On 25 June the Museum will open its doors to a special event in celebration of the international and global commitment between countries, industry, charities and academia to work together against Neglected Tropical Diseases (NTDs). This commitment was first agreed upon in London in 2012 and has since been termed the London Declaration On NTDs.

By joining forces to fight NTDs the world would achieve a huge reduction in health inequality paving the way to sustainable improvements in health and development especially amongst the worlds poor. The 25 June sees the launch of the third progress report, 'Country Leadership and Collaboration on Neglected Tropical Diseases'. A pragmatic overview of what has been done, what has worked, what hasn't and what key areas still need to be achieved.

The Museum is thrilled to be participating in this event, having a long-standing history in parasitic and neglected tropical disease research. As both a museum and an institute of research our mission is to answer questions of broad significance to science and society using our unique expertise and collections and to share and communicate our findings to inspire and inform the public. We are excited to be hosting a day of free public events on Neglected Tropical Diseases.

What are NTDs?

Neglected Tropical Diseases are termed in this way because they infect hundreds of thousands to millions of people, predominantly the world's poorest and most vulnerable communities, and yet receive comparatively little funding for basic, clinical or drug-development research and even less attention from governments, people and the media of affluent countries. Until now!

In total the WHO has identified 17 diseases or groups of diseases that fall within this category.

World Health Organization has identified 17 Neglected Tropical Diseases. 10 of these have been targeted for control and elimination by 2020

The 10 selected by the WHO for control and elimination by 2020 are:

1. Onchocerciasis (aka river blindness): A blood worm infection transmitted by the bite of infected blackflies causing severe itching and eye lesions as the adult worm produces larvae and leading to visual impairment and permanent blindness.
2. Dracunculiasis (aka Guinea-worm disease): A roundworm infection transmitted exclusively by drinking-water contaminated with parasite-infected water fleas. The infection leads to meter-long female worms emerging from painful blisters on feet and legs to deposit her young. This leads to fever, nausea and vomiting as well as debilitating secondary bacterial infections in the blisters.
3. Lymphatic filariasis: A blood & lymph worm infection transmitted by mosquitoes causing abnormal enlargement of limbs and genitals (elephantiasis) from adult worms inhabiting and reproducing in the lymphatic system.
4. Blinding trachoma: A chlamydial infection transmitted through direct contact with infectious eye or nasal discharge, or through indirect contact (e.g. via flies) with unsafe living conditions and hygiene practices, which if left untreated causes irreversible corneal opacities and blindness. Trachoma is the leading cause of blindness in the word.
5. Schistosomiasis (aka bilharzia): A blood fluke infection transmitted when larval forms released by freshwater snails penetrate human skin during contact with infested water. The infection leads to anaemia, chronic fatigue and painful urination/defaecation during childhood, later developing into severe organ problems such as liver and spleen damages, bladder cancer, genital lesions and infertility.
6. Visceral leishmaniasis (aka Kala azar): A protozoan blood parasite transmitted through the bites of infected female sandflies which attacks internal organs which can be fatal within 2 years. 
7. Soil-transmitted helminths: A group on intestinal worm infections transmitted through soil contaminated by human faeces causing anaemia, vitamin A deficiency, stunted growth, malnutrition, intestinal obstruction and impaired development.
8. Leprosy: A complex disease caused by infection mainly of the skin, peripheral nerves, mucosa of the upper respiratory tract and eyes.
9. Chagas disease: A life-threatening illness caused by a blood protozoan parasite, transmitted to humans through contact with vector insects (triatomine bugs), ingestion of contaminated food, infected blood transfusions, congenital transmission, organ transplantation or laboratory accidents.
10. Human African trypanosomiasis (aka sleeping sickness): A protozoan blood parasitic infection spread by the bites of tsetse flies that is almost 100% fatal without prompt diagnosis and treatment to prevent the parasites invading the central nervous system.

