A QUANTUM OF SCIENCE
Mouse virus is implicated in causation of #2 male cancer killer
Prostate cancer strikes one in six American men, and is the second most likely cancer to cause death in men. New research now suggests that prostate cancer may in fact be linked to a virus that could be sexually transmitted.
The suspect is xenotropic murine leukemia-related virus (XMRV), a gammaretrovirus similar to viruses known to cause cancer in animals. Retroviruses are known cancer-causing agents because they integrate themselves into the host’s genetic material; when this takes place in or near a segment of DNA associated with a gene that controls growth, cancer – unrestricted cell growth – can result. Some retroviruses also contain cancer-causing genes of their own, such as the src gene in Rous sarcoma virus. The three most common cancer-causing viruses are human papilloma virus (HPV), Hepatitis B virus (Hep B), and the Eppstein Barr Virus (EBV).
Scientists working in collaboration between Columbia University and the University of Utah found XMRV in over 25% of prostate tissue samples, especially malignant ones. Moreover, the virus was found to be significantly more infective when present in semen. Another semen component, acid phosphatase, increased XMRV infectivity of human prostate cells by over 100-fold.
The strongest theory at present for the biology of XMRV-linked prostate cancer suggests that an infected man has viral particles present in his genital tract and deposits them in his partner when he has unprotected intercourse. The acid phosphatase in the semen activates the viral particles and makes them substantially more infective, making the partner at risk of transmitting the virus during future intercourse.
More research is needed to substantiate this theory, but this discovery could also lead to new treatments based on anti-retroviral therapies already known to medicine.
For more information:
Viral Cause For Prostate Cancer? (New Scientist)
Retroviruses (Wikipedia)
© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation
Showing posts with label virus. Show all posts
Showing posts with label virus. Show all posts
Monday, September 28, 2009
Thursday, July 9, 2009
You Give Me Fever
A QUANTUM OF SCIENCE
Emergent viral outbreaks show Ebola is not the only "hot zone" virus worth fearing
Sub-Saharan Africa has long been known as the Hot Zone, a place from which some of the world’s most deadly viruses originated. Among them are the well-known Ebola and Marburg viruses, members of the viral hemorrhagic fever (VHF) family that cause extreme fever, internal and external bleeding and rapid death among a frighteningly high percentage of those infected. Other "Old World" (i.e. African) hemorrhagic viral diseases include dengue and yellow fever. Most VHF viruses are carried by rodents – which seem largely immune – and are spread to humans by liquid contact, though some are capable of aerosol infections. (This latter category includes the Marburg virus, which was weaponized by the former Soviet Union in the 1980’s.) Less well-known cousins in this same family are the so-called New World viruses such as hantavirus, as well as the Argentine, Bolivian, and Venezuelan hemorrhagic fevers.
Late last fall an African travel agent was flown from the city of Lusaka to Johannesburg, South Africa, suffering from high fever and external bleeding. She died a few days later. Within the next several days, the paramedic who received her into the hospital, a nurse who cleaned the room following the travel agent’s death, and a nurse who attended the paramedic after he became ill, all perished from the same virus. Another nurse who treated the paramedic was given an antiviral treatment and survived. This was the beginning and end – for now – of an outbreak of the Lujo Virus, named for the two cities where it was first observed (Lusaka and Johannesburg). A member of the VHF family, it has more in common with the New World branch than it does Ebola or Marburg. Genetic analysis by researchers at Columbia University showed that the Lujo virus was a member of the arenaviridae genus (the name comes from the Latin word for sand, referring to the way viral particles of this genus appear when viewed under a microscope). Strangely, arenaviruses are almost unknown in Africa but have several species native to South America. Comparing the genetic sequence of Lujo to other VHF species from Africa showed significant differences, strongly suggesting that Lujo was not a simple mutant or even a more virulent strain caused by reassortment of viral chromosomes (such as is often the case for the influenza virus). Instead, Lujo appears to be the first high-morbidity, high-mortality VHF virus to emerge from Africa’s hot zone in the last thirty years.
In 2006 a paper was published by Dr. C.J. Peters, a member of the University of Texas Medical Branch, discussing the factors that affect the accelerating rate of emergence of new viruses and increasingly deadly outbreaks. He referenced the Emerging Microbial Threats reports issued by the Institute of Medicine in 1992 and updated in 2002, in which all the data pointed to two major factors at play in the increasing danger of deadly microbial outbreaks: multiple ecologic niches and ever-accelerating human travel and transport. In this paper he describes an arenavirus outbreak in a small village in Bolivia in 1962. The village suffered an outbreak of "black typhus" and out of 600 villager there were 107 cases, of which more than four out of ten perished. This is roughly the same morbidity and mortality rates recorded for the medieval scourge of bubonic plague, better known as the Black Death.
