Evaluation of the New Modular Biogents BG-Pro Mosquito Trap in Comparison to CDC, EVS, BG-Sentinel, and BG-Mosquitaire Traps.

Mosquito surveillance is an essential component of mosquito control and mosquito traps are a universally employed tool to monitor adult populations. The objective of this paper was to evaluate the new modular Biogents BG-Pro mosquito trap (BGP) and compare its performance to 4 widely used traps for adult mosquitoes: the BG-Sentinel (BGS), the BG Mosquitaire (BGM), the CDC miniature light trap (CDC), and the encephalitis vector survey trap (EVS). One semi-field and 9 field Latin square trials were performed in 7 countries. Results showed that the collection performance of the BGP was equivalent to or exceeded that of the BGS, BGM, CDC, and EVS traps in head-to-head comparisons. The BGP uses 35% less power than the CDC and 75% less than the BGS and BGM. This lower power consumption allows it to run at 5 V for 2 days using a small lightweight 10,000-mAh rechargeable power bank. The BG-Pro is an excellent alternative for the surveillance of mosquito species that are usually monitored with BG-Sentinel, CDC, or EVS traps.

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.

Host Associations of Culex pipiens: A Two-Year Analysis of Bloodmeal Sources and Implications for Arboviral Transmission in Southeastern Virginia.

Understanding vector-host interactions is crucial for evaluating the role of mosquito species in enzootic cycling and epidemic/epizootic transmission of arboviruses, as well as assessing vertebrate host contributions to maintenance and amplification in different virus foci. To investigate blood-feeding pattern of Culex pipiens, engorged mosquitoes were collected on a weekly basis at 50 sites throughout Suffolk, Virginia, using Centers for Disease Control and Prevention miniature light traps, BG-Sentinel traps, and modified Reiter gravid traps. Vertebrate hosts of mosquitoes were identified by amplifying and sequencing portions of the mitochondrial cytochrome b gene. Of 281 Cx. pipiens bloodmeals successfully identified to species, 255 (90.7%) contained solely avian blood, 13 (4.6%) mammalian, 1 (0.4%) reptilian, and 12 (4.3%) both avian and mammalian blood. Nineteen avian species were identified as hosts for Cx. pipiens with American robin (n = 141, 55.3% of avian hosts) and northern cardinal (n = 57, 22.4%) as the most common hosts. More American robin feedings took place in areas of higher development. Three mammalian species were also identified as hosts for Cx. pipiens with Virginia opossum and domestic cat as the most common hosts in this class (each n = 6, 46.2% of mammalian hosts). There was no significant seasonal difference in the proportion of bloodmeals obtained from avian hosts, but there was a decrease in the proportion of bloodmeals from mammalian hosts from spring to fall. One engorged specimen of Cx. pipiens with Virginia opossum-derived bloodmeal tested positive for West Nile virus (WNV), and another with black-and-white warbler-derived bloodmeal tested positive for eastern equine encephalitis virus. Our findings, in conjunction with the results of vector competence studies and virus isolation from field-collected mosquitoes, lend additional support that Cx. pipiens serves as the principal enzootic vector and potential epizootic/epidemic vector of WNV in southeastern Virginia.

Host interactions of Aedes albopictus, an invasive vector of arboviruses, in Virginia, USA.

