Several invasive mosquito species that are nuisances or of medical and veterinary importance have been introduced into the Southeastern region of the USA, posing a threat to other species and the local ecosystems and/or increasing the risk of pathogen transmission to people, livestock, and domestic pets. Prompt and effective monitoring and control of invasive species is essential to prevent them from spreading and causing harmful effects. However, the capacity for invasive mosquito species surveillance is highly variable among mosquito control programs in the Southeast, depending on a combination of factors such as regional geography and climate, access to resources, and the ability to interact with other programs. To facilitate the development of invasive mosquito surveillance in the region, we, the Mosquito BEACONS (Biodiversity Enhancement and Control of Non-native Species) working group, conducted a survey on the capacities of various public health agencies and pest control agencies engaged in mosquito surveillance and control in seven Southeastern states (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, and South Carolina). Ninety control programs completed the survey, representing an overall response rate of 25.8%. We report key findings from our survey, emphasizing the training and resource needs, and discuss their implications for future invasive mosquito surveillance and control capacity building. By increasing communication and collaboration opportunities (e.g., real-time sharing of collection records, coordinated multistate programs), the establishment of Mosquito BEACONS and the implementation of this survey can accelerate knowledge transfer and improve decision support capacity in response to or in preparation for invasive mosquito surveillance and can establish infrastructure that can be used to inform programs around the world.
In the Southeastern USA, several invasive mosquito species of medical and veterinary importance have been detected through multiple modes of introduction and dispersal. Incursions have occurred by transportation of used tires and artificial containers through shipping routes and road networks at global and domestic scales, importation of lucky bamboo (Dracaena sanderiana), and movement along river corridors (Hawley et al. 1987, O'Meara et al. 1995, Linthicum et al. 2003, Demeulemeester et al. 2014, Kaufman and Fonseca 2014, Sames et al. 2021). Some of these invasive mosquito species such as Aedes aegypti (L.), Ae. albopictus (Skuse), and Culex coronator Dyar and Knab have become dominant members of the local mosquito fauna. Their presence increases the risk of pathogen transmission to people, livestock, and domestic pets (Ledesma and Harrington 2011, Kendrick et al. 2014, Hinojosa et al. 2020), which places an additional burden on the response capacity of state and local mosquito control programs. Additional invasive mosquito species that have recently expanded their ranges in the USA such as Ae. japonicus (Theobald), Ae. scapularis (Rondani), and Mansonia titillans (Walker) have a potential to also pose public health risks (Cartner et al. 2018, McKenzie et al. 2019, Campbell et al. 2021).
Timely and effective monitoring and control of invasive mosquito species is often difficult, particularly if the species has highly adapted to urban and agricultural landscapes, breeding in a many obscure or unique breeding habitats (Fonseca et al. 2013) that are hard to reach. Managing multiple invasive species in an area can also be highly complex because a variety of trapping methods are required for species that have different biology. If a species is new to a region, early and accurate identification is a crucial requisite for continuous monitoring but often remains difficult because of the knowledge gap of range expansion pathways or a lack of resources.
Current mosquito management programs develop integrated pest management approaches 3–4 that encourage the use of a variety of pest control techniques 3–4 to reduce or minimize the negative impact of mosquitoes on human health in an environmentally safe and economically and socially acceptable manner (Dara 2019, CDC 2020). Successful management of invasive species often involves the following steps: early detection, prevention, control, restoration, education, and monitoring (Pyšek and Richardson 2010). Effective identification and detection of invasive species are important tenets of integrated mosquito management programs (CDC 2020, UC IPM 2022) and often require diverse surveillance approaches that target multiple life stages and physiological states, including immature stages, resting adults, and gravid females (Reiter and Gubler 1997, McKenzie et al. 2019). Corresponding to the respective biology of a wide variety of invasive species, specialized surveillance methods over and above standard CDC traps are applied, methods such as the Biogents (BG) Sentinel trap, the BG Counter (Biogents AG, Regensburg, Germany) (Farajollahi et al. 2009, Day et al. 2020), and mechanical aspirators in combination with resting shelters (Sloyer et al. 2022). Species identification of newly introduced mosquitos can be improved when the local mosquito populations are well characterized through existing surveillance efforts (King et al. 1942, Darsie and Ward 2005, Burkett-Cadena 2013, Harrison et al. 2016). Additional information such as county or regional mosquito surveillance records, seasonal distribution, mosquito behavior (e.g., oviposition preference), and trap bias (e.g., phototaxis, chemotaxis) can improve the accuracy and efficiency of the identification process (Giordano et al. 2020, 2021).
