CASTRIES, St Lucia (CMC) - Health authorities here yesterday warned the population to take all precautionary steps to prevent the spread of the dengue fever, given the rapid onset of the rainy season.The Ministry of Health and Wellness said dengue fever is one of the most common vector-borne viral illnesses affecting humans, transmitted through the bite of the female Aedes aegypti mosquito, and to a lesser extent the Aedes albopictus.