Description and lessons learned from the 2014 Dengue outbreak in Dar es Salaam, Tanzania. Knowledge, attitudes and bite prevention practices among those with confirmed Dengue

Abstract

BackgroundThe frequency and magnitude of Dengue epidemics have increased dramatically in the past 40 years throughout the tropics largely due to unplanned urbanization, globalization and lack of effective mosquito control. Dar es Salaam, Tanzania has recently experienced Dengue outbreaks that occur with increasing frequency. Currently, only one serotype is recorded. Without adequate vector monitoring and control, it is certain that further outbreaks will occur. Methods/FindingsA retrospective study followed 100 individuals with confirmed Dengue fever in Kinondoni, Dar es Salaam during the 2014 outbreak. Houses were inspected for mosquito breeding sites and gathered information on Socio-economic Status (SES) and Dengue prevention knowledge.Higher SES tertile had the most Dengue cases: 53 (55%) followed by medium and lower SES with 33 (34%) and 11 (11%) respectively. The highest number of mosquito breeding sites was also found in higher SES households. Kinondoni wards of Manzese, Mwananyamala, Tandale and Mabibo had the socioeconomic groups, combined. The public was ill-informed about Dengue fever: 84% think bed nets can prevent Dengue, and 60% of the patients only became aware of Dengue while in the hospital with the illness. The study established a habitat suitability score, a tool to be used to estimate breeding habitat capacity before rains begin. Scattered containers especially tyres remain ideal breeding sites.The study highlights the need for waste management to avert future outbreaks.

Occurrence of 4 Dengue Virus Serotypes and Chikungunya Virus in Kilombero Valley, Tanzania, During the Dengue Outbreak in 2018

“…Furthermore, DENV-1 was detected in a traveler returning from Tanzania to Japan in 2019 [ 26 ], and DENV-3 had been reported in Japan from a traveler who had visited Tanzania in 2010 [ 36 ], supporting its existence in the country. During the repeated DENV outbreaks in Tanzania, the reported disease severity was low to moderate with few deaths, that is, 4 and 13 deaths in the 2014 and 2018–2019 outbreaks, respectively [ 22 , 24 ]. Out of the 4 deceased cases in 2014, 1 had presented with DHF and 1 with multiple organ failure.…”

“…In Tanzania, DENV outbreaks were reported in 2010, 2012–2014 [ 9 , 18–20 ], and recently in 2018 and 2019 [ 21 ]. The 2014 outbreak resulted in 1018 confirmed cases and 4 deaths, mainly in Dar es Salaam [ 22 ], with a few confirmed cases in Kilosa district [ 10 ]. However, the worst documented dengue outbreak occurred in 2019 in Dar es Salaam and later in Tanga [ 21 ], with 6873 cases and 13 deaths [ 21 ].…”

Occurrence of Four Dengue Virus Serotypes and Chikungunya Virus in Kilombero, Tanzania during Dengue Outbreak in 2018

“…During the repeated DENV outbreaks in Tanzania, the reported disease severity was low to moderate with few deaths, i.e. 4 and 13 deaths in 2014 and 2018-2019 outbreaks, respectively [11]. Out of the four deceased cases in 2014, one had presented with DHF, and one with multiple organ failure.…”

“…The vector of transmission for both viruses is the day-biting Aedes aegypti mosquito, which is commonly found throughout the tropical and subtropical areas [9, 10]. The diverse breeding habitats for Aedes mosquitoes account for DENV and CHIKV epidemics during the dry seasons and contribute to urban transmission of the diseases [11-13].…”

“…In Tanzania, DENV outbreaks were reported in 2010, 2012-2014 [14, 23-25] and recently in 2018 and 2019 [26]. The 2014 outbreak resulted in 1,018 confirmed cases and 4 deaths mainly in Dar es Salaam [11], and a few confirmed cases in Kilosa district [15]. However, the worst documented dengue outbreak occurred in 2019 in Dar es Salaam and later in Tanga [26] with 6,873 cases and 13 deaths [26].…”