[The mosquitoes (Diptera: Culicidae) of Djibouti: bibliographical review (1970-2023)]. / Les moustiques (Diptera : Culicidae) de Djibouti : revue bibliographique (1970-2023).

Background and justification: The Republic of Djibouti is located in the Horn of Africa, on the Gulf of Aden and the Bab-el-Mandeb detroit, at the southern entrance to the Red Sea. Prior to its independence in 1977, the Republic of Djibouti was known by two names: "Côte française des Somalis" until 1967, then "Territoire Français de Afars et Issas". As part of our doctoral research on the ecology of mosquitoes in Djibouti, we noted a lack of information on the species encountered, and felt it essential to draw up a list of species before embarking on ecological monitoring. The aim of this work is to survey publications on mosquitoes in Djibouti and to synthesize data from this scientific literature in order to update the national inventory of Culicidae. Materials and methods: An exhaustive search of electronic bibliographic databases (PubMed, Scopus, HAL Open Archive, Science Direct and Google Scholar) was carried out. Reference lists were filtered to access additional articles in order to obtain more data. Two keywords were used: "Djibouti" and "French Territory of Afars and Issas". A selection of scientific publications on Djibouti mosquitoes and/or diseases transmitted by mosquito vectors was made. Researches were conducted in articles selected. The names of the species listed were checked and validated by referring to the site Mosquito Taxonomic Inventory. Results: A total of 13 studies, published between 1970 and 2023, were found. Over the years, the composition of the Culicidae fauna has become well known. In part, the movement of people traveling to and from neighboring countries has been linked to the detection of new species and the reappearance of mosquito species in Djibouti. Numerous studies have been carried out over the years, including purely taxonomic studies and others focusing on the incrimination of mosquito vectors and the characterization of the pathogens they transmit. A total of 37 species, belonging to two subfamilies (Anophelinae and Culicinae), of mosquitoes divided between 7 genera (Aedes, Anopheles, Culex, Culiseta, Lutzia, Mimomyia and Uranotaenia) have been mentioned across the country. The number of species per genus is distributed as follows: 5 species of Aedes including 1 subspecies, 14 species of Anopheles including two subspecies, 12 species of Culex including 1 subspecies, 1 species for each of the genera Culiseta and Lutzia and finally 2 species respectively for the genera Mimomiya and Uranotaenia. Five species have been incriminated as vectors of diseases such as malaria, dengue fever, yellow fever, West Nile virus and chikungunya. Others are known for their potential role in pathogen transmission, including Zika and Rift Valley virus. Discussion - Conclusion: The bibliographical research enabled us to summarize the research carried out over more than half a century in the history of Djibouti, and to update the inventory of the country's mosquitoes, which now includes 37 species. Species names were reviewed and updated, and the case of Anopheles gambiae was also addressed. Two species mentioned as part of the Culicidae fauna of Djibouti appeared to be doubtful and are up for discussion. These results provide a useful information base for defining vector control priorities in Djibouti. They will also inform, guide and facilitate future consultations of our database. In addition, this study will help to identify research ways on mosquitoes in Djibouti.

A DNA barcode reference library of Croatian mosquitoes (Diptera: Culicidae): implications for identification and delimitation of species, with notes on the distribution of potential vector species.

BACKGROUND: Mosquitoes pose a risk to human health worldwide, and correct species identification and detection of cryptic species are the most important keys for surveillance and control of mosquito vectors. In addition to traditional identification based on morphology, DNA barcoding has recently been widely used as a complementary tool for reliable identification of mosquito species. The main objective of this study was to create a reference DNA barcode library for the Croatian mosquito fauna, which should contribute to more accurate and faster identification of species, including cryptic species, and recognition of relevant vector species. METHODS: Sampling was carried out in three biogeographical regions of Croatia over six years (2017-2022). The mosquitoes were morphologically identified; molecular identification was based on the standard barcoding region of the mitochondrial COI gene and the nuclear ITS2 region, the latter to identify species within the Anopheles maculipennis complex. The BIN-RESL algorithm assigned the COI sequences to the corresponding BINs (Barcode Index Number clusters) in BOLD, i.e. to putative MOTUs (Molecular Operational Taxonomic Units). The bPTP and ASAP species delimitation methods were applied to the genus datasets in order to verify/confirm the assignment of specimens to specific MOTUs. RESULTS: A total of 405 mosquito specimens belonging to six genera and 30 morphospecies were collected and processed. Species delimitation methods assigned the samples to 31 (BIN-RESL), 30 (bPTP) and 28 (ASAP) MOTUs, with most delimited MOTUs matching the morphological identification. Some species of the genera Culex, Aedes and Anopheles were assigned to the same MOTUs, especially species that are difficult to distinguish morphologically and/or represent species complexes. In total, COI barcode sequences for 34 mosquito species and ITS2 sequences for three species of the genus Anopheles were added to the mosquito sequence database for Croatia, including one individual from the Intrudens Group, which represents a new record for the Croatian mosquito fauna. CONCLUSION: We present the results of the first comprehensive study combining morphological and molecular identification of most mosquito species present in Croatia, including several invasive and vector species. With the exception of some closely related species, this study confirmed that DNA barcoding based on COI provides a reliable basis for the identification of mosquito species in Croatia.

