Browsing by Author "Epstein, Adrienne"

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    The impact of stopping and starting indoor residual spraying on malaria burden in Uganda
    (Nature communications, 2021) Namuganga, Jane F.; Epstein, Adrienne; Nankabirwa, Joaniter I.; Mpimbaza, Arthur; Kiggundu, Moses; Sserwanga, Asadu; Kapisi, James; Arinaitwe, Emmanuel; Gonahasa, Samuel; Opigo, Jimmy; Ebong, Chris; Staedke, Sarah G.; Shililu, Josephat; Okia, Michael; Rutazaana, Damian; Maiteki-Sebuguzi, Catherine; Belay, Kassahun; Kamya, Moses R.; Dorsey, Grant; Rodriguez-Barraquer, Isabel
    The scale-up of malaria control efforts has led to marked reductions in malaria burden over the past twenty years, but progress has slowed. Implementation of indoor residual spraying (IRS) of insecticide, a proven vector control intervention, has been limited and difficult to sustain partly because questions remain on its added impact over widely accepted interventions such as bed nets. Using data from 14 enhanced surveillance health facilities in Uganda, a country with high bed net coverage yet high malaria burden, we estimate the impact of starting and stopping IRS on changes in malaria incidence. We show that stopping IRS was associated with a 5-fold increase in malaria incidence within 10 months, but reinstating IRS was associated with an over 5-fold decrease within 8 months. In areas where IRS was initiated and sustained, malaria incidence dropped by 85% after year 4. IRS could play a critical role in achieving global malaria targets, particularly in areas where progress has stalled.
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    Rapid shifts in the age‑specific burden of malaria following successful control interventions in four regions of Uganda
    (Malaria journal, 2020) Kigozi, Simon P.; Kigozi, Ruth N.; Epstein, Adrienne; Mpimbaza, Arthur; Sserwanga, Asadu; Yeka, Adoke; Nankabirwa, Joaniter I.; Halliday, Katherine; Pullan, Rachel L.; Rutazaana, Damian; Sebuguzi, Catherine M.; Opigo, Jimmy; Kamya, Moses R.; Staedke, Sarah G.; Dorsey, Grant; Greenhouse, Bryan; Rodriguez‑Barraquer, Isabel
    Malaria control using long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) has been associated with reduced transmission throughout Africa. However, the impact of transmission reduction on the age distribution of malaria cases remains unclear. Methods: Over a 10-year period (January 2009 to July 2018), outpatient surveillance data from four health facilities in Uganda were used to estimate the impact of control interventions on temporal changes in the age distribution of malaria cases using multinomial regression. Interventions included mass distribution of LLINs at all sites and IRS at two sites. Results: Overall, 896,550 patient visits were included in the study; 211,632 aged < 5 years, 171,166 aged 5–15 years and 513,752 > 15 years. Over time, the age distribution of patients not suspected of malaria and those malaria negative either declined or remained the same across all sites. In contrast, the age distribution of suspected and confirmed malaria cases increased across all four sites. In the two LLINs-only sites, the proportion of malaria cases in < 5 years decreased from 31 to 16% and 35 to 25%, respectively. In the two sites receiving LLINs plus IRS, these proportions decreased from 58 to 30% and 64 to 47%, respectively. Similarly, in the LLINs-only sites, the proportion of malaria cases > 15 years increased from 40 to 61% and 29 to 39%, respectively. In the sites receiving LLINs plus IRS, these proportions increased from 19 to 44% and 18 to 31%, respectively. Conclusions: These findings demonstrate a shift in the burden of malaria from younger to older individuals following implementation of successful control interventions, which has important implications for malaria prevention, surveillance, case management and control strategies.
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    Relationships between test positivity rate, total laboratory confirmed cases of malaria, and malaria incidence in high burden settings of Uganda: an ecological analysis
    (Malaria journal, 2021) Okiring, Jaffer; Epstein, Adrienne; Namuganga, Jane F.; Kamya, Victor; Sserwanga, Asadu; Kapisi, James; Ebong, Chris; Kigozi, Simon P.; Mpimbaza, Arthur; Wanzira, Humphrey; Briggs, Jessica; Kamya, Moses R.; Nankabirwa, Joaniter I.; Dorsey, Grant
    Malaria surveillance is critical for monitoring changes in malaria morbidity over time. National Malaria Control Programmes often rely on surrogate measures of malaria incidence, including the test positivity rate (TPR) and total laboratory confirmed cases of malaria (TCM), to monitor trends in malaria morbidity. However, there are limited data on the accuracy of TPR and TCM for predicting temporal changes in malaria incidence, especially in high burden settings. Methods: This study leveraged data from 5 malaria reference centres (MRCs) located in high burden settings over a 15-month period from November 2018 through January 2020 as part of an enhanced health facility-based surveillance system established in Uganda. Individual level data were collected from all outpatients including demographics, laboratory test results, and village of residence. Estimates of malaria incidence were derived from catchment areas around the MRCs. Temporal relationships between monthly aggregate measures of TPR and TCM relative to estimates of malaria incidence were examined using linear and exponential regression models. Results: A total of 149,739 outpatient visits to the 5 MRCs were recorded. Overall, malaria was suspected in 73.4% of visits, 99.1% of patients with suspected malaria received a diagnostic test, and 69.7% of those tested for malaria were positive. Temporal correlations between monthly measures of TPR and malaria incidence using linear and exponential regression models were relatively poor, with small changes in TPR frequently associated with large changes in malaria incidence. Linear regression models of temporal changes in TCM provided the most parsimonious and accurate predictor of changes in malaria incidence, with adjusted R2 values ranging from 0.81 to 0.98 across the 5 MRCs. However, the slope of the regression lines indicating the change in malaria incidence per unit change in TCM varied from 0.57 to 2.13 across the 5 MRCs, and when combining data across all 5 sites, the R2 value reduced to 0.38. Conclusions: In high malaria burden areas of Uganda, site-specific temporal changes in TCM had a strong linear relationship with malaria incidence and were a more useful metric than TPR. However, caution should be taken when comparing changes in TCM across sites.