Identifying spanish areas at more risk of monthly BTV transmission with a basic reproduction number approach

Bluetongue virus (BTV) causes a disease that is endemic in Spain and its two major biological vector species, C. imicola and the Obsoletus complex species, differ greatly in their ecology and distribution. Understanding the seasonality of BTV transmission in risk areas is key to improving surveillance and control programs, as well as to better understand the pathogen transmission networks between wildlife and livestock. Here, monthly risk transmission maps were generated using risk categories based on well-known BTV R0 equations and predicted abundances of the two most relevant vectors in Spain. Previously, Culicoides spp. predicted abundances in mainland Spain and the Balearic Islands were obtained using remote sensing data and random forest machine learning algorithm. Risk transmission maps were externally assessed with the estimated date of infection of BTV-1 and BTV-4 historical outbreaks. Our results highlight the differences in risk transmission during April-October, June-August being the period with higher R0 values. Likewise, a natural barrier has been identified between northern and central-southern areas at risk that may hamper BTV spread between them. Our results can be relevant to implement risk-based interventions for the prevention, control and surveillance of BTV and other diseases shared between livestock and wildlife host populations

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

Actualización del catálogo de Culicoides Latreille, 1809 (Diptera, Ceratopogonidae) de España

The number of studies on arthropods of genus Culicoides Latreille (Diptera, Ceratopogonidae) has increased considerably in Spain in recent decades. This is due to the role these insects play as vectors of arboviruses that cause disease in animals, but also in humans. This work undertakes an updated catalogue of the species of this genus in our country, through a critical review of the literature, clarifying chronological aspects of these publications carried out for over a century of research. This update shows a total of 81 species of Culicoides in Spain, among which are some to be considered as directly related to the transmission of diseases such as bluetongue and African horse sickness.El número de estudios acerca de los artrópodos del género Culicoides Latreille (Diptera, Ceratopogonidae) en España ha experimentado un elevado incremento en las últimas décadas. Principalmente ello es debido al papel que estos dípteros juegan como vectores de arbovirus causantes de enfermedades en los animales, aunque también en humanos. Este trabajo acomete una actualización del catálogo de las especies que conforman este género en nuestro país, mediante una revisión crítica de la literatura existente, clarificando aspectos cronológicos sobre estas publicaciones llevadas a cabo durante más de un siglo de investigación. Esta actualización muestra un total de 81 especies de Culicoides para España, entre las que se encuentran algunas a tener en cuenta por estar directamente relacionadas con la trasmisión de enfermedades como la Lengua Azul o la Peste Equina Africana

The use of path analysis to determine effects of environmental factors on the adult seasonality of Culicoides (Diptera: Ceratopogonidae) vector species in Spain

Culicoides biting midges (Diptera: Ceratopogonidae) are the main vectors of livestock diseases such as bluetongue (BT) which mainly affect sheep and cattle. In Spain, bluetongue virus (BTV) is transmitted by several Culicoides taxa, including Culicoides imicola, Obsoletus complex, Culicoides newsteadi and Culicoides pulicaris that vary in seasonality and distribution, affecting the distribution and dynamics of BT outbreaks. Path analysis is useful for separating direct and indirect, biotic and abiotic determinants of species' population performance and is ideal for understanding the sensitivity of adult Culicoides dynamics to multiple environmental drivers. Start, end of season and length of overwintering of adult Culicoides were analysed across 329 sites in Spain sampled from 2005 to 2010 during the National Entomosurveillance Program for BTV with path analysis, to determine the direct and indirect effects of land use, climate and host factor variables. Culicoides taxa had species-specific responses to environmental variables. While the seasonality of adult C. imicola was strongly affected by topography, temperature, cover of agro-forestry and sclerophyllous vegetation, rainfall, livestock density, photoperiod in autumn and the abundance of Culicoides females, Obsoletus complex species seasonality was affected by land-use variables such as cover of natural grassland and broad-leaved forest. Culicoides female abundance was the most explanatory variable for the seasonality of C. newsteadi, while C. pulicaris showed that temperature during winter and the photoperiod in November had a strong effect on the start of the season and the length of overwinter period of this species. These results indicate that the seasonal vector-free period (SVFP) in Spain will vary between competent vector taxa and geographic locations, dependent on the different responses of each taxa to environmental conditions

Experimental study of the mechanical transmission of rabbit hemorrhagic disease virus (RHDV2/b) by Aedes Albopictus (Diptera: Clicidae) and Phlebotomus papatasi (diptera: psychodidae); 34447999

Rabbit hemorrhagic disease (RHD) is caused by a lagovirus mainly affecting European rabbits (Oryctolagus cuniculus), although other European and North American lagomorph species are also susceptible to fatal infection by the new viral variant RHDV2/b. In the present work, direct mechanical transmission of the rabbit hemorrhagic disease virus (RHDV2/b variant) by the hematophagous Diptera Aedes albopictus (Skuse) (Diptera: Culicidae) and the sand fly Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae) was tested. For each species, six and three laboratory rabbits were exposed to bites of dipterous females partially fed on RHDV2/b viral suspension 2 h and 24 h prior to exposure, respectively. The rabbits were then monitored for clinical changes and mortality for 35 d, and seroconversion was assessed by indirect ELISA. No rabbit died or showed clinical signs of disease, and seroconversion was recorded in two rabbits challenged with P. papatasi females fed the viral suspension 2 h prior to exposure. The number of RHDV2/b RNA copies/female was higher in Ae. albopictus than in P. papatasi but the decrease over time of RNA load in Ae. albopictus was greater than that in P. papatasi. The results of this study suggest the inability of Ae. albopictus to serve as a direct mechanical vector of RHDV2/b, but sand flies could play a role in the local transmission of RHD. © The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America