Genetic variability of Aedes aegypti (Diptera: Culicidae) in El Salvador and Honduras: presence of a widespread haplotype and implications for mosquito control.

BACKGROUND: This study examined population genetics of Aedes aegypti in El Salvador and Honduras, two adjacent countries in Central America. Aedes aegypti is associated with yellow fever, dengue, chikungunya, and Zika. Each year, thousands of cases of dengue are typically reported in El Salvador and Honduras. METHODS: In El Salvador, collections were obtained from five Departments. In Honduras, samples were obtained from six municipalities in four Departments. Mitochondrial DNA cytochrome oxidase I (COI) was sequenced, and consensus sequences were combined with available sequences from El Salvador to determine haplotype number, haplotype diversity, nucleotide diversity, and Tajima's D. A haplotype network was produced to examine the relationship between genotypes. RESULTS: In El Salvador, there were 17 haplotypes, while in Honduras there were 4 haplotypes. In both El Salvador and Honduras, Haplotype 1 is most abundant and widespread. In El Salvador, haplotype H2 was also widespread in 10 of 11 sampled municipalities, but it was not present in Honduras. The capital of El Salvador (San Salvador) and the eastern region of ES had the highest haplotype diversity of regions sampled. CONCLUSIONS: Haplotype 1 and H2 each belong to different phylogenetic lineages of Ae. aegypti. The most geographically widespread haplotype (H1) may have been present the longest and could be a remnant from previous eradication programs. These data may contribute to future control programs for Ae. aegypti in the two countries.

Island mosquitoes of Thailand: an update on species diversity and DNA barcoding.

Mosquitoes (Diptera: Culicidae) are among the most medically significant insects, with several species acting as vectors for human pathogens. Although there are frequent reports of mosquito-borne diseases in the border island areas of Thailand, comprehensive data on the diversity and DNA barcoding of these mosquito species remain limited. This study investigated mosquito diversity in two main archipelagos in Thailand-the Trat archipelago (comprising Chang Island and Kood Island) and the Ranong archipelago (comprising Chang Island and Phayam Island)-and generated DNA barcode data from the mosquitoes found there. The survey across these islands discovered a total of 41 species, highlighting the presence of several species known to be vectors for human diseases. Thirty-seven mosquito species from the island areas were documented to provide reference DNA barcode sequences for mosquitoes in Thailand's island regions. Two species, Aedes fumidus and Finlaya flavipennis, have been added as new COI sequence records in the database. DNA barcoding was highly effective in classifying almost all species by identifying barcoding gaps, except for Anopheles baimaii and Anopheles dirus, which could not be distinguished. Additionally, the study noted that geographical variations might influence certain mosquito species, such as Anopheles barbirostris A3 and Mansonia dives, causing them to be split into two distinct subgroups. The findings of this study are crucial, as they aid in classifying mosquito species using molecular techniques and expand our knowledge of disease vectors in these biodiverse regions.

Application of computer vision and deep learning models to automatically classify medically important mosquitoes in North Borneo, Malaysia.

Mosquito-borne diseases have emerged in North Borneo in Malaysia due to rapid changes in the forest landscape, and mosquito surveillance is key to understanding disease transmission. However, surveillance programmes involving sampling and taxonomic identification require well-trained personnel, are time-consuming and labour-intensive. In this study, we aim to use a deep leaning model (DL) to develop an application capable of automatically detecting mosquito vectors collected from urban and suburban areas in North Borneo, Malaysia. Specifically, a DL model called MobileNetV2 was developed using a total of 4880 images of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus mosquitoes, which are widely distributed in Malaysia. More importantly, the model was deployed as an application that can be used in the field. The model was fine-tuned with hyperparameters of learning rate 0.0001, 0.0005, 0.001, 0.01 and the performance of the model was tested for accuracy, precision, recall and F1 score. Inference time was also considered during development to assess the feasibility of the model as an app in the real world. The model showed an accuracy of at least 97%, a precision of 96% and a recall of 97% on the test set. When used as an app in the field to detect mosquitoes with the elements of different background environments, the model was able to achieve an accuracy of 76% with an inference time of 47.33 ms. Our result demonstrates the practicality of computer vision and DL in the real world of vector and pest surveillance programmes. In the future, more image data and robust DL architecture can be explored to improve the prediction result.

Surveillance of mosquitoes harnessing their buzzing sound.