Individual state and local programs are often tasked with deciding which surveillance tools to utilize, determining mosquito abundance, distribution, and degree of pathogen activity (i.e., arboviral surveillance). Elements of an integrated vector management strategy that is ideal for vector control and disease management include (1) advocacy, social mobilization, and legislation, (2) collaboration among health sectors, control programs, and others, (3) integrated approaches, (4) evidence-based decision making, and (5) capacity; for more details see the World Health Organization's Guidance on Policy-Making for Integrated Vector Management (Berg et al. 2012). A scarcity of elements, for example, a paucity of communication and collaboration efforts (e.g., real-time sharing of collection records, coordinated multistate programs) and slow transfer of knowledge (e.g., delayed publications, outdated county records, lack of insecticide resistance status), are likely to hinder effective decision making and mosquito control. As well, uncoordinated surveillance and control efforts across districts or states can be costly (Peper et al. 2022), resulting in incomplete risk assessments, suboptimal use of insecticides, biased estimates of mosquito diversity and abundance, missed opportunities to detect new threats to public health and safety, and delayed control efforts. Mosquito control agencies with greater funding resources are more likely to possess the necessary resources to effectively carry out their mission. However, even with relatively high funding levels, mosquito control agencies may still not be sufficiently funded depending on the context.
Although the Southeast has experienced continued establishment of invasive mosquito species and often serves as an invasion frontier (Wilke et al. 2020), no studies have investigated the invasive mosquito surveillance and mosquito control capacity across agencies. Elements that are crucial for a robust and effective mosquito control program remain to be assessed. Although recent efforts to promote surveillance and taxonomic data sharing can promote early recognition of newly introduced species (Rund et al. 2019; Giordano 2021, 2022; Giordano et al. 2022), a cohesive and integrated system currently does not exist in the Southeast (Riles and Killingsworth 2021). Moreover, invasive mosquito surveillance capacity varies in budget and resource availability across the Southeast, which likely results in fragmentary and incomplete risk assessments that are further confounded by nonstandard sampling approaches (e.g., trap type, trap densities, and attractive baits/lures).
Here we assessed the capacity of vector control programs within seven Southeastern states using survey questions that were formulated to address elements of an ideal integrated vector management strategy. We sought to establish baseline information on regional surveillance capacities. This study is part of a recently established scientific communication and engagement program called Mosquito BEACONS (Biodiversity Enhancement and Control of Non-native Species). Our collective research and outreach working group seeks to improve surveillance and control capacity in the South through improved communication and collaboration opportunities, data visualization, and access to information. The work presented here describes the current strengths and limitation of current invasive species detection and mitigation approaches and provides insights into opportunities to improve surveillance and control capacities.
MATERIALS AND METHODS
The survey was created using Qualtrics software version 05.2021 (Qualtrics, Provo, UT). The anonymous survey was administered to 323 mosquito surveillance and control programs by direct email or phone call or indirect contact from corresponding state mosquito control associations across seven states: Alabama, Georgia, Florida, Louisiana, Mississippi, North Carolina, and South Carolina. We sent 379 emails to agencies that contained a PDF invitation and link to the survey, and 121 calls were made. Programs were contacted three times. The survey was available for responses from August to December 2021.
We encouraged responses from at least 1 lead administrative coordinator (e.g., manager or director) within each program. The survey qualified for exempt review (minimal risk) by the University of Florida Institutional Review Board on June 22, 2021 (IRB202101286). Survey questions were developed to measure program demographics, annual budgets for mosquito surveillance, perceptions about invasive species, mosquito surveillance capacity, personnel training and education, research priorities and resources, collaboration, and data sharing, and needs for program capacity enhancements. The survey questions relevant to this report are provided in the Supplemental Material Appendix.
Survey results were exported to Microsoft Excel 2010 and organized using Excel PivotTable functions. We calculated the mean of respondents per state. The average of responses within each state to each question was calculated, and the 95% confidence intervals (CI95) was determined using the Wald formula (Laplace 1812). Qualitative comments from open questions were analyzed and grouped into categories based on conceptual similarities. Figures were generated in R version 4.1.2 and Python version 3.10.2 using matplotlib version 3.5.1 (Hunter 2007), numpy version 1.22.3 (Harris et al. 2020), and pandas version 1.4.1 libraries (Pandas Development Team 2020).
Ninety mosquito control programs from seven states completed the survey, representing a 25.9% response rate. Geographic distribution of survey respondents varied greatly. Forty-seven percent of respondents were from Florida. Georgia, North Carolina, and South Carolina each represented 13.3–15.6% of respondents. Alabama and Mississippi had the lowest participation with only 2 respondents each.
Most control programs (73% of the respondents) operate within an entire county, whereas 10% operate within a city or area within a county (e.g., homeowner associations), 4% are statewide, and 1% offer services in multiple counties (Table 1).
