disease – Australian Science

The Ten Hallmarks of Cancer

Buddhini Samarasinghe — Tue, 03 Sep 2013 00:14:44 +0000

This series of articles originally appeared on Know The Cosmos. I will be reposting the articles here for AusSci with added commentary over the coming weeks!

In 2002, Robert Weinberg and Douglas Hanahan published a review article in the journal Cell titled “The Hallmarks of Cancer

Cite this article:
Samarasinghe B (2013-09-03 00:14:44). The Ten Hallmarks of Cancer. Australian Science. Retrieved: May 19, 2024, from http://australianscience.com.au/biology/the-ten-hallmarks-of-cancer/
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Mosquito-borne diseases: Fighting fire with fire

Markus — Tue, 14 May 2013 00:14:07 +0000

I have a decidedly “live and let live” approach to life. There are no animals in this world which I harbour any malicious feelings towards, regardless of how many of those animals would think nothing of poisoning, eating, maiming, or otherwise killing me (it’s a tough world out there). No animals, with one exception. I absolutely detest mosquitos – and not irrationally so.

You see, you might not realise it, but mosquitos are actually the most dangerous animal in the world. Yes, seriously. They may not look like much, but every year, mosquitos will spread diseases to 700 million people. That’s 10% of the human population on this planet. Many of the diseases spread by mosquitos are potentially fatal, and mosquitos are responsible for over 2 million deaths every year. Needless to say, some way of curbing the spread of mosquito-borne disease would be a huge success in combating illness worldwide.

Interestingly, an unusual but potentially effective method has been devised by Ary Hoffmann and Michale Turelli at the University of Melbourne. I say unusual, because their method of preventing mosquitos from spreading disease is to actually infect the mosquitos with a disease of their own.

When mosquitos are infected with a type of bacteria called wolbachia, it renders them unable to spread viruses such as dengue fever. Dengue is a particularly nasty disease spread by mosquitos, for which no real treatments or vaccines are available. Around 40,000 people die every year from dengue, with around 2,400 cases reported over the past few years in Northern Australia.

Wolbachia bacteria are actually surprisingly common, existing naturally in around 70% of all insects. The particular strain used in this study was discovered by Hoffmann in 1988, in Australian fruit flies. Nature, it seems, is full of serendipities. In 2011, studies showed a great success. Mosquitos infected with wolbachia cannot spread the dengue virus!

However, there was still a problem to address. Wolbachia also affected the mosquitos eggs, preventing them from hatching. While this may seem, at first, like a good thing in that it may cull the mosquito population, the problem lies in the fact that if the infected mosquitos all die off, the remaining insects will still be quite able to spread disease.

The solution, perhaps even more counterintuitively, involves giving the mosquitos resistance to insecticide. At first glance, this idea may seem unappealing, but it isn’t without merit. In fact it’s quite ingenious. Areas which are particularly prone to mosquito-borne infections tend to use insecticides as a way to control the mosquito populations and curb disease. In these regions, the non-infected mosquitos would be killed off by insecticide, so that the population of mosquitos would adapt. The end result would be a population of mosquitos which cannot spread the dengue virus.

Similarly, the insecticide resistance gene would not be able to be passed to any non-infected mosquitos. A female mosquito would pass on both the gene and the bacteria to her eggs, while any non-infected female mating with an infected male would lead to eggs which will never hatch (due to cytoplasmic incompatibility). The end result would be that the only offspring from this population of infected mosquitos would also be infected, and therefore would be unable to spread viral infections to humans.

As well as dengue, the method is promising as a way of preventing other mosquito-borne illnesses, such as yellow fever, and perhaps eventually even malaria. The latest strain of bacteria which Hoffmann and Turelli are working with, named wMelPop, is a strong blocker of dengue and other viruses. Perhaps this method could eventually help to eradicate mosquito-borne diseases altogether.

the meantime, I’m noticing that typing up this article is having the psychosomatic effect of making me feel rather itchy. I’m going to take this as a sign that I should stop writing about mosquitos now. And perhaps take a shower…

Image: A Tasmanian mosquito feeding on human blood. Credit: J. J. Harrison/Wikimedia Commons

Cite this article:
Hammonds M (2013-05-14 00:14:07). Mosquito-borne diseases: Fighting fire with fire. Australian Science. Retrieved: May 19, 2024, from http://australianscience.com.au/health/mosquito-borne-diseases-fighting-fire-with-fire/
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The Contagion of Violence

Charles Ebikeme — Wed, 06 Mar 2013 00:04:56 +0000

When Professor Plum killed Dr Black, in the library, with the candlestick it was for no other reason than murder is a disease. Murder is infectious and the contagion of violence is everywhere.

Violence begets violence.Violence within nations and cultures. It occurs within families and between partners. It increases the risk of violence directed at children and increases the risk of the children behaving violently themselves. Violence within a community perpetuates and spreads. Children catch it from their parents, and parents can catch it from their children. Violence is highly contagious in all respects it seems.

It was a 2012 essay by L. Rowell Huesmann that sparked off a study, appearing in Justice Quarterly. A study with a simple premise and question; if homicide is infectious, it should diffuse through communities, infecting those susceptible, and that diffusion should be detectable. Much in the same way we can track the flu from year to year, we can track the spread of murder as an epidemic. It offers an interesting way of looking at murder and homicide.

Welcome to Newark, New Jersey. A city that houses roughly 277,000 people has a homicide and murder rate over three times greater than that of anywhere else in the US. There were 104 murders and 504 shooting victims in 2006 alone. Firearms were used in 71% of the 380 reported murders in 2011. Suffice it to say, Newark is not a safe place.

