In 1970 MRCU set up a new department on Cayman Brac under the supervision of Mr. Michael Nathan assisted by Mr Floyd Banks. The principle role of this department was to rid the island of Aedes aegypti; the Dengue mosquito. This was achieved using an aggressive campaign of house spraying and yard surveys. In 1972 the WHO declared the Sister Islands free of this mosquito, although avoiding immigration of this species from Grand Cayman is still one of the vital tasks carried out by the Cayman Brac Unit.
Today the Unit is based on Songbird Drive on the Bluff. Day to day activities involve survey of private yards and other premises to check for standing water where mosquitoes breed. Breeding sites are reduced by tipping out water or the addition of larvicidal products (pellets and oils). Surveys are also conducted on Little Cayman several times per year. Truck mounted fogging in residential areas is utilized during the rainy season to keep homeowners as comfortable as possible.
Like the department in Grand Cayman, Cayman Brac also has a network of traps for monitoring mosquito populations. This consists of nine traps of various designs (BG Sentinel Traps, New Jersey Traps, Fay Traps and Mosquito Magnet traps) Mosquitoes collected are identified in the lab, allowing staff to make informed control decisions. Additional to this there is a New Jersey Trap located at the airport in Little Cayman that is collected weekly. The unit also has a network of ovitraps on Cayman Brac which are used as a first warning sign of the appearance of the dengue mosquito.
In an effort to maintain an absence of the Dengue mosquito in the Sister Islands, the Unit also carries out Port Disinsection in Cayman Brac and Little Cayman. This is a vital part of keeping invading mosquitoes to a minimum. All aircraft and sea traffic are treated with a pyrethroid insecticide to kill any invading mosquitoes. Containers bringing in supplies are also targeted as they are known to be one of the ways in which mosquitoes travel. However fresh refrigerated food stuffs are not sprayed.
Like the Department on Grand Cayman the goal of this Unit is to keep nuisance mosquitoes to a minimum and keep the islands free from mosquito borne diseases.