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
Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, P. O. Box 7072, Kampala, Uganda.
Department of Microbiology and Immunology, School of Medicine, Kabale University, P. O Box 314, Kabale, Uganda.
Trop Med Health. 2024 Nov 14;52(1):86. doi: 10.1186/s41182-024-00656-7.
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.
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 multi-locus linkage disequilibrium (LD) were assessed through genotyping of seven neutral microsatellite markers: Poly-α, TA1, TA109, PfPK2, 2490, C2M34-313, and C3M69-383. Genetic data analysis was performed using appropriate genetic analysis software.
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 F values ranging from 0.0034 to 0.0105 among P. falciparum parasite populations in asymptomatic and symptomatic uncomplicated/complicated infections.
There is a high level of P. falciparum genetic diversity and MOI among both symptomatic and asymptomatic 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.
恶性疟原虫仍是全球重大的公共卫生挑战，尤其是在撒哈拉以南非洲地区，该地区99%的疟疾感染由其引起。恶性疟原虫感染的结果各不相同，从无症状感染到严重感染，且与宿主免疫力、寄生虫遗传多样性和感染复数（MOI）等因素有关。本研究使用七个中性微卫星标记，调查了乌干达无症状和有症状疟疾患者中恶性疟原虫的遗传多样性和MOI。
这项横断面研究分析了225份来自无症状和有症状疟疾患者的恶性疟原虫分离株，患者年龄从6个月至≥18岁。通过对七个中性微卫星标记（Poly-α、TA1、TA109、PfPK2、2490、C2M34 - 313和C3M69 - 383）进行基因分型，评估恶性疟原虫的遗传多样性、MOI和多位点连锁不平衡（LD）。使用适当的遗传分析软件进行遗传数据分析。
在无症状和有症状个体中，恶性疟原虫感染均表现出高度的遗传多样性。平均期望杂合度（He）范围从有症状非复杂性疟疾病例的0.79到无症状个体的0.81。无症状和有症状感染个体之间的MOI无显著差异（p = 0.33），平均MOI范围从有症状复杂性病例的1.92到无症状个体的2.10。多克隆感染普遍存在，从有症状复杂性疟疾的58.5%到有症状非复杂性疟疾病例的63%不等。在无症状和有症状非复杂性/复杂性感染之间观察到显著的连锁不平衡（LD）（p < 0.01）。遗传分化较低，在无症状和有症状非复杂性/复杂性感染的恶性疟原虫种群中，F值范围为0.0034至0.0105。
乌干达有症状和无症状个体中恶性疟原虫的遗传多样性和MOI水平较高。无症状携带者携带多种寄生虫，这给疟疾控制带来挑战，需要有针对性的干预措施来制定有效的策略。