Personnel demographics were summarized as percentage of staff by employment type, training, and education (Supplemental Table S1). Most mosquito control personnel are certified and licensed pest applicators (69%, CI95 = 59–77%) and full-time employees (77%, CI95 = 68–86%). Approximately one-third of all staff are part-time (33%, CI95 = 23–43%) or seasonal (30%, CI95 = 21–40%), and 8% are interns or students (CI95 = 2–13%). Just under half hold bachelor's or associate's degrees (44%, CI95 = 34–54%). Twenty-two percent of staff have master's degrees (CI95 = 13–31%), and 15% have completed their doctorate (CI95 = 8–22%).
Funding and budgets.
Program funding and budget are important considerations for assessing surveillance and control capacity. They influence the number of personnel hired and the availability of resources for equipment and supplies. Fifty-nine programs reported annual budget allocations (Fig. 1). Louisiana ($6.3 million, CI95 = $3.2–9.4 million), Florida ($4.3 million, CI95 = $1.9–6.6 million), and Georgia (1.3 million, CI95 = $0.3–2.3 million) reported the largest average annual budgets. North Carolina ($388,875, CI95 = $36,373–741,377), South Carolina ($519,875, CI95 = $190,345–849,406), Alabama ($189,000), and Mississippi ($651,021) reported under a $1 million annual budget. Three programs in Georgia, South Carolina, and North Carolina reported a $0 annual budget, and the responding North Carolina program reported that they are a volunteer organization. In general, states with a higher annual budget generally show higher survey response rates (Fig. 1A).
Agencies were asked if budgetary constraints limit their ability to monitor and control invasive mosquito species. Sixty-one agencies responded with 59% indicating that they agree that budgetary constraints limit their ability (CI95 = 50–78%), while 13.1% disagreed (CI95 = 3–30%) and 27.9% were neutral (CI95 = 12–40%). Florida, Georgia, Louisiana, North Carolina, and South Carolina indicated that a majority of their agencies (> 46% of responses for each state) suffered from these budgetary constraints, while Alabama and Mississippi received only 1 response each (Fig. 1B).
Invasive species priority rank.
We asked programs to rank a list of 8 invasive species from 1 (most important) to 8 (least important). Species priority scores were given between 1 and 8 based on their rank. For example, species ranked 1 were given a priority score of 8, and species with no ranking received score of 0. The sum of priority scores (Supplemental Table S2) was used to generate pie charts for each state (Fig. 2). Alabama, Louisiana, Florida, Georgia, North Carolina, and South Carolina all identified Ae. aegypti and Ae. albopictus as the 2 most important species in the southern region; Mississippi identified Ae. albopictus and Cx. coronator (Fig. 2).
Mosquito surveillance is essential for the control of invasive mosquitoes and the prevention of the pathogens they transmit. In our survey, most of the agencies (78%, CI95 = 69–87%) reported that they conduct mosquito surveillance and/or mosquito control, but only 59% of respondents expressed having adequate resources to monitor invasive mosquito species (CI95 = 66–85%) (Fig. 3A). Only 27% reported that they conduct arbovirus surveillance. Fifty-eight percent of the agencies reported that they increase their trapping efforts (frequency and/or number of traps) in response to a recorded arbovirus transmission event such as sentinel chicken seroconversion or a human cases (CI95 = 47–68%). Forty-three percent of the agencies reported that they increase trapping efforts after an arbovirus-positive mosquito pool is identified (CI95 = 33–53%).
We asked respondents to report what morphological identification keys they use to identify mosquitoes to species. The options included were Darsie and Morris (2003), Darsie and Ward (2005), Burkett-Cadena (2013), and Harrison et al. (2016). Respondents were also given the option to specify other sources that were not listed. Of the agencies that completed the survey responses across all states, the most used identification keys were Burkett-Cadena (2013) (24%, CI95 = 13–27%) and Darsie and Ward (2005) (23.3%, CI95 = 11–27%). On average, respondents used 1.6–2.6 different keys for mosquito identification (Fig. 3B). Other forms of identification that were listed by the agencies included the use of online resources, extension services from universities, state-specific identification keys, and institutional knowledge (Fig. 3B).
Sixty-four respondents provided an answer for their perceived importance of mosquito surveillance at port authorities, airports, and shipping yards. Eighty-eight percent of respondents expressed that surveillance at areas deemed high risk for invasive species introductions is either important (59%, CI95 = 48–72%) or very important (28%, CI95 = 17–41%). Eighty-nine percent of respondents (N = 64) agreed that cooperation between port authorities, airports, and shipping yards is either important (54%, CI95 = 44–68%) or very important (34%, CI95 = 23–48%).
