- Author: Kathy Keatley Garvey
It's well deserved!
Scott, a UC Davis distinguished professor who officially retired in 2015, is internationally known for his work on the ecology and epidemiology of dengue, a mosquito-borne viral infection transmitted mainly by Aedes aegypti. He now resides in Luck, Wis., where his wife's family is from.
Only 1 percent of researchers make the global list of Highly Recited Researchers, as announced by Clarivate. The Web of Science Group, the information and technology provider for the global scientific research community, annually honors the 1 percent of scientists whose publications are the most cited in scientific papers.
"Of the world's scientists and social scientists, Highly Cited Researchers truly are one in 1,000," according to the Web of Science website.
Scott is one of 14 researchers from UC Davis--and one of some 6660 worldwide--to achieve the 2021 honor.
Scott's 19 publications listed in the report have been cited a total of 402 times. His most cited publication: “The Current and Future Global Distribution and Population at Risk of Dengue,” published in Nature Microbiology in 2019.
“Being a Highly Cited Researcher means a lot to me because it's an objective measure of the extent to which the scientific community finds helpful the work that my colleagues and I did,” said Scott, who joined the UC Davis Department of Entomology (now the Department of Entomology and Nematology) in 1996. “ I was privileged to work with exceptionally smart, hard-working, and insightful people. We had a lot of fun, but we also took our science seriously. We challenged each other in constructive and collegial ways. We are proud of the results of our efforts.”
Healthy Cites, Healthy People. Scott co-chairs a Lancet Commission that focuses on how prevention of viruses transmitted by Aedes mosquitoes fits into the growing Healthy Cities, Healthy People movement. Lancet Commissions are tasked with identifying the most pressing issues in science, medicine, and global health, with the aim of providing recommendations that change health policy or improve practice. “In this case, we are making the case for Cities without Aedes,” Scott said. "We aim to reduce the burden and threat from Aedes transmitted viruses through improved construction and management of modern urban environments that build Aedes mosquitoes out of cities and towns.”
Scott is a collaborator in a clinical trial designed to demonstrate and quantify the protective efficacy of a spatial repellent to reduce human mosquito transmitted virus infection in Sri Lanka. “This new project,” he said, “builds on a randomized controlled clinical trial that my colleagues I recently completed in Iquitos, Peru, which revealed a significant protective efficacy of a spatial repellent against human infection. Publication of those results a currently under review.”
“In addition to the clinical trial, my colleagues and I are publishing a series of papers from Iquitos that examine the role of people with in-apparent and mild infections in virus transmission. By accounting for factors underlying variation in each person's contribution to transmission we will be able to better determine the type and extent of effort needed to prevent disease.”
Scott's other activities include being a scientific advisor for a clinical trial in Brazil that is testing the public health benefit of Wolbachia for prevention of viruses transmitted by Aedes mosquitoes. “The study will assess the efficacy of releasing Wolbachia-infected Aedes aegypti into the environment in reducing human virus infection compared to standard vector control measures alone,” he said.
Scott serves on three World Health Organization committees, “which I find particularly rewarding because of their potential to improve public health policy and thus global health.”
Among his other activities:
- Chair of a group that is writing a chapter on Dengue Vector Control Guidelines that will be included in the updated version of WHO guidelines for dengue diagnosis, treatment, prevention, and control.
- Co-chair of the Wolbachia Evidence Review Group. “Mosquitoes infected with the endosymbionic bacteria Wolbachia are designed to have reduced capacity to become infected with and transmit a variety of viruses, which is expected to reduce human disease,” Scott explains. “Results from our deliberations will help the World Health Organization to develop guidelines for member States on the application of this exciting new intervention strategy.”
- Member of the World Health Organization Technical Advisory Group on the Global Integrated Arboviruses Initiative. The Arbovirus Initiative focuses on strengthening the coordination, communication, capacity building,research, preparedness, and response needed to mitigate the growing risk of epidemics due to arthropod transmitted viral diseases. Scott describes it as “a collaborative effort between the World Health Emergency Program, the Department of Control of Neglected Tropical Diseases, and the Immunization, Vaccines, and Biological Department at WHO. Members of the Technical Advisory Group have a broad range of expertise (clinical management, diagnostics, epidemiology, vector control, virology, vaccines, and travel medicine) and serve in an advisory capacity to WHO with a focus on essential and strategic guidance on management of disease. Our current focus is finalizing the Global Integrated Arboviruses Initiative, which will be presented to the World Health Assembly for review and approval.”
