Emergent diversity of an ecologically important parasite group

Lead Research Organisation: University of Exeter
Department Name: Biosciences

Abstract

As organisms that can cause death and disease in their hosts, parasites are forms of life that can have important ecological effects on the host populations that they exploit. Switches in host can occur as parasites jump to new host species in new environments and in the process will adapt their biology. As every different animal is a new potential host, parasites can diversify greatly and huge numbers of uncharacterized parasite species may exist. Each of these parasites could potentially represent a future danger both to human health and ecosystems. This great diversity of parasites is not immediately obvious because of their mainly microscopic and hidden nature, which means that they cannot be easily seen or described without sampling and dissecting hosts. Therefore how many different species of parasites exist and how successfully they transfer to new hosts and habitats are still unknown factors. DNA-based methods represent a rapid and inexpensive way to sample a wide range of biological diversity present in environmental samples, and importantly provide a means to survey previously unsampled microscopic lifeforms. It is now possible to collect a wide diversity of invertebrates and other small animals present in soil, ponds and marine environments and then extract the DNA from all these organisms along with that of their associated parasites and use state of the art gene sequencing technology to sequence the same gene for each parasite in the sample. By studying the diversity of this DNA we can identify the number and diversity of microscopic parasites present in the original sample. Here we will use this strategy to begin to enumerate the number of particular parasite groups in diverse environments, varying in geographic location, season, and including marine, terrestrial and freshwater environments. The group of parasites that we will survey are the microsporidia. These are highly unusual relatives of fungi that are adapted to live inside the cells of a variety of different animals. In humans, microsporidia can cause serious infections in those with seriously impaired immune systems, for example in people in the late stages of AIDS, or recipients of organ transplants. They also infect economically important animals such as farmed fish and honeybees. Microsporidia have been found in all major animal lineages and in all environment types worldwide. Currently over 1200 species of microsporidia are known to exist, though research suggests that large amounts of uncovered species are present in the environment. We intend to sample freshwater, estuarine, marine and soil environments across different seasons and geographic locations and use DNA methodologies to enumerate the distinct molecular types of microsporidia in each sample as a measure of species number. We can then use this data to try to understand: 1) How our current estimates of parasite species numbers compares to actual environmental numbers 2) Whether numbers of microsporidian species vary with geographic location 3) Which environmental factors, for example season, latitude, or environment type are associated with high levels of diversity of microsporidian parasites This type of quantification of different species will enable us to tell how successfully microsporidia have diversified in different environments. It will indicate whether there are particular environments that have allowed these parasites to thrive over evolutionary timescales. By characterising the differences in types of parasites found in different environments we can understand whether climate change or human movement by trade or travel has the potential to introduce new parasites into new areas. This can indicate how much potential there is for microsporidia to cause new infections in humans and wildlife.

Publications

10 25 50
 
Description The aim of this research was to understand the full diversity of a group of animal parasites (The Microsporidia) using environmental DNA seqeuncing techniques.

The aim of this research was to understand the full diversity of a group of animal parasites (The Microsporidia) using environmental DNA sequencing techniques.

We took samples from freshwater, marine, soil and estuarine environments and extracted all DNA from all organisms in the samples. We used PCR with specific primers to amplify microsporidian DNA which was then sequenced. This allowed us to find new lineages of multiple in many different environments. This demonstrates that we currently have a poor understanding of the diversity of microsporidia even though they economically important pathogens in humans and other animals.
Sectors Environment

 
Description Developing a lateral flow device for diagnosing Nosema infections in honeybees
Amount £14,263 (GBP)
Organisation Higher Education Funding Council for England 
Sector Public
Country United Kingdom
Start 01/2012 
End 08/2012
 
Description NERC iCASE
Amount £86,776 (GBP)
Funding ID NE/N008588/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 10/2016 
End 10/2020
 
Description Diversity of protistan parasites in UK invertebrates 
Organisation Natural History Museum
Country United Kingdom 
Sector Public 
PI Contribution A joint analysis of the data resulting from this grant
Start Year 2011
 
Description Invited seminar: Microsporidia in bees and other animals 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Invited seminar at the Devon Beekeepers Association annual general meeting. This was the result of impact plan activities associated with this grant where we collaborated with Devon Beekeepers to survey the diversity of bee pathogens in the county.

I was invited to give further talks at local beekeeping associations
Year(s) Of Engagement Activity 2013
 
Description Microsporidia and Beekeeping 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Talk to the East Devon Beekeepers Association. The talk sparked discussion on the causes of bee ill health and colony collapse disorder.

After my talk I questions about recent research into bee health and I was able to point people to some recent literature on the subject. I was also approached by a local school teacher to set up some outreach work at local schools. This was not followed up as I went on maternity leave very soon after the talk, but this will be followed up now that I have returned from leave.
Year(s) Of Engagement Activity 2014