They were selected because the tools to achieve control are already available to us and, for some, elimination should be achievable.

Take the Guinea Worm:

Guinea worm infection - from over 3.5 million people infected in the 80s to less than 130 cases in 2014. Set to be second human disease to be eradicated after smallpox (photo credits David Hamm&Peter Mayer)

In the 1980s over 3.5 million people were infected with Dracunculiasis (i.e. Guinea worm disease), with 21 countries being endemic for the disease. Now, thanks to the global health community efforts and extraordinary support from the Carter Center, only 126 cases were reported in 2014 and only 4 endemic countries remain: Chad, Ethiopia, Mali and South Sudan! If the WHO goal of global eradication of Guinea Worm by 2020 is met then Dracunculiasis is set to become the second human disease in history to be eradicated (the first, and only one, being smallpox). Not bad for an NTD! But there are still challenges!

At the Museum we have a long history of working on health related topics. Indeed our founding father Sir Hans Sloane was a physician who collected and identified plants from all over the world for the purpose of finding health benefits - in fact he developed chocolate milk as a health product.

Today we have a vast and biologically diverse collection of parasites and the insects/crustaceans/snails/arachnids that carry and transmit them. These are used by researchers both in the museum (such as myself and colleagues) but also internationally through collaborative work.

Collaboration is key - Zanzibar Elimination of Schistosomiasis Transmission (ZEST) programme key players: the Zanzibar Ministry of Health, Public Health Laboratories Pemba, the World Health Organization, SCI, SCORE, Swiss TPH, NHM and others

We are immensely proud of our collections and the work we do in this field especially of the biological information we can contribute to health programmes in endemic countries. One of our most exciting contributions is to the Zanzibar Elimination of Schistosomiasis Transmission (ZEST) programme where we are working in collaboration with the Zanzibar Ministry of Health, various NGOs, the World Health Organization and the local communities to identify and implement the best tools and methods to achieve schistosomiasis elimination in Zanzibar. This would be the first time a sub-Saharan African country would achieve schistosomiasis elimination. Fingers-crossed we are up to the challenge! You can read more about this project in an earlier post on our Super-flies and parasites blog

On Thursday we are bringing out our Parasites and Vectors specimens to showcase them to the public galleries and answer any questions relating to these fascinating yet dangerous organisms. Our wonderful scientists and curators will be on hand to talk to people about our collections and research as will collaborating scientists from the London Centre of Neglected Tropical Disease Research who will talk to you about the diseases and the challenges faced to achieve the WHO 2020 goals. Please do pop by and say hello, come and look at our specimens and help us raise awareness of these devastating diseases and the fight to control and eliminate them.

We are working together with schools, communities, government and research institutes to fight Neglected Tropical Diseases. Schistosomiasis fieldwork photo with the team from the National Institute for Medical Research in Tanzania

Hello Super-flies & Parasites fans!

This time we are departing from the familiar world of blood flukes and having a look at something new and exciting: Welcome to the ‘Forever Flies’series of blog posts. I’ve really enjoyed writing this bit as it’s totally new to me and I’m learning so much from our wonderful scientists in the Forensic Entomology group of the Parasites & Vectors division here at the Museum.

About forensic entomology

I think I mentioned forensic entomology way back in the first ever Super-flies and Parasites post. But to refresh our memories and delve a bit deeper here’s an explanation taken from the group’s website:

'Forensic entomology is the study of insects and other arthropods (ie spiders, mites) in a situation where a crime may have been committed. The insects recovered from a crime scene can provide vital information for the investigating team. The most common role for Museum forensic entomologists is establishing a minimum time since death in suspicious cases, by analysing the carrion insects on the body.'

Flies use the bodies of dead animals to grow and develop, fulfilling a vital nutrient recycling role in an ecosystem. They can turn one vertebrate body into thousands or millions of flies, which are then fed on by other animals - insects, frogs and birds for example. The rate at which they do this, going from eggs to larvae to pupa to adult fly, is pretty consistent.

