Mosquito Species Composition and Abundance in Quebec, Eastern Canada

Molecular Analysis Reveals a High Diversity of Anopheline Mosquitoes in Yanomami Lands and the Pantanal Region of Brazil

Identifying the species of the subfamily Anophelinae that are Plasmodium vectors is important to vector and malaria control. Despite the increase in cases, vector mosquitoes remain poorly known in Brazilian indigenous communities. This study explores Anophelinae mosquito diversity in the following areas: (1) a Yanomami reserve in the northwestern Amazon Brazil biome and (2) the Pantanal biome in southwestern Brazil. This is carried out by analyzing cytochrome c oxidase (COI) gene data using Refined Single Linkage (RESL), Assemble Species by Automatic Partitioning (ASAP), and tree-based multi-rate Poisson tree processes (mPTP) as species delimitation approaches. A total of 216 specimens collected from the Yanomami and Pantanal regions were sequenced and combined with 547 reference sequences for species delimitation analyses. The mPTP analysis for all sequences resulted in the delimitation of 45 species groups, while the ASAP analysis provided the partition of 48 groups. RESL analysis resulted in 63 operational taxonomic units (OTUs). This study expands our scant knowledge of anopheline species in the Yanomami and Pantanal regions. At least 18 species of Anophelinae mosquitoes were found in these study areas. Additional studies are now required to determine the species that transmit Plasmodium spp. in these regions.

Effect of Incandescent Light on Collection of West Nile Virus Vectors Using CDC Miniature Light Traps in Northern Colorado

To evaluate whether the presence of clear incandescent light was attractive or refractive to host-seeking mosquitoes in northern Colorado, a Bayesian hierarchical model was created to measure differences in trap effectiveness based on presence or absence of phototactic cues. A total of eight CDC miniature light traps (with and without light) were set weekly across four locations in northern Colorado between Weeks 23 and 32 of year 2020. Culex mosquitoes (Diptera: Culicidae) accounted for 81% of all collections in this study with two vectors of West Nile virus being represented. The probability of catching both Culex tarsalis Coquillett and Culex pipiens Linnaeus was reduced when traps were equipped with light, but the difference was not statistically significant for Culex tarsalis. The clear reduction in the number of Culex pipiens caught when these traps were equipped with light indicates negative phototactic behavior and underestimation with current surveillance strategies. Removal of light from these traps may aid our understanding of these species' distribution within the environment, improve collection efficiency, and help guide implementation of targeted control measures used in public health mosquito control.

Mosquitoes Know No Borders: Surveillance of Potential Introduction of Aedes Species in Southern Québec, Canada

Current climatic conditions limit the distribution of Aedes (Stegomyia) albopictus (Skuse, Diptera: Culicidae) in the north, but predictive climate models suggest this species could establish itself in southern Canada by 2040. A vector of chikungunya, dengue, yellow fever, Zika and West Nile viruses, the Ae. Albopictus has been detected in Windsor, Ontario since 2016. Given the potential public health implications, and knowing that Aedes spp. can easily be introduced by ground transportation, this study aimed to determine if specimens could be detected, using an adequate methodology, in southern Québec. Mosquitoes were sampled in 2016 and 2017 along the main roads connecting Canada and the U.S., using Biogent traps (Sentinel-2, Gravide Aedes traps) and ovitraps. Overall, 24 mosquito spp. were captured, excluding Ae. Albopictus, but detecting one Aedes (Stegomyia) aegypti (Skuse) specimen (laid eggs). The most frequent species among captured adults were Ochlerotatus triseriatus, Culex pipiens complex, and Ochlerotatus japonicus (31.0%, 26.0%, and 17.3%, respectively). The present study adds to the increasing number of studies reporting on the range expansions of these mosquito species, and suggests that ongoing monitoring, using multiple capture techniques targeting a wide range of species, may provide useful information to public health with respect to the growing risk of emerging mosquito-borne diseases in southern Canada.

