Division of Parasitology, Department of Preclinical Sciences, Faculty of Medicine; Center of Excellence in Molecular Biology and Pharmacology of Malaria and Cholangiocarcinoma, Thammasat University, Pathumthani, Thailand.
Faculty of Medical Technology, Rangsit University, Pathumthani, Thailand.
J Vector Borne Dis. 2021 Jul-Sep;58(3):257-264. doi: 10.4103/0972-9062.316274.
Background&objectives: Changes in parasite biology, particularly the gametocytogenesis process, could be one of the important contributing factors for worldwide malaria resurgence. The present study investigated the prevalence rates of pretreatment gametocyte carriage and density in Plasmodium falciparum and P. vivax infections in the low malaria-endemic area on the Thai-Myanmar border.
One hundred and twenty-six blood samples were collected from patients with signs and symptoms of malaria who attended malaria clinics. Malaria positive cases detected by microscopic examination were confirmed by species-specific nested-PCR in 97 (29 and 68 samples for P. falciparum and P. vivax, respectively).
The proportion of P. vivax and P. falciparum-infected samples was 70.1: 29.9%. The density in P. falciparum positive samples [median (95%CI): 10,340 (5280-19,200) μ/l] was significantly higher than P. vivax positive samples [4508 (3240-6120) μ/l]. Sixteen out of twenty-nine (55.2%) and 36 out of 68 (52.9%) P. falciparum- and P. vivax-infected samples, respectively, were gametocyte-positive. Gametocyte density in the P. falciparum-infected[124 (69-253) /μl] was significantly higher than that of the P. vivax-infected [54 (45-70)/μl] samples. A significant correlation between gametocyte density and pretreatment parasitemia was only detected in P. falciparum-infected, but not P. vivax-infected samples.
INTERPRETATION & CONCLUSION: The observed high prevalence rates of pretreatment gametocyte carriage of both malaria species, which serves as a large malaria reservoir, particularly in P. falciparum infection, could have a significant impact on malaria control in the endemic populations.
寄生虫生物学的变化，特别是配子体形成过程，可能是导致全球疟疾死灰复燃的一个重要因素。本研究调查了泰国-缅甸边境低疟疾流行地区恶性疟原虫和间日疟原虫感染患者治疗前配子体携带和密度的流行率。
从就诊于疟疾诊所的有疟疾症状和体征的患者中采集了 126 份血样。通过显微镜检查检测到的疟疾阳性病例通过种特异性巢式 PCR 进行确认，其中 97 份为阳性（29 份为恶性疟原虫，68 份为间日疟原虫）。
恶性疟原虫和间日疟原虫感染样本的比例为 70.1:29.9%。恶性疟原虫阳性样本的密度[中位数（95%CI）：10340（5280-19200）μ/l]明显高于间日疟原虫阳性样本[4508（3240-6120）μ/l]。29 份恶性疟原虫感染样本中有 16 份（55.2%），68 份间日疟原虫感染样本中有 36 份（52.9%）为配子体阳性。恶性疟原虫感染患者的配子体密度[124（69-253）/μl]明显高于间日疟原虫感染患者[54（45-70）/μl]。仅在恶性疟原虫感染患者中检测到配子体密度与治疗前寄生虫血症之间存在显著相关性，而在间日疟原虫感染患者中未检测到。
观察到两种疟疾的治疗前配子体携带率均较高，这是一个巨大的疟疾储存库，特别是在恶性疟原虫感染中，这可能对流行地区的疟疾控制产生重大影响。