Challenging and Rewarding. “I am excited about and enjoy all these activities,” the medical entomologist commented. “They are challenging and rewarding extensions of the work I have done for that past 40 years.”
Scott, who holds bachelor and master's degrees from Bowling Green (Ohio) State University, received his doctorate in ecology in 1981 from Pennsylvania State University and did postdoctoral research in epidemiology at Yale University School of Medicine's Arbovirus Research Unit, part of the Department of Epidemiology and Public Health. He served on the faculty of the Department of Entomology, University of Maryland, from 1983 to 1996 before joining the UC Davis entomology faculty as a professor of entomology and director of the Vector-Borne Disease Laboratory. He was acting director of the UC Davis Center for Vector-Borne Research from 1996 to 1999, and director of the UC Davis Arbovirus Research Unit (2001-2003). He was selected vice chair of the Department of Entomology in 2006, serving until 2008.
Highly honored by his peers, Scott won the coveted Harry Hoogstraal Medal from the American Society of Tropical Medicine and Hygiene in 2018. His other honors include fellow of three organizations: American Society of Tropical Medicine and Hygiene (2014), Entomological Society of America (2010), and the American Association for the Advancement of Science (2008). He was named a UC Davis distinguished professor in 2014. In 2015, he won the Charles W. Woodworth Award, the highest honor awarded by the Pacific Branch of the Entomological Society of America.
The methodology that determines the “who's who” of influential researchers draws on the data and analysis performed by bibliometric experts and data scientists at the Institute for Scientific Information at Clarivate. It also uses the tallies to identify the countries and research institutions where these citation elite are based.
- Author: Kathy Keatley Garvey
Travelers know Iquitos as the "capital of the Peruvian Amazon" but scientists know it as a hot spot for dengue, a mosquito-borne viral disease with raging outbreaks in many tropical and subtropical countries.
Amy Morrison, stationed in Iquitos full-time, has directed dengue research activities there for the past 15 years. An epidemiologist who joined the UC Davis laboratory of medical entomologist Thomas Scott (now professor emeritus) in 1996, she's a project scientist and scientific director of the Naval Medical Research Unit No. 6 (NAMRU-6) Iquitos Laboratory.
Morrison is back in the states to present a UC Davis seminar on "Targeting Aedes Aegypti Adults for Dengue Control: Infection Experiments and Vector Control in Iquitos" from 4:10 to 5 p.m., Wednesday, Jan. 10, in 122 Briggs Hall, Kleiber Hall Drive.
Hosted by the UC Davis Department of Entomology and Nematology, it's the first in a series of winter seminars coordinated by assistant professor Rachel Vannette and Ph.D student Brendon Boudinot of the Phil Ward lab.
Dengue is a threat to global health, says Morrison, who holds a doctorate in epidemiology from Yale University and a master's degree in public health from UCLA. According to the World Health Organization (WHO), the incidence of dengue has increased 30-fold over the last 50 years and almost half of the world population is now at risk. It's ranked as "the most critical mosquito-borne viral disease in the world."
"Each year, an estimated 390 million dengue infections occur around the world," according to the World Mosquito Program. "Of these, 500,000 cases develop into dengue hemorrhagic fever, a more severe form of the disease, which results in up to 25,000 deaths annually worldwide."
Of the dengue project in Iquitos, Morrison says: "Comprehensive, longitudinal field studies that monitor both disease and vector populations for dengue viruses have been carried out since 1999 in Iquitos. In addition, to five large scale-vector control intervention trials, ongoing data collection has allowed the evaluation of Ministry of Health emergency vector control using indoor ULV space sprays with pyrethroids in concert with larviciding through multiple campaigns, as well as characterize local DENV (dengue virus) transmission dynamics through two and one novel DENV serotype and strain invasions into the city."
