First Record of Aedes japonicus japonicus in Oklahoma, 2017

COUNTY RECORDS FOR AEDES JAPONICUS IN GEORGIA

Consolidating and updating distributional data for mosquito species within a state is a good practice. These updates have an immediate impact by providing documented species distribution information for public use and by serving as a resource to researchers who need background information about a species's state distribution. In Georgia, Aedes japonicus, an introduced species, was peer review reported from 7 counties (2002-06): Fulton, Habersham, Lumpkin, Rabun, Towns, Union, and White. No further records were found in peer-reviewed journals or in the Symbiota Collections of Arthropods Network. This study consolidated the 7 peer-reviewed county records for Ae. japonicus with 73 new county records from surveillance data collected by the Georgia Department of Public Health. This study documented the presence of Ae. japonicus in 80 of the 159 counties in Georgia.

Invasive Aedes japonicus Mosquitoes Dominate the Aedes Fauna Collected with Gravid Traps in Wooster, Northeastern Ohio, USA

Aedes japonicus (Diptera: Culicidae), or the Asian rock pool mosquito, is an invasive mosquito in Europe and America. It was first detected outside of Asia in 1990 in Oceania. It has since expanded to North America and Europe in 1998 and 2000, respectively. Even though it is classified as a secondary vector of pathogens, it is competent to several arboviruses and filarial worms, and it is contributing to the transmission of La Crosse virus (LACV) and West Nile virus (WNV). In this study, CDC light, BG-sentinel, and gravid traps were used to collect mosquitoes between June and October 2021, in Wooster, Northeastern Ohio, USA. Morphological identification or/and Sanger sequencing were performed to identify the collected mosquitoes. Our results revealed that (adult) Ae. japonicus mosquitoes were the most abundant mosquito species collected with gravid traps in Wooster in 2021, confirming its establishment in Ohio. Molecular analyses of Ae. japonicus showed 100% nucleotide similarity with Ae. japonicus collected in Iowa (USA) and Canada, suggesting multiple introductions. Its presence may increase the risk of future arbovirus outbreaks in Wooster, Ohio. This study stresses the importance of actively monitoring the density and distribution of all members of the Ae. japonicus complex.

Culex nigripalpus Distribution Expansion: First Record in Virginia, New County Records in North Carolina, and Revised United States Map

Theobald first described Culex nigripalpus in 1901 from St. Lucia Island of the Lesser Antilles. It is a Neotropical mosquito species that is documented throughout Central and South America, the Caribbean, and the southeastern USA. Reports within the last 3 decades show the species has expanded its range farther into North America and is not only being discovered sporadically but appears to be establishing itself in several states, of which data are underreported and difficult to find. Five female specimens were collected-4 on October 13 and 1 on December 6, 2017-at 3 separate sites in the city of Suffolk, VA-2 in a BG-Sentinel 2® trap, 3 in Centers for Disease Control and Prevention light traps-during routine mosquito surveillance; subsequent collections were made in 2019 and 2020. These findings represent the 1st record of Cx. nigripalpus in the state of Virginia and the most northeastern records in the USA. An updated mosquito species checklist for the state of Virginia is provided. Additionally, this report serves to update the records of North Carolina to 28 total counties reporting Cx. nigripalpus. These new records, along with other reports and published studies, show this species now documented in 201 jurisdictions in 16 states of the USA. As recent literature on this species is scarce, we provide a review of the bionomics, defining morphological characters, and an updated US distribution map.

Mosquito-borne parasites in the Great Plains: searching for vectors of nematodes and avian malaria parasites

