all Department of Immunology and Infectious Diseases stories

Working to snip malaria drug resistance

404132862 — Sat, 16 Feb 2008 20:11:49 -0500

Useful genetic maps showing the inner workings of drug-resistant malaria parasites, and where they live around the world, are being created as part of a major drive against the persistent tropical disease.

HSPH, Broad map malaria genetic diversity

70652986 — Mon, 26 Mar 2007 05:46:55 -0400

Researchers have created the first map of genetic diversity of the malaria parasite, providing new insights in the fight against a public health scourge that kills one person every 30 seconds.

In work that focused on the most deadly of the four malaria parasites that infect humans, Plasmodium falciparum, researchers found nearly double the diversity they expected. They also identified genetic regions linked to resistance to two anti-malarial drugs.

The advance, by an international team led by researchers at the Broad Institute of Harvard and the Massachusetts Institute of Technology (MIT), can rapidly translate to improvements on the ground, such as better diagnosis of specific malaria strains and monitoring for the emergence of drug resistance, according to Dyann Wirth, chair of the Harvard School of Public Health's Department of Immunology and Infectious Diseases, co-director of the Broad Institute's Infectious Disease Initiative, and the study's senior author.

"One of the immediate applications is that we should be able to develop a tool to detect the emergence of drug resistance in populations and map its spread," Wirth said.

The early detection of drug resistance is critical in better managing the disease. If doctors understand early on that a patient is infected with a strain resistant to a particular drug, they can use other medications and strategies to fight the disease, rather than a blind trial-and-error approach.

"This is a way for one to get ahead of the curve, instead of waiting for clinical failure," Wirth said.

The research represents a critical intersection of advancing technology and basic science aimed at understanding the human genome - pioneered under the leadership of Eric Lander at the Broad Institute - and their application to modern public health problems.

Researchers discover mechanism that regulates bone growth

Fri, 13 Jul 2007 09:35:58 -0400

Harvard researchers have identified a protein that helps regulate bone growth and may lead to new drug targets to fight osteoporosis, the bone loss condition that the National Institutes of Health terms "a major public health threat" to more than half of people age 50 or older.

The research, conducted by scientists at the Harvard School of Public Health and Harvard Medical School, identified a protein in mice called Schnurri-3 that when absent results in dramatic increases in bone mass.

Vitamin D critical to human TB response

70652986 — Mon, 26 Mar 2007 06:25:09 -0400

Vitamin D plays a critical role in the human body's response to tuberculosis, according to new research that explains why people of African descent are more susceptible to TB.

The research also suggests a new way to fight one of the world's deadliest diseases: with a simple dietary supplement.

Tuberculosis, usually caused when a person inhales tuberculosis bacteria, killed an estimated 1.7 million people in 2003 and is the leading cause of death for people afflicted with AIDS, according to the World Health Organization (WHO).

People of African descent are more susceptible to tuberculosis than Caucasians, with higher rates of infection and more severe cases once infected, trends that had puzzled researchers until now. Sub-Saharan Africa, for example, has the world's highest per capita rates of both tuberculosis cases and deaths from the disease, roughly twice the next-highest region, according to WHO statistics.

The research, conducted by a team from the University of California, Los Angeles (UCLA), and the Harvard School of Public Health, shows that vitamin D plays a key role in the production of a molecule called cathelicidin, which kills the tuberculosis bacteria.

The body produces vitamin D when sunlight hits the skin. The skin pigment melanin - more abundant in darker skin - shields the body from the sun's rays, reducing damage from ultraviolet light, but also reducing vitamin D production.

HSPH find AIDS drugs work well in Botswana

50443248 — Thu, 19 Jul 2007 16:47:25 -0400

Africa's first large-scale public program to distribute critical AIDS drugs to a developing nation is as successful as similar programs in industrialized countries, a Harvard School of Public Health study has shown, helping put to rest concerns that such programs can't work in developing nations.

TB susceptibility gene identified

70652986 — Mon, 26 Mar 2007 06:17:55 -0400

As many as one out of three people in the world are infected with the bacteria that causes tuberculosis, public health experts estimate. That could lead to a global plague were it not for the fact that only one out of 10 infected people actually develops the disease. Still, TB is a major global health problem, particularly in developing countries. It sickens 8 million additional people each year, of which 2 million will die. So if scientists could find out what is gong on in the bodies of the other nine people, they might be able to save millions of lives and a great deal of suffering. Part of the problem involves environmental factors such as poverty, stress, malnutrition, and companion diseases like AIDS.

