Browsing by Author "Mwesigwa, Alex"

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    Assessment of different genotyping markers and algorithms for distinguishing Plasmodium falciparum recrudescence from reinfection in Uganda.
    (Springer Nature, 2025) Mwesigwa, Alex; Golumbeanu, Monica; Jones, Sam; Cantoreggi, L. Sara; Musinguzi, Benson; Nankabirwa, I. Joaniter; Bikaitwoha, Everd Maniple; Kalyango, N. Joan; Karamagi, Charles; Plucinski, Mateusz; Nsobya, L. Samuel; Nsanzabana, Christian; Byakika-Kibwika, Pauline
    Antimalarial therapeutic efficacy studies are vital for monitoring drug efficacy in malaria-endemic regions. The WHO recommends genotyping polymorphic markers including msp-1, msp-2, and glurp for distinguishing recrudescences from reinfections. Recently, WHO proposed replacing glurp with microsatellites (Poly-α, PfPK2, TA1). However, suitable combinations with msp-1 and msp- 2, as well as the performance of different algorithms for classifying recrudescence, have not been systematically assessed. This study investigated various microsatellites alongside msp-1 and msp-2 for molecular correction and compared different genotyping algorithms across three sites in Uganda. Microsatellites 313, Poly-α, and 383 exhibited the highest diversity, while PfPK2 and Poly-α revealed elevated multiplicity of infection (MOI) across all sites. The 3/3 match-counting algorithm classified significantly fewer recrudescences than both the ≥ 2/3 and Bayesian algorithms at probability cutoffs of ≥ 0.7 and ≥ 0.8 (P < 0.05). The msp-1/msp-2/2490 combination identified more recrudescences using the ≥ 2/3 and 3/3 algorithms in the artemether-lumefantrine (AL) treatment arm, while msp-1/msp- 2/glurp combination classified more cases of recrudescence using the ≥ 2/3 in the dihydroartemisinin-piperaquine (DP) arm. Microsatellites PfPK2 and Poly-α, potentially sensitive to detecting minority clones, are promising replacements for glurp. Discrepancies in recrudescence classification between match-counting and Bayesian algorithms highlight the need for standardized PCR correction practices
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    Distribution and Antifungal Susceptibility Profile of Oropharyngeal Candida Species Isolated from People Living with HIV in the Era of Universal Test and Treat Policy in Uganda.
    (Kabale University, 2024) Musinguzi, Benson; Turyamuhika, Laban; Mwesigwa, Alex; Nalumaga, Pauline Petra; Kabajulizi, Immaculate; Njovu, Israel Kiiza; Mwebesa, Edson; Luggya, Tonny; Ocheng, Francis; Kateete, David Patrick; Itabangi, Herbert; Mboowa, Gerald; Obondo, James Sande; Achan, Beatrice
    Background: Despite the increased frequency of oropharyngeal candidiasis among people living with human immunodeficiency virus (HIV), its management is no longer effective due to empirical treatment and the emergence of antifungal resistance (AFR). This study sought to investigate the prevalence of oropharyngeal candidiasis and assess the antifungal susceptibility profile of oropharyngeal Candida species isolated from people living with human immunodeficiency virus. Additionally, we evaluated the correlation between oropharyngeal candidiasis and CD4 T cell as well as viral load counts. Methods: A descriptive cross-sectional study was carried out from April to October 2023 in which 384 people living with HIV underwent clinical examination for oral lesions. Oropharyngeal swabs were collected and cultured on Sabouraud Dextrose agar to isolate Candida species identified using the matrix-assisted laser desorption ionization-time of flight mass spectrometry. Additionally, the antifungal susceptibility profile of Candida isolates to six antifungal drugs was determined using the VITEK® (Marcy-l’Étoile, France) compact system. Data on viral load were retrieved from records, and a CD4 T cell count test was performed using Becton Dickinson Biosciences fluorescent antibody cell sorter presto. Results: The prevalence of oropharyngeal candidiasis was 7.6%. Oropharyngeal candidiasis was significantly associated with low CD4 T cell count and high viral load. A total of 35 isolates were obtained out of which Candida albicans comprised 20 (57.1%) while C. tropicalis and Cglabrata comprised 4 (11.4%) each. C. parapsilosis, C. dubliniensis and C. krusei accounted for 2 (5.7%) each. Additionally, 7 (20%) isolates were resistant to fluconazole, 1 (2.9%) to flucytosine and 0.2 (5.7%) isolates were intermediate to caspofungin. However, specific species isolates like C. albicans showed 20% (4/20), C. glabrata 50% (2/4) and C. krusei 50% (1/2) resistance to fluconazole. Additionally, C. krusei showed 50% resistance to flucytosine. Conclusion: The prevalence of oropharyngeal candidiasis (OPC) among people living with HIV was low, and there was a significant association between OPC and CD4 T cell count as well as viral load. C. albicans was the most frequently isolated oropharyngeal Candida species. C. glabrata and C. krusei exhibited the highest AFR among the non-albicans Candida species. The highest resistance was demonstrated to fluconazole.
