Mosquito surveillance is used to determine changes in the geographical distribution and density of the local mosquito population, evaluate control measures, obtain relative measurements of the vector population over time and facilitate appropriate and timely decisions regarding interventions. Surveillance may also serve to identify areas of higher than normal infestation or periods of population increase. A number of methods are available for detecting or monitoring immature and adult mosquito populations. Selection of appropriate sampling methods depends on the surveillance objectives, levels of infestation, available funding and skills of personnel.