Vector control against infectious diseases: Towards the sustainable development of insect repellents in New Caledonia

More than 80% of the world’s population is threatened by vector-borne diseases with populations in tropical regions most at risk. The World Health Organization (WHO) thus promotes the use of mosquito repellents to prevent infectious diseases. In New Caledonia, the office of Social and Health Affairs Direction (DASS) approved 4 active substances of insect repellents for personal anti-vector protection, among these para-menthan-3,8-diol or PMD. This joint-project between James Cook University (JCU) and the University of New Caledonia (UNC) aimed to identify essential oil bearing plants within the flora of New Caledonia that can supply significant quantities of PMD or its precursor citronellal. The study subsequently identified the essential oil of Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson of the Myrtaceae family already produced in New Caledonia as an important candidate for the production of PMD. This oil provides a significant amount of citronellal, which after an acid-catalyzed thermal cyclisation hydration sequence leads to a mixture of cis and trans isomers of PMD. On the basis of a published method, a standard operating procedure for the conversion of citronellal to PMD has been provided to a distillery in New Caledonia. The distillery has since produced and marketed this renewable insect repellent