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6 Posts tagged with the human_health tag
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Prof. Mel Greaves FRS, Institute of Cancer Research

 

Friday 5 December 12 noon,  Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)

 

All cancers share the common feature of being clonal expansions of mutant cells that, over years or decades, disseminate within and between tissues, hijacking essential normal functions. But cancers differ widely in their tissue of origin, underlying mutational spectra, time frame of progression, pathological impact and clinical course. The systematics or classification of cancer subtypes therefore poses a considerable challenge with biologists, histopathologists and oncologists applying differing criteria.

 

Over recent years, a new conceptual framework has emerged that makes biological sense of all the diversity. This views cancer as a process of somatic cell evolution driven by mutational diversification and natural selection or adaptation within the specialised ecosystem habitats of the body. The implications of this new vision for diagnosis, prognostication and control of disease are very substantial.

 

More information on attending seminars at http://www.nhm.ac.uk/research-curation/news-events/seminars/

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Life Science Seminar: The unique development of the fox tapeworm Echinococcus multilocularis: a hopeful, but terrible monster

 

Uriel Koziol, Seccion Bioquimica y Biologia, Universidad de la Republica, Iguá, Uruguay & University of Würzburg, Germany

 

Wednesday 26 November 11:00,  Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)

 

 

The larva of the fox tapeworm Echinococcus multilocularis causes a zoonotic disease called polycystic hydatidosis that is difficult to treat and almost impossible to cure. The reason why it is so dangerous is directly related to its unique morphology and development, that unlike most tapeworms, involves proliferative, tumour-like growth within the tissues of the host as well as asexual multiplication. In this talk, I will describe the unique development of E. multilocularis and our current efforts to elucidate its genetic underpinnings and evolutionary origins.

 


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More information on attending seminars at http://www.nhm.ac.uk/research-curation/news-events/seminars/

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The Parasites and Vectors division in Life Sciences  has been re-designated as the World Health Organisation Collaborating Centre for Identification & Characterization of Schistosome Strains & their Snail Intermediate Hosts until December 2016.  This is in recognition of the importance of their work and expertise on Schistosoma species, the parasitic blood flukes that cause  the debilitating disease schistosomiasis, and is a good example of how the NHM contributes to the solution of global problems of health and wellbeing.

 

The group has had a  long-standing research focus on Schistosoma parasites, initially born from research on the molluscan (snail) intermediate  hosts and host-parasite interactions. Schistosomes have a two-host life cycle  involving an intermediate snail host and a definitive vertebrate host. The  relationship between the schistosomes and the snail is such that precise  identifications of both are required in order to understand the transmission  and the epidemiology of the disease. By researching the factors involved in Schistosoma parasite - snail host infection dynamics, the  team can provide expert advice to countries affected by schistosomiasis.

 

What is schistosomiasis?  A staggering number of people are infected by  schistosomes, over 200 million people worldwide with over 700 million people at  risk of infection. It is a disease of low socio-economic status, affecting the  poorest communities and most neglected, vulnerable people; it is therefore  classified as a neglected tropical disease (NTD). Infants and children are  especially prone to infection and the damage caused by schistosomes can lead to  blood in urine, painful urination, diarrhoea, bloody stool, anaemia, stunted  growth, enlarged liver and spleen, bladder and liver damage. In certain cases  early childhood infections can lead to bladder cancer and liver fibrosis in  adulthood. Over 90% of infected  people live in sub-Saharan Africa, and the NHM team concentrates its research  efforts in areas such as Tanzania, Niger and Senegal, working with teams in  country to help find better solutions to reduce the impact of this debilitating  disease.

 

Research at the NHM - The group at the Museum  is involved in a number of collaborations with research organisations here and  overseas:

 

  • SCORE -  The Schistosomiasis  Consortium for Operational Research and Evaluation (SCORE), funded by the Bill and Melinda Gates  Foundation aims to aid national control programs by defining the best intervention  methods and cost effective strategies for schistosomiasis control in  sub-Saharan Africa. Part of the research undertaken at the NHM monitors the  impact of Praziquantel (the only oral drug effective in treating all forms of schistosomiasis  in sub-Saharan Africa), on parasite populations, in order to monitor for the  potential development of drug resistance.
  • SCAN -  The Museum, with funding from the Wellcome Trust, has set up a rapidly  expanding schistosome repository called SCAN (Schistosomiasis Collection at the  NHM) which preserves and documents schistosome samples collected from Africa in  order to provide material for researchers both within and outside the Museum.  
  • ZEST -  ZEST (Zanzibar  Elimination of Schistosomiasis Transmission) is being led collaboratively by  the Zanzibar Ministry of Health and the Museum’s David Rollinson (funded by  SCORE), director of the NHM -WHO collaborating Centre. This ambitious programme  is attempting to eliminate schistosomiasis – the first time in a sub-Saharan  African country.