Diversity of mosquito fauna (Diptera, Culicidae) in higher-altitude regions of Croatia

Global climate change and the accompanying rise in temperature could affect the biology and ecology of a number of vectors, including mosquitoes. High altitude areas that were previously unsuitable for the spread of mosquito vector populations could become suitable. The aim of this research was to study the distribution of mosquito species in higher altitude regions of Croatia. Samples were collected in three areas: Slavonian Mountains, Gorski Kotar, and Middle Velebit. Specimens were morphologically determined and confirmed by DNA barcoding and other genetic markers and showed the presence of 16 species belonging to six genera. The most abundant species were the Culex pipiens complex with 50% of the collected specimens. Both pipiens (Linnaeus, 1758) and molestus (Forskal, 1775) biotypes and their hybrids were identified within the complex, followed by Culex torrentium (Martini, 1925) (20.2%), Culiseta longiareolata (Macquart, 1838) (8.5%), and the invasive species Aedes japonicus (Theobald, 1901) (7.8% of the total number of collected specimens). The remaining 12 species made up 14.7% of the collected specimens. Intraspecific COI p-distances were within the standard barcoding threshold for OTUs, while interspecific genetic distances were much higher, confirming the existence of barcoding gaps. Mosquito fauna of Croatian mountains showed a moderate variety and made 30.8% of the total number of recorded mosquito species in Croatia thus far.

Modeling host-feeding preference and molecular systematics of mosquitoes in different ecological niches in Canada

Several mosquito-borne viruses (mobovirus) cause infections in Canada. Ecological data on mosquito species and host range in Canada remains elusive. The main aim of the current study is to determine the host range and molecular systematics of mosquito species in Canada. Mosquitoes were collected using BG-Sentinel traps and aspirators at 10 trapping sites in Canada during 2018 and 2019. Mosquitoes collected were identified via morphology and molecular techniques. Mosquito sequences were aligned by MUSCLE algorithm and evolutionary systematics were drawn using MEGA and SDT software. Moreover, the source of blood meals was identified using a DNA barcoding technique. A total of 5,708 female mosquitoes over 34 different taxa were collected. DNA barcodes and evolutionary tree analysis confirmed the identification of mosquito species in Canada. Of the total collected samples, 201 specimens were blood-fed female mosquitoes in 20 different taxa. Four mosquito species represented about half (51.47%) of all collected blood-fed specimens: Aede cinereus (39 specimens, 19.11%), Aedes triseriatus (23, 11.27%), Culex pipiens (22, 10.78%), and Anopheles punctipennis (21, 10.29%). The most common blood meal sources were humans (49 mosquito specimens, 24% of all blood-fed mosquito specimen), pigs (44, 21.5%), American red squirrels (28, 13.7%), white-tailed deers (28, 13.7%), and American crows (16, 7.8%). Here, we present the first analysis of the host-feeding preference of different mosquito species in Canada via molecular techniques. Our results on mosquito distribution and behavior will aid in the development of effective mitigation and control strategies to prevent or reduce human/animal health issues in regards to moboviruses.

Autochthonous Transmission of West Nile Virus by a New Vector in Iran, Vector-Host Interaction Modeling and Virulence Gene Determinants

Using molecular techniques and bioinformatics tools, we studied the vector-host interactions and the molecular epidemiology of West Nile virus (WNV) in western Iran. Mosquitoes were collected during 2017 and 2018. DNA typing assays were used to study vector-host interactions. Mosquitoes were screened by RT-PCR for the genomes of five virus families. WNV-positive samples were fully sequenced and evolutionary tree and molecular architecture were constructed by Geneious software and SWISS-MODEL workspace, respectively. A total of 5028 mosquito specimens were collected and identified. The most prevalent species was Culex (Cx.) pipiens complex (57.3%). Analysis of the blood-feeding preferences of blood-fed mosquitoes revealed six mammalian and one bird species as hosts. One mosquito pool containing non-blood-fed Cx. theileri and one blood-fed Culex pipiens pipiens (Cpp.) biotype pipiens were positive for WNV. A phylogram indicated that the obtained WNV sequences belonged to lineage 2, subclade 2 g. Several amino acid substitutions suspected as virulence markers were observed in the Iranian WNV strains. The three-dimensional structural homology model of the E-protein identified hot spot domains known to facilitate virus invasion and neurotropism. The recent detection of WNV lineage 2 in mosquitoes from several regions of Iran in consecutive years suggests that the virus is established in the country.