Since the 1960's, large sections of the Amazonian plateau have been deforested, and human activity in those regions has reached levels never before seen. The same is true of sub-Saharan Africa, where the Lujo virus emerged in 2008; had the Lujo virus not been caught before it spread thanks to current medical expertise not available in 1962, the "black typhus" outbreak may well have paled in comparison to the devastation Lujo might have wrought.
The story of ecological niches created through human activity has become hauntingly familiar, and authorities predict that the problem will only worsen as population pressures push humans deeper into the hot zones of viral reservoirs in both the Old World and the New.
For more information:
Viral hemorrhagic fever (overview)
Googleblog article on early news of the Lujo outbreak
News article on Columbia researcher’s efforts to analyze Lujo
Genetic Detection and Characterization of Lujo Virus, a New Hemorrhagic Fever–Associated Arenavirus from Southern Africa (Lipkin et al).
NOVA interview discussing Soviet weaponization of Marburg virus
© A Quantum of Science / P. Smalley
Reproduction with attribution is appreciation
Emergent viral outbreaks show Ebola is not the only "hot zone" virus worth fearing
Sub-Saharan Africa has long been known as the Hot Zone, a place from which some of the world’s most deadly viruses originated. Among them are the well-known Ebola and Marburg viruses, members of the viral hemorrhagic fever (VHF) family that cause extreme fever, internal and external bleeding and rapid death among a frighteningly high percentage of those infected. Other "Old World" (i.e. African) hemorrhagic viral diseases include dengue and yellow fever. Most VHF viruses are carried by rodents – which seem largely immune – and are spread to humans by liquid contact, though some are capable of aerosol infections. (This latter category includes the Marburg virus, which was weaponized by the former Soviet Union in the 1980’s.) Less well-known cousins in this same family are the so-called New World viruses such as hantavirus, as well as the Argentine, Bolivian, and Venezuelan hemorrhagic fevers.
Late last fall an African travel agent was flown from the city of Lusaka to Johannesburg, South Africa, suffering from high fever and external bleeding. She died a few days later. Within the next several days, the paramedic who received her into the hospital, a nurse who cleaned the room following the travel agent’s death, and a nurse who attended the paramedic after he became ill, all perished from the same virus. Another nurse who treated the paramedic was given an antiviral treatment and survived. This was the beginning and end – for now – of an outbreak of the Lujo Virus, named for the two cities where it was first observed (Lusaka and Johannesburg). A member of the VHF family, it has more in common with the New World branch than it does Ebola or Marburg. Genetic analysis by researchers at Columbia University showed that the Lujo virus was a member of the arenaviridae genus (the name comes from the Latin word for sand, referring to the way viral particles of this genus appear when viewed under a microscope). Strangely, arenaviruses are almost unknown in Africa but have several species native to South America. Comparing the genetic sequence of Lujo to other VHF species from Africa showed significant differences, strongly suggesting that Lujo was not a simple mutant or even a more virulent strain caused by reassortment of viral chromosomes (such as is often the case for the influenza virus). Instead, Lujo appears to be the first high-morbidity, high-mortality VHF virus to emerge from Africa’s hot zone in the last thirty years.
In 2006 a paper was published by Dr. C.J. Peters, a member of the University of Texas Medical Branch, discussing the factors that affect the accelerating rate of emergence of new viruses and increasingly deadly outbreaks. He referenced the Emerging Microbial Threats reports issued by the Institute of Medicine in 1992 and updated in 2002, in which all the data pointed to two major factors at play in the increasing danger of deadly microbial outbreaks: multiple ecologic niches and ever-accelerating human travel and transport. In this paper he describes an arenavirus outbreak in a small village in Bolivia in 1962. The village suffered an outbreak of "black typhus" and out of 600 villager there were 107 cases, of which more than four out of ten perished. This is roughly the same morbidity and mortality rates recorded for the medieval scourge of bubonic plague, better known as the Black Death.
Since the 1960's, large sections of the Amazonian plateau have been deforested, and human activity in those regions has reached levels never before seen. The same is true of sub-Saharan Africa, where the Lujo virus emerged in 2008; had the Lujo virus not been caught before it spread thanks to current medical expertise not available in 1962, the "black typhus" outbreak may well have paled in comparison to the devastation Lujo might have wrought.