"Our research group has also been conducting contact cluster investigations on DENV-infected and febrile control individuals since 2008," Morrison relates. "These studies demonstrated that attack rates were consistent between houses where cases were first detected and recently visited contact houses independent of distance between these locations. Furthermore, contact cluster investigations allow us to identify viremic individuals across the spectrum of disease outcomes including inapparent infections."
"Using DENV positive individuals captured through these and other febrile surveillance protocols, we exposed laboratory reared (F2) Aedes aegypti mosquitoes directly on their arms or legs, and obtained blood samples with and without EDTA for exposure of mosquitoes in an artificial membrane feeder. After a 58-participant pilot study comparing feeding methods, we initiated a direct feeding protocol exposing participants (78 feeds in 31 participants to date). Feeding, survival, midgut infection and systemic dissemination are all higher using direct feeding than indirect feeding methods. Of 22 participants without detectable fluorescent focus assay titers in their serum at the time they were exposed to mosquitoes, 14 infected mosquitoes by at least one method."
"Although virus titer was a predictor of mosquito infection, mosquitoes became infected at low or undetectable titers and with subjects experiencing mild disease. We have evaluated insecticide-treated curtains and a novel lethal ovitrap (Attractive Lethal OviTrap = ALOT) for dengue control. Only the ALOT traps showed a significant impact on dengue incidence corresponding to a modest decrease in vector densities and a shift of the mosquito population age structure in the trap area to younger mosquitoes. Recent evaluations of indoor ULV interventions with pyrethroids suggest that ULV campaigns that reduce Aedes aegypti for at least 3 weeks through multiple fumigation cycles can mitigate DENV transmission during the same season."
Bottom line: "We argue that Aedes aegypti control should focus on interrupting transmission rather than long-term suppression at operationally unachievable levels and that emergency control should be applied at area-wide scales rather than reacting to individual DENV cases."
- Author: Kathy Keatley Garvey
The mosquito transmits the Zika virus, currently "the" hot medical topic.
But it also transmits dengue, yellow fever and chikungunya viruses.
Especially dengue.
“Dengue infects 400 million people worldwide each year, and 4 billion people or nearly half of the world's population are at risk for dengue,” says medical entomologist Thomas Scott, distinguished professor and now emeritus, UC Davis Department of Entomology and Nematology.
Scott, who has studied dengue more than 25 years and is recognized as the leading expert in the ecology and epidemiology of the disease, emphasizes that “There is no vaccine nor drug that is effective against this virus." There are four serotypes: DENV-1 through DENV-4.
Now for the groundbreaking news.
Scott and his colleagues just published a study in the Public Library of Science (PLOS), Neglected Tropical Diseases, that is sure to rock the world of everyone who has ever contracted dengue.
Well, yes, you can. "Lifetime of immunity" is false.
“Our most significant result from this study is that immunity to dengue viruses does not always provide perfect protection from reinfection,” Scott said. “The public health implications include evaluation of dengue vaccines, interpretation of a person's virus exposure history and susceptibility to new infections, and design of dengue surveillance programs.”
“Our data indicate that protection from homologous DENV re-infection may be incomplete in some circumstances, which provides context for the limited vaccine efficacy against DENV-2 in recent trials,” the research team wrote. “Further studies are warranted to confirm this phenomenon and to evaluate the potential role of incomplete homologous protection in DENV transmission dynamics.”
Former UC Davis researcher Steve Stoddard and senior author of the paper said it well:
“It has long been thought that infection with any one of the viruses produced lifetime immunity to that virus. This finding could help explain results of dengue vaccine trials that showed poor efficacy against one of the four serotype. It also has broad implications for vaccine development.”
The research team investigated the "validity of the fundamental assumption" by analyzing a large epidemic caused by a new strain of DENV-2 that invaded Iquitos, Peru, in 2010-2011, 15 years after the first outbreak of DENV-2 in the region.
Read more about the research on the UC Davis Department of Entomology and Nematology website and in PLOS, Neglected Tropical Diseases.
- Author: Kathy Keatley Garvey
Mosquitoes will take the spotlight, front line and center, this month.
