World Leprosy Day 2015

World Leprosy Day 2015Leprosy is among the oldest human-specific infections we currently know about. The common ancestor of the two modern bacterial species that cause leprosy, Mycobacterium leprae and M. lepromatosis, is thought to have become a parasite in early humans millions of years ago. This makes it far older than our own species, Homo sapiens. Nevertheless, leprosy continues to afflict hundreds of thousands of people every year.

World Leprosy Day raises awareness of the suffering caused by the disease. It remains endemic in India, where more than half of all worldwide cases occur, and in parts of South East Asia and Africa. World Leprosy Day is observed on the last Sunday of January to coincide with the anniversary of the assassination of Mahatma Gandhi, a vocal supporter of the fight against leprosy.

What is leprosy?
Leprosy is a chronic bacterial infection caused by two members of the genus Mycobacteria. It is usually thought to be transmitted between people via droplets when people breathe or cough, although armadillos may also play a role in transmitting the disease to humans.

Despite its continued prevalence, leprosy is actually one of the least infectious diseases we know. Globally, only about 5% of people are actually susceptible to leprosy due to a malfunction in the gene responsible for conferring immunity; the rest of the human population is immune. Furthermore, of the clinical cases that do occur, some 85% are non-infectious.

The number of new leprosy cases – roughly 200,000 a year – is all the more remarkable given the low risk of acquiring and transmitting the disease.

Symptoms
Since M. leprae and M. lepromatosis reproduce very slowly, the incubation time of leprosy can be up to five years. Symptoms may not appear for as long as 20 years, so the disease is rarely diagnosed in its early stages. When symptoms do appear, they include growths and discoloured lesions on the skin, and eye problems that can lead to blindness. The mucosal layers of the respiratory tract are also affected, leading to nosebleeds and breathing difficulties.

If it is not treated, leprosy can cause permanent damage to nerves and muscle paralysis in the extremities and face. Patients’ ability to sweat and feel pain is impaired, and injuries are common as a result. This can lead to the characteristic loss of fingers and whole limbs in many people who have leprosy.

Treatment
In the 1940s, a drug called Dapsone was developed which stalled the disease and, if taken over many years, could cure it. However, the length of time required for treatment meant that patients could rarely take it consistently and for long enough. Furthermore, Dapsone-resistant strains of M. leprae began to appear soon after the introduction of the drug.

In the 1960s, two other drugs – rifampicin and clofazimine – were added to the drug combination  used to treat leprosy, which became known as multi-drug treatment (MDT). MDT is effective in treating the disease and has been made available for free around the world since 1995.

Leprosy was technically eliminated on a global scale in 2000. This means that less than 1 case occurs per 10,000 people worldwide. However, the disease is still endemic in a number of countries, so the fight to completely eradicate it is not over.

With free MDT treatment available around the world, the most important measure to eliminate leprosy is to raise awareness of the disease and to remove the stigma associated with it. “Leper colonies” still exist in many areas where the disease is endemic, cutting infected people off from their families and support networks. Educating the population on leprosy, maintaining a regular supply of free MDT doses even in remote regions and monitoring the progress of elimination programmes are all crucial in ensuring that leprosy can soon become a thing of the past.

For further information, please see our article on Leprosy in the August 2014 edition of our quarterly magazine, Microbiology Today.

Jon Fuhrmann

Image credit: Erik Törner on Flickr under CC BY-NC-SA 2.0.
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Crimean-Congo Haemorrhagic Fever: A Phantom Menace

ResearchBlogging.orgA tick Hyalomma marginatum on human skin.Viral haemorrhagic fevers are a poorly understood group of diseases, but they have entered the public consciousness in unprecedented fashion due to the Ebola outbreak in West Africa. The viruses that cause these diseases are transmitted by a range of vectors that can include primates, rodents and insects. They rely on these animals to survive and don’t always pose a risk to them; however, the viruses cause disease when they infect humans. A team of researchers at Public Health England’s Porton Down laboratories have now studied the Crimean-Congo Haemorrhagic Fever virus (CCHF) and developed a new vaccine against the disease, which infects up to 1,500 people each year and kills between 10-40% of them. We spoke to lead author Dr Karen Buttigieg to find out how they did it.

CCHF: a brief introduction
Like many viruses, Crimean-Congo Haemorrhagic Fever, or CCHF, is named after the place – or, in this case, places – it was first discovered. The virus was first identified by Soviet scientists in 1944 and provisionally named Crimea virus, although they could not isolate the virus to formally describe it until June 1967. However, four months earlier, a virus called Congo virus had been officially described in the East African Medical Journal – and the two turned out to be identical. Because the Congo virus discovery was published first, the International Committee on Taxonomy of Viruses proposed the name Congo-Crimean Haemorrhagic Fever virus. However, Soviet authorities insisted on the Crimean-Congo nomenclature and as a result of the extreme tensions of the cold war at the time, this variant of the name was adopted. This remains one of only a handful of virus name changes as a result of political pressure.

