July 09, 2018

Click here to read part I

By Kathleen Apakupakul, Institute for Conservation Medicine

Following up on the health assessments of Galápagos tortoises conducted by Drs. Laura Kleinschmidt and Ainoa Nieto-Claudín (ICM PhD student), I traveled to the island of Santa Cruz in the Galápagos in February 2018 to continue the Institute for Conservation Medicine’s (ICM) research on these giant tortoises.  As Research Associate for the ICM, I was sent to provide molecular diagnostic testing of pathogens on collected tissue samples.  We test for four pathogens that threaten reptile species worldwide:  Mycoplasma species and three viruses: herpes, adeno, and rana.  Drs. Nieto and Deem (Director of the ICM) have suspected that tortoises exposed to human-disturbed areas are more susceptible to diseases caused by these agents than those that live in relative isolation from human influence.  One might think that it would have been far easier to send the samples back here in the U.S. for processing, but CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) restrictions prohibit the exportation of tissue from endangered species outside of the home country without a permit.  Besides that, this trip provided an excellent opportunity to train Dr. Nieto in these techniques so that she could learn a new skill and train others in the Galápagos and wherever her career takes her.

Upon arrival, the first thing Dr. Nieto and I had to do was set up the lab at the Charles Darwin Foundation!  Our first day involved unpacking a lot of equipment, organizing, and cleaning.  There are several things that go into setting up a lab and fortunately, many things were already in place.  Being on a remote island presented some challenges, a major one being the mere ability to get the things we needed, which had to come by plane or boat.  Unfortunately, the brand-new autoclave (sterilizer) that had been delivered by boat and had been shipped in a very heavy crate needed repairs and had to be re-packed and returned to the mainland.  Luckily I had brought some back-up supplies, so we were able to continue with our work.

Once the equipment was unpacked and our lab was set-up, we dove into disease diagnostics.  A common way to detect pathogen presence is to look for a piece of a particular microbe or virus’s DNA in a tissue sample.  On a previous trip, Drs. Kleinschmidt and Nieto swabbed the insides of the tortoises’ mouths, cloacae, and eyes using cotton swabs.  If any tortoise had been infected with a pathogen, the DNA of that pathogen would be found on those swabs.  In the lab, Dr. Nieto and I used a process called polymerase chain reaction, or PCR, to amplify targeted copies of known size of pathogen DNA from those swab samples to the point where we could detect if an individual tortoise was infected.  In order to visualize those DNA copies, we then ran them through a gel, which separates different-sized pieces of DNA in a PCR sample.  If we see the DNA band of the expected size on our gel, then we know that that particular individual has the pathogen.  Dr. Nieto will continue to conduct this testing on all her swab samples on different groups of tortoises to see if the ones that live near humans are prone to infections versus those that live in relative isolation from human activity and therefore may not even be at risk for infection.

In addition to providing pathogen testing on the Galápagos, this trip also served to pilot the logistics of implementing a mobile molecular diagnostic lab for use in future trips at our other field sites; in essence, taking an entire functioning lab and plopping it down anywhere on earth.  While I left most of the mobile equipment for Dr. Nieto to use in the meantime, in theory we would be able to travel to a place, conduct molecular diagnostic testing, and in this way be able to get quickly the diagnostic answers we need to determine next steps in a particular study or health assessment.  A mobile lab obviates the hassle and logistics of exporting samples (if even allowed) and provides teaching opportunities to budding scientists at these various sites.  Of course, this work would not be possible without the work of the field crew to collect samples to test, a true example of the transdisciplinary nature of One Health/conservation medicine work.

Click on the photos below to see a larger image.

Photo 1:  Traveling with a mobile lab

Photo 2:  Teaching how to extract DNA from swab samples collected from Galápagos tortoises

Photo 3:  Dr. Nieto loading a gel with PCR samples