On Wednesday, April 8, Regents Professor Michael Strand of the University of Georgia, Athens, and internationally recognized for his research on parasite-insect host interactions, will speak on "The Role of Microorganisms in Growth, Development and Reproduction of Mosquitoes” at the UC Davis Department of Entomology and Nematology seminar from 12:10 to 1 p.m. in 122 Briggs.
Next the Pacific Branch of the Entomologist Society of America (PBESA) will honor medical entomologist Thomas W. Scott, distinguished professor of entomology, UC Davis Department of Entomology and Nematology, at its 99th annual conference, April 12-15, in C'ouer d'Alene, Idaho. He will receive the coveted C. W. Woodworth Award for his outstanding work on dengue, a mosquito-transmitted disease.
And then on Friday, April 24, UC Davis will co-host the fourth annual Bay Area World Malaria Day Symposium, set from 8 a.m. to 4 p.m., Friday, April 24 on the Clark Kerr campus, UC Berkeley. UC Davis and Zagaya, a non-profit organization that envisions a malaria-free world, are partnering on the project.
Michael Strand Seminar April 8
Professor Strand's talk is much anticipated. "Mosquitoes are well recognized as the most important arthropod vectors of disease-causing pathogens," Strand says in his abstract. "Interest in the gut microbiota of mosquitoes has risen recently as a potential tool for manipulating vector competency. In contrast, much less is known about the role of this community in mosquito growth, development and reproduction. In this talk I will discuss recent results from our lab group regarding the composition of the gut microbiome in different mosquito species and insights we have gained about the function of this community in mosquito biology and evolution."
Strand focuses his research in the areas of parasite-host interactions, virology, immunity and development. Current projects center on virus-host interactions, function of the insect immune system, and regulation of reproduction in mosquitoes and other insects.
Strand will be introduced by molecular biologist Shirley Luckhart, professor in the Department of Medical Microbiology and Immunology School of Medicine, and co-director of the UC Davis-based Center for Vector-borne Diseases (CVEC).
Talk will turn to dengue at the PBESA meeting in Co'eur d'Alene, Idaho. Professor Scott, who has researched mosquito-borne disease for 35 years and is retiring in June, is a global authority on the epidemiology of mosquito-borne disease, mosquito ecology, evolution of mosquito-virus interactions, and evaluation of novel products and strategies for mosquito control and disease prevention. Among the top vector biologists in the world, he is recognized as the leading expert in the ecology and epidemiology of dengue.
Scott is known for his holistic and comprehensive approach in finding solutions to protect the world's population from dengue, a disease that infects some 400 million per year. Some 4 billion people in 128 countries, more than half of the world's population, are at risk for dengue. Currently no vaccine or drug is effective against this life-threatening disease.
Scott's most significant research contributions concern the ecology and epidemiology of dengue:
- Blood feeding behavior, longevity, dispersal, and vector-virus interactions of the mosquito Aedes aegypti;
- Longitudinal cohort studies of spatial and temporal patterns in human dengue virus infection in Peru and Thailand; (dengue research in Peru, Thailand, Puerto Rico and Mexico for the past 25 years)
- Impact of human movement on mosquito contact rates and spatial dimensions of dengue virus transmission; and
- Mathematical and computer simulation modeling of mosquito population biology and mosquito-borne pathogen transmission.
Scott co-founded the Center for Vector-Borne Research (CVEC), comprised of researchers throughout the UC System. See more information on Scott.
Patrick Duffy, chief of the National Institutes of Health's Laboratory of Malaria Immunology and Vaccinology, will keynote the fourth annual Bay Area World Malaria Day Symposium, set Friday, April 24 on the Clark Kerr campus, UC Berkeley. The symposium, to take place from 8 a.m. to 4 p.m., will be co-hosted by UC Davis and Zagaya.
Duffy is an internationally recognized expert in human malaria pathogenesis, malaria in pregnancy, and malaria vaccine development. He has published more than 100 papers on malaria over his nearly 25-year career.
UC Davis co-host Shirley Luckhart, professor in the Department of Medical Microbiology and Immunology School of Medicine, and co-director of the Center for Vector-borne Diseases, will be one of the speakers.
