An Association between Rainy Days with Clinical Dengue Fever in Dhaka, Bangladesh: Findings from a Hospital Based Study

Abstract

Background: Dengue, a febrile illness, is caused by a Flavivirus transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Climate influences the ecology of the vectors. We aimed to identify the influence of climatic variability on the occurrence of clinical dengue requiring hospitalization in Zone-5, a high incidence area of Dhaka City Corporation (DCC), Bangladesh.; Methods and Findings: We retrospectively identified clinical dengue cases hospitalized from Zone-5 of DCC between 2005 and 2009. We extracted records of the four major catchment hospitals of the study area. The Bangladesh Meteorological Department (BMD) provided data on temperature, rainfall, and humidity of DCC for the study period. We used autoregressive integrated moving average (ARIMA) models for the number of monthly dengue hospitalizations. We also modeled all the climatic variables using Poisson regression. During our study period, dengue occurred throughout the year in Zone-5 of DCC. The median number of hospitalized dengue cases was 9 per month. Dengue incidence increased sharply from June, and reached its peak in August. One additional rainy day per month increased dengue cases in the succeeding month by 6% (RR = 1.06, 95% CI: 1.04-1.09).; Conclusions: Dengue is transmitted throughout the year in Zone-5 of DCC, with seasonal variation in incidence. The number of rainy days per month is significantly associated with dengue incidence in the subsequent month. Our study suggests the initiation of campaigns in DCC for controlling dengue and other Aedes mosquito borne diseases, including Chikunguniya from the month of May each year. BMD rainfall data may be used to determine campaign timing.Lancet. 2007 Nov 10;370(9599):1644-52. (PMID: 17993365); Lancet Infect Dis. 2017 Nov;17(11):1118. (PMID: 29115257); Southeast Asian J Trop Med Public Health. 2002 Mar;33(1):42-8. (PMID: 12118459); Lancet. 2019 Dec 14;394(10215):2149-2150. (PMID: 31839186); Am J Trop Med Hyg. 1983 Jan;32(1):154-6. (PMID: 6824120); PLoS One. 2018 Jun 21;13(6):e0199457. (PMID: 29928055); BMC Infect Dis. 2012 Apr 24;12:98. (PMID: 22530873); Am J Trop Med Hyg. 1997 Feb;56(2):159-67. (PMID: 9080874); Am J Trop Med Hyg. 2006 Feb;74(2):263-5. (PMID: 16474082); Am J Trop Med Hyg. 1987 Jan;36(1):143-52. (PMID: 3812879); PLoS One. 2012;7(11):e50972. (PMID: 23226436); Emerg Infect Dis. 2002 Jul;8(7):738-40. (PMID: 12095447); PLoS Negl Trop Dis. 2015 Jul 10;9(7):e0003907. (PMID: 26161995); Nature. 2013 Apr 25;496(7446):504-7. (PMID: 23563266); Sci Total Environ. 2010 Oct 15;408(22):5521-8. (PMID: 20817262); Am J Trop Med Hyg. 2016 Jun 1;94(6):1359-61. (PMID: 27114293); Mymensingh Med J. 2007 Jul;16(2):204-8. (PMID: 17703160); PLoS Negl Trop Dis. 2015 Jul 10;9(7):e0003901. (PMID: 26161895); Clin Microbiol Rev. 1998 Jul;11(3):480-96. (PMID: 9665979); Am J Trop Med Hyg. 2012 Jan;86(1):58-64. (PMID: 22232452); Emerg Infect Dis. 2003 Nov;9(11):1411-4. (PMID: 14718084); Trans R Soc Trop Med Hyg. 2015 Oct;109(10):619-27. (PMID: 26333430); Bull World Health Organ. 1980;58(1):1-21. (PMID: 6966540); Glob Health Action. 2009 Nov 11;2:. (PMID: 20052380); Science. 1988 Jan 29;239(4839):476-81. (PMID: 3277268); Trop Med Int Health. 2012 Sep;17(9):1086-91. (PMID: 22809407); Indian J Med Res. 2012 Jul;136(1):32-9. (PMID: 22885261). Linking ISSN: 16604601. Subset: MEDLINE; Date of Electronic Publication: 2020 Dec 18. ; Original Imprints: Publication: Basel : MDPI, c2004- <br />