Knowing enough about the species of flies we can exploit this information when they develop on corpses. By determining how long the insects have been feeding on the tissues of the corpse, we can determine the length of time elapsed since flies found the body; thereby providing crime scene investigators with a minimum post-mortem interval.

Some flies however don’t hang about and wait for death, they prefer feeding on live animal tissues, and can cause a horrible disease called myiasis, a major economic and animal welfare problem.

Female Bluebottle blow fly, Calliphora vicina, and maggots feeding on a dead pig.

Dr Martin Hall and colleagues within the Museum and around the world work together on the taxonomy and biology of flies that develop as larvae on living or dead vertebrate animals. Their expertise and research greatly contributes to the control of a painful and damaging disease, myiasis, but also to the field of forensic entomology, helping CSIs determine crucial information from a crime scene.

So there you have it, some real life crime scene investigation stuff! These are the guys CSIs turn to for help! (Cue CSI theme song!)

The beauty of maggots lies in their mouthparts

I asked Martin for a little blurb to get the Forever Flies series rolling and he sent me some surprisingly beautiful photos of maggots! Here’s what he has to say about them:

To most people maggots are repulsive creatures; they all look much the same and have zero redeeming features.

Maggots, thought of as repulsive creatures with zero redeeming features. Read on to see how they are transformed by confocal microscopy into beautiful works of art.

However, viewed under a microscope they become much more interesting, with a range of characters that can be used in discrimination, especially when you look at the business end of the maggot, its mouthparts!

 

It’s not so easy to ask a tiny 2mm long newly hatched maggot to 'open wide' to view the teeth, and traditionally we have been limited to viewing slide-mounted specimens by light microscopy. Scanning electron microscopy has its merits, but only for the external features. In normal light microscopy, imaging of these mouthpart structures is limited by problems of resolution, illumination and depth of field.

Greenbottle blowfly, Lucilia sericata light microscope high power image. With normal light microscopy the relationship of the sclerites of the cephaloskeleton (mouthparts) to each other is unclear.

At the Museum we have been using a laser confocal microscope for the first time to look inside these maggots to view the mouthparts, the so-called cephaloskeleton, in three dimensions. The mouthparts are crucial to the maggots in establishing themselves on their food source, be it a live animal or a decomposing corpse. The images produced by the confocal microscope rely on the autofluorescence of structures of the cephaloskeleton.

Greenbottle blowfly, Lucilia sericata confocal microscope low power image - relationships are still unclear but, with the autofluorescence under laser light, the structures look so much more beautiful!

We were especially interested in the relationships of the small sclerites to each other and the so called 'hump', present in newly hatched larvae of Lucilia greenbottle blowflies but absent in Calliphora bluebottles.

Greenbottle blowfly, Lucilia sericata confocal microscope high power image: The structure relationships are becoming clearer (the 'hump' is arrowed) and this is finalised in the next image.

The 177 optical sections scanned by the confocal microscope enabled us to rotate and view this structure in three dimensions (see green false-coloured sclerite in image below) and see clearly for the first time how it relates to other structures.

 

In addition to their academic and practical value in identification, the images are also things of beauty in their own right and would not look out of place in an art gallery!

Greenbottle blowfly, Lucilia sericata confocal microscope high power image and false colour sclerites. We have rotated the original to give three dimensionality. The red wavelength was selected, as this is the wavelength that gave most autofluorescence of the cephaloskeleton, to enable us to discard other structures and here false-colour has been added to show the different structures, including the 'hump' (in green) or epistomal sclerite.

The work was done at the Museum and involved Drs Andrzej Grzywacz (a visitor under the EC-funded SYNTHESIS project) and Krzysztof Szpila from the Nicolaus Copernicus University in Torun, Poland, collaborating with Tomasz Góral and Martin Hall. We used the Museum’s Nikon A1-Si Confocal Microscope.

