LPHI, MIVEGEC, CNRS, INSERM, University of Montpellier, Montpellier, France.
Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia.
Malar J. 2024 Jan 17;23(1):22. doi: 10.1186/s12936-024-04836-y.
BACKGROUND: Chronic carriage of asymptomatic low-density Plasmodium falciparum parasitaemia in the dry season may support maintenance of acquired immunity that protects against clinical malaria. However, the relationship between chronic low-density infections and subsequent risk of clinical malaria episodes remains unclear. METHODS: In a 2-years study (December 2014 to December 2016) in eastern Gambia, nine cross-sectional surveys using molecular parasite detection were performed in the dry and wet season. During the 2016 malaria transmission season, passive case detection identified episodes of clinical malaria. RESULTS: Among the 5256 samples collected, 444 (8.4%) were positive for P. falciparum. A multivariate model identified village of residence, male sex, age ≥ 5 years old, anaemia, and fever as independent factors associated with P. falciparum parasite carriage. Infections did not cluster over time within the same households or recurred among neighbouring households. Asymptomatic parasite carriage at the end of dry season was associated with a higher risk of infection (Hazard Ratio, HR = 3.0, p < 0.0001) and clinical malaria (HR = 1.561, p = 0.057) during the following transmission season. Age and village of residence were additional predictors of infection and clinical malaria during the transmission season. CONCLUSION: Chronic parasite carriage during the dry season is associated with an increased risk of malaria infection and clinical malaria. It is unclear whether this is due to environmental exposure or to other factors.
背景:无症状低密度恶性疟原虫在旱季的慢性携带可能支持对临床疟疾的获得性免疫的维持。然而,慢性低密度感染与随后发生临床疟疾发作的风险之间的关系尚不清楚。
方法:在冈比亚东部进行的一项为期 2 年的研究(2014 年 12 月至 2016 年 12 月)中,在旱季和雨季进行了 9 次使用分子寄生虫检测的横断面调查。在 2016 年疟疾传播季节期间,被动病例检测确定了临床疟疾发作。
结果:在所采集的 5256 个样本中,有 444 个(8.4%)为恶性疟原虫阳性。多变量模型确定了居住的村庄、男性、年龄≥5 岁、贫血和发热是与恶性疟原虫寄生虫携带相关的独立因素。在同一家庭内,感染不会随时间聚集,也不会在相邻家庭中复发。旱季末无症状寄生虫携带与下一个传播季节感染(危险比,HR=3.0,p<0.0001)和临床疟疾(HR=1.561,p=0.057)的风险增加相关。年龄和居住的村庄是传播季节感染和临床疟疾的其他预测因素。
结论:旱季慢性寄生虫携带与疟疾感染和临床疟疾的风险增加相关。尚不清楚这是由于环境暴露还是其他因素所致。
Lancet. 1995-8-19
Front Immunol. 2019-10-15