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Mosquitoes can be vectors of disease carrying pathogens from one host to another and many pathogens must pass certain stages of their life history within mosquitoes. Moreover, most viruses exhibit a latent period after penetrating the mosquito, and until the incubation period is over no transmission is possible. Aedes aegypti mosquitoes are apparently unaffected by infection with the dengue virus and dengue fever will not shorten its life span nor will it alter its behavior in any detectable manner. However, environmental hazards can determine whether Aedes aegypti will survive long enough to pass-on the dengue virus it carries. Among the determinants of dengue transmission are the environmental or geographical areas where the vector develops and contacts the host population. As compiled from the literature, these geographical and climatological parameters may be used to stratify the areas where the expected transmission may be endemic, epidemic, or sporadic.  Consider the following: 1. Dengue is mainly transmitted in the tropical and sub-tropical regions of the Americas that lie between 45 degrees North and 35 degrees South Latitudes. 2. Elevation is a limiting factor for vector and virus development. At lower elevations, mean annual temperature, humidity, and rainfall are the conditions that affect vector survival and reproduction 3. Temperature also affects viral replication in the vector: ambient temperature range: 15 - 40 degrees C relative humidity: moderate to high.