The CCHF virus is transmitted to humans predominantly through bites from ticks of the Hyalomma and Haemaphysalis genera, which also bite animals such as cattle and ostriches. The blood and bodily fluids of infected people are also infectious, so transmission of the virus in hospitals is possible.

Like most viral haemorrhagic fevers – including Ebola – CCHF’s early symptoms are not particularly dramatic or specific and include a fever, vomiting, rashes and aching joints. However, these symptoms escalate to generalised haemorrhaging quite quickly, usually within just five days of the first observation of symptoms. Within a day or two of the onset of bleeding, patients will generally either start to get better or succumb to the virus. On average, between 10-40% of patients die of the disease, a lower figure than for Ebola.

Why do we need a vaccine?
CCHF is endemic in parts of Africa, Asia and the Middle East, but particularly in parts of Eastern Europe. Its range is mostly limited by the habitats of the ticks that spread the disease, but these habitats are likely to expand into the rest of Europe as a result of future climatic change. For now, the presence of the virus in areas frequently visited by tourists could be a cause of concern; for example, 1,300 CCHF cases and 62 fatalities were recorded in Turkey in 2009, and the first case in Greece was recorded in 2008. From these areas, the disease could be imported to the UK on flights.

Indeed, a CCHF case was imported to the UK just two years ago. A man took ill while flying to Glasgow from Kabul in Afghanistan and was eventually transferred to the Royal Free Hospital in London, where he succumbed to the disease in the hospital’s isolation ward.

Dr Buttigieg notes that war zones are areas particularly at risk of increased transmission and spread of CCHF. Livestock and pets can be rare in such areas, meaning that a higher proportion of mammals are likely to be humans. Under these circumstances, the ticks carrying the CCHF virus are more likely to bite humans and transmit the virus to them.

Developing a vaccine
An experimental vaccine against CCHF was developed in 1974 in Bulgaria, where the disease remains endemic. This vaccine consists of live CCHF viruses inactivated with chloroform and injected into mouse brains. The brains are subsequently crushed using a mortar and pestle, and the resulting solution is absorbed into aluminium hydroxide before being administered to patients. While this vaccine shows some efficacy and is still used in Bulgaria for at-risk population groups, a lack of clinical studies and its crude production process mean that it has never received regulatory approval in the EU or the USA.

Dr Buttigieg and her colleagues used a more elegant approach to produce a vaccine. Initially, the team considered using the Hazara virus, the virus most closely related to CCHF virus, to produce a vaccine. The Hazara virus causes a disease similar to CCHF in mice, but it is not known to be harmful to humans. This means that the stringent precautions required for working with CCHF – known as Biosafety Level 4 (BSL-4) – are not needed. However, we simply do not know whether Hazara virus-based vaccine might mutate or undergo changes in the presence of CCHF that could make it dangerous to humans. This means that the Hazara virus is unsuitable for vaccine development.

While the Hazara virus cannot be used for vaccines itself, it has nevertheless proven useful because it has allowed laboratories with lower biosafety levels to investigate potential avenues for CCHF vaccine development. This has left the BSL-4 facilities free to prioritise the most promising projects and trial them with the actual CCHF virus – and also to respond to emergencies such as the current West African Ebola outbreak.

Dr Buttigieg and her team at Porton Down used a smallpox vaccine known as MVA to create their CCHF vaccine. Since smallpox was eradicated worldwide in the 1980s, the substance itself has become obsolete. MVA is based on a live virus that is a distant relative of smallpox, but it cannot cause disease because most of its genetic material is lost in the process of vaccine production. The researchers adapted MVA to deliver proteins found on the surface of the CCHF virus into the body. These proteins are harmless on their own and allow the immune system to learn to defend the body against the CCHF virus without being exposed to the virus itself.

Next steps
The human immune system produces two different types of immunity called antibodies and immune cells, respectively, which Dr Buttigieg describes as “separate but complementary arms of the immune system”. While the new vaccine protected 100% of the animals that received it from the CCHF virus, she says that her team are not yet sure whether it encourages the production of antibodies or immune cells.

This is a crucial question to answer before the vaccine can move on to the human clinical trial stage. The mice the vaccine was tested could simply be infected with CCHF to see whether the vaccine worked – clearly this is not an option in human trials. In humans, scientists will have to investigate whether the immune system has produced appropriate immunity to protect the body from CCHF – and to do so, they will have to know what immune response to look for.

The new Crimean-Congo Haemorrhagic Fever vaccine developed at Porton Down has shown great promise in preventing a disease that has the potential of spreading and infecting growing numbers of people. Until it is approved for human use, however, it is important for people in areas where CCHF is endemic to protect themselves in the old-fashioned way. Avoiding getting bitten by ticks by wearing long clothing and ankle protection is the simplest way to do so, although high-power insect repellents using DEET also help.