Mosquito surveillance for vector-borne disease management relies on traditional morphological and molecular techniques, which are tedious, time-consuming, and costly. The present study describes a simple and efficient recording device that analyzes mosquito sound to estimate species composition, male-female ratio, fed-unfed status, and harmonic convergence interaction using fundamental frequency (F0) bandwidth, harmonics, amplitude, and combinations of these parameters. The study examined a total of 19 mosquito species, including 3 species of Aedes, 7 species of Anopheles, 1 species of Armigeres, 5 species of Culex, 1 species of Hulecoetomyia, and 2 species of Mansonia. Among them, the F0 ranges between 269.09 ± 2.96 Hz (Anopheles culiciformis) to 567.51 ± 3.82 Hz (Aedes vittatus) and the harmonic band (hb) number ranges from 5 (An. culiciformis) to 12 (Ae. albopictus). In terms of species identification, the success rate was 95.32 % with F0, 84.79 % with F0-bandwidth, 84.79 % with harmonic band (hb) diversity, and 49.7 % with amplitude (dB). The species identification rate has gone up to 96.50 % and 97.66 % with the ratio and multiplication of F0 and hb, respectively. This is because of the matrices that combine multiple sound attributes. Comparatively, combinations of the amplitude of the F0 and the higher harmonic frequency band were non-significant for species identification (60.82 %). The fed females have shown a considerable increase in F0 in comparison to the unfed. The males of all the species possessed significantly higher frequencies with respect to the females. Interestingly, the presence of male-female of Ae. vittatus together showed harmonic convergence between the 2nd and 3rd harmonic bands. In conclusion, the sound-based technology is simple, precise, and cost-effective and provides better resolution for species, sex, and fed-unfed status detection in comparison to conventional methods. Real-time surveillance of mosquitoes could potentially utilize this technology.

Kenya must wake up to the threat of cryptic Anopheles species and their impact on residual malaria transmission.

Malaria remains a major health problem in Kenya despite the huge efforts put in place to control it. The non-relenting malaria threat has partly been attributed to residual malaria transmission driven by vectors that cannot effectively be controlled by the two popularly applied control methods: long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). Reports indicate that residual transmission is widely spread in areas where malaria is endemic. This could mean that the World Health Organization's vision of a world free of malaria remains a mirage as elimination and prevention of re-establishment of malaria are rendered unachievable. Amongst the major contributors to residual malaria transmission are cryptic rare species, species of mosquitoes that are morphologically indistinguishable, but isolated genetically, that have not been the focus of malaria control programs. Recent studies have reported extensive new Anopheles cryptic species believed to be involved in malaria transmission in Kenya. This underscores the need to understand these malaria vector species, their distribution and bionomics and their impact on malaria transmission. This article discusses reports of these cryptic species, their importance to malaria transmission, especially in the arid and semi-arid areas, and what can be done to mitigate the situation.

Mosquito population structure, pathogen surveillance and insecticide resistance monitoring in urban regions of Crete, Greece.

BACKGROUND: In Greece vector borne diseases (VBD) and foremost West Nile virus (WNV) pose an important threat to public health and the tourist industry, the primary sector of contribution to the national economy. The island of Crete, is one of Greece's major tourist destinations receiving annually over 5 million tourists making regional VBD control both a public health and economic priority. METHODOLOGY: Under the auspices of the Region of Crete, a systematic integrative surveillance network targeting mosquitoes and associated pathogens was established in Crete for the years 2018-2020. Using conventional and molecular diagnostic tools we investigated the mosquito species composition and population dynamics, pathogen infection occurrences in vector populations and in sentinel chickens, and the insecticide resistance status of the major vector species. PRINCIPAL FINDINGS: Important disease vectors were recorded across the island including Culex pipiens, Aedes albopictus, and Anopheles superpictus. Over 75% of the sampled specimens were collected in the western prefectures potentially attributed to the local precipitation patterns, with Cx. pipiens being the most dominant species. Although no pathogens (flaviviruses) were detected in the analysed mosquito specimens, chicken blood serum analyses recorded a 1.7% WNV antibody detection rate in the 2018 samples. Notably detection of the first WNV positive chicken preceded human WNV occurrence in the same region by approximately two weeks. The chitin synthase mutation I1043F (associated with high diflubenzuron resistance) was recorded at an 8% allelic frequency in Lasithi prefecture Cx. pipiens mosquitoes (sampled in 2020) for the first time in Greece. Markedly, Cx. pipiens populations in all four prefectures were found harboring the kdr mutations L1014F/C/S (associated with pyrethroid resistance) at a close to fixation rate, with mutation L1014C being the most commonly found allele (≥74% representation). Voltage gated sodium channel analyses in Ae. albopictus revealed the presence of the kdr mutations F1534C and I1532T (associated with putative mild pyrethroid resistance phenotypes) yet absence of V1016G. Allele F1534C was recorded in all prefectures (at an allelic frequency range of 25-46.6%) while I1532T was detected in populations from Chania, Rethymnon and Heraklion (at frequencies below 7.1%). Finally, no kdr mutations were detected in the Anopheles specimens included in the analyses. CONCLUSIONS/SIGNIFICANCE: The findings of our study are of major concern for VBD control in Crete, highlighting (i) the necessity for establishing seasonal integrated entomological/pathogen surveillance programs, supporting the design of targeted vector control responses and; ii) the need for establishing appropriate insecticide resistance management programs ensuring the efficacy and sustainable use of DFB and pyrethroid based products in vector control.

