Featured Research

from universities, journals, and other organizations

Study of human blood fluke parasites identifies drug resistance mutations

Date:
November 21, 2013
Source:
Texas Biomedical Research Institute
Summary:
An international group of scientists has identified the mutations that result in drug resistance in a parasite infecting 187 million people in South America, Africa and Asia. The new finding allows detailed understanding of the drugs’ mechanism of action and raises prospects of improved therapies.

An international group of scientists led by Tim Anderson Ph.D., at the Texas Biomedical Research Institute and Philip LoVerde Ph.D., at the University of Texas Health Science Center at San Antonio has identified the mutations that result in drug resistance in a parasite infecting 187 million people in South America, Africa and Asia. The new finding allows detailed understanding of the drugs' mechanism of action and raises prospects of improved therapies.

"This is a major advance," said Claudia Valentim, Ph.D., the primary author of the report, who worked at both institutions. "We were able to identify the critical gene by crossing resistant and sensitive worms in the laboratory and then analyzing the genomes of the progeny. This method is commonly used for fruit flies and other laboratory organisms, but has not previously been possible for schistosome parasites."

"This really shows the utility of genome sequencing," says Anderson. "The schistosome genome was published in 2009. Without the sequence, the work would have been painfully slow."

The new study -- funded by the National Institutes of Health (NIH), the World Health Organization, the Wellcome Trust and the Robert A. Welch Foundation -- appears in the November 21 online edition of the journal Science.

Adult schistosome parasites are half an inch long and live in the human blood vessels, laying thousands of eggs, many of which become lodged in the liver or bladder wall, causing portal hypertension, liver failure and bladder cancer. "We don't know the death toll from these parasites," says LoVerde, "but our best estimate is that more than 200,000 people die every year from this infection in Africa alone, making this parasitic disease second only to malaria in terms of mortality."

No vaccine exists for schistosomiasis, so this disease is controlled using drug treatment, which must be repeated periodically because people become reinfected through contact with water where the intermediate snail hosts live. The problem is that there are very few effective drugs available.

The drug oxamniquine, the subject of this research, kills just one of the three species of schistosome parasite that infect humans. The research raises hope that this drug can be redesigned to kill the two major schistosome species responsible for 99 percent of schistosomiasis cases worldwide.

John Hart, Ph.D., a key collaborator on this study from the Health Science Center, explains: "By using X-ray crystallography and computational methods we were able to precisely pinpoint how the drug interacts with the critical protein in one Schistosome species, and to identify the key differences in this protein in the related parasite species. With some targeted chemical modification, we think it will be possible to make a drug that kills both major schistosome species. This is what we are working on now."

Only one drug currently is available for treating schistosomiasis and resistance has been reported, so new drugs are urgently needed.


Story Source:

The above story is based on materials provided by Texas Biomedical Research Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. L. L. Valentim, D. Cioli, F. D. Chevalier, X. Cao, A. B. Taylor, S. P. Holloway, L. Pica-Mattoccia, A. Guidi, A. Basso, I. J. Tsai, M. Berriman, C. Carvalho-Queiroz, M. Almeida, H. Aguilar, D. E. Frantz, P. J. Hart, P. T. LoVerde, T. J. C. Anderson. Genetic and Molecular Basis of Drug Resistance and Species-Specific Drug Action in Schistosome Parasites. Science, 2013; DOI: 10.1126/science.1243106

Cite This Page:

Texas Biomedical Research Institute. "Study of human blood fluke parasites identifies drug resistance mutations." ScienceDaily. ScienceDaily, 21 November 2013. <www.sciencedaily.com/releases/2013/11/131121142123.htm>.
Texas Biomedical Research Institute. (2013, November 21). Study of human blood fluke parasites identifies drug resistance mutations. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2013/11/131121142123.htm
Texas Biomedical Research Institute. "Study of human blood fluke parasites identifies drug resistance mutations." ScienceDaily. www.sciencedaily.com/releases/2013/11/131121142123.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Courts Conflicted Over Healthcare Law

Courts Conflicted Over Healthcare Law

AP (July 22, 2014) Two federal appeals courts issued conflicting rulings Tuesday on the legality of the federally-run healthcare exchange that operates in 36 states. (July 22) Video provided by AP
Powered by NewsLook.com
Why Do People Believe We Only Use 10 Percent Of Our Brains?

Why Do People Believe We Only Use 10 Percent Of Our Brains?

Newsy (July 22, 2014) The new sci-fi thriller "Lucy" is making people question whether we really use all our brainpower. But, as scientists have insisted for years, we do. Video provided by Newsy
Powered by NewsLook.com
Scientists Find New Way To Make Human Platelets

Scientists Find New Way To Make Human Platelets

Newsy (July 22, 2014) Boston scientists have discovered a new way to create fully functioning human platelets using a bioreactor and human stem cells. Video provided by Newsy
Powered by NewsLook.com
Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins