Nsengimana Isidore, Hakizimana Emmanuel, Mupfasoni Jackie, Hakizimana Jean Nepomuscene, Chengula Augustino A, Kasanga Christopher J, Eastwood Gillian
Department of Veterinary Microbiology, Parasitology and Biotechnology, Sokoine University of Agriculture, Morogoro P.O. Box 3000, Tanzania.
Rwanda Inspectorate, Competition and Consumer Protection Authority, Kigali P.O. Box 375, Rwanda.
Pathogens. 2025 Jan 8;14(1):47. doi: 10.3390/pathogens14010047.
Rift Valley fever virus (RVFV) is an emerging mosquito-borne arbovirus of One Health importance that caused two large outbreaks in Rwanda in 2018 and 2022. Information on vector species with a role in RVFV eco-epidemiology in Rwanda is scarce. Here we sought to identify potential mosquito vectors of RVFV in Rwanda, their distribution and abundance, as well as their infection status. Since an outbreak of RVF occurred during the study period, data were obtained both during an interepidemic period and during the 2022 Rwanda RVF outbreak. Five districts of the eastern province of Rwanda were prospected using a combination of unbaited light traps and Biogents (BG Sentinel and Pro) traps baited with an artificial human scent during three periods, namely mid-August to mid-September 2021, December 2021, and April to May 2022. Trapped mosquitoes were morphologically identified and tested for viral evidence using both RT-PCR and virus isolation methods on a Vero cell line. A total of 14,815 adult mosquitoes belonging to five genera and at least 17 species were collected and tested as 765 monospecific pools. was the most predominant species representing 72.7% of total counts. Of 527 mosquito pools collected before the 2022 outbreak, a single pool of showed evidence of RVFV RNA. Of 238 pools collected during the outbreak, RVFV was detected molecularly from five pools (two pools of , two pools of , and one pool of sensu lato), and RVFV was isolated from the two pools of , from Kayonza and Rwamagana districts, respectively. Minimum infection rates (per 1000 mosquitoes) of 0.4 before the outbreak and 0.6-7 during the outbreak were noted. Maximum-likelihood phylogenetic analysis indicates that RVFV detected in these mosquitoes is closely related to viral strains that circulated in livestock in Rwanda and in Burundi during the same RVF outbreak in 2022. The findings reveal initial evidence for the incrimination of several mosquito species in the transmission of RVFV in Rwanda and highlight the need for more studies to understand the role of each species in supporting the spread and persistence of RVFV in the country.
裂谷热病毒（RVFV）是一种新出现的、具有“同一健康”重要性的蚊媒虫媒病毒，曾于2018年和2022年在卢旺达引发两次大规模疫情。关于在卢旺达裂谷热病毒生态流行病学中起作用的媒介种类的信息很少。在此，我们试图确定卢旺达裂谷热病毒的潜在蚊媒、它们的分布和丰度，以及它们的感染状况。由于在研究期间发生了裂谷热疫情，因此在疫情间期和2022年卢旺达裂谷热疫情期间都获取了数据。在三个时间段，即2021年8月中旬至9月中旬、2021年12月以及2022年4月至5月，使用未诱饵的诱蚊灯和用人工体香诱饵的Biogents（BG Sentinel和Pro）诱捕器对卢旺达东部省的五个区进行了勘查。对捕获的蚊子进行形态学鉴定，并使用RT-PCR和在Vero细胞系上的病毒分离方法检测病毒证据。总共收集了14815只成年蚊子，分属于五个属，至少17个物种，并作为765个单物种样本进行检测。 是最主要的物种，占总数的72.7%。在2022年疫情爆发前收集的527个蚊子样本中，一个 的样本显示有裂谷热病毒RNA证据。在疫情期间收集的238个样本中，从五个样本（两个 的样本、两个 的样本和一个 广义样本）中分子检测到裂谷热病毒，并且分别从卡永扎区和鲁瓦马加纳区的两个 的样本中分离出裂谷热病毒。注意到疫情爆发前的最低感染率（每1000只蚊子）为0.4，疫情期间为0.6 - 7。最大似然系统发育分析表明，在这些蚊子中检测到的裂谷热病毒与2022年同一裂谷热疫情期间在卢旺达和布隆迪家畜中传播的病毒株密切相关。这些发现揭示了卢旺达几种蚊种在裂谷热病毒传播中被牵连的初步证据，并强调需要更多研究来了解每个物种在支持裂谷热病毒在该国传播和持续存在中的作用。
