Japanese encephalitis (JE), caused by mosquito-borne Japanese encephalitis virus (JEV), presents significant public health challenges. To facilitate effective prevention and control, this study conducted an epidemiological and genomic characterization of JEV in mosquitoes across China during the period from 2021 to 2022, utilizing the national surveillance system for mosquito-borne pathogens. In total, 832 734 female mosquitoes were collected at 130 surveillance sites spanning 29 provinces. with a minimum infection rate (MIR) of 0.20‰. JEV was detected in 12 provinces and five different mosquito species. The highest MIR was observed in Culex tritaeniorhynchus, reaching 0.73‰. The highest detection rate of JEV was found in the pigsty habitat (MIR: 0.95‰). Notably, peak JEV infections in mosquitoes occurred in July, preceding the peak incidence of human cases observed in August. Eight JEV sequences were obtained from six provinces, seven of which were near full-length. Phylogenetic analysis of the whole genome showed that eight JEV strains obtained from provinces in northern and southern China belonged to the emerging variant of GIb-clade 2. In comparison to vaccine strains, current strains displayed between 12 and 14 amino acid variations within the E protein, and there was an additional glycosylation site at N108 resulting from a G110S mutation. These findings underscore active transmission of JEV across multiple mosquito species within China, highlight critical vector and habitat risks, and advocate for enhanced mosquito surveillance as an early warning system. The nationwide dissemination of GIb-clade 2 strains provides a scientific foundation for targeted control measures against JE.

This study explored how polymorphisms in cell surface Toll-like receptors (TLRs) influence susceptibility to Bartonella and ectoparasite infections in striped hamsters. Among six TLR genes, four sites in TLR1, TLR4, and TLR10 genes were associated with Bartonella susceptibility, while twelve sites across TLR4, TLR5, and TLR10 contributed to flea resistance. Similarly, eleven sites in TLR5, TLR6, and TLR10 were linked to gamasid mite parasitism. Genetic polymorphism analysis revealed that when heterozygous or rare genotypes protected the host from infections, the polymorphisms of these sites in uninfected individuals exceeded that of the infected group. The distribution of these sites on the three-dimensional structure of TLRs varied. All Bartonella-related sites were in the extracellular domain, whereas some of those related to fleas and gamasid mites were located in other domains. This research highlights the importance of cell surface TLRs in immune regulation and provides insights into evolutionary dynamics in natural environments.

BACKGROUND:Dengue fever outbreaks have occurred in Chinese mainland in recent years, especially in 2014 and 2019. In 2023, following the Corona Virus Disease 2019 pandemic, dengue fever has exhibited some new trends and characteristics. METHODS:Descriptive epidemiological methods were used to analyse temporal, spatial and demographic distribution. Flow map and Sankey diagram were used to explore the flow of domestic and overseas dengue cases. RESULTS:In 2023, a total of 14,585 indigenous cases, 3,632 domestic imported cases, and 1,579 overseas imported cases were identified in 10, 28, and 22 provinces, respectively among 31 provinces in Chinese mainland. Dengue fever exhibited seasonal characteristics, with peak periods occurring in late summer and early autumn. Most dengue cases were reported in Yunnan Province (70.4% of indigenous cases and 74.4% of overseas imported cases) and Guangdong Province (25.8% and 7.9%, respectively). Of the domestic imported cases, 91.5% were from the Yunnan Province. Additionally, only 30.6% of domestic imported cases were transmitted between provinces. Overseas imported cases were mainly from Myanmar (68.9%), Laos (8.4%), and Thailand (7.2%). Indigenous cases emerged from low to high latitudes during the months of the year, with further spatial growth in the western (Sichuan Province and Chongqing Municipality) and central (Hunan and Hubei provinces) regions. There was a significant increase in the number of domestic imported cases, and the proportion of farmer for dengue cases was substantially higher in 2013 than before. CONCLUSIONS:The findings from the dengue fever analysis in 2023 can help in formulating targeted and strategic plans and implementing effective public health prevention and control measures.

With the improvement of transportation and the rise of tourism on the Qinghai-Xizang Plateau, the scope of human activities has continuously expanded, increasing opportunities for contact with wildlife, also exacerbating the outbreak rate of zoonotic emerging infectious diseases. Currently, research on the gut microbiota of wildlife, especially Marmota himalayana (M. himalayana), which are reservoir hosts for plague, is scarce. In this study, we investigated the composition, function, and regional variations of the gut microbiota in M. himalayana based on the metagenomic sequencing of 45 fecal samples from the Sanjiangyuan National Nature Reserve in Qinghai Province. The results indicated that at the phylum level, the dominant bacterial phyla in the gut microbiota of the M. himalayana were Firmicutes, Bacteroidota, and Proteobacteria, collectively accounting for 74.16 % of the community. At the genus level, the top three most abundant genera were Alistipes (11.86 % ± 1.56 %), Bacteroides (6.68 % ± 0.95 %), and Clostridium (4.92 % ± 1.04 %). Kyoto encyclopedia of genes and genomes (KEGG) database annotation results showed that the most enriched functional categories of the marmot gut microbiota were metabolism, genetic information processing (GIP), and environmental information processing (EIP). These active functions played a crucial role in food digestion, nutrient absorption, metabolic balance maintenance, and pathogen defense, aiding the marmot in better adapting to the extreme environment of the Qinghai-Xizang Plateau. The study provided critical insights into host-microbe interactions, highlighting the role of microbiota in the survival and conservation of endangered species in unique habitats.

