Antimicrobial Oregano Soap

The other day I was given a sample of some lovely (if a little strange) oregano and rose soap. I was rather surprised to be told by the shop assistant that oregano could kill MRSA. It seems I missed this story towards the end of last year about a University of West England project that had received funding to further investigate the potential. The antimicrobial properties are apparently due to a compound called carvacrol. This looks like an interesting line of research, but what about my soap? How much cavracrol do you need to be effective, and how much of it is there in my soap?

I only have access to the abstracts on pubmed, but this study indicates a concentration of 200mg/l had an antimicrobial effect on E. Coli and this study found an antimicrobial effect with carvacrol levels of approximately 1.0%. Wikipedia tell me that carvacrol has a density of 0.9772 g/cm3, so that would make a 1% concentration in the order of 9800 mg/l, or almost 50 times more than the first study. I'm not sure of the details of the studies and how they would affect the concentrations of carvacrol required, but clearly they make a big difference. In lieu of further information, I'll go with the 1% figure for now.

The soap list oregano oil (origanum vulgare) as one of its ingredients, of which carvacrol makes up between 44 and 85% according to this paper. So, it would take roughly 2% of the soap being oregano oil to reach the 1% concentration. You can't tell from the list of ingredients just how much oregano oil is used, but 2% sounds reasonable to me*. I haven't taken into account dilution of the soap in water, but I have taken the conservative figures in the calculations, so I think that it shows that the soap is plausibly acting as an antimicrobial.

*This is definitely a weak spot in my analysis, I have no soap making experience on which to base this statement.

Swine Flu

Reading this blog reminded me that I wanted to look into the real risk of swine flu. What are the chances of catching it? What are the chances of dying from it? Is this all a storm in a teacup?

Typing "swine flu mortality" into Google yields this article (as the first page, no less) that nicely explains the concepts of virulence, case fatality ratio (CFR) and mortality. I'm not a medical expert in any respect, but it does pass my "common sense test", so I will summarise it (although I really recommend that reading it for yourself if you are interested):

• virulence is severity of the disease the virus produces (note that this is related not only to the virus, but also the host. I'm only going to be talking about humans)


• CFR is a measure of virulence - it is the probability of someone who has caught swine flu dying from it


• mortality rate is the percentage of the population that die from swine flu


• it is very difficult to put accurate numbers to these rates

However I have noticed that many places are using mortality rate interchangeably with CFR, but I will try to stick to the definitions above.


World Health Organisation (WHO) figures (via the UK government) as of the 26th June are 59,814 cases worldwide and 263 deaths. This gives a CFR of just over 0.4%. For comparison Wikipedia gives the following figures:

1918 flu pandemic >2.5%
Asian flu <0.1%
Hong Kong flu <0.1%
Seasonal flu <0.05%

So, it looks like swine flu is more deadly than normal seasonal flu, but not nearly as deadly as the 1918 pandemic, once you've caught it. But how easy is it to catch it?

The WHO has declared swine flu to be a phase 6 pandemic, meaning that there is widespread human infection. Their assessment of the pandemic includes:

"H1N1 appears to be more contagious than seasonal influenza. The secondary attack rate of seasonal influenza ranges from 5% to 15%. Current estimates of the secondary attack rate of H1N1 range from 22% to 33%."

So swine flu is easier to catch than normal flu, as well as being more virulent. However is is worth noting that the World Health Organisation FAQ about swine flu "what is level 6?" says that the pandemic is moderate.

The moderate assessment reflects that:

* Most people recover from infection without the need for hospitalization or medical care.
* Overall, national levels of severe illness from influenza A(H1N1) appear similar to levels seen during local seasonal influenza periods, although high levels of disease have occurred in some local areas and institutions.
* Overall, hospitals and health care systems in most countries have been able to cope with the numbers of people seeking care, although some facilities and systems have been stressed in some localities.

