Kirsty Clarke (BSc1 student) was awarded an Animal Care Trust summer studentship for the summer of 2017. She worked with Mercedes Sanchez-Garzon on: "study design for the transmission of Pinworm into laboratory animals (mice and rats) by animal technicians who are in contact with rodents or have rodents pets at home".
Kirsty provides a summary of the project below:
Pinworms are parasites that are found in mammals. Syphacia muris, S. obvelate and Aspiculuris tetraptera are pinworm species that are found specifically in rodents (mice and rats particularly). Laboratory mice and rats are consistently diagnosed with pinworm, despite the availability of anthelminthic treatments and barrier caging systems. It is thought that their persistence in the laboratory have multiple causes, including continual reintroduction by feral rodents or from infections in recently arrived laboratory rodents, egg persistence in the environment, the lack of an ovicidal disinfectant for environmental decontamination and inefficiencies in diagnosis. In significant infestations, mice and rats show decreased weight gain and/or unthriftiness. Immunodeficient animals are more susceptible to disease including immune system disturbances and intestinal mucosal invasion leading to colitis. Additionally, infestations can compromise collaborations between facilities if one facility excludes these parasites from their colony.
The hypothesis for this project was ‘Does having rodent pets at home or being in contact with rodents or other pet species outside of a laboratory animal unit make it a risk for the transmission of pinworm into the laboratory animal units’ rodents?’ The method aimed to collect fur and faecal samples from pets of animal technicians and vets (who worked in labs), as well as skin swabs from the staff themselves to be tested for pinworm. The study first had to gain ethical approval from the RVC Ethics and Welfare Committee. This was granted, provided each participant signed a consent form.
Next, participants had to be identified by sending out a questionnaire to possible subjects. This was a group of 34 staff who worked in animal laboratory facilities, and had pets at home. The questionnaire determined who was willing to participate in the study, as well as learning a bit about the lifestyle of the subjects. Questions asking about the cleaning routine required of the staff before entering the facility, and the necessary hygienic requirements once inside, allowed us to understand where pinworm could be transferred from human to rodent. Out of the 34 people who were sent the survey, 16 people responded. 8 of those consented to provide samples for the study. 3 were vets and 5 were animal technicians. Only 1 of these people had rats at home, which made the testing group quite small and made it hard for the results to be statistically significant. Swab samples were taken from the fur of the non-rodent pets by the owners themselves. Both fur and faecal samples were collected from the rodent pets by the owner. Skin swabs of the hands and faces of the staff were acquired, as well as swabs from the shoes of the staff. Two samples of each were taken so as to allow for back-up tests if necessary. These samples were then sent off to be tested. The fur samples for the rodents came back positive for S. muris, while all the other results were negative for pinworm.
While there was no evidence that the owner of the rats was transferring pinworm to the laboratory rodents, the possibility was there. With more funding and a larger pool of subjects to be tested on, this study could be taken further to more deeply examine why pinworm still persists in laboratory animals despite our best efforts.