Progress 10/01/19 to 09/30/20
Outputs
Target Audience:This project involved outreach regarding applied research endeavors to the several audiences and collaborating groups during the past period. One of the main interactions was with the Michigan Mosquito Control Association attendees, 154 attendees and registrants. The PI was the chairperson of the organizing committee for the entire conference, and organized the program for the first day of this two day meeting, held at Michigan State University's Kellogg Center, on February 5 and 6, 2020. This special symposium on day one of this meeting focused on the emergent problem of eastern equine encephalitis (EEE) virus in the upper Midwest region, particularly Michigan, and modes of response. Included in speakers were veterinarians, medical doctors, public health officials, vector surveillance and control officials, and academics including a medical ethicist. Additional outreach during the period was to Michigan's private and public sector pesticide applicator community for mosquito control, with a comprehensive training meeting held in Bay City, Michigan in late October, 2020. Attended by 227 individuals. The PI spoke at the meeting, giving one hour-long address, and also answered questions and participated in workshops. In addition, the PI attended and spoke at the annual ArborCon 2020 arborists meeting held at the Lansing Center on February 11-12, 2020, addressing issues of risk and risk mitigation for arborists in relation to tick and mosquito borne disease. Also, the PI spoke at the annual meeting of the Northeast Mosquito Control Association on the topic of EEE in Michigan, highlighting its biogeography and landscape associations, links to mosquitoes, and to dynamics over time in relation to outbreaks and human risk of disease. Other outreach included three talks and public meetings in the Kalamazoo, Michigan, area in relationship to the EEE problem. This interaction resulted in professional relationships with the Kalamazoo and Calhoun County health departments and the Binder Park Zoo to establish EEE studies in summer, 2020. These studies were partially disrupted by the arrival of the covid pandemic. Changes/Problems:Beacuse of the resurgence of eastern equine encephalitis virus in our region and the strong public response for assistance with this problem, new research activities related to those previously proposed and under way have been designed, implemented, and intended for future work. One major problem was the appearance of the covid pandemic, which intefered severely with field research plans anticipated for the summer of 2020. What opportunities for training and professional development has the project provided?The PI provided training to the private and public sector mosquito control community in Michigan through a training workshop held in late October, 2019, in Bay City, Michigan. In addition, the PI hired two student interns supported by the Midwest Center of Excellence in Vector Borne Diseases to carry out research on the EEE virus system in summer 2020. These two individuals conducted individualized projects associated with the center and this disease system after procedures were put in place in July 2020 for work to commence given covid pandemic restrictions. In addition, the PI employed 5 other undergraduate student workers on mosquito borne virus surveillance, research, and testing activities during this time period, affording these collective 7 students to garner experiences in research, laboratory and field procedures, sample and data management, and reporting. How have the results been disseminated to communities of interest?Results have been disseminated to communities of interest by the aforementioned public meetings and interactions and by publication in scientific journals. What do you plan to do during the next reporting period to accomplish the goals?Our original goals towards elucidating population structure and genetic basis of host choice for Culex pipiens remain in place. These studies involve developing and applying microsatellite locus markers as a means of assessing genetic diversity and associating that diversity with host choice as determined by blood meal analysis of field caught, blood fed, female Culex pipiens. The research is important because host choice is an important determinant of human risk of exposure by bite to West Nile virus, carried by this species of mosquito. This work was to have taken place in the Chicago metropolitan area but field work was hampered by the covid pandemic which inhibited interstate travel and team deployment. We will deploy teams and commence these studies pending changes in the covid restrictions on research activities and abilities to move about freely and sample populations in locations remote to the main campus. Other research will be