SciBlogs

Homeopathy Awareness Week Siouxsie Wiles Apr 14

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April 10th-16th is World Homeopathy Awareness week, organised by the World Homeopathy Awareness Organisation. April 10th is the birthday of the originator of homeopathy, Samuel Hahnemann. In case you need reminding what homeopathy is, it is based on Hahnemann’s bizarre doctrine that substances which cause disease symptoms in healthy people will cure similar symptoms in sick people, but only if they have been diluted to such a degree that there is unlikely to be a single molecule of the substance left in the preparation. Oh, and while being diluted, the solution has to be beaten against a bible. In other words, homeopathy is magic water.

This year the focus is on men’s health and I found an interesting presentation on the website of the New Zealand Council of Homeopaths which seems to be suggesting that homeopathy can be used to treat erectile dysfunction, heart-related issues and hypertension. It is just as well then that the Australian National Health and Medical Research Council (NHMRC) has recently released a draft paper which provides a plain language summary of their assessment of the evidence for homeopathy to treat 68 health conditions. NHMRC’s conclusion?

“There is no reliable evidence that homeopathy is effective”.

You can see why they reached that conclusion when you peruse the list of scientifically controlled double blind studies which have conclusively demonstrated the efficacy of homeopathy.

I’ll leave you with this wonderful piece on homeopathy by comedians David Mitchell and Robert Webb, which I will never tire of watching. And please, in the last few days of this year’s Homeopathy Awareness Week, do your little bit to raise awareness of the fact that homeopathy is nonsense by sharing this post with your friends and family.

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Monday Micro – Bioluminescent bacteria photobooth Siouxsie Wiles Apr 14

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For those curious how our bioluminescent photo booth went at Auckland’s Museum of Transport and Technology (MOTAT) recently, the results are up on Flickr. As a quick reminder, the light being used to illuminate the subjects was being supplied by glowing bacteria growing on large petri dishes. We used a 6 second exposure to take the pictures which has led to some interesting photos. Going by the number of blurry faces, I think it’s safe to say that most children can’t sit still for that long! Take a look and see if you recognise anyone. Here’s my favourite:

Jimmy

Science Street Fair Siouxsie Wiles Apr 02

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Want your picture taken by the glow of bioluminescent bacteria? Then come along to Auckland’s inaugural Science Street Fair this weekend!

Those in Auckland this weekend should come along to MOTAT on Sunday for the inaugural Science Street Fair. They’ll be a whole heap of science on display, including a hovercraft, 3D printing, DNA extractions and many more. They’ll also be plenty of scientists around so if you’ve any burning science questions then pop along to the ‘Ask the Scientist’ tent. I’ll be there with the glowing squid Rebecca Klee and I made for Art in the Dark last year, and Danny Dillon will be 3D printing a squid too. I’m also hoping to have a bioluminescent photo booth so come along and have your photo taken by the light of glowing bacteria. Here’s one I made earlier :)

By the light of the glowing bacteria...

By the light of the glowing bacteria…

science street fair

April’s Fool or just plain Fool? Siouxsie Wiles Apr 01

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The number of people who have died in Guinea from Ebola virus infection is now at 78, and Médecins sans Frontières says the country faces an unprecedented epidemic. Two sisters have died in neighbouring Liberia, one of whom had recently returned from Guinea, and Senegal has closed its borders with the west African country.

Despite there being no treatment or vaccine against this highly lethal virus, according to Joette Calabrese there is hope. “Fortunately for us, homeopathy has great renown for its healing ability in epidemics” she tells us.

In her blog post “Bioterrorism and Epidemics: Knowing Homeopathy Can Help Make the World a Less Scary Place” she writes: “The symptoms of Ebola and other hemorrhagic fevers resemble those of malaria, dengue fever, yellow fever and viral hepatitis. In homeopathy, remedies are often chosen based on the symptom picture, so the remedies most often used for Ebola will be the same as for these other diseases.” She goes on to list six homeopathic remedies which she says should be given every hour “…but as the severity of the symptoms decrease, frequency is reduced. If no improvement is seen after 6 doses, a new remedy ought to be considered”.

