Department of Medicine, University of California San Francisco, San Francisco, USA.
Infectious Diseases Research Collaboration, Kampala, Uganda.
Malar J. 2018 Feb 5;17(1):67. doi: 10.1186/s12936-018-2221-9.
Submicroscopic malaria parasitaemia is common in both high- and low-endemicity settings, but its clinical consequences are unclear.
A cohort of 364 children (0.5-10 years of age) and 106 adults was followed from 2011 to 2016 in Tororo District, Uganda using passive surveillance for malaria episodes and active surveillance for parasitaemia. Participants presented every 90 days for routine visits (n = 9075); a subset was followed every 30 days. Participants who presented with fever and a positive blood smear were treated for malaria. At all routine visits microscopy was performed and samples from subjects with a negative blood smear underwent loop-mediated isothermal amplification for detection of plasmodial DNA.
Submicroscopic parasitaemia was common; the proportion of visits with submicroscopic parasitemia was 25.8% in children and 39.2% in adults. For children 0.5-10 years of age, but not adults, having microscopic and submicroscopic parasitaemia at routine visits was significantly associated with both fever (adjusted risk ratios [95% CI], 2.64 [2.16-3.22], 1.67 [1.37-2.03]) and non-febrile illness (aRR [CI], 1.52 [1.30-1.78], 1.26 [1.09-1.47]), compared to not having parasitaemia. After stratifying by age, significant associations were seen between submicroscopic parasitaemia and fever in children aged 2-< 5 and 5-10 years (aRR [CI], 1.42 [1.03-1.98], 2.01 [1.49-2.71]), and submicroscopic parasitaemia and non-febrile illness in children aged 5-10 years (aRR [CI], 1.44 [1.17-1.78]). These associations were maintained after excluding individuals with a malaria episode within the preceding 14 or following 7 days, and after adjusting for household wealth.
Submicroscopic malaria infections were associated with fever and non-febrile illness in Ugandan children. These findings support malaria control strategies that target low-density infections.
在高和低疟疾流行地区，亚微观疟疾寄生虫血症都很常见，但它的临床后果尚不清楚。
2011 年至 2016 年，乌干达托罗罗区对 364 名儿童（0.5-10 岁）和 106 名成年人进行了一项队列研究，通过被动监测疟疾发作和主动监测寄生虫血症进行监测。参与者每 90 天进行一次常规就诊（n=9075）；其中一部分人每 30 天进行一次随访。出现发热和阳性血涂片的参与者接受疟疾治疗。在所有常规就诊时进行显微镜检查，对血涂片阴性的样本进行环介导等温扩增以检测疟原虫 DNA。
亚微观寄生虫血症很常见；儿童就诊中出现亚微观寄生虫血症的比例为 25.8%，成人就诊中出现亚微观寄生虫血症的比例为 39.2%。对于 0.5-10 岁的儿童，但不是成年人，在常规就诊时既有微观寄生虫血症又有亚微观寄生虫血症，与发热（调整后的风险比[95%CI]，2.64[2.16-3.22]，1.67[1.37-2.03]）和非发热性疾病（aRR[CI]，1.52[1.30-1.78]，1.26[1.09-1.47]）显著相关，而不是没有寄生虫血症。按年龄分层后，在 2-<5 岁和 5-10 岁的儿童中，亚微观寄生虫血症与发热（aRR[CI]，1.42[1.03-1.98]，2.01[1.49-2.71]）和 5-10 岁的儿童中，亚微观寄生虫血症与非发热性疾病（aRR[CI]，1.44[1.17-1.78]）显著相关。在排除 14 天内或 7 天后有疟疾发作的个体后，以及在调整家庭财富后，这些关联仍然存在。
在乌干达儿童中，亚微观疟疾感染与发热和非发热性疾病有关。这些发现支持针对低密度感染的疟疾控制策略。
