Surge in Mosquito Numbers Following Recent Weather

GRAND CAYMAN, Cayman Islands (4 August 2025) – Heavy rains and high tides have resulted in a significant increase in mosquito numbers across Grand Cayman. The Mosquito Research and Control Unit (MRCU) says it is responding swiftly.
Current Situation:
MRCU crews have increased both aerial and ground spraying to bring mosquito levels back down.

Grand Cayman is  currently in the middle of one mosquito emergence, with another expected to begin around 15 August, due to Saturday’s heavy rainfall and standing water.

MRCU teams are working extended hours targeting adult mosquitoes (the ones that bite) and treating standing water to prevent larvae from hatching.

“We’re doing everything we can to reduce mosquito numbers as quickly as possible,”
– Dr Alan Wheeler, MRCU Director

What Should Residents Expect?

• You’ll likely notice improvements in mosquito numbers in the next few days.
• Another spike is likely mid-month due to recent rainfall.
  

What You Can Do

Protect Your Pets:

• The black salt marsh mosquito (Aedes taeniorhynchus)—the main species currently causing discomfort—can also transmit heartworm to dogs and cats.
• Pet owners should speak with their veterinarians to ensure their animals are protected with the right preventive medication.

Report Unusual Mosquito Activity:

• If you notice unusually high mosquito biting, please email the MRCU at mrcu@gov.ky.
• Include your location and the time of day the biting occurred.
• This information helps MRCU target problem areas more effectively.

Mosquito Numbers at a Glance

So far this year, mosquito trap counts have more than doubled compared to the same period in 2024.

• 2024: Average of 5.8 mosquitoes per trap per night
• 2025: Average of 13.9 mosquitoes per trap per night

Nights with high mosquito counts:

• 2025: 23 nights so far
• 2024: Only 4 nights

Stay updated by following the MRCU website and social media platforms for the latest information and advice.

For questions or to report mosquito problems, contact MRCU at mrcu@gov.ky.