 

London Centre for  Neglected Tropical Disease Research - The Museum is also a  founding member of the new London Centre for Neglected Tropical Disease  Research, launched on the 30 January 2013 in collaboration with the London School  of Hygiene and Tropical Medicine and Imperial College. This important new  initiative is a valuable step forward as it brings together world-class skills  and expertise to answer important research questions concerning the biology and  control of neglected tropical diseases in partnership with governments, the  private sector, academic institutions and other key NTD centres.

 

 

Ian Owens
Director of Science

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Recently, a group of Scientists from the NHM (Shelley Cook, Ralph Harbach, Lorna Culverwell, Erica McAlister, Entomology; and David Bass, Zoology) and a research student from the University of Oxford (Ed Glucksman) joined forces with Unité des Virus Emergents, Marseille, Université de la Méditerranée (Gregory Moureau and Laurence Bichaud) for a cross-disciplinary collecting trip.

 

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Ralph apparently playing Crazy Golf, but he and Erica are in fact collecting adults and immatures…..

 

 

The aims of the trip, conceived by Shelley, were threefold; firstly, the Collection of voucher specimens of mosquito species present in the region for morphological and molecular identification work, and for the Collections here at the Museum. Voucher specimens simply means specimens that are collected and kept in collections for reference – in contrast to simply identifying in the field or lab and not keeping them. In total, approximately 100 mosquitoes will be processed for voucher work, which includes both morphological and molecular characterisation, and many more flies will be added as well. The molecular analysis will be for specific DNA sequences that are now widely used in molecular identification – often called DNA barcodes.  These use mitochondrial cytochrome c oxidase subunit I and II (COI and COII sequence).

 

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Preparing to use the aspirator - a device for sucking up insects

 

The second aim was the collection of bulk samples of adult and immature mosquitoes onto dry ice for screening for flaviviruses; 2010 saw the first two cases of dengue fever (caused by a flavivirus) in patients in metropolitan France (near Nice) with no history of travel and whom were most likely to have been infected by mosquitoes from a local population. In total, approximately 2000 samples were plated for later screening. Previous similar studies conducted by our group have shown a prevalence of novel flaviviruses of up to 10%. Any virus positives will be isolated, characterised and sequenced before publication in scientific journals..

 

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Shelley concentrating on numbering samples

 

 

And thirdly, together with David Bass from Zoology, the collection of a range of plant, water and insect specimens were put into liquid nitrogen followed by extraction of small RNA fractions. These will be tested via Illumina sequencing to test whether this method can detect signatures of viral infection and to compare viral biodiversity across a range of environmental samples - including in particular in association with mosquitoes and protists (single-celled organisms).

 

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David wading to collect samples - always that temptation to go a bit deeper than the length of the waders...

 

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Team photograph

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Intestinal schistosomiasis, caused by Schistosoma mansoni, is endemic to Lake Victoria, with high prevalence of the disease in human lakeshore communities.  Schistosomiasis caused by S. mansoni and a number of other species affects over 200 million people worldwide and is classified by the World Health Organisation as a Neglected Tropical Disease, associated with poverty and limited access to public health services.

 

Schistosoma mansoni is a trematode worm, related to flukes, and is the focus of research by a number of NHM research scientists.  Understanding the life-cycle (part of which takes place in a snail vector, Biomphalaria) and evolution of the parasite is essential to enable effective disease control to be put in place.  Intestinal schistosomiasis causes a range of debilitating chronic health problems, including organ damage, which contribute to a low quality of life for those affected.

 

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A scanning electron microscope image of male and female Schistosoma mansoni

 

Although research has led to much better understanding of the life-cycle, nonhuman primates have until recently been overlooked as potential hosts of the disease, despite known susceptibility. NHM PhD student Claire Standley is lead author on a new study, with Russell Stothard and Richard Kane (Zoology) and other co-authors, that has looked at transfer of the parasite between chimps and humans.