Reading Joette’s post on April 1st, I thought this must surely be a joke. But it seems not.

I’ll leave you with another useful product (AKA should be an April Fool’s gag), for those who are feeling a little run down and worried your diet might be lacking these core ingredients. One tablet daily is all you need, apparently.

Hat/tip to @zeno001, @cammerschooner and @nccomfort on twitter for these gems.

dna

Monday Micro – First documented cases of cat to human transmission of TB Siouxsie Wiles Mar 31

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A paper just published in the Veterinary Journal documents the first cases of transmission of Mycobacterium bovis* (the bacterium responsible for TB in cattle and many other species) to humans (1). Before anyone get’s into a panic, it was a year ago.

Alas, the article is behind a paywall, but according to the free abstract a vet practice in Newbury, in the UK, diagnosed nine domestic moggies with M. bovis infection between December 2012 and March 2013. The nine cats ‘belonged’ to different households** and six of them resided within a 250 metre radius. The animals presented with varying symptoms and severity and 6 were euthanased or died, while the three surviving animals were responding well to treatment. At the time of the article, no new cases had been detected in local cats since March 2013.

As people can become infected with M. bovis, Public Health England offered to screen 39 people identified as having come into contact with the infected moggies. 24 people accepted their offer; 2 people were found to have active M. bovis TB (this means they would be infectious), while another 2 people were found to be latently infected (and therefore not infectious). All are reported to be responding to treatment.

Molecular analysis has shown that the M. bovis isolated from the infected cats and people with active TB infection were indistinguishable, indicating transmission of the bacterium from an infected. The same strain has also been found in cattle from nearby herds, although according to Professor Noel Smith, Head of the Bovine TB Genotyping Group at the UK Animal Health and Veterinary Laboratories Agency, the cats are unlikely to have caught if directly from the cattle but from infected wildlife. He probably means badgers.

If you are curious how often cats are diagnosed with bovine TB in the UK, the Department for Environment, Food and Rural Affairs (DEFRA) have put up a spreadsheet with data going back to 1997 (the data for 2013 is provisionally as it only covers up to September). As you can see from the graph below, 2013 was far from the highest year. That honour goes to 2009 with 26 cases.

TB cats

It’s not just cats that have been diagnosed with M. bovis though. Pet dogs, pigs and even a few ferrets have had TB.

TB domestic

To put all these numbers in perspective, according to DEFRA the number of cattle compulsorily slaughtered in 2013 alone because they tested positive for M. bovis, or are direct contacts of positive animals, was 32,620. So the cats are really just a drop in the ocean. What this case does show though is just how versatile M. bovis is when it comes to picking a host. It also shows that we share our microbes with our pets, for better and worse.

And finally, an update on last week’s Monday Micro, the current Ebola outbreak in west Africa. The strain of Ebola responsible is Zaire, the strain most frequently associated with outbreaks and the one with the highest mortality. So far the total number of suspected and confirmed cases in Guinea has increased to 103, with 66 deaths, a mortality rate of 64%. Both Sierra Leone and Liberia have now alerted the WHO of suspected cases and deaths consistent with Ebola infection among people who have recently traveled to Guinea. The numbers for Liberia are 8 suspected cases, including 6 deaths, while for Sierra Leone it is 6 suspected cases, including 5 deaths.

Reference:
1. Gibbens N (2014). Mycobacterium bovis infection in cats. Veterinary Record 174:331-332 doi:10.1136/vr.g2344

*As an aside, the TB vaccine, commonly referred to as Bacille de Calmette et Guérin or BCG, is derived from a strain of M. bovis that was cultured in a laboratory for many years until it had lost some crucial genes that it needs to cause disease.