The story of ecological niches created through human activity has become hauntingly familiar, and authorities predict that the problem will only worsen as population pressures push humans deeper into the hot zones of viral reservoirs in both the Old World and the New.
For more information:
Viral hemorrhagic fever (overview)
Googleblog article on early news of the Lujo outbreak
News article on Columbia researcher’s efforts to analyze Lujo
Genetic Detection and Characterization of Lujo Virus, a New Hemorrhagic Fever–Associated Arenavirus from Southern Africa (Lipkin et al).
NOVA interview discussing Soviet weaponization of Marburg virus
© A Quantum of Science / P. Smalley
Reproduction with attribution is appreciation
Tuesday, May 19, 2009
Canadian scientists sequence H1N1 genome
A QUANTUM OF SCIENCE
Now we know the complete blueprint for H1N1; now what?
Today it was announced that scientists in Canada have fully sequenced the entire genome of the H1N1 influenza virus. While it's not the first viral genome to be fully sequenced, it is a landmark achievement and all the more so for having been completed in one week of around-the-clock work by scientists at Canada's National Microbiology Laboratory in Winnipeg. This is, as the saying goes, kind of a big deal.
These findings shed some intriguing light on the outbreak of H1N1 but raises even more questions, as most scientific discoveries do. For example, researchers found virtually no difference between the Mexican strains and those occurring in the US or Canada. Why, then, have so many more cases in Mexico proven fatal? The answers may not lie in the genes themselves, but rather in differences of health infrastructure and health policy. Benefits of this breakthrough include faster analysis of future strains, a better understanding of how and why H1N1 mutations or reassortments occur, and a better H1N1 vaccine - with this last being of crucial importance as major pharmaceutical companies begin the laborious process of choosing which sequences to use for their vaccines. With an improved understanding of the variations in the H1N1 genome, conserved sequences can be selected for use vaccines, resulting in a stronger, more robust protection against future infection.
Perhaps it is a little cynical, but one might consider that the timing of this announcement seems a little too convenient considering that today is the second day of the 62nd World Health Assembly, the annual meeting of the World Health Organization whose handling of the H1N1 outbreak has been criticized by many science and health professionals. Then again, maybe it is simply a case of serendipity; regardless, it is good news and that's worth remembering.
Plus, if you want to apply for the position of Viral Genome Curator at a company in Bethesda, MD, you now have one more fully-sequenced genome to add to the list.
For more information:
http://www.canada.com/Health/Canadian+completes+sequencing+virus/1569084/story.html
© A Quantum of Science / Peter Smalley (2009)
Reproduction with attribution is appreciation
Now we know the complete blueprint for H1N1; now what?
Today it was announced that scientists in Canada have fully sequenced the entire genome of the H1N1 influenza virus. While it's not the first viral genome to be fully sequenced, it is a landmark achievement and all the more so for having been completed in one week of around-the-clock work by scientists at Canada's National Microbiology Laboratory in Winnipeg. This is, as the saying goes, kind of a big deal.
These findings shed some intriguing light on the outbreak of H1N1 but raises even more questions, as most scientific discoveries do. For example, researchers found virtually no difference between the Mexican strains and those occurring in the US or Canada. Why, then, have so many more cases in Mexico proven fatal? The answers may not lie in the genes themselves, but rather in differences of health infrastructure and health policy. Benefits of this breakthrough include faster analysis of future strains, a better understanding of how and why H1N1 mutations or reassortments occur, and a better H1N1 vaccine - with this last being of crucial importance as major pharmaceutical companies begin the laborious process of choosing which sequences to use for their vaccines. With an improved understanding of the variations in the H1N1 genome, conserved sequences can be selected for use vaccines, resulting in a stronger, more robust protection against future infection.
Perhaps it is a little cynical, but one might consider that the timing of this announcement seems a little too convenient considering that today is the second day of the 62nd World Health Assembly, the annual meeting of the World Health Organization whose handling of the H1N1 outbreak has been criticized by many science and health professionals. Then again, maybe it is simply a case of serendipity; regardless, it is good news and that's worth remembering.
Plus, if you want to apply for the position of Viral Genome Curator at a company in Bethesda, MD, you now have one more fully-sequenced genome to add to the list.
For more information:
http://www.canada.com/Health/Canadian+completes+sequencing+virus/1569084/story.html
© A Quantum of Science / Peter Smalley (2009)
Reproduction with attribution is appreciation
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