Imagine, if you will, a tiny creature with the ability to invade your body, hijack your cells, change your DNA, and modify you physically and behaviorally to suit its own devious goals. Sound like science fiction?
Maybe, but it's also the modus operandi of the real-life parasitic organisms that live among, and inside, the rest of us animals. While some parasites, in their quest for survival and propagation, may live undetected in the bodies of their hosts, others can cause sickness or death.
Some of the world's most pernicious and persistent diseases are caused by these supremely successful and sophisticated organisms. But according to evolutionary biologists, parasites have also played a significant role in shaping the human species -- including why we use sex to reproduce. (Nice job, little friends!)
Just when you thought it was safe to go back in the water, Jim McKerrow returns to Ask a Scientist with more strange and wonderful tales of parasite biology.
Note to the squeamish: beware!
Jim McKerrow is Director of the Sandler Center for Research on Parasitic Diseases.
Any of about 21 species (genus Glossina, family Muscidae) of African bloodsucking dipterans that are robust, sparsely bristled, and usually larger than a housefly. They have stiff, piercing mouthparts. Only two species commonly transmit the protozoan parasites (trypanosomes) that cause human sleeping sickness: G. palpalis, found primarily in dense streamside vegetation, and G. morsitans, found in more open woodlands. The female requires a sufficient blood meal to produce viable larvae, but both sexes suck blood almost daily.
No Scientist on US money?
Ben Franklin on the $100 Bill!
Scientist? I think so!
Thomas Jefferson? Agriculteral Research!
He became a president of the American Philosophical Society, it was begun by Benjamin Franklin in Philadelphia, a society of gentlemen devoted to scientific investigation. This was the era of the Enlightenment, when man began to cast off, as Jefferson would say, “The wool of ignorance from their eyes to a mistrust of their own vision,” and began to believe that they themselves were responsible for the improving of their condition and that the laws of nature and nature’s god were amenable to pursuing science.
What did Thomas Jefferson do as a scientist?
It's true that Thomas Jefferson contributed some new knowledge directly to science and technology. But his main scientific contribution was as a statesman of science. For half a century in public office and in private life, he led the growth of American optimism about science, technology, and the future. Jefferson wished he could be a scientist all the time. When he was leaving the presidency in early 1809, he wrote, "Nature intended me for the tranquil pursuits of science, by rendering them my supreme delight." In fact, do you know what Jefferson did during the week in 1797 when he became vice president of the United States? He presented a formal research paper on paleontology to his scientific colleagues in the American Philosophical Society! Paleontology is the study of fossils. It helps us understand all the Earth's forms of life.
Jefferson also helped invent modern agricultural science and technology. He believed agriculture was the most important science. By himself, he re-engineered the plow according to scientific principles that came from Sir Isaac Newton, the inventor of mathematical physics. Re-inventing the plow may sound boring. But ask yourself: In Jefferson's time, what technological devices were more important than the plow?
Jefferson also invented methods for excavating archeological sites. If you go to Jamestown today to watch researchers dig to discover how things really looked in the time of Pocahontas, you'll see them using methods first devised by Thomas Jefferson.
Roundworm Could Provide New Treatment for Sepsis
ScienceDaily (Mar. 11, 2011) ¡ª Research by the University of Liverpool has found that systemic inflammation caused by sepsis can be suppressed by a protein which occurs naturally in a type of roundworm.
Sepsis is a serious inflammatory condition, caused by the body over-reacting to infection. The body becomes overwhelmed by bacteria, setting off a series of reactions that lead to inflammation and clotting. It affects around 20 million people worldwide each year, and accounts for a large proportion of intensive care unit admissions.
For the past 30 years, sepsis has largely been treated by antibiotics and maintenance of blood flow. Despite these treatments -- often complicated by antibiotic-induced liver injury or the presence of multi drug-resistant bacteria -- mortality rates for those with severe illness who go into multi-organ damage and septic shock, remain as high as 50%. New treatments for septic shock are of high clinical need.
Findings by an international team, led by Professor Alirio Melendez, based at the University's Medical Research Council Centre for Drug Safety Science in the Institute of Translational Medicine, show that inflammation triggered by bacterial endotoxins in immune cells from patients with sepsis is suppressed by a protein called ES-62 which is secreted by a type of roundworm called Acanthocheilonema viteae.
Roundworms can infect the human digestive tract, lymphatic vessels, skin and muscle. They are extremely common -- particularly in parts of the world with poor sanitation -- and it is estimated that nearly a quarter of the world's population are currently infected. Roundworm can live in the human body for decades without adverse effects or triggering the immune system.
Scientists already know that the protein secreted by roundworm is capable of suppressing inflammation and people infected with worms usually benefit from reduced inflammation if they suffer from conditions such as allergies and autoimmune diseases.
Professor Melendez explained: "The protein secreted by the roundworm stimulates a process called autophagy, a process of 'self-eating' that is essential to clear damage to cellular proteins or organelles and promote cell survival and function during stress situations.
"Autophagy reduces inflammation but at the same time permits the clearance of microbial infection. The findings suggest that ES-62 could be used to induce autophagy and reduce the overwhelming inflammation that is responsible for the massive tissue damage seen in sepsis."
He added: "ES-62 has the therapeutic ability to enhance recovery in septic shock by suppressing and limiting catastrophic inflammatory responses while allowing for bacterial clearance to occur. Administration of ES-62, or a synthetic small molecule derivative, alone or in combination with antibiotics could potentially be used treatment of septic shock as well as other inflammatory diseases."
The research is published in Nature Immunology and was carried out in collaboration with colleagues from the Universities of Strathclyde, Glasgow and the National University of Singapore.
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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Liverpool.
13. Q6 (correction!!).. Bacteria and virus are parasites too!...There is no distinction between parasitism and infection, but there is a historical way in the study of metazoan parasites (helminths, arthropods, etc.) and unicellular parasites (bacteria, fungi and viruses as well)the first studied by parasitologists and the second by microbiologists. The example about ebola disease is wrong!... why ebola virus kills people son quikly?... is because human are not the natural host for ebola virus... Ebola virus is a parasite too.
That's a pretty hardcore disease (African sleeping sickness). How many veins can you keep puncturing to pass the medicine through the body before you run out since the medicine kills the vein that it is connected to?