Browsing by Author "Agaba, Bosco B."

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    Asymptomatic Malaria Infection, Associated Factors and Accuracy of Diagnostic Tests in a Historically High Transmission Setting in Northern Uganda
    (Malaria Journal, 2022) Agaba, Bosco B.; Rugera, Simon P.; Mpirirwe, Ruth; Atekat, Martha; Okubal, Samuel; Masereka, Khalid; Nabirwa, Gertrude; Nabadda, Susan; Muwanguzi, Enoch
    Asymptomatic malaria infections are important parasite reservoirs and could sustain transmission in the population, but they are often unreported. A community-based survey was conducted to investigate the prevalence and factors associated with asymptomatic malaria infections in a historically high transmission setting in northern Uganda. Using a cross-sectional design, 288 children aged 2–15 years were enrolled and tested for the presence of malaria parasites using rapid diagnostic tests (RDTs) and blood smear microscopy between January to May 2022. Statistical analysis was performed using the exact binomial and Fisher’s exact test with p ≤ 0.05 indicating significance. The logistic regression was used to explore factors associated with asymptomatic malaria infections. Overall, the prevalence of asymptomatic infection was 34.7% (95% CI 29.2–40.5) with the highest observed in children 5–10 years 45.9% (95% CI 35.0–57.0). Gweri village accounted for 39.1% (95% CI 27.6—51.6) of malaria infections. Median parasite density was 1500 parasites/µl of blood. Plasmodium falciparum was the dominant species (86%) followed by Plasmodium malariae (5%). Factors associated with asymptomatic malaria infection were sleeping under mosquito net (Adjusted Odds Ratio (aOR) 0.27; 95% CI 0.13–0.56), p = 0.001 and presence of village health teams (VHTs) (aOR 0.02; 95% CI 0.01–0.45), p = 0.001. Sensitivity and specificity were higher for the P. falciparum/pLDH RDTs compared to HRP2-only RDTs, 90% (95% CI 86.5–93.5) and 95.2% (95% CI 92.8–97.7), p = 0.001, respectively. Asymptomatic malaria infections were present in the study population and this varied with place and person in the different age groups. Plasmodium falciparum was the dominant parasite species however the presence of P. malariae and Plasmodium ovale was observed, which may have implication for the choice and deployment of diagnostic tools. Individuals who slept under mosquito net or had presence of functional VHTs were less likely to have asymptomatic malaria infection. P.f/pLDH RDTs performed better than the routinely used HRP2 RDTs. In view of these findings, investigation and reporting of asymptomatic malaria reservoirs through community surveys is recommended for accurate disease burden estimate and better targeting of control.
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    Systematic review of the status of pfhrp2 and pfhrp3 gene deletion, approaches and methods used for its estimation and reporting in Plasmodium falciparum populations in Africa: review of published studies 2010–2019
    (Malaria journal, 2019) Agaba, Bosco B.; Yeka, Adoke; Nsobya, Sam; Arinaitwe, Emmanuel; Nankabirwa, Joaniter; Opigo, Jimmy; Mbaka, Paul; Seung Lim, Chae; Kalyango, Joan N.; Karamagi, Charles; Kamya, Moses R.
    Malaria rapid diagnostic tests based on histidine-rich protein-2 have played a vital role in improving malaria case management and surveillance particularly in Africa, where Plasmodium falciparum is predominant. However, their usefulness has been threatened by the emergence of gene deletion on P. falciparum histidine rich protein 2 (pfhrp2) and P. falciparum histidine rich protein 3 (pfhrp3). Use of standard and recommended methods is key for accurate investigation, confirmation and reporting of pfhrp2 and pfhrp3 gene deletion. Methods: A systematic review was conducted to assess the status, methods and approaches that have been used for investigation, confirmation and reporting of pfhrp2 and pfhrp3 gene deletion in Africa. An online search was done using PubMed and MEDLINE Google Scholar for all articles published in English on pfhrp2/3 gene deletion in Africa. Relevant articles that met the inclusion criteria were summarized and assessed based on the protocol recommended by the World Health Organization for confirmation and reporting of pfhrp2/3 gene deletion. Results: The search identified a total of 18 articles out of which 14 (77.7%) fulfilled the criteria for inclusion and were retained for review. The articles were distributed across 12 countries where the pfhrp2 and pfhrp3 gene deletion studies were conducted and reported. The level of pfhrp2/3 gene deletion across selected studies in Africa ranged from the highest 62% to the lowest 0.4%. There was wide variation in methods and approaches including study designs, size and sampling and whether both pfhrp2 and pfhrp3 double deletions or pfhrp2 single deletion were investigated, with a wide variation in laboratory methods. Conclusion: Based on the review, there is evidence of the presence of pfhrp2/3 gene-deleted P. falciparum parasites in Africa. The approaches and methods used for investigation, confirmation and reporting of pfhrp2/3 deleted parasites have varied between studies and across countries. Countries that are considering plans to investigate, confirm and report pfhrp2/3 deletion should use recommended standard and harmonized methods to prevent unnecessary recommendations for costly switch of RDTs in Africa.