West Bay seniors get lowdown on Zika

MRCU Director Bill Petrie explains that Aedes aegypti mosquitoes can breed in something as small as a cup.

With the arrival of Zika in Cayman, much talk has been about pregnant women whose unborn children face dangers if exposed to the virus. But recently some seniors in West Bay had the chance to get information that addressed their concerns.

At a special event organized for the John Gray Memorial Church Seniors’ Fellowship at the church in West Bay on Sept. 8, Mosquito Research and Control Unit Director Bill Petrie and Renaud Lacroix of Oxitec discussed mosquitoes, the diseases they can spread, potential prevention, and the genetically modified mosquito project which is attempting to control the spread of the Zika virus.

The seniors learned that mosquitoes kill more people every year around the world than war, AIDS or most diseases. They also learned there are no specific treatments for Zika – just Panadol, bed rest and cream if the symptoms include a rash, and that a fraction of show any symptoms.

Some seniors raised their concerns about how to tell the difference between the genetically modified mosquitoes and Zika carriers, while others were anxious about the spread of the Zika virus through human contact, and some wanted to know how to protect themselves.

Eula Glidden was concerned about Zika transmission. She learned that out of all the mosquitoes in Cayman, only the Aedes aegypti, referred to by some as the Zika mosquito, can transmit the virus.

The Aedes aegypti has also been referred to historically as the yellow fever mosquito, and it also carries dengue and chikungunya. The audience heard that West Bay is the hot spot on the island for Aedes aegypti mosquitoes.

Seniors enjoy lunch after a presentation on the Zika virus. - Photos: Jewel Levy
Seniors enjoy lunch after a presentation on the Zika virus. – Photos: Jewel Levy

Mr. Petrie said the mosquito that carries Zika usually only breeds around people, houses and other premises. It does not breed in the swamps, bushes or pasture lands. He advised the audience to clean up yards, get rid of rubbish and garbage, and remove standing water from containers.

He said the eradication project being carried out in conjunction with Oxitec is releasing hundreds of thousands of male mosquitoes that have been genetically altered. The males, which do not bite, are intended to mate with the female Aedes aegypti mosquitoes that can spread Zika. The females that mate with the male GM mosquitoes lay eggs that hatch, but the larvae do not survive to adulthood.

The audience also heard that the GM mosquitoes only mate with Aedes aegypti females, assuring them that the mosquitoes could not establish themselves in the environment since they would die out once they stopped being released.

“If we do the GM release, over time the population of Aedes aegypti will come down,” Mr. Petrie said.

West Bay resident Sharlene Rogers said she noticed some mosquitoes were leaving a very nasty sting, with some worse than others.

“It’s what [the mosquito] injects into you as it is biting,” said Mr. Petrie.

“But how will we know the difference between the GM and the Zika carriers and not kill them just the same?” Ms. Rogers asked.

“We are not asking you not to kill the GM mosquitoes. Kill them if you see them,” said Mr. Petrie.

“We don’t want people to stop killing mosquitoes when Zika virus is out,” he added.

He said the genetically modified mosquitoes were being released three times a week, at locations some 200 feet apart. He said the released mosquitoes fly only 300 feet in any direction on average, and some might not survive long.

“It will take a while to get the Zika population down, but it’s a good protection in the long run from people getting Zika or dengue,” he said.

One woman asked if there was not concern that a whole new type of mosquito might be created from the genetically modified mosquitoes mating with the existing Aedes aegypti mosquitoes.

Mr. Petrie said the process is being regulated, and that it is safe for people and the environment.

He explained that similar eradication efforts have been successful in other countries, and that the genetically modified mosquitoes are a dead end in evolution since the mosquitoes cannot reproduce.

“What if one finds a way to live despite all of that? What then?” the woman asked.

“Everyone that looked at the GM mosquitoes never found that issue,” said Mr. Petrie.
Leonard Ebanks wondered if the current mosquito spraying would kill off the genetically modified mosquitoes.

Mr. Petrie said the GM mosquitoes only live a couple of days, and the MRCU is alternating spraying days with the release days.

Mr. Ebanks also asked about derelict vehicles that could cause an environmental health problem. Mr. Petrie said the MRCU is working with Environmental Health to clean up places that need it.

In response to a query about the possibility of the Zika virus becoming endemic in the Cayman Islands and what measures could be taken, Mr. Petrie said all the methods the MRCU has at its disposal are being used to get rid of the mosquitoes. None is 100 percent effective, he noted, and releasing the GM mosquitoes is a long-term strategy.

He said the MRCU is working around the clock to contain the Zika virus.