The research, published in the Sept. 15 edition of PLOS Genetics, involved the study of Anopheles arabiensis, in Kilombero Valley in Tanzania. The mosquito is the primary vector of malaria in east Africa.
"We know that blood feeding preference among mosquitoes can be species specific,” said co-author and professor Greg Lanzaro, who leads the Vector Genetics Laboratory, UC Davis Department of Pathology, Microbiology and Immunology and is an affiliate of the UC Davis Department of Entomology and Nematology. “For example, there are mosquito species that specialize in feeding on amphibians or reptiles. We also know that many species are more catholic when choosing a meal and this can have important implications to human health—it's how some disease agents move between animals and humans.”
The publication is the work of a 13-member international team. Bradley Main, a researcher in the Vector Genetics Lab, is the lead author.
“Whether there is a genetic basis to feeding preferences in mosquitoes has long been debated,” said lead author Bradley Main, a researcher in the Vector Genetics Lab. “Using a population genomics approach, we have established an association between human feeding and a specific chromosomal rearrangement in the major east African malaria vector. This work paves the way for identifying specific genes that affect this critically important trait.”
Other co-authors, in addition to Lanzaro, are Anthony Cornel of the UC Davis Department of Entomology and Nematology faculty; researchers Yoosook Lee, Heather Ferguson, Travis Collier, Catelyn Nieman, Allison Weakley, all of the Vector Genetics Lab; Katharina Kreppel, Nicodem Govella and Anicet Kihonda of the Ifakara Health Institute, Ifakara, United Republic of Tanzania; and computer scientists Eleazar Eskin and Eun Yong Kang of UCLA.
In their summary, they wrote: “Malaria transmission is driven by the propensity for mosquito vectors to bite people, while its control depends on the tendency of mosquitoes to bite and rest in places where they will come into contact with insecticides. In many parts of Africa, where coverage with Long Lasting Insecticide Treated Nets is high, Anopheles arabiensis is the only remaining malaria vector. We sought to assess the potential for An. arabiensis to adapt its behavior to avoid control measures by investigating the genetic basis for its host choice and resting behavior. Blood fed An. arabiensis were collected resting indoors and outdoors in the Kilombero Valley, Tanzania. We sequenced a total of 48 genomes representing 4 phenotypes (human or cow fed, resting in or outdoors) and tested for genetic associations with each phenotype. Genomic analysis followed up by application of a novel molecular karyotyping assay which revealed a relationship between An. arabiensis that fed on cattle and the standard arrangement of the 3Ra inversion. This is strong support that An. arabiensis blood-feeding behavior has a substantial genetic component. Controlled host choice assays are needed to confirm a direct link between allelic variation within the 3Ra inversion and host preference.”
The publication, "The Genetic Basis of Host Preference and Resting Behavior in the Major African Malaria Vector, Anopheles arabiensis," is online at http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1006303
The three recently lunched at a Davis restaurant with Hazeltine's sons, Craig of Scottsdale, Ariz.,and Lee Hazeltine of Woodland. The graduate students discussed their research and goals and thanked them for the Hazeltine family's support.
Olkowski, who studies dengue, is a four-time recipient of the competitive award. She was honored with the award in 2012, 2013, 2015 and 2016.
Since 1997, the awards have totaled a little over $46,000 to 25 recipients," Craig Hazeltine said.
About the recipients:
Sandy Olkowski is working on her doctorate in entomology, studying with major professor Thomas Scott, now emeritus professor of entomology.
“While working for a pediatrician when I was living in Thailand, I became aware of the significant disease burden that dengue places on populations in developing countries,” Olkowski said. “I returned to the United States with the goal of doing whatever I could to alleviate that burden, and subsequently applied to UC Davis because of the ground-breaking dengue research of Thomas Scott. I conducted research for my senior honors thesis in the Scott lab while completing a bachelor's degree in economics, with a focus on international development. I then continued on into a PhD in Entomology, with a designated emphasis in biology of vector-borne diseases. I am entering the 4th year of my PhD. I recently returned from 10 months of fieldwork in Iquitos, Peru.”
“My research is focused on dengue disease surveillance,” Olkowski said. “I am interested in identifying and quantifying ways that human behavior affects surveillance data. Rapid detection of increases in dengue cases is very important for public health officials, so they can implement vector control in a timely manner, but delays in treatment seeking by patients and clinical diagnosis by physicians may be impeding that process. I hope that the results of my research can be directly applied. Eventually, I would like to be able to sit down with public health officials and discuss evidence-based improvements to dengue surveillance.”
Stephanie Kurniawan is working on her master's degree, studying with major professors Ed Lewis and Shirley Luckhart. “Though I have lived in California my entire life, I often visited relatives in Indonesia,” she said. “During one trip when I was in middle school, I got dengue and had to be hospitalized for several days. No one in America knew about this disease, not even my pediatrician. This made me interested in vector-borne diseases and mosquitoes.”
Kurniawan went on to receive her bachelor's degree in animal biology with a minor in medical and veterinary entomology at UC Davis.
“I am adapting methods for estimating age structure of Anopheles mosquito populations using the captive cohort method developed by Dr. James Carey. It is a potentially inexpensive and practical alternative for real-time surveillance of mosquito populations. I currently am testing this method on local populations of Anopheles freeborni from Sutter and Butte County rice fields.”
Maribel "Mimi" Portilla, who holds a master's degree in public health, is seeking her doctorate. She studies with major professor Sharon Lawler.
