What incentives encourage local communities to collect and upload mosquito sound data by using smartphones? A mixed methods study in Tanzania.

BACKGROUND: To detect and identify mosquitoes using their characteristic high-pitched sound, we have developed a smartphone application, known as the 'HumBug sensor', that records the acoustic signature of this sound, along with the time and location. This data is then sent remotely to a server where algorithms identify the species according to their distinctive acoustic signature. Whilst this system works well, a key question that remains is what mechanisms will lead to effective uptake and use of this mosquito survey tool? We addressed this question by working with local communities in rural Tanzania and providing three alternative incentives: money only, short message service (SMS) reminders and money, and SMS reminders only. We also had a control group with no incentive. METHODS: A multi-site, quantitative empirical study was conducted in four villages in Tanzania from April to August 2021. Consenting participants (n = 148) were recruited and placed into one of the three intervention arms: monetary incentives only; SMS reminders with monetary incentives; and SMS reminders only. There was also a control group (no intervention). To test effectiveness of the mechanisms, the number of audio uploads to the server of the four trial groups on their specific dates were compared. Qualitative focus group discussions and feedback surveys were also conducted to explore participants' perspectives on their participation in the study and to capture their experiences of using the HumBug sensor. RESULTS: Qualitative data analysis revealed that for many participants (37 out of 81), the main motivation expressed was to learn more about the types of mosquitoes present in their houses. Results from the quantitative empirical study indicate that the participants in the 'control' group switched on their HumBug sensors more over the 14-week period (8 out of 14 weeks) when compared to those belonging to the 'SMS reminders and monetary incentives' trial group. These findings are statistically significant (p < 0.05 or p > 0.95 under a two-sided z-test), revealing that the provision of monetary incentives and sending SMS reminders did not appear to encourage greater number of audio uploads when compared to the control. CONCLUSIONS: Knowledge on the presence of harmful mosquitoes was the strongest motive for local communities to collect and upload mosquito sound data via the HumBug sensor in rural Tanzania. This finding suggests that most efforts should be made to improve flow of real-time information back to the communities on types and risks associated with mosquitoes present in their houses.

Epidemiological and clinical characteristics of the COVID-19 epidemic in Brazil.

The first case of COVID-19 was detected in Brazil on 25 February 2020. We report and contextualize epidemiological, demographic and clinical findings for COVID-19 cases during the first 3 months of the epidemic. By 31 May 2020, 514,200 COVID-19 cases, including 29,314 deaths, had been reported in 75.3% (4,196 of 5,570) of municipalities across all five administrative regions of Brazil. The R0 value for Brazil was estimated at 3.1 (95% Bayesian credible interval = 2.4-5.5), with a higher median but overlapping credible intervals compared with some other seriously affected countries. A positive association between higher per-capita income and COVID-19 diagnosis was identified. Furthermore, the severe acute respiratory infection cases with unknown aetiology were associated with lower per-capita income. Co-circulation of six respiratory viruses was detected but at very low levels. These findings provide a comprehensive description of the ongoing COVID-19 epidemic in Brazil and may help to guide subsequent measures to control virus transmission.

Hepatitis C seroprevalence and HIV co-infection in sub-Saharan Africa: a systematic review and meta-analysis.

BACKGROUND: An estimated 150 million people worldwide are infected with hepatitis C virus (HCV). HIV co-infection accelerates the progression of HCV and represents a major public health challenge. We aimed to determine the epidemiology of HCV and the prevalence of HIV co-infection in sub-Saharan Africa. METHODS: We searched Medline and Embase (Ovid) from Jan 1, 2002, to Dec 31, 2014, for studies containing data for HCV seroprevalence in different population groups in WHO-defined regions of sub-Saharan Africa. We estimated pooled regional prevalence estimates with a DerSimonian-Laird random-effects model. Data were further stratified by risk factor and HIV status. FINDINGS: We included 213 studies from 33 countries in sub-Saharan Africa, comprising 287 separate cohorts with 1 198 167 individuals. The pooled HCV seroprevalence from all cohorts was 2·98% (95% CI 2·86-3·10). The pooled HCV seroprevalence was 2·65% (95% CI 2·53-2·78) across all 185 low-risk cohorts, 3·04% (2·23-3·84) in antenatal clinic groups, 1·99% (1·86-2·12) in blood donors, but 6·9% (6·1-7·5) in other general population cohorts. The pooled seroprevalence of HCV was 11·87% (95% CI 7·05-16·70) across all high-risk groups and 9·95% (6·79-13·11) in patients with liver disease. 101 cohorts included HIV-positive samples tested for HCV (42 648 individuals), with a pooled seroprevalence of 5·73% (95% CI 4·90-6·56). INTERPRETATION: We recorded a high seroprevalence of HCV across populations of sub-Saharan Africa, including in HIV-positive adults, with evidence of regional variation in the general population. Monitoring of antenatal HCV prevalence might be a helpful indicator of population trends in HCV infection; however, larger population surveys are needed to monitor these trends. Access to prevention and treatment needs to be improved for both monoinfected and co-infected individuals. FUNDING: None.