Molecular and functional characterization of a conserved odorant receptor from Aedes albopictus.

BACKGROUND: The Asian tiger mosquito Aedes albopictus is a competent vector of several viral arboviruses including yellow fever, dengue fever, and chikungunya. Several vital mosquito behaviors (e.g., feeding, host-seeking, mating, and oviposition) are primarily dependent on the olfactory system for semiochemicals detection and discrimination. However, the limited number of studies hampers our understanding of the relationships between the Ae. albopictus olfactory system and the complex chemical world. METHODS: We performed RT-qPCR assay on antennae of Ae. albopictus mosquitoes of different sexes, ages and physiological states, and found odorant receptor 11 (AalbOr11) enriched in non-blood-fed female mosquitoes. Then, we examined the odorant preference with a panel of physiologically and behaviorally relevant odorants in Xenopus oocytes. RESULTS: The results indicated that AalbOr11 could be activated by ten aromatics, seven terpenes, six heterocyclics, and three alcohols. Furthermore, using post-RNA interference (RNAi) hand-in-cage assay, we found that reducing the transcript level of AalbOr11 affected the repellency activity mediated by (+)-fenchone at a lower concentration (0.01% v/v). CONCLUSIONS: Using in vitro functional characterization, we found that AalbOr11 was a broadly tuned receptor. Moreover, we found that AalbOr11 shared a conserved odorant reception profile with homologous Anopheles gambiae Or11. In addition, RNAi and bioassay suggested that AablOr11 might be one of the receptors mediating (+)-fenchone repellency activity. Our study attempted to link odor-induced behaviors to odorant reception and may lay the foundation for identifying active semiochemicals for monitoring or controlling mosquito populations.

Adult Anopheles Mosquito Distribution at a Low and High Malaria Transmission Site in Tanzania.

Malaria parasites are only transmitted by female mosquitoes of the genus Anopheles; hence, the disease's distribution is linked to that of the vector mosquitoes. As such, the goal of this study was to find out the spatial and temporal distribution of Anopheles mosquito adults in the research sites. This was a repeated cross-sectional ecological study that took place in Morogoro and Dodoma, Tanzania. Vacuum aspiration was used to collect mosquitoes both outside and inside human dwellings. All mosquito-related data was collected and entered into appropriate data collection forms. Female mosquitoes were recognized morphologically using Gillies and Coetzee morphological criteria, followed by PCR. In total, about 2742 Anopheles mosquitoes with an average collection of 18.21 ± 1.12 per day were collected outside human houses of which 1717 (10.51 ± 1.17) and 1025 (8.42 ± 1.41) were collected from Morogoro and Dodoma, respectively. Of the captured mosquitoes, 89.0%, 10.0%, and 1.0% were recognized as Anopheles arabiensis, Anopheles gambiae s.s., and Anopheles quadrianulatus, respectively. The distribution varied significantly with seasons, whereby 302 (4.72 ± 1.04) and 2440 (12.96 ± 1.52) mosquitoes were captured in the cold-dry and warm-wet season, respectively (p < 0.0001). Of the captured mosquitoes, 42.33%, 16.33%, 14.96%, and 4.27 were found on the ceiling, stored junks, verandas, and barks/tree, respectively. In malaria-endemic countries, vector control forms an important component of the malaria control efforts. This study found significant variation of Anopheles mosquito abundance in time and space with Anopheles arabiensis being the most predominant malaria vector. This signifies the need to introduce mosquito control methods that will target the less anthropophilic Anopheles arabiensis or the immature aquatic stages. The study further found that underbeds, store room/piled bags, and undisturbed curtains were the most preferred resting places by mosquitoes signifying to be the most effective strategic sites for spraying insecticides during the implementation of indoor residual spraying (IRS).

Seasonal Dynamics of Mosquito-Borne Viruses in the Southwestern Florida Everglades, 2016, 2017.

