An epizootic of rift valley fever (RVF) was suspected on 21 February 2021 in various districts of Madagascar, with a lab confirmation on 1 April 2021. A cross-sectional survey aiming to detect cases of RVF in humans and to study the circulation of rift valley fever virus (RVFV) in animals was conducted from 22 April to 4 May 2021 in the district of Mananjary. Blood samples from cattle and humans were tested using serological and molecular techniques. In cattle, the circulation of RVFV was confirmed between 5 February and 4 May 2021. The positivity rates of anti-RVFV IgG and IgM were 60% and 40%, respectively. In humans, the circulation of RVFV was observed from 1 April to 5 May 2021. The positivity rate of RVFV was estimated to be 11.7% by combining the results of the molecular and serological approaches. Of the 103 individuals who agreed to participate in the survey, 3 were determined to be positive by RT-PCR, and 10 had anti-RVFV IgM. Among them, one was positive for both. Given that previous studies have reported the circulation of RVFV during inter-epidemic periods and the occurrence of outbreaks due to imported RVFV in Madagascar, our findings suggest the importance of strengthening RVF surveillance from a “One Health” perspective by conducting syndromic and risk-based surveillance at the national and regional levels.

中文翻译：

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2021 年马达加斯加马南贾里区裂谷热再度爆发：呼吁采取行动

2021 年 2 月 21 日，马达加斯加多个地区疑似发生裂谷热 (RVF) 流行病，并于 2021 年 4 月 1 日得到实验室确认。一项横断面调查旨在检测人类裂谷热病例并研究裂谷热的传播2021 年 4 月 22 日至 5 月 4 日在马南贾里地区进行了动物谷热病毒（RVFV）检测。使用血清学和分子技术对牛和人的血液样本进行了测试。2021年2月5日至5月4日期间，在牛中确认了RVFV的循环。抗RVFV IgG和IgM的阳性率分别为60%和40%。在人类中，2021年4月1日至5月5日观察到RVFV的循环。结合分子学和血清学方法的结果估计RVFV的阳性率为11.7%。在同意参加调查的 103 人中，3 人经 RT-PCR 检测呈阳性，10 人检测出抗 RVFV IgM。其中，有一人对两者均呈阳性。鉴于之前的研究报道了裂谷热病毒在流行期间的传播以及马达加斯加输入性裂谷热病毒导致的疫情暴发，我们的研究结果表明，从“同一个健康”的角度，通过进行基于症状和风险的监测来加强裂谷热监测的重要性国家和地区层面的监督。