Browsing by Author "Auala, Joyce R."

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    Evaluation of loop‑mediated isothermal amplification as a surveillance tool for malaria in reactive case detection moving towards elimination
    (2018) Tambo, Munyaradzi; Auala, Joyce R.; Sturrock, Hugh J.; Kleinschmidt, Immo; Bock, Ronnie; Smith, Jennifer L.; Gosling, Roland; Mumbengegwi, Davis R.
    Background: As malaria transmission decreases, the proportion of infections that are asymptomatic at any given time increases. This poses a challenge for diagnosis as routinely used rapid diagnostic tests (RDTs) miss asymptomatic malaria cases with low parasite densities due to poor sensitivity. Yet, asymptomatic infections can contribute to onward transmission of malaria and therefore act as infectious reservoirs and perpetuate malaria transmission. This study compared the performance of RDTs to loop-mediated isothermal amplification (LAMP) in the diagnosis of malaria during reactive active case detection surveillance. Methods: All reported malaria cases in the Engela Health District of Namibia were traced back to their place of residence and persons living within the four closest neighbouring houses to the index case (neighbourhood) were tested for malaria infection with RDTs and dried blood spots (DBS) were collected. LAMP and nested PCR (nPCR) were carried out on all RDTs and DBS. The same procedure was followed in randomly selected control neighbourhoods. Results: Some 3151 individuals were tested by RDT, LAMP and nPCR. Sensitivity of RDTs and LAMP were 9.30 and 95.50%, respectively, and specificities were 99.27 and 99.92%, respectively, compared to nPCR. LAMP carried out on collected RDTs showed a sensitivity and specificity of 95.35 and 99.85% compared to nPCR carried out on DBS. There were 2 RDT samples that were negative by LAMP but the corresponding DBS samples were positive by PCR. Conclusion: The study showed that LAMP had the equivalent performance as nPCR for the identification of Plasmodium falciparum infection. Given its relative simplicity to implement over more complex and time-consuming methods, such as PCR, LAMP is particularly useful in elimination settings where high sensitivity and ease of operation are important.
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    Investigation of the epidemiology of Malaria in the Engela health district of the Ohangwena region in Northern Namibia
    (University of Namibia, 2016) Auala, Joyce R.
    Namibia has seen a decline in reported malaria cases of up to 97.4% between 2001 and 2011. The country was nominated as one of 8 countries in Southern Africa (E8) ready to move from the control phase to the elimination phase by 2020. However, interventions that were successful in bringing down malaria cases during the control phase may no longer be appropriate now that malaria transmission patterns have changed. Gaps in knowledge about infection risk factors at low malaria transmission, such as cross border movement and the possibility of localized malaria hotspots where residual malaria may still persist create an obstacle to eliminating malaria. An effective surveillance system may contribute to zero local transmission of malaria in Namibia. Currently, passive surveillance of malaria cases is conducted; however, this can be complimented by reactive case detection (RACD) which focuses on detection of additional malaria cases within the community. An RACD study was piloted in the Engela Health District of the Ohangwena region from December 2012 to July 2014. All individuals with fever testing malaria positive by rapid diagnostic test (RDT) from the 17 clinics in the district were recruited into the study and visited at their homesteads. Consenting individuals living in the case household were screened for malaria by RDT and interviewed to ascertain the presence of possible malaria risk factors; four surrounding households were also selected and recruited into the study. For the control arm, households in the enumeration area where malaria was not reported were recruited as controls for the study and their four surrounding households were also recruited. During the study period, a total of 190 confirmed malaria cases were reported from Engela Health District of which 70 (36.5%) were local individuals residing within the district and 8 (4.2%) were asymptomatic cases discovered during RACD. From the remaining cases, 47 (24.7%) were of Angolan nationals who do not reside within the district but only crossed the border seeking medical treatment and 65 (35.2%) were regarded as untraceable cases due to various factors such as lack of or false information given at the health facility. Risk mapping and geo-locating of confirmed local cases and asymptomatic cases revealed pockets of infection in the northern regions of the district parallel to areas where clustering occurred. Increased probability of malaria infection in these areas was estimated at a mean of 2.2%, with a range of 0.04% - 28.3%. Travel, insecticide residual spraying (IRS) and mosquito net coverage were among the top significant contributors to increased risk of malaria infection. Travel was found to be more common among male individuals from case neighbourhoods with the most frequent destination being Angola. Net coverage was 4% lower in case neighbourhoods compared to control neighbourhoods with statistical analysis showing that risk of infection was much lower among net users as opposed to non-users (OR=0.89, 95% CI: 0.45-1.74). From control neighbourhoods, 67.4% of sleeping structures were not sprayed compared to 72.2% of sleeping structures from case neighbourhoods. With the presence of eaves in 70.2% of unsprayed case neighbourhood sleeping structures, risk of exposure to mosquitoes was increased due to ease of entry. Despite the need to improve the quality of information collected from patients at health facilities, RACD is a plausible method for monitoring malaria elimination and identifying asymptomatic reservoirs in the district. With RACD, the chance of finding an asymptomatic case was 8 times more likely to occur in the index household where a malaria case was initially reported while also making it possible to identify potential hotspots of infection. Risk factors associated with the likelihood of being a confirmed case were travel, IRS and net coverage which highlighted possible reasons towards continued malaria transmission. However, the perception of low malaria risk due to significant decrease in malaria transmission results in the need to re-educate communities on the importance of continued practice and implementation of vector control strategies such as IRS and net coverage and use in order to bring transmission down to zero.
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    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.
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    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.
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    The use of traditional medicinal plants as antimicrobial treatments
    (University of Namibia Press, 2015) Mumbengegwi, Davis R.; Du Preez, Iwanette C.; Dushimemaria, Florence; Auala, Joyce R.; Nafuka, Sylvia N.
    Microbial infections are a major cause of morbidity and sometimes mortality, especially in developing countries such as Namibia. Severe poverty is the root cause of this undesirable situation as it leads to malnutrition, inadequate sanitation and consumption of unclean food and drink. This, compounded by lack of education and access to primary healthcare, results in infections by microorganisms such as viruses, bacteria, fungi and protozoa (Table 4.1). The most vulnerable to infectious diseases caused by microbial agents are children under the age of five, where 66% of deaths in this age group are a result of such diseases; 34% of all deaths are attributed to infectious diseases. This was underscored by WHO’s (World Health Organization’s) Regional Director for Africa, Luis Gomes Sambo, in 2011 when he said 63% of deaths on the continent were caused by microbial infections, with HIV/AIDS accounting for 38.5% of these (Anon, 2012). Thus, the most vulnerable groups are young children and individuals whose immune systems are compromised by HIV infection (Table 4.2). Community-acquired bacteraemia is a major cause of death in children at rural sub-Saharan district hospitals. A study by Berkley et al. (2005) showed that 12.8% of infants younger than 60 days had bacteraemia. Escherichia coli and group b streptococcus were the predominant infectious agents.