Duah-Quashie Nancy Odurowah, Opoku-Agyeman Philip, Bruku Selassie, Adams Tryphena, Tandoh Kwesi Zandoh, Ennuson Nana Aba, Matrevi Sena Adzoa, Abuaku Benjamin, Quashie Neils Ben, Watters Chaselynn, Wolfe David, Quijada Hugo Miranda, Sanders Terrel
Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana.
West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana.
Front Epidemiol. 2022 Oct 14;2:1011938. doi: 10.3389/fepid.2022.1011938. eCollection 2022.
Rapid diagnostic tests (RDTs) are used to diagnose malaria in Ghana and other malaria endemic countries. histidine-rich protein 2 (PFHRP2 based RDTs are widely used, however the occurrence of deletions of the gene in some parasites have resulted in false negative test results. Monoclonal antibodies of PFHRP2 cross reacts with PFHRP3 because they share structural similarities and this complements the detection of the parasites by RDT. These two genes were investigated in Ghanaian parasite population to detect deletions and the polymorphisms in exon 2 of the and genes. Parasite isolates (2,540) from children ≤ 12 years with uncomplicated malaria from 2015 to 2020 transmission seasons were used. Both genes were amplified using nested PCR and negative results indicated the presence of the deletion of genes. Amplified genes were sequenced for the detection of the amino acid repeats. Deletions were observed in 30.7% (780/2,540) and 17.2% (438/2,540) of the samples for and respectively with increasing trends over the three time periods (χ2 -10.305, = 0.001). A total of 1,632 amplicons were sequenced for each gene, analysis was done on 1,124 and 1,307 good quality sequences for and respectively. repeat polymorphisms were dominantly of types 2 (AHHAHHAAD) and 7 (AHHAAD) with large numbers of variants. A novel variant of type 14 (AHHANHATD) was seen for . For the repeat types, 16 (AHHAAN), 17 (AHHDG) and 18 (AHHDD) were the dominant types observed. Variants of type 16 (AHHAAH) and (AHHASH) were also dominant. Repeat types 1, 2, 3, 4, 5, 6, 7, 8, 11, 13, 15, 16, and 19 were observed be shared by both genes. The haplotype diversity of both genes ranged between 0.872 and 1 indicating high diversity of the polymorphisms in the isolates. The implication of the findings of the frequencies of the and deletions as well as the variants of the main epitopes of the monoclonal antibodies for the RDT (types 2 and 7) in our isolates is an indication of decreased sensitivity of the RDTs in diagnosing malaria infections in Ghana.
快速诊断检测(RDTs)被用于在加纳及其他疟疾流行国家诊断疟疾。基于富含组氨酸蛋白2(PFHRP2)的RDTs被广泛使用,然而一些寄生虫中该基因缺失的出现导致了检测结果为假阴性。PFHRP2的单克隆抗体与PFHRP3发生交叉反应,因为它们具有结构相似性,这补充了RDT对寄生虫的检测。对加纳寄生虫群体中的这两个基因进行了研究,以检测PFHRP2和PFHRP3基因外显子2中的缺失和多态性。使用了2015年至2020年传播季节中12岁及以下患单纯性疟疾儿童的2540份寄生虫分离株。使用巢式PCR对这两个基因进行扩增,阴性结果表明存在基因缺失。对扩增的基因进行测序以检测氨基酸重复序列。分别在30.7%(780/2540)和17.2%(438/2540)的样本中观察到PFHRP2和PFHRP3基因的缺失,且在三个时间段内呈上升趋势(χ2 = 10.305,P = 0.001)。每个基因共对1632个扩增子进行了测序,分别对PFHRP2的1124个和PFHRP3的1307个高质量序列进行了分析。PFHRP2重复多态性主要为2型(AHHAHHAAD)和7型(AHHAAD),有大量变体。在PFHRP3中发现了一种新的14型变体(AHHANHATD)。对于PFHRP3重复类型,观察到的主要类型为16型(AHHAAN)、17型(AHHDG)和18型(AHHDD)。16型变体(AHHAAH)和(AHHASH)也占主导地位。观察到PFHRP2和PFHRP3基因共享重复类型1、2、3、4、5、6、7、8、11、13、15、16和19。这两个基因的单倍型多样性在0.872至1之间,表明分离株中多态性的高度多样性。我们分离株中PFHRP2和PFHRP3缺失频率以及RDT单克隆抗体主要表位变体(2型和7型)的研究结果表明,RDTs在加纳诊断疟疾感染中的敏感性降低。