Guest guest Posted May 12, 2005 Report Share Posted May 12, 2005 This is interesting Kathy. Makes me think of all the leprosy in Jerusalem and surrounding areas during the time of Christ's presence on the earth. Epidemiology is very interesting and at times downright fascinating but I don't always put full faith in what most of these folks have to say. lynn --- Kathy <vanokat wrote: > > MEDICAL: DISEASES: LEPROSY : MEDICAL: HISTORY: > International Team Determines Geographic Origin of > Leprosy > > National Institute of Allergy and Infectious > Diseases (NIAID) > NIH News > International Team Determines Geographic Origin of > Leprosy > EMBARGOED FOR RELEASE > Thursday, May 12, 2005 > 2:00 p.m. ET > <http://www.nih.gov/news/pr/may2005/niaid-12.htm> > > Leprosy likely originated in East Africa and > spread to Asia and Europe before being > imported into West Africa by explorers, report > scientists in this week's issue of Science. The > findings enrich the historical understanding of > leprosy's global migration and contradict a > commonly held view that leprosy spread to > West Africa directly from East Africa, say the > researchers. > > The international team of investigators, who > identified rare genetic variations among strains > of the bacterium that causes leprosy, included > Patrick J. Brennan, Ph.D., of Colorado State > University in Fort Collins. Dr. Brennan is a grantee > > of the National Institute of Allergy and Infectious > Diseases (NIAID), part of the > National Institutes of Health. > > " Using modern genetic techniques, these > researchers uncovered clues to the origin of a > disease that, since ancient times, has been one > of the most stigmatizing, " notes NIAID Director > Anthony S. Fauci, M.D. " Their findings may help > public health officials better track and treat > leprosy, > which remains a significant problem in some parts > of the world today. " > > The research team included scientists from > institutions in the United States, France and seven > other countries. Led by Stewart T. Cole, Ph.D., > of the Institut Pasteur in Paris, the investigators > scanned the genetic material of Mycobacterium > leprae, the bacterium that causes leprosy, for tiny > variations known as single nucleotide polymorphisms > (SNPs). SNPs, pronounced " snips, " are variations > in a single " letter " of DNA's four-letter code. > Scientists can use SNPs to trace the lineage of an > organism, in this case M. leprae, and to develop a > picture of how leprosy spread from its point of > origin. > The team looked for SNPs in 171 clinical specimens > of M. leprae taken from people infected with the > bacterium. The specimens came from 21 countries > representing five continents. > > Four types of SNP appeared in the samples, but > their distribution was not random. Instead, the > investigators discovered a fairly close correlation > between SNP type and geographic location of the > leprosy patient. Type 2, predominant in a small > region > of East Africa and Central Asia, is the rarest and > oldest, > the scientists believe. Type 1, present in Asia and > the > Pacific region, represents the eastward migration of > l > eprosy, while type 3, seen in Europe, North Africa > and the Americas, is the form that migrated west. > The most recently evolved, type 4, is predominant > in West Africa. Because type 4 leprosy is more > closely related to type 3 than it is to either type > 1 or 2, > the researchers concluded that North Africans or > Europeans probably brought the disease to West > Africa. > > Compared with other disease-causing organisms, M. > leprae has very few SNPs — only one in every > 28,400 letter pairs. The rarity of SNPs is an > indication > of extreme genetic stability: all the strains of > leprosy > throughout the world are essentially identical. > > The discovery of the four SNP types could help > health officials better understand leprosy in > present > day human populations, says Christine Sizemore, > Ph.D., of NIAID's Division of Microbiology and > Infectious Diseases. Aggressive therapy with > multiple > drugs has helped drive down the number of registered > > leprosy cases around the world, notes Dr. Sizemore. > However, despite drug treatment, the number of new > cases of leprosy detected each year has stayed the > same or risen. The new understanding of the genetic > makeup of the leprosy bacterium will allow > clinicians > to characterize at a molecular level the M. leprae > strain > infecting a leprosy patient, which will show whether > the > patient has a new infection or if the previous > infection > was incompletely treated and has returned. This, in > turn, will aid efforts to fully treat patients so > that the > bacteria are completely eliminated. > > NIAID is a component of the National Institutes of > Health, an agency of the U.S. Department of Health > and Human Services. NIAID supports basic and > applied research to prevent, diagnose and treat > infectious > diseases such as HIV/AIDS and other sexually > transmitted > infections, influenza, tuberculosis, malaria and > illness from > potential agents of bioterrorism. NIAID also > supports > research on transplantation and immune-related > illnesses, > including autoimmune disorders, asthma and > allergies. > Reference: M Monet et al. On the origin of leprosy. > Science 308 (2005) DOI: 10.1126/science.1109759. > > > > > Lynn Quote Link to comment Share on other sites More sharing options...
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