Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Ridgeway Campus, Lusaka, Zambia.
Malar J. 2020 Nov 23;19(1):430. doi: 10.1186/s12936-020-03504-1.
Imported malaria is a major challenge for countries that are in malaria elimination stage such as Zambia. Legitimate cross-border activities add to the risk of transmission, necessitating determination of prevalence, characteristics and risk factors of imported and local malaria.
This cross-sectional study was conducted in 103 consented child and adult patients with clinical malaria symptoms, from selected health facilities in north-western Zambia. Patient demographic data and blood samples for malaria microscopy and full blood count were obtained. Chi-square and penalized logistic regression were performed to describe the characteristics and assess the risk factors of imported and local malaria in North-Western Province.
Overall, malaria prevalence was 78.6% with 93.8% Plasmodium falciparum and 6.2% other species. The local cases were 72 (88.9%) while the imported were 9 (11.1%) out of the 81 positive participants. About 98.6% of the local cases were P. falciparum compared to 55.6% (χ = 52.4; p < 0.01) P. falciparum among the imported cases. Among the imported cases, 44% were species other than P. falciparum (χ = 48; p < 0.01) while among the local cases only 1.4% were. Gametocytes were present in 44% of the imported malaria cases and only in 2.8% of the local cases (χ = 48; p < 0.01). About 48.6% of local participants had severe anaemia compared to 33.3% of participants from the two neighbouring countries who had (χ = 4.9; p = 0.03). In the final model, only country of residence related positively to presence of species other than P. falciparum (OR = 39.0, CI [5.9, 445.9]; p < 0.01) and presence of gametocytes (OR = 23.1, CI [4.2, 161.6]; p < 0.01).
Malaria prevalence in North-Western Province is high, with P. falciparum as the predominant species although importation of Plasmodium ovale and Plasmodium malariae is happening as well. Country of residence of patients is a major risk factor for malaria species and gametocyte presence. The need for enhanced malaria control with specific focus on border controls to detect and treat, for specific diagnosis and treatment according to species obtaining, for further research in the role of species and gametocytaemia in imported malaria, cannot be overemphasized.
对于像赞比亚这样处于消除疟疾阶段的国家来说，输入性疟疾是一个主要挑战。合法的跨境活动增加了传播的风险，因此有必要确定输入性和本地疟疾的流行情况、特征和危险因素。
本横断面研究在赞比亚西北部选定的卫生机构中，对 103 名有临床疟疾症状的儿童和成年患者进行了研究。收集了患者的人口统计学数据和疟疾显微镜检查和全血细胞计数的血液样本。采用卡方检验和惩罚逻辑回归来描述西北部输入性和本地疟疾的特征，并评估其危险因素。
总体而言，疟疾的患病率为 78.6%，其中 93.8%为恶性疟原虫，6.2%为其他物种。本地病例为 72 例（88.9%），而阳性参与者中输入性病例为 9 例（11.1%）。与输入性病例中 55.6%（χ=52.4；p<0.01）的恶性疟原虫相比，本地病例中恶性疟原虫的比例约为 98.6%。在输入性病例中，44%为恶性疟原虫以外的其他物种（χ=48；p<0.01），而在本地病例中仅为 1.4%。输入性疟疾病例中有 44%存在配子体，而本地病例中只有 2.8%（χ=48；p<0.01）。与来自两个邻国的参与者（χ=4.9；p=0.03）相比，约 48.6%的本地参与者有严重贫血。在最终模型中，只有居住地与存在恶性疟原虫以外的其他物种（OR=39.0，CI[5.9，445.9]；p<0.01）和存在配子体（OR=23.1，CI[4.2，161.6]；p<0.01）呈正相关。
西北部省份的疟疾患病率很高，以恶性疟原虫为主，但也有卵形疟原虫和间日疟原虫的输入。患者的居住地是疟疾种类和配子体存在的主要危险因素。必须加强疟疾控制，特别是加强边境控制以发现和治疗疟疾，根据疟原虫种类进行特异性诊断和治疗，进一步研究疟原虫种类和配子体血症在输入性疟疾中的作用，这一点至关重要。