**Any cat owner will tell you its more like the other way around….

Monday Micro – Ebola outbreak in Guinea Siouxsie Wiles Mar 24

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The news is full of reports of an outbreak of Ebola in the west African country of Guinea. Ebola is one of a group of related viruses which cause viral haemorrhagic fever. There is no vaccine or treatment for these viruses. So far reports are that there have been at least 80 cases with 59 deaths.

Here’s a little FAQ for those of you wanting to know more about these amazing and terrifying viruses.

1. What is Ebola?

Ebola is one of two members of the Filoviridae family of single-stranded RNA viruses. The other member is Marburg. There are five types of Ebola virus, named after where outbreaks first appeared, and which differ in their mortality rates:
(i) Zaire ebolavirus (ZEBOV) – most frequent cause of outbreaks (last in the Democratic Republic of Congo 2008) and highest mortality rate (47-100%)
(ii) Sudan ebolavirus (SEBOV) – mortality rate of 42-65%, last outbreak in 2012 in Uganda
(iii) Reston ebolavirus (REBOV) – Discovered in 1989 when there was an outbreak of disease in laboratory macaques in Reston, Virginia, USA. Has since been found in nonhuman primates in Pennsylvania, Texas and Italy. Did not cause disease in exposed human laboratory workers*
(iv) Côte d’Ivoire ebolavirus (CIEBOV) (or Tai ebolavirus) – killed chimpanzees in Tai national park in 1994, only human case was in one of the scientists performing the necropsies on the infected chimps but they recovered
(v) Bundibugyo ebolavirus – two outbreaks to date (2007 in Uganda and 2012 in the Democratic Republic of Congo), mortality rate of 34-50%

2. How is Ebola transmitted?

The primary mode of transmission of Ebola is unknown. Bats are thought to be the most likely reservoir (1). Some people have caught Ebola from contact with or by eating infected bushmeat. Secondary spread occurs through direct contact with infected patients, their body fluids or remains, so family members, hospital workers and those burying the dead are at greatest risk. The incubation period for infection ranges from 2 to 21 days (mean 4-9 days).

An interesting paper was published in the journal Scientific Reports in 2012 in which piglets were inoculated oronasally with Zaire ebolavirus (2). The piglets had a high temperature and rapid breathing for a few days but soon recovered. But they were infectious, spreading the virus through the air to macaques who developed symptoms of Ebola infection and had to be euthanised.

3. What’s the largest recorded Ebola outbreak?

The biggest outbreak to date was in Uganda in 2000, when 425 people were infected with Sudan ebolavirus – 224 died. Ebola is a little like the great white shark of the virus world. Before this current outbreak, there had only been 2317 clinical cases and 1671 confirmed deaths in the last 50 years (3), a negligible number compared to many other infectious diseases.

4. Do people with viral haemmorrhagic fever really bleed out of every orifice before they die?

The name viral haemorrhagic fever is a bit of a misnomer. In less than 10% of Ebola cases, patients will experience bleeding from their mucous membranes, including those in the nose, gums, gastrointestinal tract and vagina. Death occurs by multiple organ failure. Most frequently infected people will have a fever with chills, malaise, joint and muscle pain. They also may have a rash. Other symptoms include nausea, diarrhoea, vomiting, stomach pains, throat and chest pain, a cough. From there patients experience severe headaches and confusion which can progress to delirium and coma.

5. Why is this such a big story?

With the exception of the dead chimps and the scientist who recovered in the Ivory Coast, Ebola has never been reported from west Africa; the majority of outbreaks have been in central Africa. What has alarmed many is that the cases have moved from forest communities to the capital city, Conakry. The capital has a port and airports and, with an estimated population of 2 million, will be difficult to quarantine should the need arise.

6. Can survivors continue to shed virus?

Yes. Survivors from an outbreak in 1995 in the Democratic Republic of the Congo which killed 244 of the 315 people infected, were followed for several months afterwards. Researchers tested their tears, sweat, faeces, urine, saliva, semen, and vaginal secretions. For semen, 4 of the 5 convalescents tested had at least 1 specimen that tested positive for Ebola genetic material. The latest semen sample was obtained over 3 months after the onset of infection (4). There were no cases of transmission from those individuals with positive semen samples.