conducted to evaluate the impact of insecticide treated resting stations on density, survivorship, and infection rate for EEE virus in populations of Culiseta melanura mosquitoes at field sites within the EEE endemic zone of southwestern Michigan. Theaim isto develop and evaluate a system for treating resting stations with environmentally-friendly insecticides targeting the mosquito species Culiseta melanura in order to reduce the vectorial capacity of populations of this species of mosquito for transmission of eastern equine encephalomyelitis virus. The scope of work involves research at Michigan State University main campus, and at field sites located in southwestern Michigan. There is both laboratory and field research involved, over the course of two years, emphasizing the summer months when the mosquitoes are active (June to October). Research for a single yearwill focus on analysis of toxicological effects of pyrethroid-treated resting stations. Stations will be constructed and treated with one of two registered residual insecticides (tau fluvalinate as Mavrik Perimeter formulation, and lambda-cyhalothrin as Proflex Encapsulated Solutions formulation) and tested for acute toxicity and residual activity with laboratory colonies and field collected mosquitoes. This work will establish whether these insecticides are suitably toxic, and how long they last on sprayed surfaces. Some stations will be treated, placed in the field, retrieved, and returned for toxicity tests to examine the effects of field exposure. Field teams will establish sampling regimes at field sites to assess abundance and age structure of Culiseta melanura, using the parity method, and will compare the resting station and dry-ice baited CDC light trap as sampling tools for this species of mosquito. These teams will also sample mosquitoes for testing for EEE virus during the course of the summer at these sites. In addition, to address the issue of the number of treated resting stations required for adequate coverage of a EEE endemic focus, a field study will be conducted in which nontreated resting stations are placed in different numbers over time and the saturation or deflection point of return of Culiseta melanura females and males is achieved. It will provide an estimate of the number of treated stations required per unit area of a site. If these results are promising, then a second season of work will be conceived and proposed to CDC for research on scaled up assessment of treated resting stations at EEE endemic sites. If the resting stations are effective, then the anticipated outcomes are lower population density of Culiseta melanura adults, younger age structure as reflected by parity rates and estimated probability of daily survival, and reduced infection rate for EEE virus. If such is this case, these findings will be communicated to the public health community with the idea that the stations offer a possible new control tool for communities impacted by EEE outbreaks. There is also the strong possibility of commercialization of the concept to the form of a product.
Impacts
What was accomplished under these goals?
Culex pipiens and Culex restuans are the primary enzootic and epizootic vectors of West Nile virus in the upper midwest region. Agencies responsible for suppressing pouplations of these vector species utilize methods directed at both the larval and adult stages of the mosquitoes. With regard to adult mosquito control, insecticides of the synthetic pyrethroid category and formulated for ultralow volume application during the dusk, dark, and dawn hours when the mosquito flight is the highest are applied by equipment mounted onto pickup trucks moving at 10 miles per hour for low rates of application ("ultralow volume") with finely generated and dispersed droplets. We had previously commenced analyses of susceptibility and resistance to one of these synthetic pyrethroids (permethrin) and reported on a regional survey in last year's report, covering 28 sampled sites across 7 states. Susceptibility to permethrin was high in populations of both species, with only 7 sites showing reduced susceptibility which was alleviated by inclusion of the synergist piperonyl butoxide in the phenotpic bottle bioassays used as the assessment method. We continued this with new research, not previously reported, involvingsusceptibility studies with collaborators at the Northwest Mosquito Abatement District in metropolitan Chicago where West Nile virus is endemic and where the agency uses both permethrin and another synthetic pyrethroid, etofenprox. The focus of the research was to determine if either species was differentially susceptible to these two active ingredients. Indeed, results showed that while both species were generally susceptible to permethrin within acceptable dosage ranges, Culex