"Just like many scientists, I am driven by curiosity, but often found myself wondering how I could apply myself in a way that would help others," she said. "I discovered public health, which incorporated my love for biology and my growing interest in social issues. At UC Berkeley School of Public Health, I was able to study health and disease within a larger context, and learned to consider the biological and the social determinants of disease. As I completed my degree, I realized I really missed the research experiences I had as an undergraduate. So, I looked for a way to bridge my new-found passion for public health and basic science research. This led me to UC Davis, where I learned about One Health and am now pursuing a Ph.D in medical entomology. Medical entomology is a perfect example of a One Health field, where I can seek out how interactions between humans and animals impact health. I am particularly interested in researching how disease risk may change as people manipulate the environment."
"For example, environmental manipulation is a classic pest control technique, yet the indirect effects of changing the environment are not always well understood. I am focusing on how the management practices of the invasive exotic weeds, Brazilian waterweed (Egeria densa) and water hyacinth (Eichhornia crassipes), in the Sacramento-San Joaquin Delta impact mosquitoes and their habitat. My goal is to better understand the ecology of these management practices in order to inform and create better techniques to reduce both mosquito and weed problems."
"Due to my diverse interests and skill set, I am very open about my career choices. I have extensive teaching experience, and would love to be a professor with both teaching and research opportunities. However, there are many opportunities beyond academia. My research is introducing me to many other ways in which my work and research can help keep people safe and healthy. I hope to develop a strong research skill set while at UC Davis, and find a career path which takes advantage of my diverse abilities and love for One Health and Public Health."
William Emery Hazeltine II (1926-1994), for whom the Bill Hazeltine Student Research Award is named, worked tirelessly in mosquito research. He managed the Butte County Mosquito Abatement District, Oroville, from 1966 to 1992, and the Lake County Mosquito Abatement District from 1961-1964. 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.
Prior Recipients of Hazeltine Awards:
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
The event, billed as "A Conversation with Professor Lanzaro," will be hosted by Professor Jared Shaw of the UC Davis Department of Chemistry. Shaw founded the Davis Science Café in 2012. Science Café is held the second Wednesday of each month. All programs are free and open to the public. Science Café is affiliated with the Capital Science Communicators.
Lanzaro, a noted malaria mosquito researcher, is the former director of the UC Statewide Mosquito Research Program, UC Agriculture and Natural Resources.
Her presentation is part of the weekly seminars hosted by the Program in International and Community Nutrition (PICN) seminars, all held Wednesdays from 12:10 to 1 p.m. in the Foster Room (Room 1138) of Meyer Hall.
Luckhart's research includes the molecular cell biology and biochemistry of malaria parasite transmission, the functional characterization of the immunological crosstalk and cell signaling that occurs between the mosquito and the mammalian host during bloodfeeding, and the impact of endemic co-infections on malaria parasite development and transmission.
She just received the 2016 “Award for Excellence in Service to Graduate Students,” presented April 8 by the UC Davis Graduate Student Association for outstanding teaching and mentoring. She earlier received the 2012 Outstanding Mentor Award from the UC Davis Consortium for Women and Research.
Luckhart, who joined the UC Davis faculty in 2004 from Virginia Tech, received her master's degree in entomology from Auburn University, and her doctorate in entomology from Rutgers, the State University of New Jersey.
Access the website for upcoming PICN seminars.
The lecture, to take place at 10:45 a.m. in the Alpha Gamma Rho (AGR) Hall, is sponsored by the College of Agricultural and Environmental Sciences and the Storer Life Sciences Endowment of UC Davis.
At Penn State, Thomas serves as the Huck Scholar in Ecological Entomology and directs the Ecology Institute, in addition to his duties as a professor of entomology in the Department of Entomology and Centre for Infectious Disease Dynamics.
He will be introduced by Professor Shirley Luckhart of the UC Davis Department of Medical Microbiology and Immunology, coordinator of the event.
Thomas researches many aspects of the ecology and evolution of insect pests and diseases in his drive to understand the consequences of global change and to improve the effectiveness and sustainability of pest and disease management. His work involves predicting and understanding the impact of invasive species, and researching biodiversity and ecosystem health, plus many aspects of biological control.
Last December Thomas and his research team at Penn State, in collaboration with partners in Europe and Africa, received a five-year, $10.2 million grant from the Bill and Melinda Gates Foundation to investigate a new method for preventing the transmission of malaria.
“The method involves limiting mosquito access to houses by blocking openings and installing ‘eave tubes' that contain a unique type of insecticide-laced mosquito netting developed by Dutch partner In2Care that kills the insects as they attempt to enter,” according to a Penn State news release.
Thomas was quoted as saying: “Nearly half of the world's population is at risk of contracting malaria, and according to the most recent World Health Organization report, an estimated 438,000 people died from the disease in 2015. The use of insecticides to control mosquitoes has saved millions of lives, but this tactic is increasingly challenged because mosquitoes quickly evolve resistance to the very limited number of insecticides currently used in public health. The eave tube approach presents a novel strategy to help combat this challenge by simultaneously making houses more mosquito proof and providing a novel way of delivering insecticides, which creates opportunities for using a wider range of insecticidal products."
"The small amount of insecticide used in the tubes means that it is cheap to treat an entire house," said Thomas. "Furthermore, retreatment is easy, as it requires simple replacement of small pieces of netting within the tubes."
Internationally recognized, Thomas is a recipient of the Commonwealth Scientific and Industrial Research Organization (CSIRO) Medal for Research Achievement, is a fellow of the American Association for the Advancement of Science, and an honorary professor at the University of Witwsatersand, South Africa. He also received Penn State's Alex and Jessie Black Award for Research Excellence.