Argentina and one from Chile. DNA extracted from the third passage of the isolates of Argentina and Chile were processed by PCR, resulting in partial sequences for three rickettsial genes (gltA, ompB, ompA). These sequences were concatenated and aligned with rickettsial corresponding sequences available in GenBank. Phylogenetic analysis revealed that the A. pavitarsum rickettsial agent grouped under high bootstrap support in a clade composed by the SFG pathogens R. sibirica, R. africae, R. parkeri, Rickettsia sp. strain Atlantic rainforest, and two unnamed SFG agents of unknown pathogenicty, Rickettsia sp. strain NOD, and Rickettsia sp. strain ApPR. The pathogenic role of this A. parvitarsum rickettsia cannot be discarded, since several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections.

Review of ten-years presence of Aedes albopictus in Spain 2004-2014: known distribution and public health concerns

Ten years have gone by since the Asian tiger mosquito Aedes albopictus was recorded for the first time in Spain. In this paper, all relevant published information about this vector in Spain for the period 2004-2014 is reviewed. The known distribution for 2014 is provided, including all historical records (published and unpublished data) and the results from samplings of the last year. The consequences on public health about the presence of the Asian tiger mosquito in Spain are also highlighted. Further, legal aspects and control plans related to the management and diseases transmitted by this invasive vector species are also discussed.