Twenty-six programs indicated that they operate in a region or area with an active shipping port. Only 1 program confirmed that the port authority in their jurisdiction performs mosquito surveillance (Fig. 4). Twelve programs said no surveillance was performed, and 13 were not certain. Only 1 program indicated that the port authority in their jurisdiction shares surveillance information with them. Four agencies provided comments that the State Port Authority does not allow them access into the port. One agency cited lack of personnel to carry out surveillance. Ten agencies reported that they do not conduct surveillance.
Personnel training and education.
Mosquito identification training is an essential part of improving detection capacity for invasive mosquito species in the region. Timely recognition of the presence of newly introduced species is crucial for meeting the operational requirements of the mosquito control or public health agency. Distinguishing morphological traits to monitor for invasive species may require additional taxonomic reference material for proper identification. Fifty-two percent (N = 33/64) of respondents indicated that they provide institutional training on mosquito identification to employees (CI95 = 39–64%), and 48% do not (CI95 = 36–61%). Six percent (CI95 = 0–20%) of programs provided institutional training on mosquito identification and do not send their staff for training elsewhere. Thirty-eight percent (CI95 = 27–52%) of respondents do not provide institutional training but opt to send their personnel to attend training in mosquito identification elsewhere. Thirteen percent (CI95 = 2–27%) indicated that they do not provide any training on mosquito identification to their staff.
An agency may not perceive the need for mosquito identification training if they already have a mosquito identification expert in house, and therefore, we asked survey participants about the proficiency level for their staff. Programs reported the proportion of staff in each of the following experience classifications: beginner (e.g., few informal training opportunities, less than 2 years of experience), intermediate (e.g., informal training, 2–5 years of experience), or expert (e.g., Advanced Mosquito Identification and Certification or equivalent training, 5 or more years of experience). Louisiana, North Carolina, and Florida programs generally have at least 1 expert in mosquito identification in house (Fig. 5). Forty-four percent (N = 90, CI95 = 34–56%) agree that program staff have received training pertaining to surveillance and control of invasive mosquito species, while 8% disagree (CI95 = 0–19%), 15% were neutral (neither agreed nor disagreed; CI95 = 6–27%), and 32% did not answer this question (95% CI 22–44%).
Regarding staffing, 47.7% of respondents said their agency was understaffed (CI95 = 38–59%), 6.6% stated staffing was adequate (CI95 = 0–18%), 14.4% responded with a neutral opinion (CI95 = 4–26%), and 31.1% did not respond (CI95 = 21–42%). Of those that indicated that they were understaffed, 60.5% agreed that their staff experience and training limit their ability to monitor and control invasive mosquito species (CI95 = 47–75%), 16.3% disagreed (CI95 = 2–30%), and 23.3% were neutral on the topic (CI95 = 9–37%).
Respondents from most states felt more strongly about the need to study insecticide-resistant mosquito populations than the driving forces behind invasive mosquito species. Ninety-two percent of respondents expressed that the research on insecticide resistance is either very important (48%, CI95 = 38–62%) or important (42%, CI95 = 31–56%), while 60% of the responders expressed that research on driving forces behind invasive mosquito species is either very important (28%, CI95 = 17–41%) or important (56%, CI95 = 45–70%). Thirty percent of mosquito control districts agreed that information on invasive mosquito species is easily accessible (CI95 = 18–41%).
Mosquito control agencies were asked about the resources they commonly used to collect information. Agencies were asked if they “agree,” “neutral,” or “disagree” with statements of receiving information from the Centers for Disease Control and Prevention (CDC), state mosquito control association, county/state public health agency, cooperative extensive programs, peer-reviewed scientific journals, trade journals, social media, and word of mouth. The most used source of information across the responses was the state mosquito control association (78% agreement, CI95 = 44–65%; Fig. 6), followed by peer-reviewed scientific journal articles (73%, CI95 = 40–61%) and trade journals (68%, CI95 = 38–59%). Among the least utilized resources for invasive mosquito species information were county/state public health agencies (41% agreement, CI95 = 20–42%), cooperative extension programs (32%, CI95 = 12–34%), and social media (20%, CI95 = 3–25%).
Collaboration and data sharing.
An average of 61% of mosquito control agency staff recognized the importance of sharing data with neighboring or regional agencies, state public health agencies and mosquito control programs, and research institutions (Table 2). Of the respondents who indicated an importance of sharing data, 78.2% (CI95 = 70–87%) responded that their agency currently shares surveillance and collection data with neighboring or regional agencies, and 21.8% (CI95 = 13–30%) responded that they currently do not share this information (Fig. 7A). The reasons provided for why they do not share data with neighboring or regional agencies include a lack of personnel, funding, or dedicated program.