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    Distribution of Candida Species Isolated from People Living with Human Immunodeficiency Virus With Oropharyngeal and Oral Candidiasis in Africa in the Era Of Universal Test and Treat Policy: A Systematic Review and Meta-Analysis.
    (Kabale University, 2024) Musinguzi, Benson; Obuku, Ekwaro A.; Mwesigwa, Alex; Migisha, Richard; Kinengyere, Alison Annet; Ndagire, Regina; Baguma, Andrew; Okek, Erick Jacob; Olum, Ronald; Itabangi, Herbert; Mboowa, Gerald; Sande, Obondo James; Achan, Beatrice
    Background The introduction of antiretroviral therapy (ART) and the implementation of the human immunodeficiency virus (HIV) universal test and treat (UTT) policy have led to a decline in the incidence of opportunistic infections. However, oropharyngeal and oral candidiasis remain prevalent and continue to pose challenges among people living with human immunodefciency virus (PLHIV) in Africa, indicating the need for a better understanding of the distribution of Candida species responsible for these infections. This systematic review and meta-analysis aimed to determine the distribution of Candida species isolated from PLHIV with oropharyngeal and oral candidiasis in Africa in the era of UTT policy. Methods The review followed the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. A comprehensive search was conducted to identify eligible studies to be included in the meta-analysis and analyzed using a random effects model in STATA version 17. The risk of bias was assessed using the Joanna Briggs Institute quality assessment tool. Results Fourteen studies with 4281 participants were included in the review. Overall, 2095 Candida isolates were reported, 78.7% (1650/2095) of which were C. albicans, 19.6% (410/2095), non-albicans Candida (NAC), and 1.7% (35/2095) could not be identified to the Candida specific species level. The most prevalent NAC species were C. glabrate (26.3%), followed by C. tropicalis (24.9%), C. krusei (15.6%), C. parapsilosis (11%), and C. dubliniensis (6.3%). The pooled prevalence of oropharyngeal and oral candidiasis was 48% (95% CI 34–62%). The prevalence of oropharyngeal candidiasis was higher in the pre-UTT era, at 56% (95% CI 40–72%, p<0.001), than in the post-UTT era, at 34% (95% CI 10–67%, p<0.001). The risk of bias assessment revealed that 71.4% (10/14) of the included studies had a low risk of bias and that 28.6% (4/14) had a moderate risk of bias. Conclusions While C. albicans remains, the predominant species causing oropharyngeal and oral candidiasis among PLHIV in Africa, NAC species also contribute significantly to the infection burden. Despite ART and UTT policies, oropharyngeal candidiasis remains prevalent, emphasizing the need for targeted interventions.
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    Genetic diversity and population structure of Plasmodium falciparum across areas of varied malaria transmission intensities in Uganda.