 

For more information see the article published online in Parasitology Research on 19 September 2014.

By Dr Martin Hall

I hope you enjoyed the first 'Forever Flies' post. For more on flies head over to Erica McAlister's Diptera blog.

There will be more coming soon but just to let you know there may be a couple of weeks break whilst some important maintenance work is done to the site and my life

See you soon

Jambo from Tanzania,

I realise I'm a bit late with this post so lets get straight to it. Just a warning though, this will be a rather disgusting post so get ready to be grossed out.

You'll remember from my previous post about our school visits that we collect stool samples from infected children. This is because we collect the miracidia larval stage that hatches out of the parasite eggs. And these eggs come out with stool.

The blood fluke life cycle - a recap

Schistosoma. The worm pair releases schistosome eggs into the blood system. The eggs pierce through the wall of the intestinal/urinary tract and exit the host when he/she defecates or urinates. They reach fresh water and hatch out into a larval stage called miracidia.

Life cycle of Schistosome, blood fluke parasite and the specimens we collect during our fieldwork (circled in yellow).

So in order to collect miracidia we need stool from infected children. Diagnosis of infection is achieved using the Kato Katz method: a specimen of stool viewed on a microscope slide. If schistosome (blood fluke) eggs are observed in the stool specimen then the person is infected with at least one pair of schistosomes. For more information on diagnosis have a look at this video.

Collecting eggs from stool

Once we know which kids are infected we go to the schools and get stool samples (see previous post). We take these back to the lab and then a long process of stool filtering begins. We filter the stool for schistosome eggs, these we place in water and light. This induces them to hatch out into miracidia. We collect the miracidia onto special cards that store their DNA. We transport these back to the UK.

We use a pair of filters called Pitchford funnels (devised by Pitchford & Visser). The inner smaller funnel has bigger pores that allow the schistosome eggs to pass through but stops larger pieces of stool. The outer funnel is made of a finer mesh with pores that stop schistosome eggs from going through, this allows us to pour lots of water through the funnel thereby washing the eggs of stool material that may stop them from hatching.

Pitchford Funnels (devised by Pitchford & Visser). Credit Fiona Allan.

Stool Samples. Credit Fiona Allan.

Sieve to break up stool. Credit Fiona Allan.

Using the sieve to break up the stool sample.

Pouring stooly water through Pitchford Funnel. Credit Fiona Allan.

Myself and Mr John processing stool samples. Credit Fiona Allan.

Adding formalin to left over stool samples to kill of anything inside. These are disposed of safely later. Credit Fiona Allan.

>Revocatus adding formalin to stool. Credt Fiona Allan.

My Nagai releasing the eggs and some water into a petri dish.

Petri dishes of eggs and water. Waiting to hatch.

Fiona starts checking for miracidia swimming in the petri dish.

Fiona and James in the lab in National Institute for Medical Research in Mwanza.

Sometimes out in rural areas where we use local hospitals to process our samples things can go wrong, such as a power cut. No electricity means no light through the microscope. Thankfully we rise to the challenge and strap our head torches round our microscopes as an alternate source of light. Not quite as clear but it still works.

Even a power cut will not stop us, we use our head torches as a light source and continue working.

So that's it for now. Tune in for the next post - snail collecting on the banks of Lake Victoria.

Hello super-fly and parasite enthusiasts. Time for blog post 2, which is coming to you from the Mwanza region of Tanzania, bordering the banks of Lake Victoria. My colleague and I are here to collect specimens of the blood fluke Schistosoma from infected humans and snails.

Infection with the blood fluke Schistosoma causes a disease called Schistosomiasis (aka Bilharzia). Over 200 million people worldwide are infected with over 700 million people living at risk of infection. Over 80% of infected people live in sub-Saharan Africa. It is a disease of low socio-economic status, affecting the poorest communities and most neglected, vulnerable people. Infants and children are especially prone to infection due to their less developed immune system.

