PhD Thesis
Dar es Salaam city of Tanzania has experienced continued Dengue outbreaks with
increased incidence since 2010. However, there is inadequate evidence of vector dynamics
and transmission risk in the region. This study aimed to determine mosquito species
composition, abundance and transmission risk of Dengue in Kinondoni district, Dar es
Salaam, Tanzania. Specifically, this study aimed to: (i) determine mosquito species
composition and abundance in Kinondoni district; (ii) examine Aedes mosquito breeding
sites and establish container productivity rates; (iii) determine Dengue virus (DENV)
infection rate and genetically characterize DENV in mosquito vectors. This cross-sectional
study was conducted in Kinondoni district, Dar es salaam, Tanzania. Three wards:
Mikocheni, Mwananyamala and Mzimuni were purposively selected. In each ward, three
streets were randomly selected as sampling sites. The study involved sampling adult and
immature mosquitoes, morphological identification and screening for DENV in collected
female Aedes mosquitoes using a one-step reverse transcription polymerase chain reaction
(RT-PCR). Three mosquito species were identified in 2001 collected mosquitoes namely
Culex quinquefasciatus (53.1%), Aedes aegypti (23.2%) and Mansonia mosquitoes (23.6%)
of which Culex quinquefasciatus was observed to be the most abundant species in
Kinondoni district. The common water-holding containers observed to be breeding sites of
Aedes mosquitoes included used car tires, flowerpots and plastic water buckets. The
overall House Index (HI), Container Index (CI) and Breteaux Index (BI) of Kinondoni
district were 55.1%, 60.4% and 114.2, respectively. DENV was not detected in all collected
female Aedes Mosquitoes. Generally, Kinondoni district continues to be at risk of
transmission of Dengue as Aedes aegypti, a DENV vector was observed to be present.
Although DENV was not detected in mosquito vectors, the presence of potential breeding
sites around Kinondoni district and higher Aedes HI, CI and BI put Kinondoni at risk of
DENV transmission. Vector control interventions specifically integrated mosquito control
approaches are recommended to be directed towards the elimination of breeding sites and
adult mosquitoes.
SACIDS Foundation