* Go read Richard Preston’s book The Hot Zone, which is all about the outbreak in Reston.

Reference:
1. Leroy EM, Kumulungui B, Pourrut X, Rouquet P, Hassanin A, Yaba P, Délicat A, Paweska JT, Gonzalez JP, Swanepoel R (2005). Fruit bats as reservoirs of Ebola virus. Nature. 2005 Dec 1;438(7068):575-6.
2. Weingartl HM, Embury-Hyatt C, Nfon C, Leung A, Smith G, Kobinger G (2012). Transmission of Ebola virus from pigs to non-human primates. Sci Rep. 2012;2:811. doi: 10.1038/srep00811. Epub 2012 Nov 15.
3. Leroy EM, Gonzalez JP, Baize S (2011) Clin Microbiol Infect. 17(7):964-76. doi: 10.1111/j.1469-0691.2011.03535.x
4. Rowe A1, Bertolli J, Khan AS, Mukunu R, Muyembe-Tamfum JJ, Bressler D, Williams AJ, Peters CJ, Rodriguez L, Feldmann H, Nichol ST, Rollin PE, Ksiazek TG (1999). Clinical, virologic, and immunologic follow-up of convalescent Ebola hemorrhagic fever patients and their household contacts, Kikwit, Democratic Republic of the Congo. Commission de Lutte contre les Epidémies à Kikwit. J Infect Dis. 1999 Feb;179 Suppl 1:S28-35.

Monday Micro – Semen and the twitchy clap Siouxsie Wiles Mar 10

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Neisseria gonorrhoeae is the bacterium responsible for the sexually transmitted infection gonorrhoea, also known as the clap. Symptoms often include pain when peeing and a nasty discharge from your nether regions, although some people can be asymptomatic. The microbe isn’t hugely fussy about where it causes an infection, so you can also get gonorrhoea of the throat and anus if that’s where the bacteria are deposited.

Despite the fact that gonorrhoea can be prevented by using condoms, there are apparently more than 100 million estimated new cases worldwide each year. Unfortunately N. gonorrhoeae is becoming increasingly resistant to antibiotics, so researchers are trying to find out more about how the microbe is transmitted and exactly how it causes infection to develop new strategies to combat it.

Mark Anderson and colleagues have just published a paper in the open access journal mBio showing that various proteins in the fluid of semen makes N. gonorrhoeae mobile, through a mechanism called twitching motility. This is where the bacterium rapidly extends and retracts hairlike appendages found on its surface to make it move. The researchers also found that N. gonorrhoeae forms little microcolonies when exposed to seminal proteins, making it stick better to human cells. This work shows that the semen environment changes the bacterium to prime it for transmission between people.

In case you need an incentive to use a condom, here’s a movie of twitching motility in action, for another bacterium called Pseudomonas aeruginosa. So guys, you could have those little critters twitching around in your semen. Seriously. If you ever have a discharge, go see a doctor.

YouTube Preview Image

Reference:

Anderson MT, Dewenter L, Maier B, Seifert HS. 2014. Seminal plasma initiates a Neisseria gonorrhoeae transmission state. mBio 5(2):e01004-13. doi:10.1128/mBio.01004-13.

Where do all the women go – revisited Siouxsie Wiles Mar 08

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I’ve had a go at making my first infographic, of the data from the mBio paper about women speakers at American Society of Microbiology meetings (1). I used Piktochart.

Picture below and interactive version on the web here. Let me know what you think.

TechWoman

Reference:
1. Casadevall A, Handelsman J. 2014. The presence of female conveners correlates with a higher proportion of female speakers at scientific symposia. mBio 5(1):e00846-13. doi:10.1128/mBio.00846-13

Where do all the women go? Siouxsie Wiles Mar 06

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This weekend is International Women’s Day and the theme this year is Inspiring Change.

According to the UNESCO Institute for Statistics, just 30% of science researchers are women. They have produced a nifty tool to see where those women work and in what fields.

