Browsing by Author "Haindongo, Erastus H."
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Item Investigation into the risk factors for Malaria transmission in the Omusati region(University of Namibia, 2016) Haindongo, Erastus H.; ;Namibia has achieved great success in the reduction of malaria case numbers from over 500 per 1000 population in 2000 to between 1 -2 per 1000 population in 2013 (MoHSS-NVDCP, 2009). The gains in the reduction of malaria case numbers have seen the country transitioning from the control phase of malaria epidemiology to the pre-elimination phase, and has subsequently adopted the goal of malaria elimination by 2020 (MoHSS-NVDCP, 2010; Pindolia et al., 2012). Since the year 2008, there were no significant reductions in cases per annum, despite continued interventions (such as Indoor Residual spraying, Insecticide treated nets and larviciding) geared towards vector and parasite control. These interventions are aimed at the realization of malaria elimination. These uninformed and untargeted interventions leave certain groups or individuals at an increased risk of infection. Furthermore in a low transmission setting, parasite density decreases and a considerable number of people harboring Plasmodium parasites are asymptomatic. As a consequence, untargeted at risk populations continue to harbor parasites, which continues to fuel transmission and thus poses as a challenge to elimination. This highlights the need for establishing the unknown risk factors and detection of low parasite density asymptomatic infections with more sensitive molecular diagnostics since the current Point of Care (P.O.C) diagnostics, the Rapid Diagnostic Tests (RDTs) do not detect some of these low density infections. These will ultimately allow for evidence-based targeting of interventions, for the final drive to eliminate malaria. A household level cluster case-control study was carried out between January – May 2014 in the Oshikuku and Outapi health district of the Omusati Region, north central Namibia. Case households were identified by Re-Active Case Detection (RACD), a surveillance tool which involves the screening of individual residing in proximity of a case detected passively at a health facility. Control households were randomly selected from National Census Enumeration Areas (EA). A semi- structured questionnaire was administered to all eligible and consenting members. Questions pertaining to the demographics (age and gender), net ownership and usage, presence of breeding site, travel in the past 6 weeks, outdoor nocturnal behavior, household spraying, and treatment seeking behavior following the self-reported history of fever were elicited from all eligible study participants. RDT and Dried Blood Spots were collected and stored for analysis of the presence of Plasmodium parasites using Loop-mediated isothermal Amplification (LAMP) and Cytochrome B nested Polymerase Chain Reaction (nPCR). RACD identified 59 index case households for investigation and an additional randomly selected 77 households were investigated as controls. The distribution of males and females was comparable in both case and control households. The following factors were found to be associated with the increased risk of being a malaria case: Household with a low Socio-Economic status(SES); Long lasting insecticide treated bed net ownership (O.R=3.89, p-value: 0.05), net usage ( O.R=1.4, p-value:0.01); Age group: 35 – 45 (O.R=15.06, p-value: <0.001); Presence of breeding site (O.R=2.21, p-value= 0.01) ; distance of household to a Health facility (O.R=6.26, p-value:0.01) and poor treatment seeking behaviour. RDTs had a sensitivity and specificity of 76.47(95%CI:50.10-93.19) and 95.88 (95%CI:92.45-96.51), with its calculated Positive Predictive Value (PPV) being 35.14 (95%CI:18.57-49.13). Hence, when compared to LAMP and nPCR, the sensitivity and specificity of RDTs was the lowest. When using the reference method of nPCR, the sensitivity (100%) and specificity (97.89%) of LAMP was comparable to that of nPCR although LAMP detected 48% more positives than nPCR. However, LAMP had a PPV of 52% since most of its positives were considered false. This study indicates that RACD can be used as a tool to establish the risk factors associated with malaria at household level and can thus inform elimination programmes on the appropriate intervention tools that should be employed. LAMP had a higher sensitivity, specificity, PPV and NPV than RDT and may potentially perform better than RDTs in detecting low density infections. However, further research is required as LAMP