Report from BSP Travel Award Recipient Sara Silva Pereira

A field report from Kenya by Liverpool PhD student Sara Silva Pereira, who was funded by a BSP International Training and Fieldwork Award.

Finding Trypanosoma congolense in Busia, Western Kenya

I was starting the second year of my PhD when my supervisor suggested a trip to Kenya to collect blood samples from cattle naturally infected with Trypanosoma congolense. I finally made it there in the beginning of my final year for a month-long stay.

Animal African Trypanosomiasis is an endemic disease in 37 sub-Saharan countries that has a significant negative effect on both animal health and livestock productivity. It is caused by trypanosome blood parasites (Trypanosoma spp.), transmitted by the bite of tsetse flies (Glossina spp.), and can result in substantial anaemia, weight loss and ultimately death of the infected animal. Efforts to develop effective prophylaxis have been undermined by the mechanism of antigenic variation, employed by the parasite for immune evasion. Antigenic variation is characterised by the sequential substitution of cell surface antigens, compromising the effectivity of an antibody-based response and thus leading to chronic infection and transmission likelihood.

In this project, I was lucky enough to work within the DVS-ILRI laboratory in Busia, which is part of a collaboration between the International Livestock Research Institute (ILRI) and the University of Liverpool through Professor Eric Fèvre. There, the veterinary surgeon Dr Maseno Cléophas was ready to coordinate and assist the project.

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Sara making blood smears from an infected cow

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The DVS/ILRI lab in Busia

We screened 900 cows in all sub-counties for trypanosomiasis by microscopic analysis of thin blood smears and high centrifugation technique. We collected blood from each positive animal every week, for 4 weeks, and purified the parasites from the blood using a DEAE cellulose column. From the recovered parasites, we extracted nucleic acids and protein, which will be used to identify and quantify transiently-expressed antigen genes and to identify the active cell surface antigen, in an attempt to better understand the relationship between genetics and antigenic switching in natural infections. At the end of the project, the animals involved were treated for trypanosomiasis and all animals screened were dewormed and given multivitamin supplements.

The most difficult part of the project was logistics. Simple things like getting a car to work in the morning, getting the farmers to pick up the phone so we could find them and the animals, having electricity to run the centrifuge, and of course, the dirt roads often flooded by overnight rains. On the bright side, I don’t think I’ll get car sick in Europe anymore! As the locals were constantly reminding me, “This is the real Kenya” and, with all its peculiarities, it is a magnificent country indeed.

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It wasn’t all work. On the second weekend, I did manage to escape to a beautiful cottage house in Kericho, where I met people from ILRI working in Nairobi. I got to ride a horse, see a waterfall and walk through sugar cane plantations praying silently not to find snakes. The remaining weekends were spent catching up on my book waiting list and, of course, sunbathing in the nearby hotel swimming pool with the local children.

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Through the International Training and Fieldwork Award, the BSP has allowed me to personally witness the difficulties and rewards of field work in remote areas, including all the logistics; to have a better understanding on how farming works in Kenya; and to further develop people and laboratory skills that would not be possible in the comfort of our highly-equipped institute in Liverpool. More importantly, the BSP and the BBSRC, who funded the rest of the project, have allowed the collection of precious materials that will be used to understand antigen-switching patterns in natural infections as well as to show an application for a variant antigen profiling methodology we have developed in the first years of my PhD. For all of this, I am deeply grateful.

-Sara Silva Pereira, Post-graduate student, Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool

Report from BSP Travel Award Recipient Eve Hanks

A field report from Leiden by Glasgow PhD student Eve Hanks, who was funded by a BSP International Training and Fieldwork Award.

Going Dutch

The first year of my PhD has been focused on understanding the protective immunity conferred to sheep when vaccinated with Barbervax ® against the parasitic nematode Haemonchus contortus. Working at the University of Glasgow and in conjunction with Moredun Research Institute, it had become clear that the majority of antibodies generated following vaccination were anti-glycan antibodies. This led to my trip to Leiden to work at the Leiden University Medical Centre (LUMC) with Dr C.H. Hokke and his team to attempt to categorise the glycan content of Barbervax  and determine the antigenicity of each component when incubated with sheep sera.

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Leiden University Medical Centre

I found myself in a truly international office known as the aquarium. PhD students from several countries with similar interests were a great source of knowledge for me and new friendships were made. Most of the current glycan work has a human focus, I was the only veterinary researcher.