While 51% of agencies (CI95 = 41–61%) share surveillance and collection data with neighboring or regional agencies, 18% do not share these data (CI95 = 10–26%), and 31% did not answer the question (Fig. 7B). Some of the reasons given by agencies that do not share these data include the inexistence of a surveillance program, minimal mosquito control due to the lack of personnel and funding, no neighboring programs with which to share information, and no perceived need for routine sharing of surveillance with neighbors, among others.
To the question about the importance of multistate and multicounty collaborations, 27% of the agencies responded that it was very important (CI95 = 18–36%), 41% said it was important (CI95 = 31–51%), 1% said it was not important (CI95 = −1–3%), 3% did not have an opinion (CI95 = −0.5–7%), and 30% did not respond to the question. Agencies were asked if collaboration between private pest management companies and public health agencies and mosquito control programs was valuable, and 33% said yes (CI95 = 23–43%), 32% said no (CI95 = 22–42%), 3% were neutral (CI95 = −0.5–7%), and 32% did not answer. Agencies were also asked if they share data with state or federal databases or agencies, and 54% indicated that they do, 16% do not, and 30% did not respond.
Program capacity needs.
Respondents answered questions pertaining to staffing and training requirements to adequately monitor and control invasive mosquito species. Thirty-three percent of respondents (N = 84) expressed that they have enough personnel (CI95 = 22–44%), while 51% indicated that they are understaffed (CI95 = 40–62%), and 15% were neutral (CI95 = 5–27%). Forty-one percent of respondents (N = 79) agreed that lack of staff expertise and training limit their ability to monitor and control invasive mosquito species (CI95 = 29–52%), 35% disagreed (CI95 = 24–47%), and 24% were neutral (CI95 = 12–36%). We asked respondents if they have the tools (e.g., traps) required to monitor invasive mosquito species. Fifty-nine percent of respondents (N = 90) agreed (CI95 = 49–69%), 32% disagreed (CI95 = 22–45%), and 9% were neutral (CI95 = 0–19%).
Agencies were asked to describe what is needed to improve their surveillance programs, and the responses were categorized into several categories including funding, personnel, training, equipment, and other needs. Across all responses, the need for additional personnel was mentioned in 37% of responses, followed by funding (25%), equipment (14.8%), training (13%), and other needs (9.3%) (Fig. 8). The other responses included expansion of trapping sites, polymerase chain reaction (PCR) testing, and on-site testing of mosquitos collected. Respondents were asked if budgetary constraints restrict the ability to monitor and control invasive mosquito species; more respondents indicated they agree (59%, CI95 = 43–75%). Significant differences were not observed between states (χ2 = 13.00, df = 12, P = 0.369).
Several invasive mosquito species of medical and veterinary importance have been introduced in the South. Recognizing the knowledge gap in this subject, a regional working group Mosquito BEACONS was formed in 2021 to foster collaboration and research on the issues surrounding invasive and nonnative mosquito species (Giordano 2021). This is the first survey that directly engaged mosquito surveillance and control programs across the Southeast to identify gaps in surveillance and knowledge related to invasive mosquito species. Survey results reported here provide current and relevant information about the capacity of Southeastern regional agencies to surveil and control invasive mosquito species. Responses from the survey allowed insight into varying capacities of vector control districts in the Southeast and how adequately they meet elements of an effective integrated vector management program.
Funding and survey participation.
Funding is directly related to the number of personnel, equipment, and supplies that can be purchased. Florida agencies have a substantial budget for arbovirus surveillance, reporting annually $13 million toward sentinel chicken surveillance and mosquito pool testing. Three states reported a moderate budget ($500,000–2.7 million) for arbovirus surveillance (Georgia, Louisiana, South Carolina), while 4 states (Alabama, Mississippi, North Carolina, and South Carolina) operate on a limited budget (< $100,000). Some programs reported that they operate 100% with volunteers. We recognize that absolute amount of funding may not be an accurate indicator of the availability of resources because each program serves a different number of people or has a different geographic area to cover. Regardless of the current funding status of the states surveyed, most vector control districts answering the survey felt that they had funding limitations and needed additional resources. Funding, personnel, and training were among the highest needs expressed by all the surveyed states, which can be supplemented only by sufficient capacity building to meet those needs. Conducting a situation analysis will adequately guide vector control programs on the resources needed to be allocated to be effective, because each state, county, or district has different requirements (Berg et al. 2012). A higher number of responses from individual programs within states can give us further data on funding at a state level as compared to regional levels. Our results show highly variable funding level from multi-million-dollar annual budget agencies to programs with little budget run by volunteers in the Southeast.
