Othnigué Nadjitolnan, Wyss Kaspar, Tanner Marcel, Genton Blaise
Ministry of Public Health, N'Djaména, Chad.
Trop Med Int Health. 2006 Feb;11(2):204-10. doi: 10.1111/j.1365-3156.2005.01551.x.
To assess malaria prevalence rates and seasonal patterns among clinically diagnosed malaria cases at the level of primary care facilities in an urban Sahelian setting.
Screening all patients consulting two private and two governmental providers on a randomly selected weekday over a period of 9 months. Patients with presumptive malaria underwent a blood test.
Of 1658 patients included in the survey, 47% were clinically diagnosed and treated as malaria cases. Malaria was more often diagnosed by private providers. There were no clear seasonal patterns in presumptive malaria. A 30% of clinically diagnosed cases were positive for Plasmodium (all falciparum) by thick film examination. Thus, false positive cases constituted more than 70% of the clinically diagnosed malaria cases. The highest positive prevalence rates were found at the end and shortly after the rainy season (44%-47%) and the lowest during the dry season (2%).
Clinical diagnosis of malaria has a very low positive predicted value in this low endemicity urban setting, and its low specificity leads to inappropriate care for a large proportion of patients. This has a major impact on economic costs for health services and households. In the Sahel, systematic use of microscopy-based diagnosis and/or rapid diagnostic tests should be considered to appropriately manage malaria and non-malaria cases.
评估在萨赫勒地区城市环境中基层医疗设施层面临床诊断疟疾病例的疟疾流行率和季节性模式。
在9个月的时间内，随机选择一个工作日，对两家私立和两家政府医疗机构的所有就诊患者进行筛查。疑似疟疾患者接受血液检测。
在纳入调查的1658名患者中，47%被临床诊断为疟疾病例并接受治疗。私立医疗机构更常诊断出疟疾。疑似疟疾没有明显的季节性模式。通过厚涂片检查，30%的临床诊断病例疟原虫（均为恶性疟原虫）呈阳性。因此，假阳性病例占临床诊断疟疾病例的70%以上。在雨季结束时和刚结束后阳性流行率最高（44%-47%），旱季最低（2%）。
在这种低流行率的城市环境中，疟疾的临床诊断阳性预测值非常低，其低特异性导致很大一部分患者接受不适当的治疗。这对卫生服务和家庭的经济成本有重大影响。在萨赫勒地区，应考虑系统使用基于显微镜的诊断和/或快速诊断检测，以妥善管理疟疾和非疟疾病例。