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I was very fortunate to be able to make use of the new glycan array technologies developed at LUMC. This is the first time that the glycan content of the Barbervax has been analysed to this extent. Having the ability to extract glycans from the native vaccination preparation and probe these arrays with the sera from a wide range of vaccinated sheep from pen and field trials was really valuable. This allowed us to compare anti-glycan antibodies across a cross section of sheep at a set time point and also longitudinally comparing lambs, yearlings and ewes as they moved through the trials. These data will hopefully aid in the understanding of the effectiveness of Barbervax in the face of failure of recombinant protein vaccine attempts. Although further analysis is required, it has been a rewarding trip which has generated novel data specific to H. contortus and the Barbervax vaccination, and will form part of my thesis.

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Having never visited The Netherlands before I made full use of my free time with trips to Amsterdam and The Hague. I travelled to Cologne to run in the half marathon race and visited Ghent and Antwerp also. During my time at LUMC I was lucky enough to be living by the sea and with unseasonable warm weather this was a perfect location.

I would like to express my sincere gratitude to the BSP for the travel award and to LUMC and all the staff and students who made this experience so rewarding and memorable.

Eve Hanks 16/10/16

BSP Travel Award Recipient Melanie Clerc

A field report from Germany by Edinburgh PhD student Melanie Clerc, who was funded by a BSP International Training and Fieldwork Award.

In my PhD, I am investigating the mechanisms that underlie interactions among co-infecting parasite species. To do so, I am using wild wood mice and their diverse parasite community to understand which processes are acting to create within-host interactions under natural conditions. Focussing on a previously-identified negative interaction between the most prevalent nematode Heligmosomoides polygyrus and the coccidian parasite Eimeria hungaryensis in UK wood mice, I am primarily asking questions about the role of the immune response in mediating this interaction, the influence of various host characteristics and how both variation in immune response and host demographics create the patterns of co-infection we observe in the wild.

In another part of my PhD I am focussing on Eimeria population genetics as a model to understand the role of genetic diversity in infection dynamics. Although laboratory studies suggest that animals can develop strain-specific protective immunity to re-infection after a single Eimeria oocyst challenge, in the wild setting we find animals being repeatedly infected with Eimeria parasites throughout their lives. This raises the question of whether the lack of protective immunity in the wild is caused by a high number of circulating strains within ourEimeria population with little degree of cross-immunity, or due to an inability of the immune system to respond appropriately given the various infectious and environmental challenges an animal encounters over its lifetime in the wild.

I was lucky enough to be awarded a BSP international training and fieldwork award to investigate this question in collaboration with Dr. Emanuel Heitlinger from the Humboldt University in Berlin. Dr. Heitlinger is an expert in the molecular characterisation of Eimeriaspp., specifically focussing on Eimeria genetic diversity at the Mus musculus musculus / Mus musculus domesticus hybrid zone that runs through central Europe. The money provided from the fieldwork award enabled me to visit his lab for four weeks in March 2016, with the aim to use genetic tools that he and his group recently developed to test faecal samples from our experimental populations for the presence of multiple Eimeria species and strains. By using multiple recapture samples per animal that I collected over the course of my PhD in various experiments, this would give us an insight not only into the general pattern of Eimeriagenetic diversity in our population, but also into the temporal patterns of strain turnover. Specifically, I’d use Sanger sequencing on 3 genomic markers which Dr. Heitlinger’s team have been working on, as well as a multifluids PCR assay that Dr. Heitlinger and his group recently optimised to increase the level of resolution within our genetic data.

With the help of staff in Dr. Heitlingers group, I managed to extract DNA from all the samples I brought to Berlin with me (over 160) and PCR test them on the 3 Sanger-markers. We did, however, also encounter technical problems in the lab, which meant that I did not reach all the goals I set myself for my 4-week stay. These problems are currently being tackled by Dr. Heitlinger’s group and we will continue to collaborate on this part of my PhD also in the future.

Even though my visit was short, I thoroughly enjoyed all the inspiring scientific interactions I was able to have with everyone in Dr. Heitlinger’s group and the entire institute. I obtained vital feedback and suggestions on my work so far by giving two presentations at intra- and inter-institutional seminars. I was also able to practice my teaching skills by passing on my experience in artificially infecting colony mice with wild-caught Eimeria strains to a student in Dr. Heitlinger’s group. Overall this visit was a great way to learn new skills and establish new connections and collaborations within the scientific community that, without the help from the BSP, I would not have been able to achieve.

Several BSP student members have recently benefitted from the BSP International Training and Fieldwork awards. For further details please see the link.