South Asia has the highest burden of dengue: Lancet Study

Picture Credit: CDC

South Asian countries have the highest burden of dengue followed by Southeast Asia and the Caribbean, according to a recent paper published in the Lancet. Amongst the South Asian nations, India reported the highest number of cases (4072.925) and Nepal the least (0.170336) in 2017.

 

The paper presents the most up-to-date estimates of the incidence, mortality, and Disability-Adjusted Life Years (DALYs) for dengue in 195 countries and territories from 1990 to 2017, using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2017.

Incidence

According to the study, in 2017 an estimated 10,47,71,911 individuals had dengue worldwide compared with 2.32,83,274 in 1990. 

“An estimated 100 million dengue infections occurred across more than 110 countries and territories in 2017, increasing from 23 million dengue infections in 1990, with potential for further spread.”

The study shows that the age-standardized incidence rate has increased in the time period 1990 to 2017. At the country level, the age-standardized (ASR) incidence rate per 1 lakh population for dengue was highest in Barbados, followed by Dominica, Indonesia and India.

81 and territories had no dengue data in 2017

Among all regions, dengue was most prominent in South Asia, Southeast Asia and the Caribbean.

  

Mortality

According to the research the number of deaths in 1990 due to dengue was approximately 16,957 and in 2017 was 40,467- an increase of around 24,000 deaths. Region-wise, deaths attributable to dengue per 1 lakh people were most frequent in the Southeast Asia super-region (1.97 deaths) and South Asia super-region (1.46 deaths) in 2017.

The highest age-standardised death rate in 2017 was found among individuals aged 0-1 years and >80 years, it says.

 

DALYs

The disability-adjusted life year is a measure of overall disease burden expressed as the number of years lost due to ill-health, disability or early death.

In 2017, there were more than 29 lakh DALYs due to dengue globally compared to 14,07,571 in 1990, showing an increase of 107.6%. At the regional level, the age-standardised DALY rate of dengue per 1 lakh population was found to be highest in Southeast Asia (154.24), South Asia (89.93) and the Caribbean (41.02) in 2017.

Cause of Dengue

The study says that dengue incidence is influenced by both climate and non-climate drivers. According to the study, the local climate and the El Nino-Southern Oscillation (ENSO) are potentially responsible for the interannual variability in dengue fever transmission. 

The linkage of ENSO to dengue is based on “the connections between ENSO and local climate anomalies in certain regions of the world as well as the influence of climate on the dengue mosquito vector and virus,” it says.

The study also highlights non-climate factors and other social-ecological drivers influencing vector populations and human exposure which may be the potential determinants of dengue incidence variability.