Vector-borne diseases in the United States have recently increased as a result of the changing nature of vectors, hosts, reservoirs, parasite/pathogens, and the ecological and environmental conditions. While most focus has been on mosquito-borne pathogens affecting humans, little is known regarding parasites of companion animal, livestock and wildlife and their potential mosquito hosts in the United States. This study assessed the prevalence of mature infections of Dirofilaria immitis and avian malaria parasites (Haemosporida) within urban mosquito (Diptera, Culicidae) communities in Oklahoma. 2,620 pools consisting of 12,686 mosquitoes from 13 species collected over two summers were tested for the presence of filarioid and haemosporidian DNA. Dirofilaria immitis-infected mosquitoes were detected only in Aedes albopictus (MIR=0.18-0.22) and Culex pipiens complex (MIR=0.12) collected in cities in central and southern Oklahoma. Two other filarioid nematode species with 91-92% similarity with Onchocerca spp. and Mansonella spp. were also detected. Haemosporidian DNA was detected in 13 mosquito pools (0.9% of pools tested) from seven mosquito species out of 13 species tested. Plasmodium DNA in four species (Cx. coronator, Cx. pipiens complex, Cx. tarsalis, and Psorophora columbiae) had high homology with published sequences of avian Plasmodium species while DNA in four other species (Cx. nigripalpus, Ps. columbiae, Anopheles quadrimaculatus, and An. punctipennis) were closely related to Plasmodium species from deer. One pool of Cx. tarsalis was positive with a 100% sequence identity of Haemoproteus sacharovi. This study provides a baseline concerning the diversity of parasites in different mosquito species present in the southern Great Plains. These studies provide important information for understanding the factors of transmission involving the mosquito community, potential hosts, and different mosquito-borne parasites in this important region involved in livestock management and wildlife conservation.

Molecular relationships of introduced Aedes japonicus (Diptera: Culicidae) populations in British Columbia, Canada using mitochondrial DNA

Aedes japonicus japonicus (Theobald) is a relatively recent immigrant to the Pacific Northwest, having been collected in Washington State in 2001 and in British Columbia (BC) since 2014. We applied a molecular barcoding approach to determine the phylogenetic relationship of Ae. j. japonicus populations in BC with those from around the world. We sequenced a 617 base-pair segment of the cytochrome c oxidase 1 gene and a 330 base-pair region of the NADH dehydrogenase 4 gene to find genetic variation and characterize phylogenetic and haplotypic relationships based on nucleotide divergences. Our results revealed low genetic diversity in the BC samples, suggesting that these populations arose from the same introduction event. However, our approach lacked the granularity to identify the exact country of origin of the Ae. j. japonicus collected in BC. Future efforts should focus on detecting and preventing new Ae. j. japonicus introductions, recognizing that current molecular techniques are unable to pin-point the precise source of an introduction.

Landscape and Anthropogenic Factors Associated with Adult Aedes aegypti and Aedes albopictus in Small Cities in the Southern Great Plains

Simple Summary

Mosquito-borne diseases are a growing human health concern in the United States. While recent studies have updated the distribution of Aedes aegypti in southern Great Plains, little is known about what factors can be used to predict where important mosquito species thrive in the region. The aim of the study assessed different factors associated with encountering adult container-breeding mosquitoes in small cities in southern Oklahoma. Collections using two types of traps were carried out over a ten week period from June to August 2017 along two geographical transects, each consisting of three cities, equally distant from the Red River/Texas border. After five rounds of collection, 6628 female mosquitoes were collected from 242 commercial or residential sites in six cities. Of the mosquitoes collected, 80% consisted of container-breeding species. Regionally, Ae. aegypti was most likely to be collected in cities closest to the Texas border while Aedes albopictus was spread throughout the region. In general, Ae. aegypti and Ae. albopictus were more associated with residential sites or sites featuring no or low vegetation. The study highlighted important factors involved in the distribution of Ae. aegypti and Ae. albopictus in small cities in the southern Great Plains.

Abstract

As mosquito-borne diseases are a growing human health concern in the United States, the distribution and potential arbovirus risk from container-breeding Aedes mosquitoes is understudied in the southern Great Plains. The aim of the study was to assess landscape and anthropogenic factors associated with encountering adult container-breeding mosquitoes in small cities in southern Oklahoma. Collections were carried out over a 10 week period from June to August 2017 along two geographical transects, each consisting of three cities, equally distant from the Red River/Texas border. Mosquitoes were collected weekly using two trap types along with data for 13 landscape, vegetation, and anthropogenic variables. After five rounds of collection, 6628 female mosquitoes were collected over 2110 trap-nights involving 242 commercial or residential sites in six cities. Of the mosquitoes collected, 80% consisted of container-breeding species: Aedes albopictus (72%), Culex pipiens complex (16%) and Aedes aegypti (8%). Regionally, Aedes aegypti was more likely present in cities closest to the Texas border while Ae. albopictus was spread throughout the region. In general, Ae. aegypti and Ae. albopictus were significantly more present in sites featuring no or low vegetation and residential sites. Variables associated with Ae. albopictus presence and abundance varied between cities and highlighted the urban nature of the species. The study highlighted the distribution of Ae. aegypti geographically and within the urban context, indicated potential habitat preferences of container-breeding mosquito species in small towns, and demonstrated the usefulness of Gravid Aedes traps (GAT) traps for monitoring Aedes populations in urban habitats in small cities.