Meanwhile, take a look at the spectacular mosquito images taken by entomologist/photographer Jena Johnson of Athens, GA (she is married to Michael Strand). This is the Aedes aegypti mosquito blood-feeding on her.
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- Author: Kathy Keatley Garvey
The Pacific Branch of the Entomological Society of America (PBESA) has announced that two distinguished professors and a graduate student from the Department of Entomology and Nematology, University of California, Davis, have won major awards.
Distinguished Professors James R. Carey and Thomas W. Scott, and doctoral candidate Mohammad-Amir Aghaee will be among those honored at PBESA's 99th annual meeting of PBESA, set April 12-15 in Coeur d'Alene, Idaho. PBESA encompasses 11 Western U.S. states, plus several U.S. territories and parts of Canada and Mexico
Carey won the Distinguished Teaching Award and his nomination packet will now advance to the national level. Scott won the C. W. Woodworth Award, the highest honor given by PBESA. Aghaee won the John Henry Comstock Graduate Student Award, the highest graduate student award given by PBESA.
Of note: Scott is the 10th UC Davis-affiliated entomologist to win the Woodworth award. This is the third consecutive year that UC Davis has won the Comstock award (previous recipients were Kelly Hamby and Matan Shelomi) and this is the second consecutive year that UC Davis has won the teaching award (Diane Ullman received the 2014 award and then went on to win the national award).
Carey last year received the 2014 Distinguished Teaching Award from the UC Davis Academic Senate, an honor given to internationally recognized professors who excel at teaching. PBESA singled him out for his technological innovations, creativity and excellence.
“Dr. Carey is not only considered the most technologically innovative and creative classroom teacher on the UC Davis campus, but his expertise is highly regarded throughout the UC statewide system,” wrote nominator Michael Parrella, professor and chair of the UC Davis Department of Entomology and Nematology. “He crafted a groundbreaking model for 21st century instruction, and his presentations are in high demand statewide, nationally and globally. His presentations have taken him from UC Davis to UC Irvine to the University of Alabama, and beyond, including Germany, Korea, Denmark, France and Africa.”
“Dr. Carey uses synergistic strategies to develop video-based learning methods for faculty research programs, professional networks and outreach programs,” Parrella said. “He has developed ‘what-you-need-to-know' videos to increase writing and speaking skills and technical fluency, as well as to understand such subjects as copyright and fair use laws. All are geared for ease of learning and increased knowledge retention.”
Carey last year received the 2014 Distinguished Teaching Award from the UC Davis Academic Senate, an honor given to internationally recognized professors who excel at teaching.
When asked his philosophy of teaching, Carey said: “My philosophy of teaching is inseparable from my philosophy of scholarship. Students need to know the big picture to understand the pixels. They need to zoom in and zoom out so that they can consider the details I present in class in the context of larger conceptual and operational frameworks.” (See more.)
Scott, a noted medical entomologist, is a global authority on dengue and other mosquito-borne diseases. In accepting the award, he will present a 30-minute talk April 13 on “Embracing Complexity: The Path to Improved Public Health Entomology.”
Scott, who has researched mosquito-borne disease for 35 years, is a global authority on the epidemiology of mosquito-borne disease, mosquito ecology, evolution of mosquito-virus interactions, and evaluation of novel products and strategies for mosquito control and disease prevention. Among the top vector biologists in the world, he is recognized as the leading expert in the ecology and epidemiology of dengue, said nominator Michael Parrella, professor and chair of the UC Davis Department of Entomology and Nematology.
Scott is known for his holistic and comprehensive approach in finding solutions to protect the world's population from dengue, a disease that infects some 400 million per year. Some 4 billion people in 128 countries, more than half of the world's population, are at risk for dengue. Currently no vaccine or drug is effective against this life-threatening disease.
Scott's most significant research contributions concern the ecology and epidemiology of dengue:
- Blood feeding behavior, longevity, dispersal, and vector-virus interactions of the mosquito Aedes aegypti;
- Longitudinal cohort studies of spatial and temporal patterns in human dengue virus infection in Peru and Thailand; (dengue research in Peru, Thailand, Puerto Rico and Mexico for the past 25 years)
- Impact of human movement on mosquito contact rates and spatial dimensions of dengue virus transmission; and mathematical and computer simulation modeling of mosquito population biology and mosquito-borne pathogen transmission. (See more.)
