The impact of population mobility on dengue: an experience from Northern Sri Lanka

Abstract

Dengue infection continues to be a major public health issue and has been a challenge to health authorities for years due to several reasons. It is well known that the virus, mosquito and human factors play significant roles in the transmission of the infection. Traditionally, several preventive measures that are targeted towards the mosquito are well implemented in several countries, including Sri Lanka. Studies have shown that human mobility is a contributing factor in dengue infection and the objective of this report is to give an account on the possibility of human mobility as a major contributing factor for the outbreak of dengue infection in northern Sri Lanka. The gateway "A9" was reopened to the public in mid-2009, as the political unrest had come to a halt by May 2009. Northern Sri Lanka was thereby reconnected with the south, which increased population mobility both ways. An increase in the incidence rate of dengue fever from 10.72 in 2008 to 539.65 in 2010, supported the hypothesis of the possible contribution of human mobility in the dengue outbreak of 2010. Human mobility factors are often overlooked when considering preventive aspects. Preventive measures targeting human movements may enhance effectiveness of dengue control programs. Dengue has been identified as a national problem, causing a huge economic burden to the Sri Lankan health sector in both primary and secondary care over the past two decades. The epidemiology of dengue depends on three key aspects, the dengue virus (DENV) including the four closely related virus serotypes (DEN-1, DEN-2, DEN-3, DEN-4 of Flavivirus genus), the vector (Aedes aegypti) and the human host. Of these, the host factors are often overlooked when considering preventive aspects. However, it is noted that the dengue virus could rapidly spread into new human populations due to human mobility. Studies have shown the role of movement of human population in the spread of dengue infection in several regions of the world. 1