As fears over the spread of the Zika virus fade, public health officials are warning of a likely outbreak of a new strain of dengue fever in the Caribbean.
There have been no new cases of Zika in the Cayman Islands since early December, but doctors and scientists at the Mosquito Research and Control Unit warn of new threats on the horizon.
A new mosquito-borne illness, the Mayaro virus, recently identified in Haiti, has been highlighted as a potential threat to the region.
Also, the Caribbean Public Health Agency has warned of a coming “epidemic” of a new strain of dengue fever, which had previously been largely found in Asia.
Doctors in the Cayman Islands are now investigating just one suspected case of Zika per week, compared with 20 at the height of the outbreak in September.
There have been a total of 31 confirmed Zika cases in the territory to date.
Of the two pregnant women confirmed to have contracted the virus, one has left the island and the status of her or her baby is unknown. In the other case, the baby was born with no complications.
Timothy McLaughlin-Munroe, public health surveillance officer in Cayman, said officials were continuing to monitor the situation as well as other potential public health threats, including a predicted dengue type 3 epidemic.
He said there had already been an imported case of the virus in the Cayman Islands.
“We are very confident that dengue will be back. The new finding of dengue type three is a serious concern,” he added.
Dengue, a mosquito-borne disease which can be fatal in severe cases, has always been a problem in the Caribbean. He said the new strain, imported to the region from Asia, posed a greater threat because people in the Caribbean had not previously been exposed to it.
The head of the Caribbean Public Health Agency, Dr. James Hospedales, warned in September that “We can predict with some degree of certainty that next year, [or] more probably 2018, the region will have a dengue type 3 epidemic. Dengue has been increasing in frequency and severity for the last 30 or so years.
“The problem is not chikungunya, Zika or dengue. The problem is our comfort with the mosquito Aedes aegypti and the multiplication in sites in which it can breed.
“The fact that you have a vector that can so effectively transmit diseases right across the population is a health security threat, a tourism threat, an economic threat,” he said.
In Grand Cayman, the MRCU argues that targeting the disease-spreading Aedes aegypti is the best way to address the public health threat posed by a variety of diseases.
Bill Petrie, director of the unit, said the fact that Zika appeared to be receding in the territory did not decrease the urgency or importance of the project to deploy genetically modified mosquitoes in an effort to eradicate the Aedes aegypti.
“We embarked on this project long before Zika or chikungunya came up. The Aedes aegypti is responsible for transmitting a number of viral diseases. There may well be another one on the horizon, with the Mayaro virus that’s come up in Haiti.”
He said new viruses, and new strains of viruses like dengue, were likely to become more common.
“It was predicted 25 years ago that globalization and the movement of human beings around the globe from continent to continent would mean diseases being transferred to new countries. We are seeing that happening now.”
With no known cures for such viruses, he said the only method to combat the threat was to “target the vector.”
Officials from across the Caribbean, facing similar problems in their own countries, have visited the MRCU to investigate the project.
In India and Brazil, where mosquito-borne diseases are a public health menace, he believes the technique could have a profound impact.
The release of some 8 million genetically modified mosquitoes, provided by British company Oxitec, in West Bay has had a significant impact in reducing populations of the disease-spreading insects in the targeted area, researchers say.
Encouraging early results
Preliminary data from the MRCU released last week showed that the genetically modified males are successfully mating with females in the wild.
In the most recent data, collected over the past two months, an embedded genetic marker showed up in 94 percent of larvae collected in the targeted zone.
Though the final results of the Cayman GM mosquito project will not be published until it is completed, Mr. Petrie believes the international community will be watching with interest.