- Author: Kathy Keatley Garvey
The seminar is from 12:10 to 1 p.m.
"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 was nominated as a seminar speaker by Professor Shirley Luckhart, Department of Medical Microbiology and Immunology, UC Davis School of Medicine and a graduate student advisor, UC Davis Department of Entomology and Nematology; Associate Dean Ed Lewis of the College of Agricultural and Environmental Sciences and professor and vice chair of the UC Davis Department of Entomology and Nematology; and Distinguished Professor James R. Carey, UC Davis Department of Entomology and Nematology.
A native of Norfolk, Va., Strand grew up in Texas. He received both his bachelor's degree in entomology (1980) and his doctorate in entomology (1985) from Texas A&M University, College Station. He accepted a fellowship from the National Science Foundation-North Atlantic Treaty Organization (NATO) as a postdoctoral scholar at the Imperial College, University of London in 1986. He then accepted a position as an assistant professor at Clemson University. In 1987, joined the faculty of the University of Wisconsin-Madison where he advanced to the position of professor. In 2002, Strand moved to the University of Georgia where he holds appointments in the Department of Entomology, the Center for Tropical and Emerging Global Diseases, Faculty of Infectious Diseases, and Department of Genetics.
Strand is a fellow of the Entomological Society of America (selected in 2012) and the American Association for the Advancement of Science (2008). ESA presented him with the national recognition award in the Physiology, Biochemistry and Toxicology Section in 2009. He served as president of the section in 2013.
Plans call for his seminar to be video-recorded and then posted at a later date on UCTV. The departmental seminars are coordinated by Professor Steve Nadler.
Links:
Upcoming seminars
Seminars Posted on UCTV
Bay Area World Malaria Day Symposium on April 24: Register now!
- Author: Kathy Keatley Garvey
The seminar will take place from 12:10 to 1 p.m. in 122 Briggs. Host is Jiawen Xu, a graduate student in the Bruce Hammock lab.
"Transmission of human disease-causing agents by mosquitoes depends on the successful completion of the pathogen's infection-cycle in the insect vector," Dimopoulous said. "The mosquito's innate immune system and microbiota represent important bottlenecks for pathogen transmission, and can thus be exploited for the development of novel disease control strategies." He will discuss "advances in our understanding of how the mosquito immune system and natural microbiota can influence Plasmodium and dengue virus infection in their respective vectors."
Dimopoulous has more than 20 years experience with molecular entomology of the vectors Anopheles. gambiae and Ae. aegypti. His research has mainly focused on the mosquito's innate immune system and the mosquito midgut microbiota, and how they interact with various the human pathogens Plasmodium falciparum and the dengue virus, using genomics, functional genomics and molecular biology techniques and approaches. His group's research over the past 8 years has contributed significantly toward the understanding of how the mosquito innate immune system and microbiota influences the mosquito and its permissiveness to human pathogen infection.
Dimopoulous received his bachelor's degree in microbiology from Stockholm University, Sweden, and his doctorate in biology from the University of Crete, Greece. He did postdoctoral work in molecular entomology at the European Molecular Biology Laboratory, Heidelberg, Germany from 1996 to 2001. In 2007 he obtained his master's of business administration from Carey Business School, Johns Hopkins University, studying management and leadership.
Since 2013, Dimopoulous has served as an adjunct professor in the Department of Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico, San Juan.
Professor Steve Nadler chairs the UC Davis Department of Entomology and Nematology seminars. Most are recorded for later posting on UCTV.
See schedule for remaining seminars of the quarter.
- Author: Kathy Keatley Garvey
The yellow fever mosquito, Aedes aegypti, a newly invasive species in central California? Check.
The West Nile virus mosquito, Culex quinquefasciatus, found throughout much of the world? Check.
The malaria mosquito, Anopheles gambiae, which wreaks worldwide havoc? Check.
Cornel's name appeared in the news this week when the UC Davis lab of Walter Leal announced that it had found the odorant receptor that repels DEET in the southern house mosquito, Culex quinquefasciatus mosquito. Cornel provided the mosquitoes that allowed the Leal lab to duplicate his colony. Proceedings of the National Academy of Sciences (PNAS) published the work Oct. 27.
Cornel's main research keys in on the population genetics and ecology of West Nile virus vectors in the United States and population genetics and ecology of major malaria vectors in Africa.
