Socio-demographic determinants of dengue infection during an outbreak in Dar es Salaam City, Tanzania

AbstractBackground: In recent years, the eastern coast of Africa has witnessed a number of dengue outbreaks. This study was carried out to determine socio-demographic determinants of dengue infection during the 2014 outbreak in Dar es Salaam, Tanzania. Methods: Unmatched case-control analysis of secondary data from a cross-sectional dengue investigation in three districts of Dar es Salaam in June 2014 was conducted. Febrile patients seeking care at health facilities were recruited. Cases were serologically-confirmed dengue-positive while controls were serologically-confirmed dengue-negative patients. A questionnaire was used to collect sociodemographic information. The association between sociodemographic variables and dengue infection was examined using univariate analysis and multivariate logistic regression analysis. Results: A total of 81 cases and 281 controls were included in the analysis. Majority of the cases and controls were males (64.2% versus 54.1%; P=0.137) and were >15 years of age (88.9% versus 72.9%; P =0.003). Living in Kinondoni (aOR = 4.28; 95% CI: 1.74 - 10.53); being employed (aOR = 2.06; 95% CI: 1.06-4.04); having piped water at home (aOR = 2.63; 95% CI: 1.40 - 4.95) and a recent visit of health facility (aOR = 1.94; 95% CI: 1.11 - 3.38) were significantly associated with dengue infection.Conclusions: Dengue infection in Dar es Salaam varied between the three districts and was associated with being employed, having piped water at home and a recent visit to the health facility. These findings provide primary understanding of the influence of socio-demographic factors on dengue and may be used to develop appropriate preventive interventions

The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014.

BACKGROUND:In 2010, 2012, 2013 and 2014 dengue outbreaks have been reported in Dar es Salaam, Tanzania. However, there is no comprehensive data on the risk of transmission of dengue in the country. The objective of this study was to assess the risk of transmission of dengue in Dar es Salaam during the 2014 epidemic. METHODOLOGY/PRINCIPAL FINDINGS:This cross-sectional study was conducted in Dar es Salaam, Tanzania during the dengue outbreak of 2014. The study involved Ilala, Kinondoni and Temeke districts. Adult mosquitoes were collected using carbon dioxide-propane powered Mosquito Magnet Liberty Plus traps. In each household compound, water-holding containers were examined for mosquito larvae and pupae. Dengue virus infection of mosquitoes was determined using real-time reverse transcription polymerase chain reaction (qRT-PCR). Partial amplification and sequencing of dengue virus genome in infected mosquitoes was performed. A total of 1,000 adult mosquitoes were collected. Over half (59.9%) of the adult mosquitoes were collected in Kinondoni. Aedes aegypti accounted for 17.2% of the mosquitoes of which 90.6% were from Kinondoni. Of a total of 796 houses inspected, 38.3% had water-holding containers in their premises. Kinondoni had the largest proportion of water-holding containers (57.7%), followed by Temeke (31.4%) and Ilala (23.4%). The most common breeding containers for the Aedes mosquitoes were discarded plastic containers and tires. High Aedes infestation indices were observed for all districts and sites, with a house index of 18.1% in Ilala, 25.5% in Temeke and 35.3% in Kinondoni. The respective container indices were 77.4%, 65.2% and 80.2%. Of the reared larvae and pupae, 5,250 adult mosquitoes emerged, of which 61.9% were Ae. aegypti. Overall, 27 (8.18) of the 330 pools of Ae. aegypti were positive for dengue virus. On average, the overall maximum likelihood estimate (MLE) indicates pooled infection rate of 8.49 per 1,000 mosquitoes (95%CI = 5.72-12.16). There was no significant difference in pooled infection rates between the districts. Dengue viruses in the tested mosquitoes clustered into serotype 2 cosmopolitan genotype. CONCLUSIONS/SIGNIFICANCE:Ae. aegypti is the main vector of dengue in Dar es Salaam and breeds mainly in medium size plastic containers and tires. The Aedes house indices were high, indicating that the three districts were at high risk of dengue transmission. The 2014 dengue outbreak was caused by Dengue virus serotype 2. The high mosquito larval and pupal indices in the area require intensification of vector surveillance along with source reduction and health education

Clinical characteristics and outcomes of confirmed COVID-19 patients in the early months of the pandemic in Tanzania: A multicentre cohort study

Background We performed a prospective cohort study of the clinical presentations and management outcomes of laboratory-confirmed COVID-19 patients in the early months of the pandemic at two hospitals in Dar es Salaam, Tanzania. Methods Between April 1 - May 31, 2020, laboratory-confirmed COVID-19 patients seen at two tertiary facilities were consecutively enrolled in the study and followed up for 21 days. Results We enrolled 121 COVID-19 patients; 112 (92.6%) were admitted while 9 (7.4%) were seen as outpatients. The median (IQR) age of patients was 41 (30-54) years; 72 (59.5%) were male. The medians (IQR) reported days from hospital admission to recovery and death was 10 (6-18) and 5.5 (3-9), respectively. Forty-four (36.4%) patients had at least one underlying condition. Of the 112 admissions, 17 (15.2%) went to ICU, of which 14 (82.3%) died. At the end of follow-up, 93(76.9%) recovered, and 18 (14.9%) died, 7 (5.8%) remained asymptomatic, and 1 (0.8%) was still ill. Overall, 46 (38.3%) patients had at least one underlying condition. Conclusion Three-quarters of all COVID-19 patients were aged less than 60 years, reflecting Africa's young population structure. High admission rates to ICU and death rates were observed

Study districts and sites in Dar es Salaam.

<p>Study districts and sites in Dar es Salaam.</p

Clinical, Virologic, and Epidemiologic Characteristics of Dengue Outbreak, Dar es Salaam, Tanzania, 2014

We investigated a dengue outbreak in Dar es Salaam, Tanzania, in 2014, that was caused by dengue virus (DENV) serotype 2. DENV infection was present in 101 (20.9%) of 483 patients. Patient age and location of residence were associated with infection. Seven (4.0%) of 176 patients were co-infected with malaria and DENV

Neighbor-joining tree depicting the four serotypes of dengue virus.

<p>Dengue virus in mosquitoes collected in Dar es Salaam (indicated in bold) clustered into serotype 2. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) is shown adjacent to the nodes.</p