Analysis of Geographical and Seasonal Variation of Dengue Fever in Nepal Based on EWARS Line Listing from 2017 to 2019

Abstract

Background: Dengue is a mosquito-borne viral disease; rapidly spreading in many countries worldwide in recent years. Dengue has been identified as one of the youngest emerging infectious diseases in Nepal, the first case reported in 2004. In 2006, 32 laboratory-confirmed cases were reported across hospitals in central and western Terai and Kathmandu during the post-monsoon season. The trend for increased magnitude has been continued with the number of outbreaks reported each year in many districts in two to three years intervals. Since 2010, dengue epidemics have continued to affect lowland districts and mid-hill areas. These all reflected need of study on geographical and seasonal variation of dengue fever and many more. This study analyzed the geographical and seasonal variation of Dengue fever in Nepal based on EWARS line listing 2017-2019 and provides recommendations for improvement of the dengue control program in Nepal. Methodology: Quantitative analysis of key variables from the Early Warning and Reporting System (EWARS) line list was applied. EWARS line listing data from 2017to 19 was received from the department of health service, epidemiology and disease control division (EDCD), Nepal and analyzed. Published literature and articles were reviewed to discuss and triangulate the findings. Microsoft excels and SPSS20 software was used for data analysis, and Mendeley software was used for referencing and citations. Based on the line listing data from EDCD, last three years dengue situation, age, gender, seasons, geography and department of registration in the sentinel sites were analyzed and discussed. The Chi-square test in 95 % confidence interval was applied to test hypothesis assessing the relationship of age group and geographical belt on the dengue cases reported in the studied years. Results: Entirely of 2273 individual cases were verified and updated by EDCD; among these 1.32 % of received data were excluded and a total of 2243 samples were analyzed and studied. The male population of the age group 20 to 40 was observed at higher risk of dengue with the infant proportion of 1.43% in Nepal. The notable infant case showed the urgency of actions needed to address this issue. Most of the dengue cases were found registered in from IPD, emergency, OPD and laboratory departments. The geographical distribution of dengue cases reflected the higher case in Terai low land districts with massively escalating in the hill, Kathmandu valley and Mountain belts. The clusters of cases to outbreak situation of dengue suggest diversity and uncertainty of dengue incidence. In the study period, the highest cases were found in Lumbini province followed by Province 01and significance cases were reported from Province 02 and Bagmati province. In contrast, the Sudurpaschim, Gandaki and Karnali provinces reported a minimum number of cases. Mountain district Dhading had reported one of the top five reporting districts in the study period. Similarly, dengue cases fluctuated based on the seasons, predominantly in the monsoon and post-monsoon season in Nepal. The test statistics, Chi-square test suggested a significant association between age group and geographical belts to the year wise dengue cases. Conclusion: Thus Dengue has been tough public health problem with a rising burden and wider geographical and seasonal coverage resulting in a frequent outbreak in Nepal. The changing disease patterns with an uncertainty of prediction increases challenge. It is strongly recommended strategic preparedness and research and developmental works to improve dengue control program for the betterment of the population's health.