The Mosquito Research & Control Unit (MRCU) was established in 1965 when Marco Giglioli arrived from the ODM London with instructions 'to establish a laboratory and conduct research with a view to advising the Cayman Government on suitable methods of control'. However, the Cayman Government insisted on actual control attempts having a high priority right from the start. The first vehicle mounted Tifa Todd thermal fogging machine was in operation by the 1966 mosquito season. Initial mosquito control efforts were concentrated on the Georgetown area and were very successful. Windrows of dead mosquitoes were reported in the streets each morning. Fogging machines increased in number to nine by 1969, mostly mounted on Mini Mokes, using malathion diluted in diesel oil.

Mosquito densities were high enough in those days to warrant fogging well past the dusk peak period and Giglioli solved the problem of staff and funding for his work by forming a corps of volunteer foggers. Many Cayman citizens, led by Captain Theo Bodden, gave large amounts of their free time in the service of mosquito control. As mosquito numbers diminished and other control methods came into operation, and the number of fogging machines was reduced and replaced by ultra-low-volume (ULV) sprayers. ULV sprayers are easier to operate and less of a hazard to the traffic in Grand Cayman. From the beginning, Giglioli was keen to attempt mosquito control by physicals means. He believed that by manipulating the swamp water levels mosquito breeding could be disrupted and as a result lead to permanent reductions in mosquito numbers.

Dyke building through the swamp began in 1967, and over the years the network of canals and dykes has grown until by 1983 when most mangrove areas around North Sound were divided into sections in which water levels could be manipulated. The creation of a more dynamic water-level regime has considerably reduced the ability of Aedes taeniorhynchus to breed in large numbers and it has become difficult to find larvae in areas historically known to produce enormous broods. The early and rapid success of the fogging program indicated that if insecticide could be applied over the huge areas of inaccessible swamp an enormous reduction in mosquitoes could result. This was tested in 1971 with a Cessna Ag-Wagon aircraft spraying malathion and proved to be extremely successful.

Much experimental work was then carried out by Giglioli and MRCU pilot J.F. Lesieur to determine the most effective and economic formulation of malathion and obtain the optimal droplet size from the Micronair atomisers with which the aircraft were equipped. Aerial spraying began to be used on a large scale in 1972 when most of Grand Cayman was treated repeatedly and unprecedented reductions in mosquito numbers resulted. Although the equipment and insecticides currently used by MRCU may be different to those applied during the early days of mosquito control in Grand Cayman, the principles on which the control strategy is based remain similar to those established by Giglioli in the 1960s and 1970s.

MRCU provides mosquito control on the Sister Islands through the Mosquito Control Unit on Cayman Brac. This Unit operates in a similar way to MRCU on Grand Cayman. Cayman Brac operates a number of truck mounted ground fogger units, carries out Port Disinsection and Aedes aegypti monitoring. On Little Cayman there is a single truck mounted ground fogger unit, Port Disinsection as required and limited Aedes aegypti monitoring.