We observed general patterns of low participation in surveys in states that reported lower annual budgets. This may be due to low level of recognition of the relatively new Mosquito BEACONS working group or limited time availability to participate in surveys. This observation may also be confounded by the limited number of personnel in states with lower annual budgets. We sought survey participation not only via email but also with phone calls and postal mail for programs that did not respond to our email contacts. The ongoing COVID pandemic during our survey in 2021 also likely impacted on our ability to reach agencies by phone. Sustained effort, such as attending state mosquito control association meetings, will be needed to connect to hard-to-reach mosquito control and public health agencies to improve the surveillance and control capacity in the region. Future surveys should be implemented in online and in-person formats to reach a broad range of programs and increase availability and accessibility.
Invasive mosquitoes of concern in the Southeast.
Most respondents (87%, CI95 = 79–95%) recognized invasive mosquito species as a major public health threat. The ranking of importance could be influenced by a variety of factors, such as the medical significance of the species, its distribution and abundance within the region, and the stage and duration of its invasion.
Most states identified Ae. aegypti and Ae. albopictus as the most important invasive species in the South (Fig. 2). Both species pose a significant threat to human health, because they are major vectors of several important human diseases, including dengue, yellow fever, and Zika (Leta et al. 2018, Paixão et al. 2018). Rapid expansion of the range of Ae. aegypti and Ae. albopictus have been a cause of concern across the USA (Kraemer et al. 2019).
In addition to these 2 vectors, Ae. japonicus is a greater concern in states such as Alabama, Mississippi, Georgia, and North Carolina compared to other surveyed states, ranking third in importance in these states. This species is considered to be a competent vector of a number of viruses (Harris et al. 2015, Yang et al. 2018) and could possibly have indirect impacts on local disease dynamics because of its interspecific interactions with other container-inhabiting mosquito vector species (Andreadis and Wolfe 2010, Armistead et al. 2012) such as Ae. triseriatus, Ae. albopictus, or Ae. aegypti (Armistead et al. 2012). Aedes japonicus has established populations in these states and appears to have the ability to rapidly adapt to a broad range of environmental conditions in newly introduced regions such as Florida (Kaufman and Fonseca 2014, Riles et al. 2017, McKenzie et al. 2019).
Culex coronator was ranked third or fourth by all 7 states as important for control operations. It has a wide distribution across the southern USA, originally observed in south Texas (Dyar 1921), and has been found in many parts of the Southeast, including Georgia, South Carolina, Tennessee, and Virginia (Sames et al. 2021). Its importance in public health is not clearly understood (Aitken et al. 1964), although the potential for Cx. coronator to transmit West Nile virus has been shown under certain conditions (Alto et al. 2014).
Mansonia titillans, a less widely distributed species in the Southeast, was ranked higher by Gulf Coast states as an important species to control as compared to North Carolina, South Carolina, and Georgia. Slow migration is occurring and has allowed this species to expand northward out of naturalized habitats within Florida and into these regions (Connelly 2019, Riles and Connelly 2020, Smith et al. 2020). The species is scattered across the Southeast and is considered a potential vector for several debilitating diseases (Burkett-Cadena 2013, Beranek et al. 2018, Cartner et al. 2018). The differences seen in importance of various vectors across these states may be because of the lack of current resources to properly identify species of interest, based on the availability of up-to-date taxonomic information. Increased communication between states can help target species of interest in the Southeast and assist in notifying neighboring regions of newly introduced species as species migrate and/or are introduced into any given region.
Two newly introduced invasive species into the USA, Ae. pertinax (Grabham) and Ae. scapularis (Rondani), were ranked of little importance within all states. Aedes pertinax, discovered in 2015, has spread throughout southern to central Florida and is considered established in the region (Riles and Connelly 2020, Kovach et al. 2022, Tyler-Julian et al. 2022). Aedes scapularis recently emerged in the southern penisualr region and has migrated into 5 counties (Campbell et al. 2021, Hribar and Cerminara 2021, Reeves et al. 2021). Aedes vittatus (Bigot) was ranked a low-priority concern for control agencies in areas where this mosquito species has yet to be introduced; its invasive status is unclear in North America at this time and is currently confined to specific Caribbean nations (Alarcon-Elbal et al. 2020, Pagac et al. 2021, Yee et al. 2021). This may be attributed to the lack of communication and access to information and gives us insights into the perception that the states have on these vectors. The group BEACONS can utilize mosquito species migratory and introduction information, distribute it to varying states, and consult on basic principles of detection to increase awareness to newly introduced mosquito species and assist in ensuring cohesive knowledge for detecting nonnative mosquito species across regions.
