Browsing by Author "Cueto, Carmen"

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    Assessing malaria risk at night-time venues in a low-transmission setting: A time-location sampling study in Zambezi, Namibia
    (2011) Jacobson, Jerry O.; Smith, Jennifer L.; Cueto, Carmen; Chisenga, Mukosha; Roberts, Kathryn W.; Hsiang, M.; Gosling, Roly; Mumbengegwi, Davis R.; Bennett, Adam
    Background:Identifying efficient and effective strategies to reach and monitor populations at greatest risk of malaria in low-transmission settings is a key challenge for malaria elimination. In Namibia’s Zambezi Region, transmis-sion is ongoing yet its drivers remain poorly understood. A growing literature suggests that night-time social activities may lead to malaria exposure that is beyond the reach of conventional preventive interventions, such as insecticide treated bed nets and indoor residual spraying.Methods:Formative research was conducted with community members in March, 2015 in the catchment areas of six randomly selected health facilities in the western Zambezi Region to identify night-time locations where large numbers of individuals regularly congregate. Using time-location sampling, a survey was conducted between March and May, 2015 at community-identified venues (bars and evening church services) to develop representative esti-mates of the prevalence of parasite infection and risk factors among venue-goers.Results:When compared to a contemporaneous household survey of the general population aged 15 and older (N =1160), venue-goers (N =480) were more likely to have spent the night away from their home recently (17.3% vs. 8.9%, P =0.008), report recent fever (65.2% vs. 36.9%, P < 0.001), and were less likely to have sought care for fever (37.9% vs. 52.1%, P =0.011). Venue-goers had higher, but not significantly different, rates of malaria infection (4.7% vs. 2.8%, P =0.740). Risk factors for malaria infection among venue-goers could not be determined due to the small number of infections identified, however self-reported fever was positively associated with outdoor livelihood activi-ties (adjusted odds ratio [AOR] =1.9, 95% CI 1.0–3.3), not wearing protective measures at the time of the survey (AOR =6.8, 9% CI 1.4–33.6) and having been bothered by mosquitos at the venue (AOR =2.7, 95% CI 1.5–4).Conclusions:Prevention measures and continued surveillance at night-time venues may be a useful complement to existing malaria elimination efforts.
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    Malaria risk factors in northern Namibia: The importance of occupation rage and mobility in characterizing high-risk population
    (PLOS ONE, 2021) Smith, Jennifer L.; Mumbengegwi, Davis R.; Haindongo, Erastus H.; Cueto, Carmen; Roberts, Kathryn W.; Gosling, Roly; Uusiku, Petrina; Kleinschmidt, Immo; Bennett, Adam; Sturrock, Hugh J.
    In areas of low and unstable transmission, malaria cases occur in populations with lower access to malaria services and interventions, and in groups with specific malaria risk exposures often away from the household. In support of the Namibian National Vector Borne Disease Program’s drive to better target interventions based upon risk, we implemented a health facility-based case control study aimed to identify risk factors for symptomatic malaria in Zambezi Region, northern Namibia. A total of 770 febrile individuals reporting to 6 health facilities and testing positive by rapid diagnostic test (RDT) between February 2015 and April 2016 were recruited as cases; 641 febrile individuals testing negative by RDT at the same health facilities through June 2016 were recruited as controls. Data on socio-demographics, housing construction, overnight travel, use of malaria prevention and outdoor behaviors at night were collected through interview and recorded on a tablet-based questionnaire. Remotely-sensed environmental data were extracted for geo-located village residence locations. Multivariable logistic regression was conducted to identify risk factors and latent class analyses (LCA) used to identify and characterize high-risk subgroups. The majority of participants (87% of cases and 69% of controls) were recruited during the 2016 transmission season, an outbreak year in Southern Africa. After adjustment, cases were more likely to be cattle herders (Adjusted Odds Ratio (aOR): 4.46 95%CI 1.05–18.96), members of the police or other security personnel (aOR: 4.60 95%CI: 1.16–18.16), and pensioners/unemployed persons (aOR: 2.25 95%CI 1.24–4.08), compared to agricultural workers (most common category). Children (aOR 2.28 95%CI 1.13–4.59) and self-identified students were at higher risk of malaria (aOR: 4.32 95%CI 2.31–8.10). Other actionable risk factors for malaria included housing and behavioral characteristics, including traditional home construction and sleeping in an open structure (versus modern structure: aOR: 2.0195%CI 1.45–2.79 and aOR: 4.76 95%CI: 2.14–10.57); cross border travel in the prior 30days (aOR: 10.55 95%CI 2.94–37.84); and outdoor agricultural work at night (aOR: 2.09 95%CI 1.12–3.87). Malaria preventive activities were all protective and included personal use of an insecticide treated net (ITN) (aOR: 0.61 95%CI 0.42–0.87), adequate household ITN coverage (aOR: 0.63 95%CI 0.42–0.94), and household indoor residual spraying (IRS) in the past year (versus never sprayed: (aOR: 0.63 95%CI 0.44–0.90). A number of environmental factors were associated with increased risk of malaria, including lower temperatures, higher rainfall and increased vegetation for the 30 days prior to diagnosis and residing more than 5 minutes from a health facility. LCA identified six classes of cases, with class membership strongly correlated with occupation, age and select behavioral risk factors. Use of ITNs and IRS coverage was similarly low across classes. For malaria elimination these high-risk groups will need targeted and tailored intervention strategies, for example, by implementing alternative delivery methods of interventions through schools and worksites, as well as the use of specific interventions that address outdoor transmission.