Department of Infectious-Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy.
Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
Malar J. 2020 Jun 26;19(1):228. doi: 10.1186/s12936-020-03300-x.
Malaria is a major travel medicine issue. Retrospective confirmation of a malaria episode diagnosed in an endemic area can have relevant implications in transfusional medicine in Europe, where blood donors are excluded from donation on the basis of positive malaria serology. However, there is scarce evidence on the dynamics of anti-malarial antibodies after a first malaria episode in non-immune individuals. The first aim of this study was to describe the dynamics of anti-malarial antibodies in a first malaria episode in non-immune travellers. Secondary objectives were to assess the sensitivity of serology for a retrospective diagnosis in non-immune travellers diagnosed while abroad and to discuss the implications in transfusional medicine.
Retrospective analysis of the results of an indirect fluorescence antibody test (IFAT) for malaria available for patients with a first malaria episode by Plasmodium falciparum and admitted at the IRCCS Sacro Cuore Don Calabria hospital in a 14-year period. The antibody titres were collected at baseline and during further follow up visits. Epidemiological, demographic and laboratory test results (including full blood count and malaria parasite density) were anonymously recorded in a study specific electronic Case Report Form created with OpenClinica software. Statistical analysis was performed with SAS software version 9.4.
Thirty-six patients were included. Among them, all but two were Europeans (one African and one American). Median length of fever before diagnosis was 2 days (IQR 1-3). Thirty-five patients had seroconversion between day 1 and day 4 from admission, and the titre showed a sharply rising titre, often to a very high level in a few days. Only a single patient remained negative in the first 5 days from admission, after which he was no more tested. Six patients were followed up for at least 2 months, and they all showed a decline in IFAT titre, tending to seroreversion (confirmed in one patient with the longest follow up, almost 4 years).
Serology demonstrated reliable for retrospective diagnosis in non-immune travellers. The decline in the anti-malarial titre might be included in the screening algorithms of blood donors, but further studies are needed.
疟疾是旅行医学中的一个主要问题。在疟疾流行地区诊断出的疟疾发作的回顾性确认在欧洲输血医学中具有重要意义，因为在欧洲，基于疟疾血清学阳性，献血者被排除在献血之外。然而，在非免疫个体首次疟疾发作后抗疟抗体的动态变化证据很少。本研究的首要目的是描述非免疫旅行者首次疟疾发作后抗疟抗体的动态变化。次要目标是评估血清学在国外诊断出的非免疫旅行者回顾性诊断中的敏感性，并讨论其在输血医学中的意义。
对 14 年间因恶性疟原虫感染而首次被诊断为疟疾并入住意大利圣心天主教大学 Sacro Cuore Don Calabria 医院的非免疫旅行者的间接荧光抗体试验（IFA）结果进行回顾性分析。在基线和进一步的随访就诊时收集抗体滴度。将流行病学、人口统计学和实验室检测结果（包括全血细胞计数和疟原虫密度）匿名记录在使用 OpenClinica 软件创建的特定于研究的电子病例报告表中。使用 SAS 软件版本 9.4 进行统计分析。
共纳入 36 例患者。其中，除 2 例外均为欧洲人（1 例非洲裔和 1 例美洲裔）。诊断前发热的中位持续时间为 2 天（IQR 1-3）。35 例患者在入院后第 1 天至第 4 天内血清转阳，滴度呈急剧上升趋势，数天内滴度常升至很高水平。仅 1 例患者在入院后前 5 天内仍为阴性，此后再未检测。6 例患者至少随访 2 个月，他们的 IFA 滴度均呈下降趋势，趋于血清学转换（在随访时间最长的 1 例患者中得到证实，几乎 4 年）。
血清学检测对非免疫旅行者的回顾性诊断可靠。抗疟抗体滴度的下降可能被纳入献血者筛查算法中，但需要进一步研究。