 

They examined 39 semi-captive wild-born chimpanzees being cared for at Ngamba Island Chimpanzee Sanctuary, Lake Victoria, Uganda, together with 37 staff members for S. mansoni infection. Miracidia (a life stage of the parasite) recovered from faeces were analysed for DNA to investigate cross-over between humans and chimpanzees.The island was also surveyed for Biomphalaria intermediate host snails, which were examined for infection with S. mansoni.

 

Chimpanzees were unequivocally shown to be infected with intestinal schistosomiasis. Miracidia hatched from chimpanzee faeces revealed three S. mansoni DNA profiles (haplotypes) commonly found in humans living throughout Lake Victoria, including staff on Ngamba  Island, as well as two previously undescribed haplotypes. At one site, a snail was observed shedding schistosome cercariae (another life stage of the parasite that is released into water and that enters humans through the skin).

 

The scientists concluded that the potential for transfer of intestinal schistosomiasis between humans and animals on Ngamba  Island is greater than previously thought. In addition, chimpanzees were excreting schistosome eggs that were capable of hatching into viable miracidia.  This suggests that these nonhuman primates may be capable of maintaining a local reservoir of schistosomiasis independently of humans - which in turn means that control strategies focused only on treating the parasite in humans may not be successful: account needs to be taken of possible persistence of schistosomes in animal populations.

 

 

Claire J. Standley, Lawrence Mugisha, Jaco J. Verweij, Moses Adriko, Moses Arinaitwe, Candia Rowell, Aaron Atuhaire, Martha Betson, Emma Hobbs, Christoffer R. van Tulleken, Richard A. Kane, Lisette van Lieshout, Lilly Ajarova, Narcis B. Kabatereine, J. Russell Stothard. Confirmed Infection with Intestinal Schistosomiasis in Semi-Captive Wild-Born Chimpanzees on Ngamba  Island, Uganda.Vector-Borne and Zoonotic Diseases. February 2011, 11(2): 169-176. doi:10.1089/vbz.2010.0156.

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Trichuriasis is a common intestinal worm infection in Africa and in other parts of the World, affecting almost 800 million people.  Trichuris is the nematode worm that causes the condition and is usually transmitted by faecal contamination of soil or food.  Heavier infestation can lead to pain and a range of health impacts that can seriously diminish quality of life and which may contribute to premature death, particularly in children. 

The World Health Organisation describes trichuriasis as one of the Neglected Tropical Diseases - diseases that thrive in conditions of poverty. Unsafe water, lack of access to health services, inadequate housing, malnutrition and poor sanitation all increase vulnerability to infection by this and other diseases such as leprosy, dengue and schistosomiasis.

It is not uncommon for people to suffer from both trichuriasis and from schistosomiasis, another condition caused by a parasite, and these may be treated by the same drugs. Research on the disease leads to better understanding and more effective treatment.

Dr Stefanie Knopp undertook her PhD research on treatment of trichuriasis at the University of Basel in collaboration with Dr David Rollinson and Dr Russell Stothard in the Museum's Department of Zoology, who are specialists in schistosomiasis.  She has recently published important research from her PhD in Clinical Infectious Diseases (a high-profile journal with an impact factor of 8.3) in a paper on on the treatment of trichuriasis in Zanzibar, Tanzania. 

Single doses of the drugs albendazole and mebendazole had in the past shown limited effectiveness in the treatment of trichuriasis. The combination of albendazole with ivermectin was known to improve treatment, but a mebendazole–ivermectin combination had not been previously investigated.

The research showed that addition of ivermectin improves the therapeutic outcomes of both albendazole and mebendazole against Trichuris trichiura, and may be considered for use in soil-transmitted helminth control programs and individual patient management.

 

Knopp S, Mohammed K A, Speich B, Hattendorf J, Khamis I S, Khamis A N, Stothard, J R, Rollinson D, Marti H and Utzinger, J  (2010) Albendazole and Mebendazole Administered Alone or in Combination with Ivermectin against Trichuris trichiura: A Randomized Controlled Trial.  Clin Infect Dis.  51 (12): 1420-1428. doi:                                                                          10.1086/657310