    (Malaria Journal, 2025) Mwesigwa, Alex; Tukwasibwe, Stephen; Cummings, Bryan; Kawalya, Hakiimu; Kiyaga, Shahiid; Okoboi, Stephen; Castelnuovo, Barbara; Bikaitwoha, Everd Maniple; Kalyango, Joan N.; Nsobya, Samuel L.; Karamagi, Charles; Byakika‑Kibwika, Pauline; Nankabirwa, Joaniter I.
    Background: Malaria remains a significant global health threat, with sub-Saharan Africa (SSA) bearing the highest burden of the disease. Plasmodium falciparum is the predominant species in the region, leading to substantial morbidity and mortality. Despite intensified control efforts over the last two decades, P. falciparum genetic diversity and multiplicity of infections (MOI) continue to pose significant challenges to malaria elimination in the region. This study assessed P. falciparum genetic diversity and population structure in areas with low, medium, and high malaria transmission intensities in Uganda. Methods: A total of 288 P. falciparum-positive samples from children (6 months to 10 years) and adults (≥ 18 years) living in Jinja (low transmission), Kanungu (medium transmission), and Tororo (high transmission) were genotyped using seven neutral microsatellite markers. Genetic diversity was assessed based on the number of alleles (Na), allelic richness (Ar), and expected heterozygosity (He). Population structure was assessed using the fixation index, analysis of molecular variance (AMOVA), and clustering analysis. Results: High P. falciparum genetic diversity was observed across all study sites, with Kanungu exhibiting the highest mean He (0.81 ± 0.14), while Jinja and Tororo had lower mean He (0.78 ± 0.16). P. falciparum MOI varied significantly,with Tororo showing the highest mean MOI (2.5 ± 0.5) and 70% of samples exhibiting polyclonal infections, compared to Jinja’s mean MOI of 1.9 ± 0.3 and 58% polyclonal infections. Significant multilocus linkage disequilibrium (LD) was noted (p < 0.01), ranging from 0.07 in Tororo to 0.14 in Jinja. Parasite population structure showed minimal genetic differentiation (FST ranged from 0.011 to 0.021) and a low AMOVA value (0.03), indicating high gene flow. Conclusion: This study demonstrates high P. falciparum genetic diversity and MOI but low population structure, suggesting significant parasite gene flow between study sites. This highlights the need for integrated malaria control strategies across areas with varying malaria transmission intensities in Uganda.
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    Plasmodium Falciparum Genetic Diversity and Multiplicity of Infection Among Asymptomatic and Symptomatic Malaria-Infected Individuals in Uganda.
    (Kabale University, 2024) Mwesigwa, Alex; Ocan, Moses; Cummings, Bryan; Musinguzi, Benson; Kiyaga, Shahid; Kiwuwa, Steven M.; Okoboi, Stephen; Castelnuovo, Barbara; Bikaitwoha, Everd Maniple; Kalyango, Joan N.; Karamagi, Charles; Nankabirwa, Joaniter I.; Nsobya, Samuel L.; Byakika‐Kibwika, Pauline
    Plasmodium falciparum (P. falciparum) remains a significant public health challenge globally, especially in sub-Saharan Africa (SSA), where it accounts for 99% of all malaria infections. The outcomes of P. falciparum infection vary, ranging from asymptomatic to severe, and are associated with factors such as host immunity, parasite genetic diversity, and multiplicity of infection (MOI). Using seven neutral microsatellite markers, the current study investigated P. falciparum genetic diversity and MOI in both asymptomatic and symptomatic malaria individuals in Uganda. Methods This cross-sectional study analyzed 225 P. falciparum isolates from both asymptomatic and symptomatic malaria patients, ranging in age from 6 months to≥18 years. P. falciparum genetic diversity, MOI, and multilocus linkage disequilibrium (LD) were assessed through genotyping of seven neutral microsatellite markers: Polyα, TA1, TA109, PfPK2, 2490, C2M34–313, and C3M69–383. Genetic data analysis was performed using appropriate genetic analysis software. Results P. falciparum infections exhibited high genetic diversity in both asymptomatic and symptomatic individuals. The mean expected heterozygosity (He) ranged from 0.79 in symptomatic uncomplicated malaria cases to 0.81 in asymptomatic individuals. There was no significant difference (p=0.33) in MOI between individuals with asymptomatic and symptomatic infections, with the mean MOI ranging from 1.92 in symptomatic complicated cases to 2.10 in asymptomatic individuals. Polyclonal infections were prevalent, varying from 58.5% in symptomatic complicated malaria to 63% in symptomatic uncomplicated malaria cases. A significant linkage disequilibrium (LD) was observed between asymptomatic and symptomatic uncomplicated/complicated infections (p<0.01). Genetic differentiation was low, with FST values ranging from 0.0034 to 0.0105 among P. falciparum parasite populations in asymptomatic and symptomatic uncomplicated/complicated infections. Conclusion There is a high level of P. falciparum genetic diversity and MOI among both symptomatic and asymp‑ automatic individuals in Uganda. Asymptomatic carriers harbor a diverse range of parasites, which poses challenges for malaria control and necessitates targeted interventions to develop effective strategies.