“Anton is a great asset to our program, a wonderful colleague, and a nice team player,” said Leal, a professor in the Department of Molecular and Cellular Biology. “We benefit greatly from his generosity by sharing not only mosquito colonies, but also his encyclopedic knowledge on mosquito biology and ecology. We shared co-authorship in a number of publications, and many more are coming.”
Cornel collaborates with Leal on oviposition attraction in Culex quinquefasciatus and “we are now endeavoring to come up with effective oviposition attractive chemical lures to use in virus surveillance and kill traps.”
“The invasion of Aedes aegypti into central California has been of great concern especially as current control methods do not appear to be working very well,” said Cornel, who works closely with state's mosquito abatement personnel. “We have found that the Aedes aegypti have insecticide resistance genes which likely explains why their ultra-low volume (ULV) and barrier spray applications have not worked as well as expected. Work will be ongoing next year when the Aedes aegypti become active again after a brief slow overwintering period from November to March.”
A native of South Africa, Cornel received his doctorate in entomology, focusing on mosquito systematics, in 1993 from the University of the Witwatersrand, Johannesburg. He completed a post-doctoral fellowship with the Entomology Branch of the Centers for Disease Control and Prevention, Atlanta, before joining UC Davis in 1997 as an assistant professor and researcher.
“Who would have thought that that the expertise that I gained on West Nile virus as a master student in South Africa would be used many years later after West Nile virus invaded and spread throughout the USA?”
For more than two decades, Cornel has teamed with fellow medical entomologist and “blood brother” Professor Gregory Lanzaro of the UC Davis School of Veterinary Medicine to study malaria mosquitoes in the West African country of Mali. Their work is starting to show significant results.
“Because of our commitment to conduct long term longitudinal studies and not static investigations,” Cornel said, “we have now shown that considerable selective processes are taking place causing spatiotemporal dynamics of gene flow and fitness events in major malaria vectors M (now Anopheles coluzzii) and S (now Anopheles gambiae) and M/S hybrids in West Africa.” Their work was published in PNAS in 2013 (vol:110:49).
“We are currently establishing further evidence of the important role of insecticide resistance traits in spatiotemporal dynamics of Anopheles coluzzii, Anopheles gambiae and the Bamako form.” Cornel noted that these results have “considerably important implications in future efficacies of insecticide treated bednets to control indoor biting malaria vectors in West Africa.”
Cornel also teams with Lanzaro and Professor Heather Ferguson of the University of Glasgow to examine the ecology and associated genetics of the major malaria vector Anopheles arabiensis in Tanzania. They began working on the project four years ago.
“We are looking at the effects of bednet use and changes in feeding patterns of this mosquito taking population structure into consideration,” Cornel said. He and his colleagues published a paper in November 2013 in G3: Genes, Genome and Genetics, titled “Diversity, Differentiation, and Linkage Disequilibrium: Prospects for Association Mapping in the Malaria Vector Anopheles arabiensis."
One of his newest projects is the study of population/genetics, insecticide resistance and cytogenetics in the major malaria vector in Brazil. Cornel and Lanzaro launched their study in September when they traveled to Brazil to begin targeting the culprit, Anopheles darlingi, a “widely distributed species that has adapted to survive in multiple ecological zones and we suspect that it may consist of multiple incipient or closely related species,” Cornel said.
“While in Brazil I collected larvae and dissected salivary glands from them to examine their polytene chromosome inversion structure and polymorphisms,” Cornel related. “Inversions are vitally important to consider in genetic analyses and it takes considerable patience to interpret the chromosomes.”
Cornel and Lanzaro collaborate with Professor Paulo Pimenta of the Laboratory of Medical Entomology, René Rachou Research Centre- FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil. The UC Davis medical entomologists hope to produce good preliminary data from their research trip to write grants and establish a long-term project in Brazil.
Cornel also studies avian malaria. That interest sparked four years ago when he began working in Cameroon with scientists from UCLA and San Francisco State University (SFSU), including SFSU's Ravinger Sehgal, who studies avian blood parasites. Cornel's graduate student Jenny Carlson, in her final year of her Ph.D studies, is investigating avian malaria in Fresno County.