results could not always be confirmed using PCR.Item Isolation and Genus identification of bacteria from urine contaminated soils of Windhoek(University of Namibia, 2016) Haindongo, Erastus H.; Bock, Ronnie A.; Nafuka, Sylvia N.; Mumbengegwi, Davis R.Public urination is a common sight in the vicinity of drinking establishments in Katutura, as well as other open spaces around Windhoek. A study was conducted to determine if there was a shift in the balance of the microflora in urine contaminated soils. It was hypothesized that, given soils from the same geographic region but under distinct urine conditions, the identity and counts of the pathogenic and actinobacteria communities would vary. For the purpose of this study, pathogenic microorganisms were limited to those known to cause infections of the urinary tract. Soil samples from 4 contaminated locations (Ara-Dorado, Hakahana, Eveline and Greenwell Matongo suburbs) and controls were qualitatively tested for urease activity. Selective media was used for the isolation and enumeration of pathogenic and beneficial actinobacterial colonies. Dorado showed the greatest extend of urease activity>>>Hakahana and Eveline>>Green well matongo. There is a significant difference between the colony counts at a contaminated and non-contaminated (control) site, p = 0.019(= 0.05). The results indicated that public urination introduces pathogenic bacteria, causing a shift in the balance of the normal flora.Item 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.Item Malaria risk in young male travelers but local transmission persists: A case–control study in low transmission Namibia(2017) Smith, Jennifer L.; Auala, Joyce R.; Haindongo, Erastus H.; Uusiku, Petrina; Gosling, Roly; Kleinschmidt, Immo; Mumbengegwi, Davis R.; Sturrock, Hugh J.Background: A key component of malaria elimination campaigns is the identification and targeting of high risk populations. To characterize high risk populations in north central Namibia, a prospective health facility-based case–control study was conducted from December 2012–July 2014. Cases (n = 107) were all patients presenting to any of the 46 health clinics located in the study districts with a confirmed Plasmodium infection by multi-species rapid diagnostic test (RDT). Population controls (n = 679) for each district were RDT negative individuals residing within a household that was randomly selected from a census listing using a two-stage sampling procedure. Demographic, travel, socio-economic, behavioural, climate and vegetation data were also collected. Spatial patterns of malaria risk were analysed. Multivariate logistic regression was used to identify risk factors for malaria. Results: Malaria risk was observed to cluster along the border with Angola, and travel patterns among cases were comparatively restricted to northern Namibia and Angola. Travel to Angola was associated with excessive risk of malaria in males (OR 43.58 95% CI 2.12–896), but there was no corresponding risk associated with travel by females. This is the first study to reveal that gender can modify the effect of travel on risk of malaria. Amongst non-travellers, male gender was also associated with a higher risk of malaria compared with females (OR 1.95 95% CI 1.25–3.04). Other strong risk factors were sleeping away from the household the previous night, lower socioeconomic status, living in an area with moderate vegetation around their house, experiencing moderate rainfall in the month prior to diagnosis and living <15 km from the Angolan border. Conclusions: These findings highlight the critical need to target malaria interventions to young male travellers, who have a disproportionate risk of malaria in northern Namibia, to coordinate cross-border regional malaria prevention initiatives and to scale up coverage of prevention measures such as indoor residual spraying and long-lasting insecticide nets in high risk areas if malaria elimination is to be realized.Item Spatial clustering of patent and sub-patent malaria infections in northern Namibia: Implications for surveillance and response strategies for elimination(2017) Smith, Jennifer L.; Auala, Joyce R.; Tambo, Munyaradzi; Haindongo, Erastus H.; Katokele, Stark; Uusiku, Petrina; Gosling, Roly; Kleinschmidt, Immo; Mumbengegwi, Davis R.; Sturrock, Hugh J.Reactive case detection (RACD) around passively detected malaria cases is a strategy to identify and treat hotspots of malaria transmission. This study investigated the unproven assumption on which this approach is based, that in low transmission settings, infections cluster over small scales.