Children in a school in Niger, West Africa, queuing to be tested for schistosomiasis. The little boy at the front is showing the swollen liver and spleen symptom. A result of being infected with schistosomiasis.

There are two forms of the disease, depending on the species of the infecting schistosome worm:

Intestinal Schistosomiasis

• diarrhoea, bloody stool
• anaemia, stunted growth
• enlarged liver and spleen
• severe damage to the liver leading to liver fibrosis

Urogenital schistosomiasis

• blood in urine, painful urination
• anaemia, stunted growth
• damage to the genitals, kidneys and bladder
• bladder cancer
• increased risk of sexually transmitted diseases like HIV

Urine samples from children infected with Schistosoma haematobium, the urogenital form of schistosomiasis. The red colour indicates blood seeping out with the urine due to the damage done by the schistosome eggs.

To help fight schistosomiasis we need to understand the complex life cycle of Schistosoma, which involves a vertebrate (in this case human) host, a snail host and transmission via water contact.

The blood fluke life cycle

Lets start with a worm pair living inside a little boy in sub-Saharan Africa. The worm pair resides in the blood system of the little boy, either around the intestinal tract or around the urinary tract depending on the species of Schistosoma.

The worm pair releases schistosome eggs into the blood system. The eggs pierce through the wall of the intestinal/urinary tract and exit the boy when he defecates or urinates. They reach fresh water and hatch out into a larval stage called miracidia. These infect a specific aquatic snail species and reproduce asexually, creating thousands of clonal larval stages called cercaraie.

Cercaraie leave the snail to locate and infect a human by piercing through exposed skin in the water. They travel to the liver via the blood system and there they mature into adult worms, ready to reproduce and continue the life cycle (see diagram below).

The life cycle of blood flukes, Schistosoma, involving a vertebrate (e.g. human) host and an aquatic snail host. Transmission is through contact with infested freshwater. The yellow circles are the stages and specimens we collect when doing fieldwork. Credit: Aidan Emery.

A schistosome worm pair. The fat male carries the thinner female worm folded in a little groove where he feeds and shelters her whilst she produces eggs. The worm pair lives inside the veins of animals.

The schistosome species I work on (Schistosoma mansoni) causes intestinal schistosomiasis. It lives in the vein blood system of the liver and intestinal tract of humans. The adult worms themselves don’t cause much harm but it is the eggs they produce that cause the disease, by:

• Piercing the barrier between the blood system and the intestinal wall = bloody diarrhoea and painful cramps.
• The eggs that don’t make it out get trapped in organ tissues, causing the immune system to overreact and damage the surrounding human tissues.
• More worm pairs = more eggs = more damage to the organs and the host. This is what causes the chronic and more severe aspects of the disease such as kidney failure, bladder cancer and liver fibrosis in adulthood.

Thankfully there is an effective oral drug called Praziquantel that kills the adult worms. However it cannot prevent children from becoming infected. So in areas where there is no clean piped water or a sewage system, the local water bodies such as Lake Victoria are the only sources of water for the local population. People have no choice but to fish, wash, bathe and collect water from these schistosome-infested waters and therefore are reinfected quickly.

Treatment needs to be repeated regularly to avoid heavy worm numbers and high egg outputs. Regular treatment means controlling the disease but does not mean eliminating it. For this we need more research to develop better tools to fight the disease. There is also a major the worry that the parasite will become resistant to the drug. If the parasite develops resistance and the drug stops working there is currently no alternative treatment.

Clean water is not available so local water-bodies are used, such as this irrigation canal in Niger, West Africa.

We are researching the impact of human treatments on the parasite population. This will reveal how the parasite is responding to ongoing treatment programmes, if the drug is working effectively and if there are any warning signs regarding drug resistance.

That’s it for now. Coming up, a visit to the schools to collect stool samples from infected children. Disgusting work but someone’s got to do it.