The Cornel-Carlson research implicates that considerable fidelity exists between Culex mosquito species and species of plasmodium they transmit. “This is contrary to the currently held belief that all Culex mosquitoes are equally capable of transmitting avian malaria,” Cornel said. “In our investigations, we described a new species of avian malaria which is very common in songbirds in Fresno County (published in Parasitology Research).”
Cornel plans to continue working with Sehgal investigating the effects of deforestation on transmission of avian parasites in Cameroon. They recently submitted a National Science Foundation grant proposal. “A large swath of primary forest is slated to be deforested in Cameroon and replaced with Palm oil plantations and we will investigate the effects of this hopefully, as it happens.”
Cornel will be starting a new mosquito-borne virus project in February. He received a Carnegie Foundation scholarly three-month fellowship to work in South Africa (February through to April). The primary objective of the project? To examine mosquito-borne viruses cycling in seven national parks in South Africa and two National Parks in Bostwana.
“It's extremely difficult to get permission to conduct field research in national parks in Southern Africa and this provides an unprecedented exciting opportunity for me to work with a friend, Professor Leo Braack from the University of Pretoria, in these parks. One has to be very careful working in some of these parks at night because of the wild predators, elephants, hippos and buffalo.”
Cornel is active in the 30- member Center for Vectorborne Diseases (CVEC), headquartered in the UC Davis School of Veterinary Medicine and considered the most comprehensive vectorborne disease program in California. Both interdisciplinary and global, CVEC encompasses biological, medical, veterinary and social sciences. Globally, the major emphasis is on research and education involving diseases such as malaria, dengue and leishmaniasis in the developing world. CVEC members study molecular biology, virology, parasitology, vector control, and epidemiology of vectorborne diseases. In addition, the center serves as the principal teaching resource for undergraduate and graduate courses in all facets of vector-borne disease sciences.
Related Links:
Proceedings of the National Academy of Sciences (research paper, PDF)
Research from Walter Leal Lab on DEET
Close Connections (Like Father, Like Son)
Nov. 5, 2012
The awards went to Jenny Carlson, avian malaria research, and Sandra "Sandy" Olkowski and Kelly Liebman, dengue research. Hazeltine's three sons, Craig of Scottsdale, Ariz; Jeff of Los Angeles; and Lee of Woodland recently visited the UC Davis campus to congratulate the winners and learn more about their research.
Carlson studies avian malaria with UC Davis associate professor/medical entomologist Anthony “Anton” Cornel, headquartered at the Kearney Agricultural Research and Extension Center, Parlier. Olkowski studies dengue with major professor/medical entomologist Thomas Scott. Liebman, also a graduate student of Thomas Scott's, now has her doctorate in entomology and is working at the Centers for Disease Control and Prevention in Atlanta, Ga.
Carlson received $2000; Olkowski, $1000' and Liebman, $580.
Carlson's research, titled “Culicine Vectorial Capacity and Its Implications for Transmission of Avian Malaria in Western United States,” involves host-feeding preferences, vector abundance and vectorial competence.
Carlson described malaria as “one of the most devastating diseases to humans” but it “also affects a wide range of other mammals, amphibians, reptiles and birds.”
Carlson, who received a Hazeltine Memorial Research Fellowship in 2010 and 2011, earned her bachelor of science degree in zoology from Colorado State University, Fort Collins, and her master's degree biology from San Francisco State University.
Olkowski's proposal is titled Association Between Preexisting DENV Immunity and Severe Disease Due to DENV-2 Infection in Iquitos, Peru.”
“Dengue fever is the most prevalent mosquito-borne viral disease in the world, with an estimated 50 to 100 million cases each year and 2.6 billion people at risk,“ Olkowski said. Illness is caused by infection with any of the four distinct viral serotypes (DENV-1, 2, 3 and 4).
“Severe severe disease was largely absent until introduction of a novel genotype of DENV-2 in 2010-11,” Olkowski said. Her research involves identifying “cohort participants who were infected with DENV-2 during the outbreak.”
“I will then use statistical models to evaluate the relationship between their serological history—by number of infections and serotype sequence—and clinical outcomes. Of particular interest are severe outcomes in persons with a single type of prior antibody, to determine if there was a spike in severity with second infection, as predicted by dengue epidemiology theory.”