Other regions, especially in the Caribbean and South America, are likely places from which invasive mosquitoes are introduced to Florida and other parts of the South. Many of the mosquito identification keys used by the respondents were 10 years old or older (Fig. 3B). Over the past decade, however, Florida alone has added more than 10 new range-expanding nonnative and invasive species to the local mosquito fauna. This resulted in identification staff having to use a wide variety of identification tools to accurately identify specimens (Fig. 3B) (Mosquito BEACONS 2022).
Unfortunately, no program mentioned identification keys from the Caribbean or other regions (e.g., South America, Africa, Asia), where invasive species likely originally migrate from. The Culicidae of Jamaica (Belkin et al. 1970), mosquitoes of southern Africa (Jupp 1996), and mosquitoes of Australia (Webb et al. 2016) are some examples that can be used to identify key morphological characteristics of invasive species in the Southeast. Even with these resources utilized, it can be challenging to identify species if differences between native and nonnative species are subtle. An updated identification and bionomics guide and lower barrier to access to such new information for mosquito control programs would be helpful to recognize nonnative and invasive species in the region (Giordano et al. 2022).
For invasive species surveillance, one can prioritize the location of surveillance to increase the likelihood of detecting an invasive mosquito species early and reduce the chance of unhindered spread. An optimized invasive mosquito surveillance program uses a variety of mosquito traps and sampling techniques in sufficient quantity and frequency. The goal is to capture different mosquito species across various life cycles and physiological states that have different degrees of attraction depending on sampling method (Giordano et al. 2020). In the survey, 59% of respondents indicated having adequate levels of resources to monitor invasive mosquito species, with many agencies not responding to the inquiry. Although another survey will be needed from Alabama and Mississippi to determine the commonly used mosquito identification guide, it is evident that each state uses a variety of identification guides for mosquito surveillance (Fig. 3B). A high diversity in the number of resources used to identify mosquitoes highlights the great level of preparedness of agencies in certain areas to adequately detect and monitor invasive species. Additional data from agencies to assess their capabilities of monitoring and detection will allow us to evaluate regional abilities to prevent the introduction of invasive mosquito species.
Strikingly, only 1 of 26 programs that had a port of entry in the jurisdiction conducted surveillance there. A separate inquiry from Mosquito BEACONS working group members indicates the lack of communication channels to initiate contact with the ports of entry. Mosquito BEACONS initiated the inquiry to the Federal Integrated Pest Management Coordinating Committee (FIPMCC) (USDA 2022) to find connections with port of authorities in our region. Since the connection between port authorities and mosquito control agencies has not been typical, sustained effort will be needed to break through barriers and open communication channels.
Having a mosquito identification expert trained in recognizing invasive and nonnative species is essential to invasive mosquito surveillance. Our survey showed that 50% or less of agencies in each state have a mosquito identification expert (Fig. 5). Although most of the agencies consider that training on invasive mosquito species biology and morphological identification of invasive species is important, only half of them provide institutional training on this topic to their employees. This can potentially lead to unidentified or misidentified species, which is detrimental to integrated vector management.
The recognition of morphologically similar invasive species can be challenging for well-trained personnel. Regular workshops or training courses that provide updated invasive mosquito ranges and tools/methods for identification would be useful and better prepare the region for timely detection and control of invasive mosquito species. In addition, it would be informative in assessing the impact of new resources and training in the change in the priorities of each species once people learn more about these newly emerged invasive and nonnative species.
Invasive mosquitoes may exhibit different ecology and behaviors in a new environment compared to those in the native range as a result of phenotypic plasticity or local adaptation (Bonizzoni et al. 2013, Medley et al. 2019). Therefore, it is important first to identify effective sampling or trapping method in their invaded habitats for developing specific control strategies to prevent the establishment and colonization. A great majority of respondents (>98%) recognize the importance of invasive mosquito research. In particular they felt strongly about learning about the insecticide resistance of invasive mosquito species.
This area of research can be logistically challenging as insecticide resistance testing requires many mosquitoes (typically 20 per bottle) that were raised in the same rearing conditions. Not all mosquitoes can be colonized in laboratory conditions. Invasive mosquitoes, especially in the early invasion stage, typically exist in low numbers. Standardized methods that require fewer mosquitoes would be helpful to advance knowledge on this matter. Sharing these strategies among the states will progress research and promote collaboration to meet research needs across the states.
Collaboration and data sharing.
Collaboration among mosquito control agencies is essential to reduce mosquito-transmitted diseases. Movement of invasive mosquito species across state and county borders can have an impact, and when collaborating agencies work in concert, incursions of unwanted species can be monitored on a higher level. However, enthusiasm seems to be lacking for data sharing. Between 30% and 50% of the mosquito agencies considered that sharing surveillance and collection data with neighboring or regional agencies, neighboring state public health or mosquito control programs, and/or research institutions was important and may help early detection of invasive species, while about 5% of Florida agencies considered these collaborations not at all important, and a significant percentage of agencies did not answer the question.
