By Cyndy McGrath
For most of us, mosquitoes are simply a summertime
annoyance - tiny pests that we squish or swat away without a second
thought. Not so in many developing countries,
where one bite can mean months of misery, or death, a serious concern noted by
today’s recognition of World Malaria Day.
Inside her laboratory in the University of Pittsburgh
Graduate School of Public Health
, Alice Tarun, Ph.D.,
studies the genes of the Plasmodium vivax
bacteria, one of the two parasites that cause the most common forms of human malaria. They are microscopic targets, but Dr. Tarun
hopes they will someday lead to a major breakthrough in malaria treatment, one
of the biggest global health threats.
|Alice Tarun, Ph.D.|
“The public health impact of malaria is second only to
tuberculosis,” says Dr. Tarun, an assistant professor in the Department of Microbiology
and Infectious Diseases. “If you look at the statistics, it’s just crazy.”
According to the
World Health Organization, malaria is endemic to 90 countries, causing an estimated
660,000 deaths a year, mostly in sub-Saharan African countries. Ninety percent
of the victims are children under the age of 5, or pregnant women.
Malaria spreads when a person gets bitten by an infected
mosquito. That mosquito deposits
parasites into the bloodstream, which travel to the liver and amplify. The parasites invade and feed off of red
blood cells, ultimately bursting out of the cells, at which time an infected
person begins to feel the symptoms of the disease: cycles of fatigue, chills
The parasite has a complicated life cycle, and infectious
disease researchers often study one phase of development or infection in the
quest for new drug targets.
Dr. Tarun’s research focuses on the liver and sexual stages
of the Plasmodium parasite.
“When the parasite is dividing in the blood, some parasites
will form the gametes, or the sexual stage.
They can’t complete their development until a mosquito picks them up by
biting an infected human,” says Dr. Tarun. “This is really an area where there
is not a lot of research.”
According to Dr. Tarun, many of the available malaria drugs
don’t kill parasites during their sexual stage.
A patient can be sick with malaria and receive treatment, yet they are
still able to transmit the parasite because gametocytes are still circulating
within their system.
“We are trying to see if there are genes and proteins that
are essential for gametocyte development,” said Dr. Tarun. “Then we mutate those genes to determine
Dr. Tarun says this approach could ultimately lead to the
development of drugs that could target and kill the gametocyte, which she
describes as “remarkably resilient.”
“If we can stop the parasite in the liver, then we can
prevent the disease and prevent transmission,” says Dr. Tarun. “Attacking
malaria on multiple fronts is really the best strategy.”