Tag Archives: Health

Natural Genetic Variation in Maize Nutritional Quality

Blogging on Peer-Reviewed ResearchThey always told you to eat your carrots, to improve your eyesight. Well, a deficiency of vitamin A (found in carrots, and lots of other foods) causes eye disease in a lot of children. In areas where Maize (corn) is a significant staple, there can be a problem because maize varies a great deal in how much vitamin A it can provide via precursor molecules. A new study in Science explores this relationship. Continue reading Natural Genetic Variation in Maize Nutritional Quality

The Origin of Syphilis

Blogging on Peer-Reviewed ResearchSyphilis is first clearly seen in Europe in 1495, when it appeared as a plague (though it was not “the plague” … Yersinia pestis) among Charles VIII’s troops. When these troops went home shortly after the fall of Naples, they brought this disease with them, staring an epidemic. The level of mortality in Europe was truly devastating. Is it the case that syphilis was brought to Europe by Columbus and his men just prior to the plague-like outbreak of 1495?

The origin of syphilis has been debated for years, really since the actual 1495 event itself. Some researchers have asserted that syphilis is present in the writings of Hippocrates, placing it squarely in the old world thousands of years prior to Columbus. Others, as suggested above, have argued that Columbus brought syphilis over to the Old World . A third (Crosby’s “combination theory”) asserts, essentially, that syphilis is both an Old World and New World disease, and that the history of the disease is complicated by the innately complex relationship between any pathogen and human populations with variable immunities, both of which tend to evolve.

A new paper is being published as we speak in PLoS Neglected Tropical Diseases, by Harper et al , called “On the Origin of the Treponematoses: A Phylogenetic Approach.” Studiously ignoring Crosby’s discussion (and I’m sure there is some unseemly story of academic infighting to explain that), the paper examines the Old World vs. New World origins hypotheses.Here is the author’s summary from the paper:

 

For 500 years, controversy has raged around the origin of T. pallidum subsp. pallidum, the bacterium responsible for syphilis. Did Christopher Columbus and his men introduce this pathogen into Renaissance Europe, after contracting it during their voyage to the New World? Or does syphilis have a much older history in the Old World? This paper represents the first attempt to use a phylogenetic approach to solve this question. In addition, it clarifies the evolutionary relationships between the pathogen that causes syphilis and the other T. pallidum subspecies, which cause the neglected tropical diseases yaws and endemic syphilis. Using a collection of pathogenic Treponema strains that is unprecedented in size, we show that yaws appears to be an ancient infection in humans while venereal syphilis arose relatively recently in human history. In addition, the closest relatives of syphilis-causing strains identified in this study were found in South America, providing support for the Columbian theory of syphilis’s origin.

 

The authors looked at 21 strains of the bacterium Treponematoses pallidum and conducted a detailed genetic (phylogenetic) study of these genomes to come to the conclusion that syphilis originates in the new world. However, a commentary on the paper, published along side it in PLoS, brings the conclusion into question. The commentary by Lukehart and Norris notes that the genetic data from the New World (which the main paper’s authors assert points to a New World origin) is weak. In addition, there are problems, partly outlined in the commentary and partly fairly obvious to anyone who reads the paper, that the issue of evolutionary change in both the pathogens and the humans who harbor them has not been sufficiently taken into account.In my view, a detailed phylogenetic study such as the one presented here is fundamentally important, but is very unlikely on its own to definitively answer the question of origin and evolution of syphilis.Need more research…

Updated: See The Science Behind Pre-Columbian Evidence of Syphilis in Europe: Research by Documentary, by Armelagos, Zuckerman, and Harper, on “Science by documentary” and “Science by press release”

This article discusses the presentation of scientific findings by documentary, without the process of peer review. We use, as an example, PBS’s “The Syphilis Enigma,” in which researchers presented novel evidence concerning the origin of syphilis that had never been reviewed by other scientists. These “findings” then entered the world of peer-reviewed literature through citations of the documentary itself or material associated with it. Here, we demonstrate that the case for pre-Columbian syphilis in Europe that was made in the documentary does not withstand scientific scrutiny. We also situate this example from paleopathology within a larger trend of “science by documentary” or “science by press conference,” in which researchers seek to bypass the peer review process by presenting unvetted findings directly to the public. © 2012 Wiley Periodicals, Inc.

See: Syphilis May Have Spread Through Europe Before Columbus.

Summary: A recent study conducted at the University of Zurich now indicates that Europeans could already have been infected with this sexually transmitted disease before the 15th century. In addition, researchers have discovered a hitherto unknown pathogen causing a related disease. The predecessor of syphilis and its related diseases could be over 2,500 years old.

Lukehart S, Mulligan C, Norris S (2008) Molecular Studies in Treponema pallidum Evolution: Toward Clarity? PLoS Negl Trop Dis 2(1).Harper KN, Ocampo PS, Steiner BM, George RW, Silverman MS, et al. (2008) On the Origin of the Treponematoses: A Phylogenetic Approach. PLoS Negl Trop Dis 2(1): e148. doi:10.1371/journal.pntd.0000148

Robert Fischell: TED Prize wish: Finding new cures for migraine, depression, malpractice

Accepting his 2005 TED Prize, inventor Robert Fischell makes three wishes: redesigning a portable migraine treatment, finding new cures for clinical depression, and reforming the medical malpractice system. He also shares three new inventions that could improve the lives of millions: His Angel Med Guardian System — a pacemaker-sized device wired into the heart — detects an elevation in the electric signal of the heart, the first sign of a heart attack. His transcranial magnetic stimulator treats migraines with a magnetic pulse. Finally, the Neuropace prevents epileptic seizures by transmitting electric signals in the brain.

Continue reading Robert Fischell: TED Prize wish: Finding new cures for migraine, depression, malpractice

Larry Brilliant: TED Prize wish: Help stop the next pandemic

Accepting his 2006 TED Prize, Dr. Larry Brilliant talks about how smallpox was finally eradicated from the planet. In a conversational style that belies the deadly seriousness of his subject, he describes the dangers of pandemic disease, and offers a solution in his dramatic TED Prize wish, a plan to use the Internet to help prevent the next pandemic. (Contains strong images.)

Continue reading Larry Brilliant: TED Prize wish: Help stop the next pandemic