BACKGROUND: As an invasive mosquito species in the United States, Aedes albopictus is a potential vector of arboviruses including dengue, chikungunya, and Zika, and may also be involved in occasional transmission of other arboviruses such as West Nile, Saint Louis encephalitis, eastern equine encephalitis, and La Crosse viruses. Aedes albopictus feeds on a wide variety of vertebrate hosts, wild and domestic, as well as humans. METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate blood feeding patterns of Ae. albopictus, engorged specimens were collected from a variety of habitat types using the Centers for Disease Control and Prevention light traps, Biogents Sentinel 2 traps, and modified Reiter gravid traps in southeast Virginia. Sources of blood meals were determined by the analysis of mitochondrial cytochrome b gene sequences amplified in PCR assays. Our aims were to quantify degrees of Ae. albopictus interactions with vertebrate hosts as sources of blood meals, investigate arboviral infection status, assess the influence of key socioecological conditions on spatial variability in blood feeding, and investigate temporal differences in blood feeding by season. Analysis of 961 engorged specimens of Ae. albopictus sampled between 2017-2019 indicated that 96%, 4%, and less than 1% obtained blood meals from mammalian, reptilian, and avian hosts, respectively. Domestic cats were the most frequently identified (50.5%) hosts followed by Virginia opossums (17.1%), white-tailed deer (12.2%), and humans (7.3%), together representing 87.1% of all identified blood hosts. We found spatial patterns in blood feeding linked to socioecological conditions and seasonal shifts in Ae. albopictus blood feeding with implications for understanding human biting and disease risk. In Suffolk Virginia in areas of lower human development, the likelihood of human blood feeding increased as median household income increased and human blood feeding was more likely early in the season (May-June) compared to later (July-October). Screening of the head and thorax of engorged Ae. albopictus mosquitoes by cell culture and RT-PCR resulted in a single isolate of Potosi virus. CONCLUSION AND SIGNIFICANCE: Understanding mosquito-host interactions in nature is vital for evaluating vectorial capacity of mosquitoes. These interactions with competent reservoir hosts support transmission, maintenance, and amplification of zoonotic agents of human diseases. Results of our study in conjunction with abundance in urban/suburban settings, virus isolation from field-collected mosquitoes, and vector competence of Ae. albopictus, highlight the potential involvement of this species in the transmission of a number of arboviruses such as dengue, chikungunya, and Zika to humans. Limited interaction with avian hosts suggests that Ae. albopictus is unlikely to serve as a bridge vector of arboviruses such as West Nile and eastern equine encephalitis in the study region, but that possibility cannot be entirely ruled out.

First Record of Culex Coronator in Virginia, with Notes on Its Rapid Dispersal, Trapping Methods, and Biology.

Culex coronator is a Neotropical mosquito species that was first described in Trinidad in the early 20th century. Since then, the species has been discovered from Patagonia to the southern USA. A single adult female Cx. coronator was collected on November 1, 2016, in Suffolk, VA, in a BG-Sentinel 2® trap during routine mosquito surveillance. This represents the 1st record of this species in the state of Virginia and the northernmost record in the USA. Based on male specimens examined from Texas and Mississippi, Cx. coronator sensu stricto seems to be the only species from the complex expanding into the southeastern USA. A comprehensive review of the available literature from the southern and southeastern USA is provided describing trapping methods, ecological, and biological information.

Evaluation of the Trapping Performance of Four Biogents AG Traps and Two Lures for the Surveillance of Aedes albopictus and Other Host-Seeking Mosquitoes.

The BG-Sentinel® (BGS) trap has recently been redesigned for increased durability and ergonomic functionality, marketed as the BG-Sentinel 2® (BGS2). We evaluated the trapping performance of these 2 traps in addition to the BG-Sentinel prototype (BGSP), a model similar to the BGS2 that was beta tested in several US states in 2014, and the BG-SNAP (SNAP), which is a prototype revision of the BG-Mosquitito™. We also evaluated 2 new Biogents AG lures: the BG-Lure cartridge and BG-Sweetscent™, as they are granular formulations replacing the original mesh BG-Lure®. Evaluations were conducted between July and September 2015 under field conditions within a suburban area in southeastern Virginia. The 4 traps were compared with their respective lure systems (BGS, BGSP, and BGS2 with BG-Lure cartridge; SNAP with BG-Sweetscent). No significant differences were seen in total female mosquito collections among the 3 BG-Sentinel models. All 3 Sentinels collected significantly more female mosquitoes than the SNAP (P ≤ 0.009); BGS and BGS2 both collected significantly more Aedes albopictus females than the SNAP (P ≤ 0.02). The 2 lures were compared in both BGS2 and SNAP traps. Although both lures performed significantly better in the BGS2 trap (P ≤ 0.0003), there were no significant differences in number of mosquitoes or species composition collected with BG-Sweetscent and BG-Lure cartridge within the same trap type.

Reduced performance of a PVC-coated Biogents Sentinel prototype in comparison to the original Biogents Sentinel for monitoring the Asian tiger mosquito, Aedes albopictus, in temperate North America.

