Browsing by Author "Kigozi, Ruth N."

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    Malaria Burden through Routine Reporting: Relationship between Incidence and Test Positivity Rates
    (The American journal of tropical medicine and hygiene, 2019) Kigozi, Simon P.; Kigozi, Ruth N.; Sserwanga, Asadu; Nankabirwa, Joaniter I.; Staedke, Sarah G.; Kamya, Moses R.; Pullan, Rachel L.
    Test positivity rate (TPR)—confirmed cases per 100 suspected cases tested, and test-confirmed malaria case rate (IR)—cases per 1,000 population, are common indicators used routinely for malaria surveillance. However, few studies have explored relationships between these indicators over time and space. We studied the relationship between these indicators in children aged < 11 years presenting with suspected malaria to the outpatient departments of level IV health centers in Nagongera, Kihihi, and Walukuba in Uganda from October 2011 to June 2016. We evaluated trends in indicators over time and space, and explored associations using multivariable regression models. Overall, 65,710 participants visited the three clinics. Pairwise comparisons of TPR and IR by month showed similar trends, particularly for TPRs < 50% and during low-transmission seasons, but by village, the relationship was complex. Village mean annual TPRs remained constant, whereas IRs drastically declined with increasing distance from the health center. Villages that were furthest away from the health centers (fourth quartile for distance) had significantly lower IRs than nearby villages (first quartile), with an incidence rate ratio of 0.40 in Nagongera (95% CI: 0.23–0.63;P= 0.001), 0.55 in Kihihi (0.40–0.75;P< 0.001), and 0.25 in Walukuba (0.12–0.51; P < 0.001). Regression analysis results emphasized a nonlinear (cubic) relationship between TPR and IR, after accounting for month, village, season, and demographic factors. Results show that the two indicators are highly relevant for monitoring malaria burden. However, interpretation differs with TPR primarily indicating demand for malaria treatment resources and IR indicating malaria risk among health facility catchment populations.
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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.