Two local Zika cases confirmed

Heidi Groves releases genetically modified mosquitoes from the back of the Mosquito Research and Control Unit van Tuesday morning. - Photo: Charles Duncan

Two people in George Town are Cayman’s first official cases of locally transmitted Zika, according to public health officials. The islands have had six cases of Zika imported by people visiting other countries, but these are the first reported incidents of the virus being acquired locally.

The Public Health Department reported Monday that the first person, a man in George Town North, began experiencing symptoms on July 25 and went to a doctor the next day. The Health Services Authority tested the man, who had not traveled to countries with Zika, and the Caribbean Public Health Agency confirmed that he had contracted the virus.

A second case, announced Tuesday, is in a woman who lives in George Town West. The Public Health Department said the woman began experiencing symptoms on July 10 and went to a private doctor two days later. Public health officials originally classified the case as imported, but later decided the woman’s travel history indicated that she contracted Zika in Cayman.

“This was anticipated,” Bill Petrie, head of Cayman’s Mosquito Research and Control Unit, said Tuesday. “This was no great surprise,” that Cayman now has locally transmitted Zika, he said.

MRCU and Oxitec workers release genetically modified mosquitoes in West Bay Tuesday morning. - Photo: Charles Duncan
MRCU and Oxitec workers release genetically modified mosquitoes in West Bay Tuesday morning. – Photo: Charles Duncan

Mr. Petrie said his unit plans to ramp up operations against the Aedes aegypti mosquitoes responsible for transmitting the Zika virus, dengue, chikungunya and yellow fever. He said the MRCU will be increasing aerial spraying and fogging from trucks.

He said the MRCU will start spraying earlier in the evening to target adult mosquitoes and will focus fogger trucks on areas that could have the Zika virus in local mosquito populations.

Premier Alden McLaughlin, in a statement released Tuesday, said, “I want to reassure the public that MRCU, with the unflinching support of this Government, will continue its eradication efforts.”

Zika can also be transmitted sexually from an infected man to a woman.

Dr. Samuel Williams-Rodriguez, Cayman’s head of public health, said in a statement on Monday, “With the rapid and ongoing transmission of the Zika virus around the world, it is not an alarming fact that local transmission has reached our shores. However, now that it has, this is even more reason for each and every one to play their part in ensuring that the spread is highly contained.”

Public health officials, citing confidentiality, declined to be more specific on where the infected people live other than George Town North and George Town West.

Responding to questions by email Tuesday, Dr. Williams-Rodriguez said people should “avoid mosquito bites at home and abroad, adopt safe sexual practices at home and abroad, pregnant women to avoid unnecessary travel to regions with large outbreak of [Zika].”

He added, “Due to the spreading pattern of the disease and the presence of the Aedes mosquito in the Cayman Islands, more cases of local transmission are expected. We encourage the public to intensify vector control measures around and inside their residence.”

Dr. Williams-Rodriguez said he is confident that with the MRCU, government and the public working together, “a large outbreak of the [Zika virus] disease will be prevented.”

The biggest danger of the Zika virus is to pregnant women. The virus can cause microcephaly, a severe birth defect, in babies born to infected mothers. The virus can also lead to Guillain-Barre syndrome, a neurological disorder that can cause paralysis and death.

Most people infected with Zika never show symptoms, according to the World Health Organization, but those who do can have a mild fever, rash, muscle and joint pain and conjunctivitis. Symptoms can last from two days to a week, and tend to be mild.

The Aedes aegypti mosquitoes breed in standing fresh water near homes, such as in old tires, bird baths or clogged rain gutters. The best way to get rid of Aedes aegypti is to dump out anything with fresh standing water and turn over things like dog bowls so mosquitoes cannot use them to breed.

GM mosquito release program

While the MRCU is boosting its spraying operations, the unit’s work with Oxitec to use genetically modified mosquitoes in West Bay is in its first week of full operation. Oxitec and the MRCU are testing the GM mosquitoes in a small section of West Bay to see how effective the method is at eliminating Aedes aegypti from the area.

Oxitec’s Tali Cohen and Heidi Groves were out in a modified van Tuesday morning to release 150,000 genetically modified male mosquitoes in hopes that the insects will mate with female Aedes aegypti mosquitoes. When a female mates with a GM male mosquito, the next generation is unable to survive to adulthood, and the hope is that this will kill off the population of mosquitoes responsible for spreading Zika and other viruses.

Cayman now joins almost 70 other countries and jurisdictions with local transmission of Zika, including almost every country in South and Central America and the Caribbean.

Public health officials in the U.S. recently announced they found local Zika transmission in one part of Miami, Florida.