Based on the above, I conclude that swine flu is indeed worse than seasonal flu, but not the end of life as we know it that some people fear. Luckily, the recommended precautions are not too onerous:

* cover your mouth and nose when coughing and sneezing, using a tissue
* throw the tissue away quickly and carefully
* wash your hands regularly with soap and water
* clean hard surfaces (like door handles and remote controls) frequently with a normal cleaning product

Homeopathy Awareness Week

The Society of Homeopaths (SOH) has declared this week (14th-21st June) Homeopathy Awareness Week. I have decided to following in the footsteps of the quackometer, zeno, neurologicablog, dcscience and skepticblog (amongst many others, I'm sure) and help to raise awareness of the con that is homeopathy.

Firstly, what is homeopathy?
From the SOH website:

Homeopathy is a system of medicine which is based on treating the individual with highly diluted substances given in mainly tablet form, which triggers the body’s natural system of healing.

The key phrase there is "highly dilute". Common sense tells us that when we dilute something that it gets weaker: think adding a cola to your JD; it doesn't taste as strong and it takes a greater volume to get you drunk than if you left the cola out. Why would we want to dilute the medicine? Luckily, the SOH foresaw that question...

Still from the SOH website:

If they are so dilute, how can they work?
After each dilution the mixture is vigorously agitated in a machine that delivers a calibrated amount of shaking. This is called succussion. It is thought that this process imprints the healing energy of the medicinal substance throughout the body of water (the diluent) as if a message is passed on. The message contains the healing energy. Even in ultra-molecular dilutions, information specific to the original dissolved substance remains and can be detected.

"Succussion"? Just because you make up a word for it, doesn't make it make any sense. Lets hope there was no agitation anyhwere previously (sewage treatment works, anyone) to imprint the water with the wrong sort of energy and pass on that message. If there is, we'll never get rid of it; even diluting it won't work. Given how long the water on earth has been going around the cycle, just imagine what messages it has picked up? It would be a wonder if the message of the healing energy would even be able to be heard over the rest of the messages? And just how does the body hear the message anyway? The SOH don't seem to have foreseen these questions. Oh well, moving on...

So how do the homeopaths pick what medicine to dilute in the first place?

It works on the principle of “like cures like” - that is, a substance that would cause symptoms in a healthy person is used to cure those same symptoms in illness. For example, one remedy which might be used in a person suffering from insomnia is coffea, a remedy made from coffee.

Have another coffee to help me sleep? I think their example speaks for itself: utter nonsense.

Logic and common sense are both failing me here, maybe there is some research to back up their claims. Although lots of studies have been done (just type homeopathy research into google), a meta-analysis of many of these studies conluded:

There is some evidence that homeopathic treatments are more effective than placebo; however, the strength of this evidence is low because of the low methodological quality of the trials. Studies of high methodological quality were more likely to be negative than the lower quality studies. Further high quality studies are needed to confirm these results.

In essence, no, there is no research to back up their claims.

To summarise, homeopathy makes no sense and does not stand up to scientific scrutiny. So please, raise awareness of homeopathy, and perhaps save someone's time, money and health from this sorry excuse for healthcare product.

Science Geekette now on Twitter

All the cool kids are doing it...

Actually I really am getting into twitter. You can follow me here: http://twitter.com/supergeekette

In the process of adding people and feeds to follow, I have really dicovered just how many good bloggers there are out there. I am quite in awe, and although this is my first venture out of my safe little corner of the internet, I hope that I will be able to make my own valuable contribution. It might take a while for me to be get the hang of it, but if I don't try, I'll never get there.

So, please follow me!! And as always, any constructive and friendly comments and advice are not just welcome, but sought after!

Girls aren't even enrolling in Engineering!

I was reading over at http://www.nerdgirlarmy.com that women accounted for only 12.7% of enrollments in engineering in Australia in 2007. The proportion of girls doing engineering has been dropping for several years now and this really worries me!

As a professional engineer, I can regale you with difficulties I have faced. But in the long run, I have clearly not found anything insurmountable, as I'm still working as an engineer.

I can (and do) extoll the virtues of engineering to friends, family, strangers on the street and, most importantly, school students. But despite many such initiatives, we seem to be going backwards. I am starting to think that we haven't defined the problem properly and until we do all our solutions are going to be ineffective.

The real question isn't "why did I choose engineering?" but "why DIDN'T girls choose it?". Of course, how we go about answering that question is a problem of it's own. (But I for one haven't given up)