Viral prevalence in giant tortoises: An interview with Gislayne Mendoza Alcívar

What was the objective of your research and what were your main conclusions?

Our research team has been working for several years to learn about the health status of Galapagos giant tortoises and the threats they face linked to human activities. This research led to us publishing our first findings of viruses in wild Galapagos giant tortoises from Santa Cruz, Española and central Isabela in 2022.

Following this publication, we conducted further sampling in other areas of Galapagos (San Cristobal and southern Isabela), where different species of giant tortoises live, to determine if these viruses were also present. Our latest work shows that tortoises in San Cristobal present one type of adenovirus (type 1), while in southern Isabela, they present a different adenovirus (type 2), which is similar to those we described in 2022. However, we did not find the presence of herpesvirus (a family of viruses that cause infections and certain diseases in animals, including humans), which has been found in other tortoise populations.

This information was used to determine the presence or absence of different virus types in different tortoise populations. This information was then provided to management institutions, including the Galapagos National Park Directorate, so that it can be incorporated into reintroduction and captive breeding programmes for tortoises.

Why are pathogens such as adenovirus and herpesvirus a conservation concern for giant tortoises?

The presence of viruses in healthy and wild tortoise populations, which we detected in our studies, does not represent a problem. All healthy populations have viruses and bacteria that are naturally present in their populations. The problem is not knowing what these viruses are and when they are present. The viruses recently detected in Galapagos giant tortoises are new viruses to science, which have potentially evolved with their hosts and therefore do not represent the same risk as a new or introduced virus that the animals cannot recognise and do not know how to fight.

It is important to know which viruses are present in which species and populations and their prevalence to anticipate a possible disease outbreak, or to avoid moving infected animals to other populations where the viruses are not present.

What are some of the challenges you face when working in the field with tortoises?

Although giant tortoises are incredibly famous on the Islands, there has been very little research into the health status of their populations, including the presence of diseases. For this reason, I think the main challenge has been starting our health research from scratch, which has included creating reference values in the blood of giant tortoises and characterising new viruses, bacteria and fungi.

Tortoises are very resistant and strong, so they do not show clinical signs that they are infected until they are in the advanced stages of a disease, making it a challenge to monitor them. In addition, due to the long distances they travel during their migrations, it is difficult to follow them throughout the year as they are often found in areas that are difficult to access. I think you have to be very well prepared physically to be able to reach wild populations and be able to adapt to changing environments. This has included setting up a makeshift laboratory to process samples. Sometimes, rocks and trees are our best allies, serving as makeshift tables and sources of shade.

How can the results of this study be applied to conservation management plans for wild and captive giant tortoises?

As researchers working with decision makers, our job is to use science to provide management institutions with the information needed to adapt and improve conservation plans. Our research helps to generate management and diagnostic tools that can be used in ecological restoration projects, captive breeding programmes and research projects focused on other species.

What inspired you to work in Galapagos and focus your research on giant tortoises?

Having grown up in Galapagos, I was inspired to focus my research on Galapagos giant tortoises. When I was a little girl, I remember participating in all the wildlife conservation programmes on San Cristobal. However, participating in an Ecology Project International (EPI) workshop in 2013 was the starting point for my future career. During the workshop, I learnt how to camp, recycle, work in a team, carry out field techniques and best of all, interact with the giant tortoises. I remember there was an activity where we had to look at tortoise faeces and sift them in sieves to identify the types of seeds they had ingested and, in doing so, learnt about their role as ecosystem engineers.

Currently, our research focuses on One Health, an approach that recognises that the health of animals, people and the environment are interconnected and interdependent. One Health allows multiple disciplines to collaborate locally, nationally and globally to achieve the optimal health of this triad, thereby improving the prevention of future threats. Applying this concept to our research is fundamental for the conservation of tortoises and the health of other species that share the same ecosystems.

This year, we are celebrating 30 years of Galapagos Conservation Trust and reflecting on our long-term relationships with partners such as the Charles Darwin Foundation. How has GCT supported your research with CDF over the years?

GCT was one of the first partners and donors to the Galapagos Tortoise Movement Ecology Programme (GTMEP) back in 2009, and the only partner that has continued to support the programme over the past 16 years. GCT has been instrumental in sustaining our conservation education programme, which has successfully engaged young people over the past 16 years. In recent years, the programme has grown and changed, but GCT’s commitment has remained and has allowed us to achieve great scientific advances in the knowledge and conservation of Galapagos tortoises.

GCT has been key to my development as a junior scientist, financing part of my salary in the first years of my profession. I think it is important to invest in researchers from Galapagos and help them protect the wildlife they have lived alongside their whole lives.