Mohammad-Amir Aghaee
Mohammad-Amir Aghaee, a doctoral candidate and researcher in the Larry Godfrey lab, is a fifth year Ph.D. candidate working on rice water weevil management in California rice. He will present a talk on the rice water weevil, Lissorhoptrus oryzophilus. He will be among the six Comstock recipients, all winners from their individual branches, honored at the national ESA meeting, Nov. 15-18, 2015 in Minneapolis, Minn.
“Mohammad took on a very difficult project for his dissertation research,” said Extension entomologist Larry Godfrey, who nominated Aghaee for the award. “His project deals with the most important invertebrate pest of rice in California, the rice water weevil. The challenges arose not only from working in the rice system--wading through mud for hours--but also from working with this insect that cannot be reared in the laboratory and which has one generation per year. Therefore, all the field studies had to be conducted within the short window of time each year.”
“Mohammad took on a very difficult project for his dissertation research,” said Extension entomologist Larry Godfrey, who nominated Aghaee for the award. “His project deals with the most important invertebrate pest of rice in California, the rice water weevil. The challenges arose not only from working in the rice system--wading through mud for hours--but also from working with this insect that cannot be reared in the laboratory and which has one generation per year. Therefore, all the field studies had to be conducted within the short window of time each year.”
Active in ESA, Aghaee captained the UC Davis debate team that won the ESA championship in 2013 and 2014. He anchored the UC Davis debate and Linnean Games teams for four years, from 2011 to 2014. He served on the UC Davis Linnaean Team (the Linnaean Games involve answering entomological questions) that won the PBESA championship in 2012. For four years, Aghaee has participated in the ESA's student 10-minute paper competitions, covering such topics as Lygus bug movements in bush beans, efficacy of Bacillus thuringiensis spp. galleriae against rice water weevil, and preliminary research on winter flooding effectiveness against rice water weevil. He won a first-place President's Award for his winter flood presentation in 2013.
Aghaee received his bachelor's degree in environmental sciences, genetics and plant biology in 2010 from UC Berkeley, with high distinction. He obtained his master's degree in entomology from UC Davis in 2012, and expects to receive his doctorate in December 2015
In his research, Aghaee seeks to develop alternative management options for rice growers as part of his dissertation. “I have examined the use of Bacillus thuringiensis spp. galleriae as a biopesticide for rice water weevil and explored the mechanisms of winter flooding rice fields as a cultural control against weevil larvae. I am currently examining the possible role of silicon augmentation as a means of increasing rice tolerance to weevil damage and the potential threat of Brown marmorated stinkbug (Halyomorpha halys) to California rice.
Aghaee and Godfrey recently published an open-access article appearing in the Journal of Integrated Pest Management that discusses the rice water weevil's life history and invasion biology, as well as management strategies and future directions of research. They told the story of the weevil since it was first identified as a pest in 1881 by C. V. Riley and L. O. Howard. They then discussed reasons why it has been able to spread so rapidly — up to 36 kilometers per year in some cases — which is partly because of its ability to reproduce asexually.
“This invasive ability is aided by a particular and peculiar aspect of this weevil's biology, the fact that a small percentage of the population in its native range reproduces by parthenogenesis,” they wrote.
The most harmful insect pest of rice in the United States, it causes yield losses of up to 25 percent. Adults inflict damage by consuming leaf tissue, and the larvae feed on the roots of rice plants. A native of the southeastern U.S., the rice water weevil invaded Japan in 1976, Korea in 1980, China in 1988, and Italy in 2004. (See more.)
Congratulations to Professors Carey and Scott and doctoral student Mohammad-Amir Aghaee! It's quite an honor to receive these awards. PBESA encompasses 11 U.S. states (Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada, Oregon, Utah, Washington and Wyoming); several U.S. territories, including American Samoa, Guam and the Northern Mariana Islands; and parts of Canada and Mexico.