restuans showed reduced susceptibility to etofenprox from three of the five multiply sampled sites compared to Culex pipiens. These data reveal either induced or natural resistance and species differences that could certain affect agency efforts to control these vector populations and contain virus transmission. A manuscript summarizing these studies is in preparation. Other field research planned for summer 2020 was to focus on the EEE virus system, biology and sampling of Culiseta melanura, establishment of field sites within the Kalamazoo and Calhoun County areas, and preliminary field tests of a novel control method involving insecticide treated, black resting stations placed strategically around EEE virus foci (tamarack sphagnum bogs and red maple swamps). Because of the covid pandemic, these studies were limited in scope, however, field work commenced in July 2020 with the opening of field programs and longitudinal sampling of mosquito populations commenced at selected sites within the city of Portage and at the Binder Park Zoo, south of Battle Creek, using a combination of dry ice baited light traps and untreated, black resting boxes. Mosquito collections are in the process of being sorted and identified to species and prepared for testing for EEE virus at the time of this writing. A subset of Culiseta melanura mosquitoes was set aside for dissection for parity to determine population age structure, an important variable related to survivorship and vectorial capacity for the EEE virus. It is anticipated at the insecticide treated resting station will be an outcome product of this project over the next two years.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Chen S, Walker ED. Genome sequence of Flavobacteriaceae strain W22, isolated from tree hole mosquito habitat. Microbiology Resource Announcements (Genome Section) 2020; 9(7): e00008-20.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Norman B, Walker ED. Succession of bacteria and fungi in leaf litter of tree hole habitats: Responses of diversity to conditioning and mosquito larvae. Aquatic Microbial Ecology 2019; 83: 237-250.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Chen S, Johnson BK, Yu T, Nelson BN, Walker ED. Elizabethkingia anophelis: Physiologic and transcriptomic responses to iron stress. Front. Microbiol. 2020; 11:804.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Chen S, Walker ED. Genome sequence of Serratia fonticola strain MSU001, isolated from the mosquito Aedes triseriatus. Microbiology Resource Announcements (Genome Section) 2020; 9(17): e00099-20.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2020
Citation:
Thompson KA, Henderson E, Fitzgerald SD, Walker ED, Kiupel M. Eastern equine encephalitis virus in two Mexican wolf (Canis lupus baileyi) pups at a zoo in southwest Michigan. Emerging Infectious Diseases (in revision).
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:This project involved outreach regarding applied research endeavors to the following audiences during the past period: (1) Michigan Mosquito Control Association attendees, 113 attendees and registrants. (2) Indiana Vector Control Association, 101 registrants. (3) North Central Mosquito Control Association, 156 registrants. (4) Toledo Sanitary District for Ohio Mosquito and Vector Control Association, 18 registrants. (5) County and District Health Departments, State of Michigan, Three 2-day workshops with 25, 31, and 21 registrants, respectively. In addition, the following audiences were reached by outreach activity: (1) American Mosquito Control Association Annual Meeting, Orlando, FL February 25th - March 1st, 2019. (2) Southwestern Branch Entomological Society of America, 67th Annual Meeting, Tulsa, OK April 14th - 18th, 2019. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?An studentintern from the College of Veterinary Medicine, Purdue University, Mr. Christopher Mapes, was hosted for the summer under funding from the CDC Midwest Center of Excellence in Vector Borne Diseases to conduct research on the effects of aging on insecticide resistance and susceptibility in Culex pipiens. Postdoctoral Dr. Trisha Dubie learned methodologies of insecticide resistance and susceptibility evaluation, and was trained in social science methods for survey research. Five undergraduate students paricipated in mosquito research. How have the results been disseminated to communities of interest?The results have been communicated to communities of interest through extensive outreach programs as described in the audiences section. What do you plan to do during the next reporting period to accomplish the goals?Research will continue on molecular genetic characterization of population structure in Culex pipiens populations as originally proposed.
Impacts
What was accomplished under these goals?