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    Temporal Changes in Plasmodium Falciparum Genetic Diversity and Multiplicity of Infection Across Three Areas of Varying Malaria Transmission Intensities in Uganda.
    (Kabale University, 2025) Mwesigwa, Alex; Kiwuwa, Steven M.; Musinguzi, Benson; Kawalya, Hakiim; Katumba, James Davis; Baguma, Andrew; Mutuku, Irene M.; Adebayo, Ismail Abiola; Nsobya, Samuel L.; Byakika‐Kibwika, Pauline; Kalyango, Joan N.; Karamagi, Charles; Nankabirwa, Joaniter I.
    Background: Malaria is a significant public health challenge in Uganda, with Plasmodium falciparum (P. falciparum) responsible for most malaria infections. The high genetic diversity and multiplicity of infection (MOI) associated with P. falciparum complicate treatment and prevention efforts. This study investigated temporal changes in P. falciparum genetic diversity and MOI across three sites with varying malaria transmission intensities. Understanding these changes is essential for informing effective malaria control strategies for the different malaria transmission settings. Methods: A total of 220 P. falciparum-positive dried blood spot (DBS) filter paper samples from participants in a study conducted during 2011–2012 and 2015–2016 were analyzed. Genotyping utilized seven polymorphic markers: Poly-α, TA1, TA109, PfPK2, 2490, C2M34–313, and C3M69–383. Genetic diversity metrics, including the number of alleles and expected heterozygosity, were calculated using GENALEX and ARLEQUIN software. MOI was assessed by counting distinct genotypes. Multi-locus linkage disequilibrium (LD) and genetic differentiation were evaluated using the standardized index of association ( IAS) and Wright’s fixation index (FST), respectively. Statistical comparisons were made using the Kruskal–Wallis test, and temporal trends were analyzed using the Jonckheere–Terpstra test, with statistical significance set at p < 0.05. Results of the 220 samples, 180 were successfully amplified. The majority of participants were males (50.6%) and children aged 5–11 years (46.7%). Genetic diversity remained high, with mean expected heterozygosity (He) showing a slight decrease over time (range: 0.73–0.82). Polyclonal infections exceeded 50% at all sites, and mean MOI ranged from 1.7 to 2.2, with a significant reduction in Tororo (from 2.2 to 2.0, p = 0.03). Linkage disequilibrium showed a slight increase, with Kanungu exhibiting the lowest IAS in 2011–2012 (0.0085) and Jinja the highest (0.0239) in 2015–2016. Overall genetic differentiation remained low, with slight increases in pairwise FST values over time, notably between Jinja and Tororo (from 0.0145 to 0.0353). Conclusions: This study highlights the genetic diversity and MOI of P. falciparum in Uganda’s malaria transmission settings, noting a slight decrease in both genetic diversity and MOI over time. Continued surveillance and targeted control strategies are essential for monitoring the impact of malaria control efforts in Uganda.