Scorpion venom blocks bone loss

70652986 — Mon, 26 Mar 2007 05:33:30 -0400

Rats given kalitoxin, from scorpion venom, enjoyed 84 percent less jawbone loss than those that didn't get the injections. "We are very excited because this is the first demonstration that this type of compound may be useful in treating periodontal disease," says Martin Taubman, Harvard professor of oral and developmental biology who chairs the Department of Immunology at the Forsyth Institute. "We hope that our findings will lead to success in alleviating the bone-ravaging effects of many other diseases." Good candidates include rheumatoid arthritis and osteoarthritis. According to researcher Paloma Valverde, who had the original idea for the experiment, kalitoxin blocks Kv1.3, a protein that plays a major role in inflammation. When Kv1.3 is blocked, it decreases the activity of another protein that plays a key role in stimulating bone-eating cells known as osteoclasts. "This is the first study we know of to show that such a blocker can decrease alveolar (jaw) bone loss," Valverde notes. "Furthermore, we observed no toxic side effects. Therefore, we now have a novel and apparently safe strategy to ameliorate bone destruction associated with periodontal disease." Before experiments with humans begin, however, there will need to be toxicology tests. The rats came out fine, but the venom ingredient must be tested for safety in people.

Harvard researchers complete genomic sequence of deadly malaria parasite

70652986 — Mon, 26 Mar 2007 05:23:30 -0400

Malaria is the world's most serious parasitic tropical disease and kills more people than any communicable disease except for tuberculosis. There is more human malaria in Africa today than at any time in history. P.falciparum, the most lethal form of the disease, accounts for the majority of infections, 200 to 300 million, resulting in 1 to 3 million deaths annually. One quarter of the world's population is at risk for infection. Now researchers are looking for clues to the mysteries that have made malaria impossible to defeat with drugs. Dyann Wirth, director of the Harvard Malaria Initiative and professor of immunology and infectious diseases at the Harvard School of Public Health, is author of two papers focusing on what has been learned from the genetic sequencing of P.Falciparum and how it can possibly be applied to public health. The papers appeared in the Oct. 3, 2002, issue of the journal Nature and the Oct. 4, 2002, issue of the journal Science.

Mouse model devised that develops asthma

70652986 — Mon, 26 Mar 2007 05:18:44 -0400

A Harvard research team led by Laurie Glimcher, Irene Heinz Given professor of immunology at the Harvard School of Public Health and a Harvard Medical School professor of medicine, two years ago discovered a molecule that they named T-bet. T-bet seemed to help control the immune system response by determining the actions of helper T cells, which are orchestrators of the immune response to disease. Glimcher's team studied mice that were engineered to lack T-bet. The mice, they found, had an uneven immune system response. Furthermore, the mice spontaneously developed the symptoms of asthma. The finding by Glimcher and her team helps to prove the case for T-bet as an important therapeutic target in several diseases, and also provides a new model for studying asthma.

Technique enables quick accounting of gene function

70652986 — Mon, 26 Mar 2007 05:17:00 -0400

Now that whole genomes have been sequenced, a group of scientists has geared up for the next phase: identification and classification of newly discovered coding regions. The DNA microchip, developed just a few years ago, has already become a standard tool in the geneticist's repertoire. With genomic sequence in hand, the researcher can synthesize all the genes in an organism -- or even just fragments of them -- and then dot them in a regular pattern on a glass slide. But for many organisms, up to 40 percent of the DNA sequences on the chip have no known function. The challenge is to design probes that make a particular spot stand out. It is a daunting task.

Shorter treatment as effective, less costly in preventing HIV in babies

70652986 — Mon, 26 Mar 2007 05:06:35 -0400

Of the more than 1,500 infants who get HIV from their infected mothers every day, 95 percent live in developing countries where the poverty level is high. Many mothers in these regions do not have access to the three- to six-month AZT treatment, now considered the standard treatment to prevent perinatal HIV transmission in developed countries. A study conducted by Harvard School of Public Health researchers and colleagues from Thailand and France demonstrated that transmission of HIV from a mother to her child can be reduced with shorter treatments of the drug AZT at one-fifth the usual cost of $1,000. "These new strategies to reduce pediatric AIDS can be applied in developing countries with success rates equal to those treatments used in industrialized nations," explained Marc Lallemant, research associate in the Department of Immunology and Infectious Diseases and senior scientist at the Institut de Recherche pour le Développement, who directed the study.