Olkowski, who is seeking her doctorate in entomology with a major interest in medical entomology and public health, received a President's Undergraduate Fellowship in May 2011.
Liebman joined the Centers for Disease Control and Prevention in Atlanta following her exit seminar on “Implications of Heterogeneities in Mosquito and Human Populations on Dengue Virus Transmission in Iquitos, Peru.” She lived in Iquitos for a year while doing her research.
“Over the past three decades, dengue virus (DENV) as emerged as one of the most important arthropod-borne viral infections of humans, causing as many as 50 million infections worldwide each year,” Liebman wrote in her application. “The mosquito vector of DENV, Aedes aegypti, is exceedingly efficient because it feeds frequently and almost exclusively on humans.”
“An improved understanding of the distribution of the bites among people in Iquitos will allow me to estimate differential risk of infection based on exposure to mosquito bites and significantly improve understanding of local DENV transmission dynamics,” she wrote.
Liebman, who received Hazeltine Memorial Fellowship Awards in 2009 and 2011, obtained her her master's degree in public health from Yale University and her bachelor's degree in biology from the University of Michigan, Ann Arbor.
The Hazeltine Memorial Fellowship Awards memorialize William “Bill” Hazeltine (1926-1994), who managed the Lake County Mosquito Abatement District from 1961-64 and the Butte County Mosquito Abatement District from 1966-1992. He was an ardent supporter of the judicious use of public health pesticides to protect public health. He continued work on related projects until his death in 1994.
Hazeltine studied entomology in the UC Berkeley graduate program from 1950-53, and received his doctorate in entomology from Purdue University in 1962.
He maintained close ties with UC Davis entomologists. UC Davis medical entomologist Bruce Eldridge eulogized him at the 2005 American Mosquito Control Association conference “as a man who made a difference.” His talk, illustrated with photos, was published in the 2006 edition of the Journal of the American Mosquito Control Association. (See PDF)
"He was a medical entomologist who had a varied career in the field of mosquito biology and control, but he will forever be remembered as a man who fought in the trenches of the pesticide controversy from 1960 until the end of his life, and who made the safe and efficient use of pesticides in public health a personal crusade," Eldridge said.
Eldridge noted that Hazeltine "was an advocate for the use of mosquito control to protect people from mosquitoes and the disease agents they transmit, and he believed chemical control to be a necessary part of the means to accomplish this. He also considered himself an environmentalist, and billed himself as such on his business cards and on his signature block. He had a vast knowledge of pesticides and pesticide legislation, and a strong belief in the scientific basis for public policy issues related to the safe and effective use of pesticides. Because the federal Endangered Species Act influenced mosquito control, he became an authority on this as well."
Eldridge described him as "an effective manager and leader at Butte County. Those who took the trouble to get to know him developed a strong allegiance to him. Most appreciated his absolute honesty and fairness. Not only was Bill honest to a fault, he expected it of people who work for him as well."
Hazeltine, born Sept. 4, 1926 in San Jose, was the youngest of six children born to Karl Snyder Hazeltine and Rachel Josephine Crawford Hazeltine. Karl, a graduate of the University of California, served on the faculty of San Jose State University, where he taught agricultural and natural science. Rachel, a graduate of San Jose State, was a teacher.
Previous recipients:
2011: Brittany Nelms Mills, Kelly Liebman and Jenny Carlson (see story)
2010: Tara Thiemann and Jenny Carlson (see story)
2009: Kelly Liebman and Wei Xu (See story)
2008: Ashley Horton and Tara Thiemann (See story)
2007: Lisa Reimer and Jacklyn Wong (See story)
2006: Christopher Barker and Tania Morgan (See story)
2005: Nicole Mans
2004: Sharon Minnick
2003: Hannah Burrack
2002: Holly Ganz and Andradi Villalobos
2001: Laura Goddard and Linda Styer
--Kathy Keatley Garvey
Communications specialist
UC Davis Department of Entomology
(530) 754-6894
Dec. 8, 2010
He managed the Butte County Mosquito Abatement District, Oroville, from 1966 to 1992. He was an ardent supporter of the judicious use of public health pesticides to protect public health.
Hazeltine studied entomology in the UC Berkeley graduate program, 1950-53, and received his doctorate in entomology from Purdue University in 1962.
