Epidemiology of dengue in Nepal: History of incidence, current prevalence and strategies for future control.

Dengue is now established as one of the most important arboviral infections. As the epidemic continues unabated globally, this Aedes mosquito-transmitted pathogen is considered a major re-emerging tropical disease and significant public health concern. Four well-established distinct serotypes of dengue virus, with a fifth one recently proposed, are responsible for causing a spectrum of clinical symptoms in humans ranging from mild fever to severe haemorrhagic manifestations. Indigenous cases of dengue were first recognised in Nepal, a Himalayan country bordered by India and China, just a decade ago in a cluster of tropical and subtropical areas. Subsequently, the range of infection has extended all over the country and now comprises not only low lying regions, but also hilly locations including the capital city Kathmandu. The two major epidemics to date, in 2010 and 2013, have demonstrated the capacity of infection outbreaks to be explosive and challenging to currently available disease control measures. There is a pressing need to undertake effective vector surveillance studies supported by provision of well-equipped diagnostic virology laboratories. However, sincere efforts are being made to map the nationwide prevalence and understand the epidemiology of dengue infection. Yet, the precise burden of dengue in Nepal remains unknown, since most reports are confined to economically affluent areas and do not account for regions of relative social deprivation in which disease is more likely to occur. This review presents a current overview of dengue in Nepal and discusses future prospects for control of this debilitating disease in the country.