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.