UNESCO - Women In Science Interactive

For NZ, the tool says that 59% of Bachelors students are female, 51% of Doctoral students and 52% of researchers. Interestingly, when the researchers are broken down by sector, a whopping 67% of academic researchers are female, while only 25% of those in the public sector and 16% in the private sector are female. As I’m in academia, I’d really like to see the breakdown for faculty positions, as its my impression that there are much fewer women the higher up the academic food chain you go.

One of the many reasons put forward for this is that more men than women are invited to speak at academic meetings and that invitations like these are of great importance for academic advancement. So its interesting to see some data on this from Arturo Casadevall & Jo Handelsman. They have just published a paper in the open access journal mBio looking at the numbers of male and females speakers at American Society for Microbiology meetings.

Here are some of their findings from analysis of 216 sessions from 3 general meetings held in 2011, 2012, and 2013:
1. 104 sessions were convened by male-only convener teams
2. 112 sessions had at least one female in the convener team.
3. In sessions convened by all men, invited female speakers averaged 25%.
4. In sessions in which the convener team included at least one woman, woman speakers averaged 43%.

Inclusion of at least one woman among the conveners increased the proportion of female speakers by 72% compared with those convened by men alone.

Something to think about the next time you organise a seminar series or meeting.

Reference:
Casadevall A, Handelsman J. 2014. The presence of female conveners correlates with a higher proportion of female speakers at scientific symposia. mBio 5(1):e00846-13. doi:10.1128/mBio.00846-13

Monday Micro – mummies and ‘kissing bugs’ Siouxsie Wiles Mar 03

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The mysterious mummy in the Bavarian State Archaeological Collection

The mysterious mummy in the Bavarian State Archaeological Collection

For over 100 years, the Bavarian State Archeological Collection in Munich, Germany, has housed an unidentified mummy. No records remained of the mummy. Where had it come from? Who was it? How had the person died? Thanks to science, know we know.

To better understand the origin and life history of the mysterious mummy, researchers examined the skeleton, organs, and ancient DNA using a range of techniques, including CT scans, isotope analysis, and tissue histology. They have just published their findings in the open access journal PLOS One.

So what did the researchers find? By radiocarbon dating, the mummy originates between 1450 and 1640 AD, and examination of the skeleton suggests its of a female, likely to have been 20-25 years old at the time of her death. Analysis of fibres taken from her hair bands suggest they came from a South American llama or alpaca, while isotope analysis of nitrogen and carbon in her hair reveal she lived on a diet of maize and seafood. This and other evidence suggests a life spent in coastal Peru or Chile.

The mummy also showed significant thickening of the heart, intestines, and the rectum, features typically associated with chronic Chagas disease. Chagas disease is a tropical parasitic infection, caused by Trypanosoma cruzi and spread mostly by biting insects known as Triatominae. During the day, these triatomines hide in crevices in the walls and roofs, emerging at night to feed on sleeping inhabitants. Because they tend to feed on people’s faces, triatomine bugs are also known as “kissing bugs”. After they bite and ingest blood, they defecate on their ‘victim’. The parasites are transmitted in the faeces left near the site of the bite wound, which are transferred into the wound when scratched. The researchers found parasites in rectum tissue samples taken from the mummy which were positive for T. cruzi DNA.

But it wasn’t Chagas disease that killed the young lady. Analysis of her skull suggests she suffered a massive blunt force trauma to the centre of her face prior to her death, leading the researchers to speculate that she may have been the victim of a ritual homicide.

Reference:
Panzer S, Peschel O, Haas-Gebhard B, Bachmeier BE, Pusch CM, et al. (2014) Reconstructing the Life of an Unknown (ca. 500 Years-Old South American Inca) Mummy – Multidisciplinary Study of a Peruvian Inca Mummy Suggests Severe Chagas Disease and Ritual Homicide. PLoS ONE 9(2): e89528. doi:10.1371/journal.pone.0089528

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