Aedes albopictus is a major nuisance pest and also a public health concern because of the role it plays in the transmission of arboviruses. There is a continuing demand for effective surveillance tools for this species. The first generation of Biogents Sentinel (BGS1) traps have proven to be an effective tool for surveillance of Ae. albopictus throughout its range, however, some defects in construction led to the eventual development of the next generation. We compared the performance of the new generation prototype trap (BGS2P) to the original. Studies were conducted in suburban and urban areas in Florida, Louisiana, New Jersey, and Virginia, USA in the summer of 2014 (July-October). BGS1 traps collected significantly more Ae. albopictus when compared to the BGS2P with or without CO2 in all locations (P<0.05). When a white cloth was wrapped around the BGS2P traps, efficiency did not change in Louisiana, New Jersey, and Virginia; however, numbers of adult Ae. albopictus collected from the BGS2P and the BGS1 were significantly different based on lure type (P< 0.0001). Results from Florida showed that BGS1with the BG lure and CO2 collected significantly higher adult numbers compared to BGS2P with a three component cartridge lure and CO2 (P< 0.0001). Overall, our results indicate that despite improvements in construction and durability of the BGS2P, this newer trap type did not increase the capture rates of Ae. albopictus in North America. Biogents modified BGS2P based on the data collected from the current study and updated as Biogents Sentinel 2 is now commercially available and its efficacy in comparison to the original will require further study.

The hitchhiker's guide to becoming invasive: exotic mosquitoes spread across a US state by human transport not autonomous flight.

Not all exotic species establish and expand aggressively (i.e. become invasive). As potential vectors of disease agents, invasive mosquitoes can have considerable impact on public health, livestock and wildlife; therefore, understanding the species characteristics and ecological circumstances promoting their invasiveness is important. The mosquito Aedes japonicus japonicus, originally from north-east Asia, was introduced at least two separate times to the north-eastern USA, as surmised from the initial existence of two populations with distinct nuclear and mitochondrial genetic signatures that later intermixed. Since these original introductions in the late 1990s, Ae. j. japonicus has expanded across 31 US states, two Canadian provinces and five European countries. Although some of the expanded range was due to other independent introductions, to understand what drove the postintroduction expansion of Ae. j. japonicus within the north-eastern USA, we performed a high-resolution landscape genetic analysis of 461 specimens collected across Virginia, a state south of the original introductions. All specimens were genotyped at seven pre-optimized microsatellite loci, and a subsample was sequenced at one mitochondrial locus. We concluded that throughout Virginia this species has primarily expanded in association with humans: genetic distance and distance along roads remained correlated after controlling for geographic distance, and proximity to I-95, a major interstate highway, strongly predicted nuclear ancestry. In contrast, there was very limited evidence of diffusion even at distances potentially suitable for autonomous mosquito flight. This implies that its association with humans (rather than innate species characteristics) is the single most important determinant of invasiveness in this mosquito.

Vector-Host Interactions of Culiseta melanura in a Focus of Eastern Equine Encephalitis Virus Activity in Southeastern Virginia.

Eastern equine encephalitis virus (EEEV) causes a highly pathogenic mosquito-borne zoonosis that is responsible for sporadic outbreaks of severe illness in humans and equines in the eastern USA. Culiseta (Cs.) melanura is the primary vector of EEEV in most geographic regions but its feeding patterns on specific avian and mammalian hosts are largely unknown in the mid-Atlantic region. The objectives of our study were to: 1) identify avian hosts of Cs. melanura and evaluate their potential role in enzootic amplification of EEEV, 2) assess spatial and temporal patterns of virus activity during a season of intense virus transmission, and 3) investigate the potential role of Cs. melanura in epidemic/epizootic transmission of EEEV to humans and equines. Accordingly, we collected mosquitoes at 55 sites in Suffolk, Virginia in 2013, and identified the source of blood meals in engorged mosquitoes by nucleotide sequencing PCR products of the mitochondrial cytochrome b gene. We also examined field-collected mosquitoes for evidence of infection with EEEV using Vector Test, cell culture, and PCR. Analysis of 188 engorged Cs. melanura sampled from April through October 2013 indicated that 95.2%, 4.3%, and 0.5% obtained blood meals from avian, mammalian, and reptilian hosts, respectively. American Robin was the most frequently identified host for Cs. melanura (42.6% of blood meals) followed by Northern Cardinal (16.0%), European Starling (11.2%), Carolina Wren (4.3%), and Common Grackle (4.3%). EEEV was detected in 106 mosquito pools of Cs. melanura, and the number of virus positive pools peaked in late July with 22 positive pools and a Maximum Likelihood Estimation (MLE) infection rate of 4.46 per 1,000 mosquitoes. Our findings highlight the importance of Cs. melanura as a regional EEEV vector based on frequent feeding on virus-competent bird species. A small proportion of blood meals acquired from mammalian hosts suggests the possibility that this species may occasionally contribute to epidemic/epizootic transmission of EEEV.