Abou Fofana/photo
Skeeter quiz
How much do you really know about mosquitoes?
Medical entomologist treks the world to solve malaria mysteries
Female mosquitoes don’t bite—they feed—on your blood. That's because they need a blood meal to develop their eggs.
UC Davis medical entomologist Gregory Lanzaro says most people are naturally curious about this global foe that's a quarter of an inch long, weighs 2.5 milligrams, drinks more blood than it weighs and possesses a brain that's the size of the period at the end of this sentence.
He is more than “curious.” Mosquitoes are his passion.
Today Lanzaro directs both the UC Mosquito Research Program, a statewide program of UC Agricultural and Natural Resources, and the UC Davis Center for Vectorborne Diseases at UC Davis, a unit of the School of Veterinary Medicine.
As a child growing up in New York City, he frequented the insect collections in the American Museum of Natural History and, while still in grammar school, began developing his own insect collections.
What were his “starter bugs?” Beetles and butterflies. Research involving “the tiny burrowing beetles that are pests on golf courses” followed, then flies associated with poultry, and now, mosquitoes.
“There are 2,500 recognized species of mosquitoes,” said Lanzaro, who finds the insects “absolutely amazing.”
Lanzaro got bit by the mosquito bug when he discovered that of all insects, the mosquito is the biggest culprit in transmitting diseases. He paired his interest in parasitology with entomology to be a medical entomologist when he realized, “It's the variety of diseases they transmit and the magnitude of the health impact of mosquito-transmitted diseases.”
In virtually every conceivable habitat
“There are species occurring in virtually every conceivable habitat,” he said. “Many occur at high elevation where they breed in freshly melted snow, others breed in natural and artificial containers such as tree holes, discarded cans and tires. Some will only breed in holes created by crabs in salt marshes and others will breed only in water trapped by plants such as bromeliads or pitcher plants.”
The female mosquito, which transmits malaria, dengue, yellow fever and West Nile and other deadly diseases, is the true terrorist of the world, Lanzaro said. She has wreaked havoc among popes, presidents and other world leaders; felled great armies; and changed the course of history.
Adult female mosquitoes are the troublemakers for several reasons, Lanzaro points out. “They suck blood, many feed on humans and they transmit human diseases including malaria, West Nile, yellow fever and dengue when the host is infected.”
Females need blood primarily to develop their eggs. Males cannot suck blood because their mouthparts are not developed to pierce the human skin. They feed on nectar, honeydew and other plant juices.
Most troubling today is that the age-old mosquito-borne diseases so endemic to developing countries are spreading globally. West Nile virus, first discovered in Uganda in 1937, emerged in New York in 1999 and appeared in California in 2002. “These diseases are not going away,” Lanzaro said.
Indeed, he said the biggest issues in entomology are related to the emergence and re-emergence of very serious diseases transmitted by mosquitoes. “At the top of the list is malaria. This disease continues to rank as one of the most important diseases of man, killing somewhere around 3 million people per year, mostly in Africa and mostly children under 5.”
Greg Lanzaro, left, points out digitized tissue on the computer screen to lab specialist Claudio Meneses. (Kathy Keatley Garvey/ UC Statewide Mosquito Research Program)
Control the best method
“Mosquito control is the most effective method of controlling these diseases,” he said. “The biggest challenge we face is developing new strategies for mosquito control that are effective and sustainable.”
Lanzaro’s work focuses on understanding patterns of gene flow among populations of Anopheles gambiae, the principal vector of malaria in sub-Saharan Africa.
“Populations of this mosquito have a very complex genetic structure,” he said. “It is important to know how genes move among populations so that we may better understand how they respond to control programs, for example, how genes that impart resistance to insecticides spread.”
Lanzaro said this information “is also critical to the design of genetic control strategies that are currently under development. These involve the introduction of genes into populations that will disrupt the mosquitoes' ability to harbor malaria parasites.”