Highlights of Medical Entomology 2018: The Importance of Sustainable Surveillance of Vectors and Vector-Borne Pathogens

The theme of the 2018 Entomological Society of America, Entomological Society of Canada, and Entomological Society of British Columbia Joint Annual Meeting was Crossing Borders: Entomology in a Changing World. Following the theme of the meeting, papers selected for the 2018 'Highlights of Medical Entomology' included reports of expanded ranges for Aedes albopictus (Skuse) (Diptera: Culicidae), Aedes japonicus japonicus (Theobald) (Diptera: Culicidae), Culex coronator Dyar and Knab (Diptera: Culicidae), Mansonia titillans (Walker) (Diptera: Culicidae), and Wyeomyia mitchellii (Theobald) (Diptera: Culicidae); a first report of mosquito feeding on earthworms and leeches; Cache Valley virus detection in Ae. j. japonicus; surveillance in high-risk areas of Canada for Lyme Disease; and increasing lone-star tick detections in Connecticut. The selection of papers served as a reminder of the increasingly difficult challenge of sustaining vector surveillance programs. Fluctuating funding and a decline in vector taxonomists and identification expertise contribute to the erosion of vector surveillance.

Differences in Mosquito Communities in Six Cities in Oklahoma

Vector-borne diseases in the United States have recently increased as a result of the changing nature of vectors, hosts, reservoirs, pathogens, and the ecological and environmental conditions. Current information on vector habitats and how mosquito community composition varies across space and time is vital to successful vector-borne disease management. This study characterizes mosquito communities in urban areas of Oklahoma, United States, an ecologically diverse region in the southern Great Plains. Between May and September 2016, 11,996 female mosquitoes of 34 species were collected over 798 trap nights using three different trap types in six Oklahoma cities. The most abundant species trapped were Culex pipiens L. complex (32.4%) and Aedes albopictus (Skuse) (Diptera: Culicidae) (12.0%). Significant differences among mosquito communities were detected using analysis of similarities (ANOSIM) between the early (May-July) and late (August-September) season. Canonical correlation analysis (CCA) further highlighted the cities of Altus and Idabel as relatively unique mosquito communities, mostly due to the presence of Aedes aegypti (L.) and salt-marsh species and absence of Aedes triseriatus (Say) in Altus and an abundance of Ae. albopictus in Idabel. These data underscore the importance of assessing mosquito communities in urban environments found in multiple ecoregions of Oklahoma to allow customized vector management targeting the unique assemblage of species found in each city.

Modeled distributions of Aedes japonicus japonicus and Aedes togoi (Diptera: Culicidae) in the United States, Canada, and northern Latin America

The Asian bush mosquito, Aedes japonicus japonicus, and the coastal rock pool mosquito, Aedes togoi, are potential disease vectors present in both East Asia and North America. While their ranges are fairly well-documented in Asia, this is not the case for North America. We used maximum entropy modeling to estimate the potential distributions of Ae. togoi and Ae. j. japonicus in the United States, Canada, and northern Latin America under contemporary and future climatic conditions. Our results suggest suitable habitat that is not known to be occupied for Ae. j. japonicus in Atlantic and western Canada, Alaska, the western, midwestern, southern, and northeastern United States, and Latin America, and for Ae. togoi along the Pacific coast of North America and the Hawaiian Islands. Such areas are at risk of future invasion or may already contain undetected populations of these species. Our findings further predict that the limits of suitable habitat for each species will expand northward under future climatic conditions.

Distribution of Culex coronator in Texas

The distribution of Culex coronator Dyar and Knab by county in Texas was updated by combining data from peer-reviewed literature, military and government reports, and university and private collections, and by collecting specimens from counties where data had not been reported. With 254 counties in Texas, the initial collection effort was focused on counties east of US Highway 277, which runs from Val Verde County on the US and Mexico border to Wichita County on the Texas and Oklahoma border. The study resulted in 127 counties with Cx. coronator presence data. The remaining 127 counties need to be surveyed for this species.