Dr Buttigieg and her colleagues also verified that MVA, the smallpox vaccine that forms the basis of the new CCHF vaccine, could also be adapted to provide protection against a range of other diseases. A previously obsolete vaccine may therefore yet be put to good use in humanity’s ongoing fight against dangerous diseases worldwide.

Jon Fuhrmann

Buttigieg, K., Dowall, S., Findlay-Wilson, S., Miloszewska, A., Rayner, E., Hewson, R., & Carroll, M. (2014). A Novel Vaccine against Crimean-Congo Haemorrhagic Fever Protects 100% of Animals against Lethal Challenge in a Mouse Model PLoS ONE, 9 (3) DOI: 10.1371/journal.pone.0091516

Image credit: Hennie Cuper on Flickr under CC BY-NC 2.0.
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To the batcave! Scientists hunting white-nose syndrome clues discover new bacteria

ResearchBlogging.orgBat with white-nose syndromeResearchers from the Czech Republic recently had a lucky break when they discovered not one but two new species of bacteria in bats that were emerging from hibernation in the Jeseníky Mountains in the north of the country. The discoveries were fortuitous coincidence, as the team were not specifically looking for new species of bacteria. As Dr Paula Garcia-Fraile, lead author of the paper describing the new species in the International Journal for Systematic and Evolutionary Microbiology, told Microbe Post, the main aim was to isolate strains of the fungus Pseudogymnoascus destructans.

P. destructans causes white-nose syndrome, a disease that has decimated the populations of numerous bat species across North America in recent years. While the fungus is associated only with diseased bats in America, both healthy and diseased bats in Europe were found to carry the fungus. The likely explanation is that European bats have developed some immunity to the fungus over time, and that it is now wreaking havoc with American bats which have not been exposed to it before. The researchers are keen to understand how P. destructans interacts with other microbes in bats and how this may affect the occurrence and fatality of white-nose syndrome. Continue reading

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New to Science: January 2015 Edition

Peach Tree: New to Science in MicrobiologyEach month, the Society for General Microbiology publishes the International Journal of Systematic and Evolutionary Microbiology, which details newly discovered species of bacteria, fungi and protists. Here are a few of the new species that have been discovered, and the places they’ve been found. The full papers are available to journal subscribers, but the abstracts are free to read.

A warm welcome to the first 2015 edition of New to Science. We hope you have had an enjoyable and restful holiday season and are settling back into the working rhythm well. Many people, after all, seem a little shell-shocked when they return to the office after a few weeks of relaxation and indulgence.

In this respect, we are not entirely unlike hibernating animals who return into the open, bleary-eyed after spending the coldest period of the year conserving as much energy as possible. A group of Czech researchers took advantage of this behaviour and studied bats as they emerged from hibernation in caves. They discovered two new bacterial species, Serratia myotis and S. vespertilionis, while looking for causes of the deadly white-nose syndrome which has devastated bat populations in North America.

While many people avoid too much food after their Christmas excesses, microbiologists continue to study a remarkable variety of food items in their search for new microbial species. But it is not just food itself that harbours life: scientists from Cornell University investigated American seafood and dairy processing facilities and discovered two new species of Listeria bacteria. While the researchers only specified that the bacteria were discovered in “the northeastern USA”, the latin name of one of the species – L. newyorkensis – rather gives it away. The other bacterium is named L. booriae. Continue reading

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Should we curb our appetite for beef?

ResearchBlogging.orgPolyomaviruses in beef: virology of new virusesIn 2012, Nobel Prize winner Harald zur Hausen noted the volume of research suggesting a causal link between beef consumption and colorectal cancer. This disease predominantly occurs in high-income countries where Western-style diets incorporate large amounts of red meat. Meanwhile, colon cancer is almost completely absent in India, where beef is largely avoided for religious reasons. Japan and Korea only began importing significant amounts of beef after World War II and the Korean War, at which point a significant increase in colon cancer rates occurred.

On the other hand, other studies have found that the risk of colon cancer is actually slightly higher for vegetarians than those of us who eat meat. What, then, is the secret behind the relationship between beef and the third most common type of cancer in the UK? We spoke to Dr Christopher Buck from the US National Institutes of Health in Bethesda, Maryland to find out more.

Despite his self-professed love for a good steak – as he says, “I’m 5% Neanderthal…I swear it’s in my genes, this love for large ruminants” – Dr Buck is leading studies to understand how consuming beef might be harmful to us. His research focuses on polyomaviruses, a group of small, DNA-based viruses that infect a range of animals. Some polyomaviruses, such as raccoon polyomavirus and the recently discovered Merkel Cell Polyomavirus, which infects humans, are known to cause cancer in their native hosts. Continue reading

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Best of the blog 2014

PodiumIt’s almost time for us to say goodbye to 2014 and wave a big hello to 2015. Before we do, it seems like the right moment to reflect on the amazing year we’ve had here on Microbe Post. I hope you’ve enjoyed reading the articles and listening to the podcasts and are as excited as we are for next year – it’s going to be a big one for us!