Lanzaro, who received his doctorate in entomology in 1986 from the University of Florida, Gainesville, first worked in biomedical research, including the National Institutes of Health and later as a professor in the pathology department at the School of Medicine at the University of Texas, Galveston.
Traveling the world for mosquitoes
His interests in entomology and parasitology led him to South and Central America and west and central Africa. He has trekked to Africa at least once a year since 1991. Last year he and “blood brother” Anthony Cornel, a medical entomologist who directs the Mosquito Research Laboratory at the UC Kearney Agricultural Center, Parlier, spent six weeks in Mali and Cameroon.
“I love Africa and the people who live there,” Lanzaro said. “I am fortunate to have outstanding colleagues there and I have had lots of opportunity to work with people in rural villages throughout most of both Mali and Cameroon.”
“My experiences in Africa have had a profound effect on my life, both professionally and personally,” Lanzaro said. “There is so much potential there. The forces opposing progress are formidable, but not insurmountable and things are improving.”
Malaria, he said, can be controlled. “Although we do not have a malaria vaccine, we do have very effective drugs and we can control the vector with insecticides and by reducing breeding sites.”
‘Inevitably all the plans fall apart once you get under way, roads are flooded and impassable, vehicles break down or get mired in the mud, there are no mosquitoes where you thought they would be abundant.’
Medical entomologist Greg Lanzaro
They develop resistance
The problem, according to Lanzaro, is that the malaria parasite develops resistance to drugs and likewise, the mosquitoes become resistant to insecticides.
“We need to develop new drugs and insecticides to stay ahead of the parasite and its vectors and develop better strategies to manage resistance,” he said. “New methods must be feasible economically, that is, they must be sustainable in the long run.”
So, Lanzaro said, major malaria control programs require a great deal of money and the political will toward spending the money to improve the affected nations' public health systems. The lack of that will, he said, “has been a major problem.”
Finally, Lanzaro sees a dire need to build scientific and administrative capacity in the areas affected by the disease. He believes that U.S. educational institutions need to step to the plate to enroll young scientists from places like Africa in programs aimed at training a new generation equipped with the knowledge required to combat malaria.
Research his first love
As a field biologist, Lanzaro said he loves being in the field collecting mosquitoes.
“I enjoy the challenge of working out the logistics of a field expedition, especially in remote places. Figuring out what locations to sample from, how long it will take, putting together routes and arranging equipment, it's great fun.”
“Inevitably all the plans fall apart once you get under way, roads are flooded and impassable, vehicles break down or get mired in the mud, there are no mosquitoes where you thought they would be abundant.”
Teaching also is high on his priority list, though. Lanzaro believes it's more important to turn out scientists than science.
He teaches an undergraduate course, “Social Issues in Animal Biology.” This year he also taught graduate seminars on genomics and is currently conducting a graduate seminar on genetically modified organisms.
“I have four Ph.D. students working in my lab, and they're great, the best I've ever had,” added Lanzaro, who has taught everything from genetics to insect taxonomy.
Pursuing the topic outside of the classroom
On the home page: The Culex tarsalis mosquito is a vector of West Nile virus. In 2005, West Nile virus killed 18 people in California and infected more than 900. (Jack Kelly Clark, UC Agriculture and Natural Resources photo)
He encourages students “to become engaged and pursue a topic beyond the classroom. In my own experience, the best courses were those that made me want to spend more time on my own pursuing a topic.”
This is what he attempts to achieve in his own teaching.
“I'm a very visual person and I really enjoy trying to express complex ideas in pictures. I know many of my colleagues would not necessarily agree, but I find using computer-projected images while lecturing a very powerful and effective tool as a means of getting students interested enough to do some reading on their own.”
His advice to prospective entomologists? “Entomology includes many aspects of biology. Couple your interest in insects with a field in the biological sciences that you find most interesting, such as systematics, genetics or physiology.”