Mosquitoes were collected for 12 consecutive months beginning June 2016, from 11 locations in the Florida Everglades, Collier County, and tested for viruses by isolation in Vero cells and subsequent identification. One species complex and 31 species of mosquitoes were identified from 668,809 specimens. Ochlerotatus taeniorhynchus comprised 72.2% of the collection. Other notable species were Anopheles crucians complex, Culex nigripalpus, Cx. erraticus, and Cx. cedecei. Seven species of virus were identified from 110 isolations: Everglades, Gumbo Limbo, Mahogany Hammock, Pahayokee, Shark River, Tensaw, and West Nile viruses. Everglades, West Nile, Tensaw, and Mahogany Hammock viruses were most frequently isolated. Largest numbers of viruses were identified from Cx. cedecei, Cx. nigripalpus, and An. crucians complex. Five species of virus were isolated from Cx. cedecei. Viruses were isolated from mangrove, cypress swamp, hardwood hammock, and sawgrass habitats. West Nile virus was isolated August through October when Cx. nigripalpus was most abundant. Everglades virus was the most frequently isolated virus from nine species of mosquitoes collected from June through August. Tensaw virus was isolated primarily from Anopheles species. Isolations were made in July, August, January, February, and April, suggesting that this virus may be present in host-seeking mosquitoes throughout the year. Mahogany Hammock, Shark River, Gumbo Limbo, and Pahayokee viruses were isolated primarily from Cx. cedecei from June through December. Shotgun metagenomic sequencing was used to document that seven pools of Cx. cedecei were infected with two arboviruses. As communities expand into the Everglades, more humans will become exposed to arboviruses.

Ecological and environmental factors affecting transmission of sylvatic yellow fever in the 2017-2019 outbreak in the Atlantic Forest, Brazil.

BACKGROUND: Yellow fever virus (YFV) is an arbovirus that, despite the existence of a safe and effective vaccine, continues to cause outbreaks of varying dimensions in the Americas and Africa. Between 2017 and 2019, Brazil registered un unprecedented sylvatic YFV outbreak whose severity was the result of its spread into zones of the Atlantic Forest with no signals of viral circulation for nearly 80 years. METHODS: To investigate the influence of climatic, environmental, and ecological factors governing the dispersion and force of infection of YFV in a naïve area such as the landscape mosaic of Rio de Janeiro (RJ), we combined the analyses of a large set of data including entomological sampling performed before and during the 2017-2019 outbreak, with the geolocation of human and nonhuman primates (NHP) and mosquito infections. RESULTS: A greater abundance of Haemagogus mosquitoes combined with lower richness and diversity of mosquito fauna increased the probability of finding a YFV-infected mosquito. Furthermore, the analysis of functional traits showed that certain functional groups, composed mainly of Aedini mosquitoes which includes Aedes and Haemagogus mosquitoes, are also more representative in areas where infected mosquitoes were found. Human and NHP infections were more common in two types of landscapes: large and continuous forest, capable of harboring many YFV hosts, and patches of small forest fragments, where environmental imbalance can lead to a greater density of the primary vectors and high human exposure. In both, we show that most human infections (~ 62%) occurred within an 11-km radius of the finding of an infected NHP, which is in line with the flight range of the primary vectors. CONCLUSIONS: Together, our data suggest that entomological data and landscape composition analyses may help to predict areas permissive to yellow fever outbreaks, allowing protective measures to be taken to avoid human cases.

Temporally consistent predominance and distribution of secondary malaria vectors in the Anopheles community of the upper Zambezi floodplain.

Regional optimisation of malaria vector control approaches requires detailed understanding both of the species composition of Anopheles mosquito communities, and how they vary over spatial and temporal scales. Knowledge of vector community dynamics is particularly important in settings where ecohydrological conditions fluctuate seasonally and inter-annually, such as the Barotse floodplain of the upper Zambezi river. DNA barcoding of anopheline larvae sampled in the 2019 wet season revealed the predominance of secondary vector species, with An. coustani comprising > 80% of sampled larvae and distributed ubiquitously across all ecological zones. Extensive larval sampling, plus a smaller survey of adult mosquitoes, identified geographic clusters of primary vectors, but represented only 2% of anopheline larvae. Comparisons with larval surveys in 2017/2018 and a contemporaneous independent 5-year dataset from adult trapping corroborated this paucity of primary vectors across years, and the consistent numerical dominance of An. coustani and other secondary vectors in both dry and wet seasons, despite substantial inter-annual variation in hydrological conditions. This marked temporal consistency of spatial distribution and anopheline community composition presents an opportunity to target predominant secondary vectors outdoors. Larval source management should be considered, alongside prevalent indoor-based approaches, amongst a diversification of vector control approaches to more effectively combat residual malaria transmission.

Landscape Anthropization Affects Mosquito Diversity in a Deciduous Forest in Southeastern Mexico.

