The Mosquito Research and Control Unit says World Mosquito Day on August 20 shows how daily life in the Cayman Islands has changed since the unit was established in 1965. The agency says its work has been central to public health, quality of life and the country’s development.

From Bodden Town to Grand Cayman and the wider islands, mosquito control has moved from a basic survival concern to a routine public service that helps residents use homes, outdoor spaces and community events. MRCU said the programme remains important because mosquito-borne disease risks have not disappeared.

A problem that shaped early Cayman

MRCU said historical records from as early as the 1800s described mosquito numbers in Cayman as a major national problem. For earlier generations, mosquitoes were not a nuisance. They affected daily routines, outdoor activity and even livestock.

Residents carried smoke pans or kept fires burning to ward off insects, while smoke was also used around animals. Outdoor life around sunset and after dark was often severely restricted. The unit said those conditions made the need for organised mosquito control clear.

The unit was established in 1965 under entomologist Dr Marco Giglioli, who was tasked with researching Cayman’s mosquito problem and developing effective methods of control. Even then, the scale of the challenge was formidable.

In 1974, a single mosquito trap in Bodden Town collected 793,103 mosquitoes in one night. MRCU said that figure helped show just how severe the problem had been before the island developed a modern control programme.

How the programme worked

Over ensuing decades, Cayman built a comprehensive mosquito management programme that combined scientific research, surveillance, wetland management, larviciding, property inspections, aircraft operations, truck fogging, resistance monitoring, disease surveillance and public education.

MRCU said no single method could control every mosquito, and no programme could eliminate mosquitoes entirely. The goal was to keep populations at manageable levels, respond when environmental conditions drove numbers up and reduce the risk of mosquito-borne disease transmission.

That work changed everyday life in Cayman in practical ways. Residents used yards and outdoor spaces with less disruption, and community and sporting events were easier to hold. Tourism and hospitality also operated in conditions far more manageable than those faced by earlier generations.

Success changed expectations

MRCU said its success had also changed what residents expected from mosquito control. Conditions that once might have been accepted as normal were now often treated as unacceptable, creating a balance the unit said it had to manage carefully.

One resident might ask that mosquito control products not be applied near a property, while neighbours in the same area might request more action because mosquitoes were affecting their ability to use homes and outdoor spaces. MRCU said operational decisions had to be based on science, public health needs, weather, resistance concerns and the wider community.

MRCU said those higher numbers did not mean the programme had failed. Instead, they showed how far Cayman had come from the extreme mosquito conditions of the past. Since 2020, MRCU has been led by Dr Alan Wheeler who has more than two decades of mosquito research and control experience. His focus has included moving the programme toward preventative, environmentally sustainable mosquito control.

“Our team is doing everything possible to bring the mosquito population back down, but the weather continues to be a major factor,” he said.

Public health remains a central concern

While nuisance control has transformed daily life, MRCU say protection against mosquito-borne disease was still one of its most important responsibilities. The Aedes aegypti mosquito, which is present in the Cayman Islands, can transmit dengue, Zika and chikungunya.

In a 2025 Cayman Government/MRCU press release, Dr Horace Cox, Director of Surveillance, Disease Prevention and Control Division at the Caribbean Public Health Agency (CARPHA), emphasised that the diseases transmitted by mosquitoes remain a serious regional threat.

He said: “Mosquitoes may be small, but the diseases they spread are not.”

MRCU noted that Cayman’s travel links mean there would always be a risk of infected travelers returning or arriving while carrying a mosquito-borne virus. That makes surveillance and rapid response essential.

During the past 10 years, from 2016 to 2025, Cayman recorded 133 mosquito-borne infections. Of these, 77 were imported and 56 were locally acquired, meaning no travel history was reported during the incubation period.

Most of the locally acquired cases occurred during two dengue outbreaks in 2019 and 2023, which accounted for 21 and 24 locally acquired dengue cases respectively. The surveillance data also included six Zika cases and two malaria cases over the same period where no travel history was indicated.

MRCU said the figures showed both Cayman’s continued vulnerability and its success in preventing mosquito-borne disease from becoming endemic. None of the events had led to sustained transmission in the community. That, the unit said, reflected the value of ongoing surveillance, mosquito control and public health response.

Surveillance data for 2026 to date showed two imported malaria cases and no locally acquired cases of dengue, malaria, chikungunya, Zika or West Nile virus.