Featured Research

from universities, journals, and other organizations

Transmission Of Tuberculosis Is Linked To Historical Patterns Of Human Migration

Date:
September 27, 2005
Source:
Cold Spring Harbor Laboratory
Summary:
Dr. Igor Mokrousov from St. Petersburg's Pasteur Institute and his colleagues have demonstrated that the evolutionary history of the causative agent of tuberculosis (TB) has been shaped by human migration patterns.

St. Petersburg, Russia -- Genghis Khan and his troops may haveunwittingly used more than just brute military force to conquer entirenations and to establish the infamous Mongolian empire. A report in theOctober issue of Genome Research suggests that Genghis Khan'sinvasions spanning the continent of Asia during the 13th century mayhave been a primary vehicle for the dissemination of one of the world'smost deadly diseases: tuberculosis.

In this study, a team of scientists led by Dr. Igor Mokrousov from St.Petersburg's Pasteur Institute demonstrated that the evolutionaryhistory of the causative agent of tuberculosis (TB) has been shaped byhuman migration patterns.

The researchers examined the genetic signatures of over 300 strains of Mycobacterium tuberculosis,rod-shaped bacteria that, when airborne, infect the pulmonary systemsof vulnerable individuals and give rise to clinical TB. The WorldHealth Organization (WHO) estimates that TB kills 5,000 peopleworldwide every day, or approximately 2 million people each year. Thepathogen is rapidly spreading and evolving multi-drug resistant strainsin susceptible regions such as Africa. Interestingly, a strong genderbias in TB infection is reported globally each year; a 70% excess ofmale TB cases is typical.

"M. tuberculosis also has aremarkable ability to persist in the human host as a latent,asymptomatic form," explains Mokrousov. "This is probably whatpermitted M. tuberculosis to co-exist with humans duringpre-industrialized times, when the primary mode of transmission waswithin families or households where there was significant physicalcontact." Today, approximately one-third of the world's population arecarriers of latent TB.

Mokrousov's team hypothesized that, given the strong gender bias of TBinfectivity and the likely family-based mode of TB transmission duringpre-industrialized times, M. tuberculosisdissemination has reflected the unidirectional inheritance of thepaternally transmitted human Y chromosome. To test this hypothesis, theauthors compared the genetic profiles of a common form of M. tuberculosis,called the Beijing genotype, with known patterns of prehistoric andrecent human migrations, as well as with global patterns ofY-chromosome variation. Strikingly, they observed that over the past60,000-100,000 years, the dispersal and evolution of M. tuberculosis appears to have precisely ebbed and flowed according to human migration patterns.

The authors describe how the Beijing genotype of M. tuberculosisoriginated in a specific human population called the K-M9 in centralAsia approximately 30,000-40,000 years ago following a second "out ofAfrica" migration event. The bacteria and its human host thendisseminated northeast into Siberia between 20,000-30,000 years ago andthroughout eastern Asia between 4,000-10,000 years ago. More recently,the Beijing genotype of M. tuberculosis was introduced intonorthern Eurasia, perhaps by Genghis Khan himself during the 1200's,and into South Africa, possibly through sea trade contacts withIndonesia or China during the last 300 years.

"The population structure of M. tuberculosisappears to have been shaped by the demographic history of its humancarrier," explains Mokrousov, "but this is the opposite of what WilliamMcNeill suggested in 1976 in his famous book Plagues and Peoples,where he so popularly described how the growth and spread of infectiousdiseases such as the Black Death have influenced human history."

Mokrousov feels that these observations have important implications fortracing the evolutionary history of microorganisms. "The timing ofhallmark changes in bacterial genomes within the last 100,000 years maybe inferred from comparison with relevant human migrations," he says.


Story Source:

The above story is based on materials provided by Cold Spring Harbor Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Cold Spring Harbor Laboratory. "Transmission Of Tuberculosis Is Linked To Historical Patterns Of Human Migration." ScienceDaily. ScienceDaily, 27 September 2005. <www.sciencedaily.com/releases/2005/09/050927081447.htm>.
Cold Spring Harbor Laboratory. (2005, September 27). Transmission Of Tuberculosis Is Linked To Historical Patterns Of Human Migration. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2005/09/050927081447.htm
Cold Spring Harbor Laboratory. "Transmission Of Tuberculosis Is Linked To Historical Patterns Of Human Migration." ScienceDaily. www.sciencedaily.com/releases/2005/09/050927081447.htm (accessed August 1, 2014).

Share This




More Health & Medicine News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Texas Quintuplets Head Home

Texas Quintuplets Head Home

Reuters - US Online Video (Aug. 1, 2014) After four months in the hospital, the first quintuplets to be born at Baylor University Medical Center head home. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Ebola Patient Coming to U.S. for Treatment

Ebola Patient Coming to U.S. for Treatment

Reuters - US Online Video (Aug. 1, 2014) A U.S. aid worker infected with Ebola while working in West Africa will be treated in a high security ward at Emory University in Atlanta. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Ebola Vaccine Might Be Coming, But Where's It Been?

Ebola Vaccine Might Be Coming, But Where's It Been?

Newsy (Aug. 1, 2014) Health officials are working to fast-track a vaccine — the West-African Ebola outbreak has killed more than 700. But why didn't we already have one? Video provided by Newsy
Powered by NewsLook.com
Study Links Certain Birth Control Pills To Breast Cancer

Study Links Certain Birth Control Pills To Breast Cancer

Newsy (Aug. 1, 2014) Previous studies have made the link between birth control and breast cancer, but the latest makes the link to high-estrogen oral contraceptives. Video provided by Newsy
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