Mosquitoes (Diptera: Culicidae) are considered the group of insects that most impacts human health. Land use change, conversion of conserved sites into agricultural environments, urbanization, defaunation, and introduction of domestic animals can affect mosquito diversity positively or negatively, increasing the risk of transmission of zoonotic diseases. Here, we describe the diversity of adult mosquitoes in two environments (deciduous forest and anthropized zone) over 2 yr (2014-2016), using eight CDC traps at each site in three climatic seasons (rainy, cold, and dry). We captured 795 individuals belonging to 22 species. We constructed rank-abundance curves to determine spatial and temporal changes in the mosquito communities. We measured alpha diversity using the Shannon index (H'), Shannon exponential (eH) and Simpson dominance (Ds), and beta diversity using Jaccard's coefficient of similarity (Ij). The most abundant species were Culex quinquefasciatus (40.5%), Culex coronator (18.3%), and Anopheles pseudopunctipennis (12.4%). The highest mosquito diversity was in the deciduous forest during the rainy season. Beta diversity analysis showed that species overlap varied among climatic seasons, with the sites sharing 65% species during the rainy season, but only 33% of species during the dry season. We found differences in the diversity of mosquitoes at the two sites, and the mosquito assemblage of the anthropized zone was significantly different from that of the deciduous forest.

First Evidence of West Nile Virus Overwintering in Mosquitoes in Germany.

Mosquitoes collected from mid-December 2020 to early March 2021 from hibernacula in northeastern Germany, a region of West Nile virus (WNV) activity since 2018, were examined for WNV-RNA. Among the 6101 mosquitoes tested in 722 pools of up to 12 specimens, one pool of 10 Culex pipiens complex mosquitoes collected in early March 2021 in the cellar of a medieval castle in Rosslau, federal state of Saxony-Anhalt, tested positive. Subsequent mosquito DNA analysis produced Culex pipiens biotype pipiens. The pool homogenate remaining after nucleic acid extraction failed to grow the virus on Vero and C6/36 cells. Sequencing of the viral NS2B-NS3 coding region, however, demonstrated high homology with virus strains previously collected in Germany, e.g., from humans, birds, and mosquitoes, which have been designated the East German WNV clade. The finding confirms the expectation that WNV can overwinter in mosquitoes in Germany, facilitating an early start to the natural transmission season in the subsequent year. On the other hand, the calculated low infection prevalence of 0.016-0.20%, depending on whether one or twelve of the mosquitoes in the positive pool was/were infected, indicates a slow epidemic progress and mirrors the still-hypoendemic situation in Germany. In any case, local overwintering of the virus in mosquitoes suggests its long-term persistence and an enduring public health issue.

Diversidad, riqueza de especies y abundancia relativa de mosquitos adultos (Diptera: Culicidae) en localidades del municipio Gran Sabana, edo. Bolívar / Diversity, species richness and relative abundance of adult mosquitoes (Diptera: Culicidae) in localities of the Gran Sabana municipality, Bolívar state

Este estudio forma parte de la primera etapa de una serie de estudios sobre la ecología, biodiversidad y biogeografía de los mosquitos de la familia Culicidae de Venezuela, principalmente en Bolívar y Delta Amacuro. El objetivo del estudio fue caracterizar la composición de especies, la abundancia y la biodiversidad de mosquitos (Diptera; Culicidae) en el municipio Gran Sabana del estado Bolívar. Las capturas de mosquitos adultos se realizaron con aspiradores bucales mediante capturas por atracción al cebo humano y con trampas de luz negra. Se determinó la riqueza de especies, su abundancia relativa e índices ecológicos de diversidad Shannon-Wiener (H'), equidad de Simpson (E) y dominancia-D, del área general de estudio y sitios o comunidades de muestreo. Los resultados del estudio, generaron el registro de 7.860 ejemplares adultos de Culicidae identificados a nivel de especie, pertenecientes a 69 especies y 17 géneros, de ellos 7.797 (99,19%) fueron hembras adultas capturadas picando o con trampas de luz y 63 (0,81%) fueron machos capturados con trampas de luz. El 16,6% (1.297) de las hembras fue atraído por trampas de luz y el 83,4% (6.500) por cebo humano. Entre las especies más abundantes del estudio están: Culex quinquefasciatus (26,67 %), Anopheles peryassui (12,32 %), Aedes aegypti (11,87 %), Coquilletidia juxtamansonia (8,28 %), Anopheles braziliensis (6,97 %) Anopheles triannulatus s.l. (6,39 %), Coquilletidia nigricans (2,88 %), Coquilletidia venezuelensis (2,51 %) y Anopheles albitarsis s.l. (2,44 %), las cuales en conjunto representan 80,33 % del total de adultos capturado. Se discuten algunos aspectos sobre su ecología, importancia médica y el riesgo epidemiológico que representan para el país algunas especies reportadas. La diversidad de Shannon-Wiener (H') del área general de estudio fue de 2,665, la equidad de Simpson (E) fue igual a 0,8787222 y la dominancia (D) fue de 0,1213. El mayor índice de diversidad (Shannon-Wiener) ocurrió en Chiririka (2,675), seguido de Betania (2,409), Santa Elena Capital (2,354), Manak-Krü (2,203) y Waramasén (2,181). En cuanto a la riqueza de especies por localidad, las comunidades con mayor riqueza de especies fueron: Santa Elena (Capital), Waramasén y Chiririka con 50, 35 y 30 especies respectivamente, seguidas por San Antonio del Morichal con 23 y Kinok-Pon Parú, con 22 especies(AU)

This is the first part of a series of studies related to biodiversity, ecological and biogeographic aspects of the mosquitoes of Culicidae family in Venezuela. The objective of this study was the ecological characterization of species composition, diversity and abundance of Culicidae mosquitoes (Diptera: Culicidae) in the Gran Sabana Municipality, Bolívar State. Mosquitoes were captured in adult collections, with aspirators on human landing catches and with black light traps. A total of 7.860 adult's mosquitoes were collected and 69 species and 17 genera of Culicidae were identified. A total of 7.797 mosquitoes (99.19%) were females and 63 (0,81%) were males. Some 16,6 % (1.297) of females mosquitoes were attracted to the light traps and 83,4% (6.500) to human bait. The most abundant species in adult stage were: Culex quinquefasciatus (26,67%), Anopheles peryassui (12,32 %), Aedes aegypti (11,87 %), Coquilletidia juxtamansonia (8,28%), Anopheles braziliensis (6,97%), Anopheles triannulatus s.l. (6,39%), Coquilletidia nigricans (2,88%), Coquilletidia venezuelensis (2,51%) and Anopheles albitarsis s.l. (2,44%). Their medical importance of some mosquito species is commented, and some ecological and epidemiological aspects of the mosquito reported are discussed. The diversity index (Shannon-Wiener) of the estudy area was 2,665, the Simpson equity index was 0, 8787222 and the index of dominance was 0, 1213. The higher diversity index was registered in Chiririka (2,675), Betania (2,409), Santa Elena Capital (2,354), Manak-Krü (2,203) and Waramasén (2,181). The higher species richness was registered in Santa Elena (50 species), Waramasén (35 species), Chiririka (30 species), San Antonio del Morichal (23 species) and Kinok-Pon Parú (22 species) (AU)

An unwanted companion reaches the country: the first record of the alien mosquito Aedes japonicus japonicus (Theobald, 1901) in Slovakia.

BACKGROUND: Invasive mosquitoes of the genus Aedes are quickly spreading around the world. The presence of these alien species is concerning for both their impact on the native biodiversity and their high vector competence. The surveillance of Aedes invasive mosquito (AIM) species is one of the most important steps in vector-borne disease control and prevention. METHODS: In 2020, the monitoring of AIM species was conducted in five areas (Bratislava, Zvolen, Banská Bystrica, Presov, Kosice) of Slovakia. The sites were located at points of entry (border crossings with Austria and Hungary) and in the urban and rural zones of cities and their surroundings. Ovitraps were used at the majority of sites as a standard method of monitoring. The collected specimens were identified morphologically, with subsequent molecular identification by conventional PCR (cox1) and Sanger sequencing. The phylogenetic relatedness of the obtained sequences was inferred by the maximum likelihood (ML) method. The nucleotide heterogeneity of the Slovak sequences was analysed by the index of disparity. RESULTS: A bush mosquito, Aedes japonicus japonicus, was found and confirmed by molecular methods in three geographically distant areas of Slovakia-Bratislava, Zvolen and Presov. The presence of AIM species is also likely in Kosice; however, the material was not subjected to molecular identification. The nucleotide sequences of some Slovak strains confirm their significant heterogeneity. They were placed in several clusters on the ML phylogenetic tree. Moreover, Ae. j. japonicus was discovered in regions of Slovakia that are not close to a point of entry, where the mosquitoes could find favourable habitats in dendrothelms in city parks or forests. CONCLUSION: Despite being a first record of the Ae. j. japonicus in Slovakia, our study indicates that the established populations already exist across the country, underlining the urgent need for intensified surveillance of AIM species as well as mosquito-borne pathogens.

The invasive Korean bush mosquito Aedes koreicus (Diptera: Culicidae) in Germany as of 2020.

