Université de Bretagne Occidentale, Service des maladies infectieuses et tropicales, Centre Hospitalier Régional Universitaire La Cavale Blanche, Brest, France.
Sorbonne Université, Institut Pierre Louis d'Épidémiologie et de Santé Publique, Inserm, Paris, France.
Clin Infect Dis. 2023 Feb 8;76(3):e884-e893. doi: 10.1093/cid/ciac641.
The impact of chemoprophylaxis targeting Plasmodium falciparum on Plasmodium vivax and Plasmodium ovale, which may remain quiescent as hypnozoites in the liver, is debated.
We conducted a nested case-control analysis of the outcomes of P. vivax and P. ovale infections in imported malaria cases in France among civilian travelers from 1 January 2006, to 31 December 2017. Using adjusted logistic regression, we assessed the effect of chemoprophylaxis on the incubation period, time from symptoms to diagnosis, management, blood results, symptoms, and hospitalization duration. We analyzed the effect of blood-stage drugs (doxycycline, mefloquine, chloroquine, chloroquine-proguanil) or atovaquone-proguanil on the incubation period. We used a counterfactual approach to ascertain the causal effect of chemoprophylaxis on postinfection characteristics.
Among 247 P. vivax- and 615 P. ovale-infected travelers, 30% and 47%, respectively, used chemoprophylaxis, and 7 (3%) and 8 (1%) were severe cases. Chemoprophylaxis users had a greater risk of presenting symptoms >2 months after returning for both species (P. vivax odds ratio [OR], 2.91 [95% confidence interval {CI}, 1.22-6.95], P = .02; P. ovale OR, 2.28 [95% CI, 1.47-3.53], P < .001). Using drugs only acting on the blood stage was associated with delayed symptom onset after 60 days, while using atovaquone-proguanil was not.
Civilian travelers infected with P. vivax or P. ovale reporting chemoprophylaxis use, especially of blood-stage agents, had a greater risk of delayed onset of illness. The impact of chemoprophylaxis on the outcomes of infection with relapse-causing species calls for new chemoprophylaxis acting against erythrocytic and liver stages.
针对恶性疟原虫的化学预防措施对间日疟原虫和卵形疟原虫的影响存在争议，间日疟原虫和卵形疟原虫可能以休眠状态（即肝期疟原虫）潜伏在肝脏中。
我们对 2006 年 1 月 1 日至 2017 年 12 月 31 日期间法国平民旅行者感染输入性疟疾中，间日疟原虫和卵形疟原虫感染的结局进行了嵌套病例对照分析。我们使用调整后的逻辑回归分析，评估了化学预防对潜伏期、从症状出现到诊断的时间、治疗、血液检查结果、症状和住院时间的影响。我们分析了血期药物（强力霉素、甲氟喹、氯喹、氯喹-伯氨喹）或阿托伐醌-伯氨喹对潜伏期的影响。我们采用反事实方法确定化学预防对感染后特征的因果影响。
在 247 例间日疟原虫感染旅行者和 615 例卵形疟原虫感染旅行者中，分别有 30%和 47%的旅行者使用了化学预防措施，分别有 7 例（3%）和 8 例（1%）为严重病例。对于两种疟原虫，使用化学预防措施的旅行者出现症状的时间均大于 2 个月的风险更高（间日疟原虫比值比 [OR]，2.91[95%置信区间{CI}，1.22-6.95]，P=.02；卵形疟原虫 OR，2.28[95% CI，1.47-3.53]，P<.001）。仅使用作用于血期的药物与 60 天后症状出现延迟有关，而使用阿托伐醌-伯氨喹则无关。
报告使用化学预防措施的间日疟原虫或卵形疟原虫感染的平民旅行者出现疾病发作延迟的风险更高，特别是使用血期药物的旅行者。化学预防措施对引起复发的感染结局的影响需要新的针对红细胞和肝期的化学预防措施。