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. Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s)

Cambio climático en España y su influencia en las enfermedades de transmisión vectorial

En las últimas décadas se ha producido en España un resurgimiento de algunas enfermedades transmitidas por vectores, que se creían bajo control, y también la aparición de otras nuevas. Asimismo, la llegada de nuevos vectores, su implantación y expansión en algunos casos, está generando nuevos riesgos para la salud pública. Estos fenómenos han estado, en general, asociados a cambios ecológicos y climáticos complejos que han favorecido e incrementado las densidades de los vectores y de sus reservorios, pero en los que también han incidido procesos propiciados o acelerados por el hombre como la globalización, la urbanización, la deforestación y la modificación de los usos del suelo. Los cambios en la distribución de los vectores y en su capacidad para trasmitir patógenos debido al cambio climático van a ser más evidentes en las zonas en las que los vectores se encuentran en el límite de su distribución como es el caso de España. A esto se añade la cercanía de África y la posible entrada de nuevos vectores y patógenos procedentes de este continente. Ante este escenario es preciso establecer programas de acción dirigidos tanto a la identificación de los riesgos y la prevención de las enfermedades vectoriales como a la gestión eficaz de los posibles brotes que se puedan producir en el futuro. Se realiza una revisión en el ámbito nacional de los escenarios que se prevén en relación con el cambio climático y su impacto en la incidencia de enfermedades transmitidas por mosquitos, flebotomos, garrapatas, otros artrópodos y roedores. In the past few decades Spain has experienced a resurgence of some vector-transmitted diseases which were thought to be under control and the appearance of new ones. Likewise, the arrival of new vectors and, in some cases, their establishment and expansion is creating to new public health risks. In general, these phenomena have been associated with complex ecological and climate-driven changes which have favored and increased the densities of vectors and their reservoirs, but they have also been affected by processes that have been triggered or accelerated by man such as globalization, urban development, deforestation and land-use changes. Changes in the distribution of vectors and their capacity to transmit pathogens owing to climate change will become more evident in areas that lie within their distribution limits, as is Spain''s case. This is compounded by Spain''s proximity to Africa and the potential entry of new vectors and pathogens from this continent. This scenario necessitates setting up action programs aimed at both identifying risks posed by vectors and preventing vector-borne diseases, and efficiently managing possible outbreaks that could occur in the future. We have reviewed the scenarios which Spain is expected to experience in connection with climate change and its impact on the incidence of diseases transmitted by mosquitoes, phlebotomine sand flies, ticks and other arthropods, and rodents

Aedes albopictus diversity and relationships in south-western Europe and Brazil by rDNA/mtDNA and phenotypic analyses: ITS-2, a useful marker for spread studies

Background: Aedes albopictus is a very invasive mosquito, which has recently colonized tropical and temperate regions worldwide. Of concern is its role in the spread of emerging or re-emerging mosquito-borne diseases. Ae. albopictus from south-western Europe and Brazil were studied to infer genetic and phenetic diversity at intra-individual, intra-population and inter-population levels, and to analyse its spread. Methods: Genotyping was made by rDNA 5.8S-ITS-2 and mtDNA cox1 sequencing to assess haplotype and nucleotide diversity, genetic distances and phylogenetic networks. Male and female phenotyping included combined landmark-and outlined-based geometric morphometrics of wing size and shape. Results: Specimens from seven populations from Spain, France and Brazil provided 12 cox1 and 162 5.8S-ITS-2 haplotypes, with great genetic variability difference between both markers (0.9% vs 31.2%). Five cox1 haplotypes were shared with other countries, mainly Italy, USA and China, but none was shared between Europe and Brazil. The 5.8S-ITS-2 showed 2–7 intra-individual (mean 4.7) and 16–34 intra-/inter-population haplotypes (24.7), including haplotypes shared between Spain, France and Brazil. A 4.3% of ITS-2 haplotypes were shared, mainly with Italy, USA and Thailand, evidencing worldwide spread and introductions from areas where recent outbreaks of Ae. albopictus-transmitted pathogens occurred. Wing size showed sex differences. Wing shape distinguished between Brazilian and European specimens. Both genetic and morphometric markers showed differences between insular Spain and continental Spain, France and Brazil. Conclusions: ITS-2 proves to be a useful marker to assess Ae. albopictus spread, providing pronouncedly more information than cox1, including intra-individual, intra-population and inter-population levels, furnishing a complete overview of the evolutionary exchanges followed by this mosquito. Wing morphometry proves to be a useful phenotyping marker, allowing to distinguish different populations at the level of both male and female specimens. Results indicate the need for periodic surveillance monitorings to verify that no Ae. albopictus with high virus transmission capacity is introduced into Europe. Graphic Abstract: [Figure not available: see fulltext.] © 2021, The Author(s)