Researchers in Grand Cayman are working to determine why 17 blue iguanas at Queen Elizabeth II Botanic Park have fallen ill or died over the past two years.
The mystery began in May 2015 when a Blue Iguana Recovery Program staff member discovered a blue iguana with signs of lethargy at the park. The iguana was taken to Island Veterinary Services and died the same day from blood poisoning that resulted from a bacterial infection.
Since then, both captive and wild blue iguanas at the park have shown symptoms including lethargy, lack of appetite, weakness of the hind quarters, collapse and sudden death. Fourteen of the sick blue iguanas have died and three recovered, according to the National Trust of the Cayman Islands.
Now, attending veterinarian Dr. Ioana Popescu is testing the theory that the endangered blues have been hit by Helicobacter bacteria, possibly spread by invasive green iguanas.
Helicobacter occurs in a range of species. In humans, the bacteria can cause gastritis, cellulitis and septicemia. In iguanas, information on its effects is limited.
Dr. Popescu has theorized green iguanas may harbor Helicobacter, threatening blue iguanas due to the close contact and genetic similarity between the two species.
“If the disease can be transmitted by the Green Iguana, that population could function as a reservoir for the infection, passing it on to Blue Iguanas at the Botanic Park and other parts of Grand Cayman, or even to the Sister Islands Rock Iguanas,” a National Trust of the Cayman Islands press release said.
In a project proposal, Dr. Popescu explained Helicobacter cases can be difficult to diagnose and research remains to be done on the strain in question.
“Presently there is no information regarding this bacteria, and nothing is known about its pathogenicity, epidemiology, geographical distribution or whether it is species specific or a multi-host pathogen,” Dr. Popescu wrote.
“Helicobacter requires extremely specific conditions to be cultured, and there are no readily available tests for the veterinary practitioner.”
Through strict quarantine, biosecurity and monitoring protocol, the park’s blue iguanas have been disease-free for six months. Researchers are unsure about the cause of blue iguana illness, however, and Helicobacter remains a concern.
In about half of the cases of blue iguana deaths, Helicobacter bacteria was found in blood and fecal samples. Examinations by personnel from St. Matthew’s University and the Wildlife Conservation Society did not find other signs of disease.
Dr. Popescu’s study will take fecal samples from euthanized green iguanas from the park and across Grand Cayman and send them to the Massachusetts Institute of Technology for Helicobacter testing. At least 100 green iguanas will be needed for the study.
The results could provide a better understanding of how the bacteria is spread, and contribute to prevention efforts.
“Results of the study may also be useful in guiding future conservation strategies, not only for the Blues, but also for the Sister Islands Rock Iguana and other native iguana populations in countries with invasive Green Iguanas,” a National Trust press release said.
Anecdotally, Helicobacter outbreaks in blue iguanas have also been associated with heavy, prolonged rains. The relationship between Helicobacter and outside variants such as this will be included in the study. Other threats to blue iguanas include feral dogs and cats, habitat conversion and traffic accidents. Results will be presented to the University of Edinburgh, the Department of Environment and the National Trust. The International Reptile Conservation Foundation has donated US$3,800 for laboratory testing. Funds were raised during IguanaFest in Topeekeegee Yugnee Park, Florida, in May 2017.
In Cayman, donations for the study can be made several ways. Direct donations can be made at www.ircf.org/donate by selecting “Blue Iguana Recovery Program” or by emailing [email protected]
Throughout September, donations can also be made through the #blueiguanarecovery challenge by shopping at Beyond Basics Medical Spa, Touch of Thai, The Salon La Femme and Renaissance Salon & Spa. Donation boxes and raffle prizes are available at each location. Raffle drawings will be held the first week of October.