He managed the Lake County Mosquito Abatement District from 1961-64 and the Butte County Mosquito Abatement District from 1966-1992. He continued work on related projects until his death in 1994.
Bruce Eldridge, emeritus professor of entomology at UC Davis, eulogized him at the 2005 annual meeting of the American Mosquito Control Association (April 4) as "a man who made a difference." His talk, illustrated with photos, was published in the 2006 edition of the Journal of the American Mosquito Control Association. (See PDF)
"He was a medical entomologist who had a varied career in the field of mosquito biology and control, but he will forever be remembered as a man who fought in the trenches of the pesticide controversy from 1960 until the end of his life, and who made the safe and efficient use of pesticides in public health a personal crusade," Eldridge said.
Eldridge noted that Hazeltine "was an advocate for the use of mosquito control to protect people from mosquitoes and the disease agents they transmit, and he believed chemical control to be a necessary part of the means to accomplish this. He also considered himself an environmentalist, and billed himself as such on his business cards and on his signature block. He had a vast knowledge of pesticides and pesticide legislation, and a strong belief in the scientific basis for public policy issues related to the safe and effective use of pesticides. Because the federal Endangered Species Act influenced mosquito control, he became an authority on this as well."
Hazeltine's message about pesticides never strayed, Eldridge sad. His positions on pesticide use and regulation included:
1. Decisions on pesticide use should be made by competent people and based on good data
2. Biological contorls are good, and must be used, but chemicals are also necessary for an effective program.
3. When you discuss pesticides, do not stipulate to something just to get acceptance.
4. There is a real need for continuing educaiotn, which is a mark of professionalism.
In closing, Eldridge said that much of AMCA's current involvement with federal legislation affecting mosquito control stems from Hazeltine's work.
Hazeltine, born Sept. 4, 1926 in San Jose, was the youngest of six children born to Karl Snyder Hazeltine and Rachel Josephine Crawford Hazeltine. Karl, a graduate of the University of California, served on the faculty of San Jose State University, where he taught agricultural and natural science. Rachel, a graduate of San Jose State, was a teacher.
William Hazeltine's son, Craig, of Scottsdale, Ariz: commented: "Three recollections: Dad grew and changed over the years. The reports may cast him as a constant iconoclast, but he learned to love and be loved. When I became a Christian in college, I felt compelled to tell my Dad 'I love you' often and to back it up with a hug. He was like a stiff board at first, but later on was almost a menace with his wonder hugs.
"Dad was not so gruff as he was 'occupied.' I figured out early on that the best way to spend time with him was to help him with his projects--and there was always something in the works. He was always reading, studying, and trying new things.
"Dad was extremely well-documented. After a debate at Chico State in the late 60s, we talked about having references at the ready to refute bad arguments. This led to a couple of very full boxes that traveled in the trunk of his car with copies of published works that backed up his positions. And that in addition to the famous stacks of re-prints in his home office."
Today the work of William Emery Hazeltine II lives on through the William Hazeltine Memorial Student Research Fellowship Awards. UC Davis students studying mosquitoes are eligible to apply for the award.
Recipients:
2016: Sandy Olkowski, Maribel “Mimi” Portilla and Stephanie Kurniawan
2015: Sandy Olkowski, Maribel “Mimi” Portilla and Stephanie Kurniawan
2014: Martha Armijos, Elizabeth “Lizzy” Glennon and Rosanna Kwok
2013: Jenny Carlson, Elizabeth “Lizzy” Glennon and Sandy Olkowski
2012: Jenny Carlson, Kelly Liebman and Sandy Olkowski
2011: Brittany Nelms Mills, Kelly Liebman and Jenny Carlson
2010: Tara Thiemann and Jenny Carlson
2009: Kelly Liebman and Wei Xu
2008: Ashley Horton and Tara Thiemann
2007: Lisa Reimer and Jacklyn Wong
2006: Christopher Barker and Tania Morgan
2005: Nicole Mans
2004: Sharon Minnick
2003: Hannah Burrack
2002: Holly Ganz and Andradi Villalobos
2001: Laura Goddard and Linda Styer
2000: Laura Goddard
1999: Linda Boose Styer
1998: Larisa Vredevoe
1997: John Gimnig
--Kathy Keatley Garvey
Communications specialist
UC Davis Department of Entomology
(530) 754-6894