Before we disappear off for our Christmas holidays, I thought I’d round up the ten most popular new blog posts we had this year, based upon their page views.

So, in classic reverse order:

10. A mind-altering microbe?

This post, taken from the series we wrote for our Annual Conference, saw Ruth Paget interview Professor Joanne Webster, from Imperial College London. Professor Webster explained how Toxoplasma gondii, a parasite commonly found in cats, might have an important role in human behavioural change and mental illness.

9. Funders focus on lack of microbiology skills

In March, UK research leaders – including Professor Sir John Savill, Chief Executive of the Medical Research Council, and Professor Jeremy Farrar, Director of the Wellcome Trust – presented evidence to Parliamentarians and civil servants during the House of Commons Select Committee hearing on antimicrobial resistance. We went along to hear what they had to say.

8. Opinion: The Longitude Prize and antibiotic research funding

The Longitude prize is now open, offering a prize of £10 million to anyone who can develop a rapid diagnostic kit that will help clinicians distinguish between bacterial and viral infections. Our Chief Executive, Dr Peter Cotgreave, gave us his thoughts on the prize shortly after it was announced.

7. 86th Anniversary of Fleming’s Discovery of Penicillin, the first antibiotic

An 86th anniversary is a bit of an odd one to mark, but we love Sir Alexander and his discovery of penicillin is simply too important not to remind people about. Jon Fuhrmann told us some more about the man and the history of the first antibiotic.

6. Chief Medical Officer names new programmes for antimicrobial research

Another story from the House of Commons Select Committee hearing on antimicrobial resistance saw us report the announcement of two new government programmes intended to coordinate antimicrobial research by Professor Dame Sally Davies – the Government’s Chief Medical Officer.

5. Nitrososphaera viennensis: a new species, genus, family, order and class of soil-dwelling archaea

In August, we reported on the discovery a new species of archaea, isolated from garden soil in Vienna. Not only is Nitrososphaera viennensis a new species, it is also the first member of the new genus Nitrososphaera.

4. Cold comfort

Winter ‘tis the season when many of us will experience the ‘joys’ of a rotten cold. During our Annual Conference, I spoke to Professor Ron Eccles from Cardiff University’s Common Cold Centre, to find out how the common cold causes our body to do some seriously weird things. Ever wondered why your nostrils block up one at time during a cold? Wonder no longer…

3. The microbial mystery at the Hungarian power plant

This is probably my favourite blog title of the year. Staff at a Hungarian power plant were confused as to what was contaminating the plant’s ultrapure water purification system. After eliminating the possibility of physical and chemical contaminants, the staff turned to Dr Erika Tóth, of Eötvös Loránd University in Budapest, who, along with her colleagues, isolated three new species of bacteria, living in the water.

2. Learning more about the Chikungunya virus

Chikungunya is a strange virus whose name means “that which bends up” in the language of the Makonde people of Tanzania and Malawi. Chikungunya is transmitted by the tiger mosquito and has seen several large-scale outbreaks in the Caribbean this year. We found out about the disease and the research that is going on to better understand it.

1. Ebola in West Africa

It can come as no surprise that our story about Ebola, written earlier in the outbreak, is the most read of 2014. We spoke to Dr Derek Gatherer, a bioinformaticist at Lancaster University who documented the data from the first six months of the outbreak. In the article, we also explained what the Ebola virus is, and about efforts to control the virus.

A huge thank you from all of us here at the Society for General Microbiology for reading our posts. We’ve already got lots of great ones planned for next year, so join us back here then! In the meantime, don’t forget to subscribe to our podcast (you can do it on iTunes, Soundcloud or Stitcher) and follow us on Twitter.

Merry Christmas and a Happy New Year to you all!

Benjamin Thompson

Image credit: Thinkstock
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Microbe Talk: December 2014

Native ScientistIn a special, end-of-the-year podcast, Ben went to do some outside recording at the Wix School in Clapham, London, where he learnt about ‘Native Scientist’, an outreach project that goes into schools to give children a chance to learn about science research in their native language. The project was co-founded by Dr Joana Moscoso, the Society for General Microbiology’s 2014 Outreach Prize winner. We spoke to her about the project, and asked a teacher at Wix what he thought the benefits of the Native Scientist are.

Show notes:

  • Native Scientist’s homepage.
  • Our interview with Joana about her Outreach Prize win can be found here.
  • Information on the Wix School can be found here.

Benjamin Thompson

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