Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.
Africa Center of Excellence for Infectious Diseases of Humans and Animals, University of Zambia, Lusaka, Zambia.
J Gen Virol. 2021 Mar;102(3). doi: 10.1099/jgv.0.001564. Epub 2021 Feb 3.
Encephalomyocarditis virus (EMCV) infects a wide range of hosts and can cause encephalitis, myocarditis, reproductive disorders and diabetes mellitus in selected mammalian species. As for humans, EMCV infection seems to occur by the contact with animals and can cause febrile illnesses in some infected patients. Here we isolated EMCV strain ZM12/14 from a natal multimammate mouse () in Zambia. Pairwise sequence similarity of the ZM12/14 P1 region consisting of antigenic capsid proteins showed the highest similarity of nucleotide (80.7 %) and amino acid (96.2%) sequence with EMCV serotype 1 (EMCV-1). Phylogenetic analysis revealed that ZM12/14 clustered into EMCV-1 at the P1 and P3 regions but segregated from known EMCV strains at the P2 region, suggesting a unique evolutionary history. Reverse transcription PCR (RT-PCR) screening and neutralizing antibody assays for EMCV were performed using collected tissues and serum from various rodents (=179) captured in different areas in Zambia. We detected the EMCV genome in 19 . (19/179=10.6 %) and neutralizing antibody for EMCV in 33 . (33/179=18.4 %). However, we did not detect either the genome or neutralizing antibody in other rodent species. High neutralizing antibody litres (≧320) were observed in both RT-PCR-negative and -positive animals. Inoculation of ZM12/14 caused asymptomatic persistent infection in BALB/c mice with high antibody titres and high viral loads in some organs, consistent with the above epidemiological results. This study is the first report of the isolation of EMCV in Zambia, suggesting that may play a role as a natural reservoir of infection.
脑心肌炎病毒(EMCV)感染范围广泛,可在某些哺乳动物物种中引起脑炎、心肌炎、生殖障碍和糖尿病。对于人类来说,EMCV 感染似乎是通过与动物接触而发生的,一些感染的患者会出现发热症状。在这里,我们从赞比亚的一只多齿囊鼠中分离到了 EMCV 株 ZM12/14。ZM12/14 的 P1 区由抗原性衣壳蛋白组成,其核苷酸(80.7%)和氨基酸(96.2%)序列与 EMCV 血清型 1(EMCV-1)的相似度最高。系统进化分析表明,ZM12/14 在 P1 和 P3 区与 EMCV-1 聚类,但在 P2 区与已知的 EMCV 株分离,提示其具有独特的进化史。使用从赞比亚不同地区采集的各种啮齿动物(=179 只)的组织和血清进行逆转录 PCR(RT-PCR)筛选和 EMCV 中和抗体检测。我们在 19 只(19/179=10.6%)中检测到 EMCV 基因组,在 33 只(33/179=18.4%)中检测到针对 EMCV 的中和抗体。然而,我们在其他啮齿动物种中未检测到 EMCV 基因组或中和抗体。在 RT-PCR 阴性和阳性动物中均观察到高中和抗体滴度(≧320)。ZM12/14 接种可引起 BALB/c 小鼠无症状持续感染,这些小鼠的抗体滴度高,一些器官中的病毒载量高,这与上述流行病学结果一致。本研究首次报道了赞比亚 EMCV 的分离,提示多齿囊鼠可能是感染的自然宿主。