At the MRC-University of Glasgow Centre for Virus Research, we are undertaking a new project ‘What makes viruses tick?’. This project aims to raise awareness and offer information on ticks and tick-borne diseases in Scotland.
Ticks and the diseases they transmit have become an increasing concern in recent years for a couple of reason. Firstly, with more people accessing the outdoors due to COVID-19 travel restrictions more people are being exposed to ticks and potential bites. This is coupled with an increased risk posed by milder winters due to climate change, which may increase the time ticks are active throughout the year. In Scotland, the largest threat from tick bites is currently Lyme disease, with an incidence of up to 5% of ticks across the country. However, Lyme disease is not the only disease transmitted through tick bites and given the recent detection of Tick-borne encephalitis virus (TBEV) in the UK it is more urgent than ever to raise awareness of the dangers posed from tick bites.
We hope by raising awareness and engaging people about ticks and tick-borne diseases we can open dialogue and empower our audiences to make informed decisions about accessing the outdoors, while also establishing long-term relationships with at-risk communities.
There is a fundamental lack of understanding regarding how tick-borne viruses replicate in ticks and how the tick innate immune system controls infection. Our research focusses on tick-borne severe fever with thrombocytopenia syndrome – an emerging viral pathogen caused by Dabie bandavirus. We aim to understand how tick-borne viruses interact with ticks and tick cells, and how this facilitates transmission to mammalian hosts.
This involves carrying out in vitro and in vivo studies, which can be divided into three specific aims:
• to understand the basic molecular biology of tick-borne virus replication
• to define the innate immune factors that control virus replication in the tick cell environment
• to examine whether virions derived from tick or mammalian cells have similar biological properties and virulence.
An in vitro study involves using a system which is outside the living organism (in our case, using a tick cell line), whereas an in vivo study focuses on using the whole living organism itself (in our case, using whole tick organisms). By carrying out both these studies, we can increase our understanding of how viruses interact with ticks, and how this interaction influences disease transmission and ultimately human health.
Our in vitro studies use two different types of cells – either cells derived from ticks, or ‘immortal’ cell lines which can divide and be used in experiments infinitely. There are benefits to both models and we use both the ‘immortal’ cell lines and our tick cell cultures for molecular research in which we try to understand what interactions are happening inside cells. Our live ticks meanwhile, are currently being used in experiments aiming to develop a way to screen ticks captured in the field for diseases before we introduce them to our laboratory colony. This will help to maintain genetic diversity in our tick colonies, so they are representative of ticks living in the wild.
Our in vivo studies typically focus on confirming that the results from our in vitro studies are applicable to the whole organism and not simply that particular cell line. We also use them to carry out more extensive research which cannot be done with just in vitro studies alone. A whole, living tick is made up of many different types of cells that can interact with each other in ways which are not achievable in a cell line.
We are currently establishing colonies for three tick species that are important in the transmission of viruses, including the most common tick found in Scotland – Ixodes ricinus. This species is particularly interesting as it has a three-host life cycle, meaning the tick uses three different host animals at different stages of its life cycle. Through combined cell culture approaches and in vivo animal experiments we will investigate the replication of viruses in the live tick. This has involved widening our understanding of the skills and knowledge required to effectively manage and sustain our colonies and we have implemented several methods to minimise fungal exposure/infection in ticks. We’re also investigating how to improve the artificial membranes used to feed the ticks. Producing these membranes involves boiling animal hair and then incubating the resulting ‘hair solution’ with the membrane which encourages the ticks to bite; we’re currently experimenting with different types of ethically sourced animal hair to see which type the ticks like best.
Scotland has seen a big increase in people enjoying the outdoors in recent years and the COVID-19 pandemic has only accelerated this trend. As more people spend their time walking, running and camping, tick bites and sightings are only going to increase. This means it’s more urgent than ever to make sure people are well informed about the risks posed by ticks and tick-borne diseases, empowering the public to understand potential risks and take informed decisions to mitigate them. Even experienced hikers and nature-lovers often lack access to detailed, reliable information when it comes to tick-borne diseases; for example, many people do not know that ticks can transmit more than just Lyme Disease, including TBEV (Tick-borne Encephalitis Virus), which has recently been detected in the UK.
By establishing laboratory colonies of the most common tick found in Scotland, we want our research to be directly applicable to the species of ticks and tick-borne diseases impacting people here. In turn, we hope to learn from the public who can report tick “sightings and bitings” to us, helping us to grow our tick map and understand the geography and frequency of tick encounters.
We hope our project will provide the public with the knowledge necessary to enjoy the outdoors with confidence, while allowing us to access valuable data on ticks collected by people all over Scotland, and the UK. We will also be working with community groups in the Outer Hebrides who are most at risk from current and emerging tick-borne diseases to understand how they would like to receive information about ticks and the diseases they carry.
Alongside this, we will be identifying communities across Scotland who wish to be upskilled and support our field work efforts to collect ticks for our lab colonies, creating a network of citizen scientists who feel ownership of research at the University of Glasgow.
Have you seen a tick?
Take part in this project by reporting any tick sightings and bitings at the ‘What makes viruses tick’ website.