BACKGROUND: The Korean bush mosquito Aedes koreicus was recently reported to have established a population in western Germany (Wiesbaden) in 2016. The species is difficult to distinguish morphologically from its close relative, the invasive Japanese bush mosquito Ae. japonicus, which is already widely distributed in many parts of Germany, including the area colonised by Ae. koreicus. Genetic confirmation of morphologically identified "Ae. japonicus" collection material, however, had only been done exceptionally before the German Ae. koreicus population became known. METHODS: Dried archived "Ae. japonicus" specimens both from the municipality of Wiesbaden and from deliberately and randomly selected distribution sites all over Germany were re-examined morphologically and genetically for admixture by Ae. koreicus. Moreover, cemeteries in the greater Wiesbaden area were sampled in 2019 and 2020 to check for Ae. koreicus spread. Korean and Japanese bush mosquitoes submitted to the German citizen science mosquito monitoring scheme "Mueckenatlas" in 2019 and 2020 were also subjected to particularly thorough species identification. The ND4 DNA sequences generated in this study in the context of species identification were phylogenetically compared to respective GenBank entries of Ae. koreicus. As a by-product, several genetic markers were evaluated for their suitability to identify Ae. koreicus. RESULTS: Aedes koreicus specimens could be identified in mosquito collection material and submissions from Wiesbaden from 2015 onwards, suggesting establishment to have happened in the same year as Ae. japonicus establishment. Detections of Ae. koreicus from 2019 and 2020 in Wiesbaden indicate a negligible enlargement of the populated area as described for 2018. Two Ae. koreicus specimens were also submitted from the city of Munich, southern Germany, in 2019 but further specimens could not be identified during immediate local inspections. Comparison of ND4 sequences generated in this and other studies demonstrate a high degree of homology, suggesting that this DNA region is not informative enough for clarification of origins and relationships of Ae. koreicus populations. For genetic identification of Ae. koreicus, PCR primers used for classical CO1 barcoding were found to lead to mismatches and produce no or incorrect amplicons. Alternative CO1 primers or a validated ND4 marker should be used instead. CONCLUSIONS: Aedes koreicus is probably introduced into Germany every now and then but rarely succeeds in becoming established. As with most European populations, the German population is characterised by a limited expansion tendency. Since Ae. koreicus is a potential vector, however, Asian bush mosquitoes found at new places should be examined quite carefully and known distribution areas of Ae. japonicus regularly checked for the presence of Ae. koreicus.

The first record of the invasive mosquito species Aedes albopictus in Chisinӑu, Republic of Moldova, 2020.

BACKGROUND: In Europe, Aedes albopictus is an important vector of chikungunya virus and Dirofilaria nematodes and has been involved in local autochthonous circulation of dengue and Zika viruses. Due to the ongoing spread, targeted field surveillance at potential points of entry of invasive Aedes mosquitoes was initiated by the Republic of Moldova in 2020 as part of the transboundary "Invasive Aedes Mosquitoes COST-Action project." METHODS: In 2020, ovitraps were positioned at each of three locations: the border crossing to Romania in Leuseni (Hancesti region), Chisinӑu International Airport and Chisinӑu Botanical Garden. RESULTS: A total of 188 Aedes spp. eggs were collected at the Chisinӑu International Airport between August and September 2020. Twenty-three adults reared in the laboratory were identified morphologically as Ae. albopictus (Skuse, 1895), and 12 selected specimens were confirmed by molecular barcoding of the cytochrome oxidase subunit I gene region. In addition, one adult Ae. albopictus female at the same site was caught with a manual aspirator. CONCLUSIONS: This is the first documented report of Ae. albopictus in the Republic of Moldova. The presence of immature and adult stages indicates the local reproduction of the species in the country. Therefore, it is crucial to extend and strengthen surveillance of the invasive Aedes mosquitoes to prevent Ae. albopictus and other exotic mosquito species from becoming established in the Republic of Moldova.

Phylogenetic analysis of the Neotropical Albitarsis Complex based on mitogenome data.

BACKGROUND: Some of the most important malaria vectors in South America belong to the Albitarsis Complex (Culicidae; Anophelinae; Anopheles). Understanding the origin, nature, and geographical distribution of species diversity in this important complex has important implications for vector incrimination, control, and management, and for modelling future responses to climate change, deforestation, and human population expansion. This study attempts to further explore species diversity and evolutionary history in the Albitarsis Complex by undertaking a characterization and phylogenetic analysis of the mitogenome of all 10 putative taxa in the Albitarsis Complex. METHODS: Mitogenome assembly and annotation allowed for feature comparison among Albitarsis Complex and Anopheles species. Selection analysis was conducted across all 13 protein-coding genes. Maximum likelihood and Bayesian inference methods were used to construct gene and species trees, respectively. Bayesian methods were also used to jointly estimate species delimitation and species trees. RESULTS: Gene composition and order were conserved across species within the complex. Unique signatures of positive selection were detected in two species-Anopheles janconnae and An. albitarsis G-which may have played a role in the recent and rapid diversification of the complex. The COI gene phylogeny does not fully recover the mitogenome phylogeny, and a multispecies coalescent-based phylogeny shows that considerable uncertainty exists through much of the mitogenome species tree. The origin of divergence in the complex dates to the Pliocene/Pleistocene boundary, and divergence within the distinct northern South American clade is estimated at approximately 1 million years ago. Neither the phylogenetic trees nor the delimitation approach rejected the 10-species hypothesis, although the analyses could not exclude the possibility that four putative species with scant a priori support (An. albitarsis G, An. albitarsis H, An. albitarsis I, and An. albitarsis J), represent population-level, rather than species-level, splits. CONCLUSION: The lack of resolution in much of the species tree and the limitations of the delimitation analysis warrant future studies on the complex using genome-wide data and the inclusion of additional specimens, particularly from two putative species, An. albitarsis I and An. albitarsis J.