A survey was developed to evaluate mosquito control practices and insecticide resistance monitoring in the upper Midwest and distributed to mosquito control practitioners and public health professionals in Michigan, Indiana, Ohio, Wisconsin, Minnesota, Illinois, and Iowa. Approximately 459 surveys were sent via email and U.S. mail, including 187 initial contacts plus an additional 272 contacts via Indiana Vector Control Association's distribution list. Responses submitted online and by mail totaled 59, including 33 participants that offered optional contact information. Most participants indicated that they are open to sharing data (YES:69.7%, NO:30.3%) or attending future workshops (YES:32, NO:10). While most respondents indicated that they conduct surveillance for larvae and adults before treatment, many do not follow specific action thresholds (YES: 61.2%, NO: 38.8%). Additionally, only 46.9% of respondents indicated that their organization conducts pre- and poet-treatment evaluation, and 70% indicated that they evaluate the effectiveness of their control programs. Most respondents indicated that they do not monitor for insecticide resistance (NO:71%), and of those that do monitor for insecticide resistance (29%), a small number have previously detected resistance (8.8%). These results were helpful to determine the needs of mosquito control programs in the region and design curriculum for training focused on insecticide resistance and effectiveness of mosquito control programs. Working with public health colleagues within regional mosquito and vector control associations, we established an outreach program using exhibitor booth space at annual conferences and 30 to 60-minute presentations. Attendees were able to ask detailed questions about insecticide resistance, and obtain bottle bioassay kits. Each kit contains the same materials provided in the CDC kit, a timer, and a binder containing the CDC bottle bioassay guidelines and other materials. Follow up emails and phone calls are currently underway to check in on the 39 bottle bioassay kit recipients and determine if they have conducted any testing for 2019, if they have had any trouble with aspects of the testing such as, rearing mosquito samples or conducting the bottle bioassay. Most recipients have indicated that the weather or abundance of Culex restuans has delayed collection and testing of Cx. pipiens, and they plan to perform assays later in July and August 2019. Additional follow up calls and emails are planned for Fall to determine how many recipients were able to successfully conduct bottle bioassays and gather any available results. Results from the survey completed in 2018 will be combined with training and outreach outcomes and prepared for publication. We conducting a regional survey of insecticide resistance of Culex mosquitoes and population structure of these mosquitoes collected from the field for susceptibility to pyrethroids and select organophosphates. We use the CDC bottle bioassay procedure and WHO guidelines for the susceptibility evaluations, and, when reduced susceptibility is shown, we will examine the mechanism of resistance via KR PCR and measurements of detoxification enzymes. Egg rafts were obtained from 26 locations within MI, WI, MN, IL, IN, OH, and IA. Samples were acquired through direct collections and by shipping using egg raft kits comprised of gravid water materials, collection equipment, appropriate packaging, and shipping labels to send back to MSU for testing. Approximately 70 individuals from various mosquito control and public health organizations were contacted, and 23 individuals responded. Collection efforts concluded October 1st. Results from evaluations using permethrin showed decreased susceptibility in mosquitoes from seven different sites. Results from evaluations using deltamethrin have varied, with few locations showing high susceptibility. Please see the table below for results from individual sites. Individual mosquitoes from these tests have been saved and will contribute to the genetic assessment of regional Cx pipiens populations. Additionally, a summer research fellow assigned to our lab conducted a series of experiments examining the susceptibility of blood fed, aged, and gravid Cx. pipiens to permethrin. Those experiments show increased susceptibility in blood fed and gravid females in addition to differences in susceptibility with age. To carry out population structure and genotyping analysis, we are currently optimizing 12 microsatellite loci for Culex pipiens and adapting a new fluorescence labeling strategy to resultant microsatellite alleles. Further, we have established a PCR based idea to discriminant Culex species (Culex salinarius, Culex quinquefasciatus, Culex pipiens), to discriminate forms within the Culex pipiens species (form Molestus and form Pipiens), and have initiated testing of the above field specimens; the majority are Culex pipiens. To evaluate the infection status of West Nile virus in wild populations of Culex mosquitoes, we sampled by light trap and gravid trap at 6 locations in Michigan weekly, and analyzed mosquitoes for West Nile virus RNA using reverse transcription, real time PCR in the ABI format. Although mosquito testing continues at the time of this writing, a total of 23,682 mosquitoes were tested. Results indicate very low virus infection rates throughout the summer season of 2019, with late season virus amplification.