Our past experience with online databases for mosquito genetic and ecological data using PopI (popi.ucdavis.edu) or CalSurv (https://maps.vectorsurv.org/arbo) suggests that it will be difficult to have people onboard without them experiencing the database themselves and making the data submission process easy. Each program also needs to be able to see the benefit of data sharing to their own program. The BEACONS working group is developing a dashboard prototype to facilitate invasive mosquito occurrence data sharing. In addition, further communication and education resources will be needed for agencies to accentuate the need for collaboration and the sharing of information.
Improving invasive mosquito surveillance and control capacity in the Southeast.
We provided baseline information about the capacity of Southeastern regional agencies to surveil and control current and new invasive mosquito species. The solutions to improve the capacity to combat invasive mosquito species are often beyond the capacity of each program such as funding, which can be translated into more staff, equipment, and other resources to improve their program. Our study serves as the first step toward improving awareness on the invasive mosquito issues in the Southeast. The ongoing publications related to the current state of mosquito surveillance and control capacity can help program managers to communicate to the program board members and/or state authorities with hard data and seek approval for additional funding or new initiatives (e.g., surveillance at ports).
In this report, we focused on training and research needs of which Mosquito BEACONS working group has a mission to improve and advance. Our survey reveals the training gaps in invasive mosquito species and resource needs that can improve detection of invasive and nonnative species in the Southeast. Our efforts also revealed that many states in the region have limited engagement with our survey, likely because of combinations of strained material, personnel, and time resources. The COVID-19 pandemic likely negatively impacted the situation. Generally, resource-poor mosquito management entities demand creative solutions to conduct surveillance, control, and research on invasive species.
We (mosquito control professionals and scientists) can contribute in some areas to improving the invasive mosquito surveillance and control capacity. For example, the Mosquito BEACONS working group has been providing in-person workshops (Giordano 2022) with new visual guides to provide key mosquito identification resources (Giordano et al. 2022) to improve detection of invasive mosquito species in the South. Practice advisory on improving trap efficiency in capturing invasive species or species diversity in general, such as combining a conventional trap with a new lure or heat source (Guindo et al. 2021), can lower the cost of surveillance by reducing the overall number of traps as well as the number of trap types. More publications about what the priority species is by mosquito control program can increase much-needed justification to seek research funding by scientists and public health professionals (Kondapaneni et al. 2021).
We hope that the formation of the Mosquito BEACONS working group and sustained efforts to improve knowledge around the issue of invasive mosquito species will improve the surveillance and control of invasive and nonnative mosquitoes in the region and positively impact reducing the mosquito-borne disease risks. This survey highlights the importance and value of regional working groups, such as Mosquito BEACONS, and can provide a framework for other regions that may consider a similar approach.
We thank Sebastian Galindo at the University of Florida for his guidance in the UF Institutional Review Board submission process. We thank anonymous survey participants who took their time to share their knowledge and thoughts through this survey. We also thank Joe LaForest at the Southern IPM Center for connecting us with FIPMCC and other program supports for the Mosquito BEACONS working group. We acknowledge funding support from the CDC, grant NU50CK000420-04-04, the Southern IPM Center (Project S21-002 and S22-027) as part of the USDA National Institute of Food and Agriculture Crop Protection and Pest Management Regional Coordination Program (Agreement No. 2018-70006-28884), the USDA National Institute of Food and Agriculture (Hatch project 1025565), and UF/IFAS CALS Dean's Award to VTN and AB. The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the funding agencies. The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the official position of the U.S. Centers for Disease Control and Prevention.
Institute of Food and Agricultural Sciences, University of Florida, Florida Medical Entomology Laboratory, Vero Beach, FL 32962.
Environmental Health Sciences, Western Carolina University, Cullowhee, NC 28723.
New Orleans Rodent, Mosquito, and Termite Control, New Orleans, LA 70122.
Florida Department of Agriculture and Consumer Services, Tallahassee, FL 32399.
Forsyth County Department of Public Health, Winston-Salem, NC 27101.
South Carolina Department of Health and Environmental Control, Columbia, SC 29201.
United States Centers for Disease Control and Prevention, Atlanta, GA 30329.
City of Jacksonville, Mosquito Control Department, Jacksonville, FL 32218.
Environmental Security Pest Control, Cantonment, FL 32533.
Department of Entomology, University of Georgia, Athens, GA 30602.
Beach Mosquito Control District, Panama City, FL 32413.
Central Life Sciences, Vector, Panama City Beach, FL 32408.