The study took a look at how murders and homicides moved and behaved over a 26-year period (1982 to 2008) across the city. Firearms and gangs were the infectious agents; spreading from within the centre of the city and spreading south-westerly over the course of nearly three decades.

Their main argument is that the way murders move across a community is not random. The elements required for disease to propagate itself may be relevant and can be applied to the movement of homicide. And if this is so, then it can be predicted and controlled.

If you take a look at a map of Newark it is hard to see a pattern. Homicides occurred in all parts of the city. Almost the entire city appears to be a hot spot for murder. But analysis over the decades suggest that there was expansion of overall homicides between 1982 and 2008 with a dip in 1997 and a sharp rise in 2000. And highlighted an area of the city (North and East) that seemed largely immune to the spread of homicide. Indeed, murder was on the move.

The criminal justice system seeks to prevent murder, but only after the fact — by deterring those that do it with the penalty that awaits them after the fact (jail and criminal prosecution). Indeed, police forces already have an eye out for certain hotspots within a location. Areas where violence is known to spark and ignite at any given moment. What they don’t know is where it will go next. The authors of the study model homicide as an infectious disease as simply a way to offer instructive understanding of how homicide works. The most telling application of this non-literal model is the fact that for homicide to spread as a disease, a population susceptible to transmission must be present. Just like every other infectious agent, except this time poverty and social inequality replace a population with no herd immunity.

Image — source

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Bacon Fans United: The Pig Genome Sequenced

rayna.s — Sat, 17 Nov 2012 00:28:42 +0000

Breeding healthier and meatier piggies has been one of the many scientific challenges of the past decades; creating more reliable models to study human diseases is another. The swine disease model is indeed much better to use when studying human disorders than the (thus far) widely used murine models. Although pigs reproduce slower than mice and are more expensive to take care of, they are more similar to humans when it comes to anatomy and physiology. These common grounds have allowed the development of accurate swine models for diabetes, cystic fibrosis or retinitis pigmentosa (a cause of blindness). In its issue of 15 November, Nature published the fully sequenced and annotated pig genome. This is a major achievement, and will allow considerable progress to be made on both the yummy and the healthy fronts.

Sus scrofa domestica, by its official name, originates from South-East Asia and then went on a visit to Europe. A closer examination of the sequenced pig genome consistently shows a clear and deep split between Asian and European wild boars rooting some 1 My ago. More precisely, the analysis allowed to date the split between the two lineages in the mid-Pleistocene (1.6–0.8 My ago), a divergence the authors explain with possible colder climate prompting isolation between populations across Eurasia.

Demographic history of wild boars. Image from Groenen et al. (Nature, 2012). The default mutation rate for human (μ) was used, and the generation time (g) was estimated to 5 years. The Last Glacial Maximum (LGM) is highlighted in grey. WBnl, wild boar Netherlands; WBit, wild boar Italy; WBNch, wild boar north China; WBSch, wild boar south China.

As the authors explain it:

Our demographic analysis on the whole-genome sequences of European and Asian wild boars revealed an increase in the European population after pigs arrived from China. During the Last Glacial Maximum (LGM; ~20,000 years ago), however, Asian and European populations both suffered population bottlenecks. The drop in population size was more pronounced in Europe than Asia, suggesting a greater impact of the LGM in northern European regions and probably resulting in the observed lower genetic diversity in modern European wild boar.

Noticeably, pigs have been faithful companions to humans for 10,000 years now. Breeding piggies and selecting for some particular features of theirs has had an important impact on the swine genome. Authors thus identified a wide range of genes and gene families to have undergone fast-paced evolution. Immunity-related genes, already known to be actively evolving in Mammals, were for instance part of this subset, and further analysis revealed evidence for specific gene duplications and gene-family expansions. Lastly, a significant expansion of the porcine olfactory receptor gene family was described. The authors explain it by the importance smell has for pigs when scavenging for food.

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Image source

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Panique au village: the revolution that caused an epidemic

Charles Ebikeme — Tue, 23 Oct 2012 00:16:20 +0000

It boasts, struts, and flaunts with that kind of assurance that only comes from the mentality of knowing that you are right, and that even if you may be wrong, others will admire you for it. This is Paris.

Where other cities flowed and spilled out to occupy a space larger than its originality, Paris said enough is enough and contained itself. To this day only the “arrondissements

Cite this article:
Ebikeme C (2012-10-23 00:16:20). Panique au village: the revolution that caused an epidemic. Australian Science. Retrieved: May 19, 2024, from http://australianscience.com.au/health/panique-au-village-the-revolution-that-caused-an-epidemic/
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The tribe that eradicated rinderpest

Charles Ebikeme — Thu, 13 Sep 2012 17:00:21 +0000

Karamoja region in northern Uganda is one of pastoral communities and closely dispersed ethnic groups that rely on livestock for their livelihood. It is within a semi-arid place like this that economies based on meat, milk, and blood from cattle thrive. In communities such as this one, cattle plague will always be the number one fear.

The morbillivirus rinderpest goes by many names — cattle plague in the old english or “loleoo

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The clues to human uniqueness

Charles Ebikeme — Mon, 02 Jul 2012 00:52:17 +0000

Over 2 million years ago, before the emergence of the genus Homo, within the rift valleys and savannah grasslands of Africa during the Pliocene period, a unique event took place. One that, with some hyperbole, admittedly, shaped the course of human evolution. The event was on a molecular scale but had its bearings on what we now call and search for as the “human condition

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