Publications
- Type:
Book Chapters
Status:
Published
Year Published:
2019
Citation:
Foster WA, Walker ED. Mosquitoes (Culicidae), Chapter 12. Pp. 207-259. In: G. Mullen and L. Durden (eds.). Medical and Veterinary Entomology, 3rd edition 2019; Academic Press, New York.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Keven JB, Walker ED, Venta P. A microsatellite multiplex assay for profiling pig (Sus scrofa domestica) DNA in mosquito blood meals. J Med Entomol 2019; DOI: https://doi.org/10.1093/jme/tjz013.
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Progress 09/01/18 to 09/30/18
Outputs
Target Audience:The target audiences are mosquito control districts, agencies, and associations in the Great Lakes region of the United States, including in the states of Minnesota, Wisconsin, Iowa, Illinois, Indiana, Michigan, and Ohio. Also included are state and local public health departments and agencies. Lastly included are personnel of the US Centers for Disease Control and Prevention. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?We have trained 4 undergraduate students in mosquito collection and survey methods including trapping and identification. We have trained 2 other undergraduate students in methods for testing wild mosquitoes for West Nile virus infection using reverse transcription, quantitative PCR. We trained yet another undergraduate student in methodology for effectiveness of insecticide applications and for methods to test for insecticide susceptibility or resistance using timed bottle bioassays. This project also involves training and learning experiences for a postdoctoral researcher in the areas of mosquito insecticide resistance and population genetic structure. How have the results been disseminated to communities of interest?We have published two scientific papers relevant to this project in 2018. We have also disseminated information on insecticide effectiveness evaluations and resistance monitoring to 59 mosquito control groups in the upper midwest region. What do you plan to do during the next reporting period to accomplish the goals?Our 5 objectives remain in place and viable within the context of the proposed research. We are pursuing our population genetic structure aim with microsatellite allele frequency based systems to determine the genetic background of form Molestus biotype in our target Culex pipiens populations, and are associating those findings with insecticide resistance monitoring and with West Nile virus infection rates. We are also summarizing the response data from our KAP survey instrument. These activities and others comprise our activities for the coming year.
Impacts
What was accomplished under these goals?
This new project was submitted for review and approval on June 26, 2018 so at the time of this reporting is only two months in progress. We have established field sites through collaborations with colleagues in Minneapolis/St. Paul, Minnesota; Milwaukee, Wisconsin; northern Cook County and Chicago metropolitan area, Illinois; Toledo, Ohio; and Saginaw, Michigan. We have conducted field sampling of Culex pipiens at these sites and intitiated genotypic characterization of them using molecular means to determine the extent of background of form Molestus. We have established a new colony of Culex pipiens from a field site at Michigan State University to use in controlled laboratory studies and as a strain for comparative testing for sensitivity or resistance to pyrethroid insecticides. We have conducted bottle bioassays with selected pyrethroid insecticides for Culex pipiens populations from the above sites and found resistant populations in northern Cook County, Illinois; and Saginaw, Michigan. We carried out an effectiveness trial of ultralow volume application of the combination insecticide Mosquito Master 4+12 containing 12% chlorpyrifos and 4% permethrin against natural populations of Culex pipiens in Toledo, Ohio; and a similar trial but using Biomist (a 4% formulation of synergized permethrin) in Saginaw, County. A planned trial in St. Paul, Minnesota, was forestalled by a citizens' group that opposed mosquito spraying, although an operational mosquito control program already exists in the area. We also conducted a regional survey of knowledge, attitudes, and practices of vector control professionals.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Nelson C, Sibley S, Hamer GL, Newman CM, Anderson TK, Walker ED, Kitron UD, Brawn JD, Ruiz MO, Goldberg TL. Evolution of West Nile virus within and between hosts and vectors demonstrates selective constraint but adaptive capacity in the Flaviviridae. Virus Evolution 2018; 12:4
Poh K, Martin EM, Walker ED, Kitron U, Ruiz MO, Goldberg TL, Hamer GL. Co-circulation of Flanders virus and West Nile Virus in Culex mosquitoes (Diptera: Culicidae) from Chicago, Illinois. Journal of Medical Entomology 2018; 55:1062-1066.
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