Plague, as an ancient zoonotic disease caused by Yersinia pestis , has brought great disasters. The natural plague focus of Marmota himalayana in the Qinghai-Tibet Plateau is the largest, which has been constantly active and the leading source of human plague in China for decades. Understanding the population genetics of M. himalayana and relating that information to the biogeographic distribution of Yersinia pestis and plague outbreaks are greatly beneficial for the knowledge of plague spillover and arecrucial for pandemic prevention. In the present research, we assessed the population genetics of M. himalayana . We carried out a comparative study of plague outbreaks and the population genetics of M. himalayana on the Qinghai-Tibet Plateau. We found that M. himalayana populations are divided into two main clusters located in the south and north of the Qinghai-Tibet Plateau. Fourteen DFR genomovars of Y. pestis were found and exhibited a significant region-specific distribution. Additionally, the increased genetic diversity of plague hosts is positively associated with human plague outbreaks. This insight gained can improve our understanding of biodiversity for pathogen spillover and provide municipally directed targets for One Health surveillance development, which will be an informative next step toward increased monitoring of M. himalayana dynamics.

IntroductionThe striped hamster, often parasitized by ectoparasites in nature, is an ideal model for studying host-ectoparasite molecular interactions. Investigating the response to ectoparasites under laboratory conditions helps elucidate the mechanism of host adaptations to ectoparasite pressure.MethodsUsing transcriptome sequencing, we analyzed gene expression in striped hamsters after short-term (3 days) and long-term (28 days) flea (Xenopsylla cheopis) parasitism. Differentially expressed genes (DEGs) were identified and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Hub genes were pinpointed using protein-protein interaction (PPI) network analysis and the MCODE in Cytoscape. Gene Set Enrichment Analysis (GSEA) was used to further clarify the functional pathways of these hub genes. Validation of DEGs was performed via RT-qPCR. Additionally, the concentrations of reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were determined using specific enzyme-linked immunosorbent assay (ELISA) detection kits for hamsters.ResultsGO analysis revealed that during early parasitism, hosts primarily responded to the ectoparasites by adjusting the expression of genes related to metabolic functions. As parasitism persisted, the immune response became prominent, activating various immune pathways against ectoparasites. KEGG analysis confirmed the ongoing roles of metabolism and immunity. Notably, the chemical carcinogenesis - reactive oxygen species pathway was upregulated during flea parasitism, with downregulation of hub genes ATP5MC1 and ATP5MC2, highlighting the importance of mitochondrial function in oxidative stress. ELISA findings revealed that on day 3, flea parasitism groups showed elevated ROS expression and reduced SOD and CAT levels compared to the control group. By day 28, only SOD expression showed a significant decrease in both parasitism groups.ConclusionThis study uncovered the dynamic changes in metabolism and immune responses of striped hamsters parasitized by Xenopsylla cheopis. Hosts adjust their physiological and immune states to optimize survival strategies during different ectoparasite stages, enhancing our understanding of host-ectoparasite interactions. This also paves the way for further research into how hosts regulate complex biological processes in response to ectoparasite challenges.

目的 分析2020—2022年中国登革热时空分布及环境因素特征。方法 采用描述性流行病学方法分析中国本地和输入性登革热分布的时空特征以及环境特征。结果 2020—2022年中国5个省发生1185例本地病例和19个省发生217例输入性病例。登革热具有季节性特征，本地病例高峰期为9—11月，输入性病例高峰期为6—11月。97.64%的本地病例发生在云南和广西。云南边境缅甸的登革热输入是其登革热本地暴发的主要原因。67.28%的输入性病例分布在广东、福建、云南和浙江，83.41%的输入性病例来自东南亚国家。广东的人口和经济条件是2020—2022年其输入性病例居首位的主要原因。结论 我国登革热仍是由输入引起的本地暴发，具有显著的地方性和季节性特征，各地要做好蚊媒、登革热以及相关环境因素监测，贯彻落实蚊媒可持续控制措施。

Epidemiological characteristics of human rabies in mainland China, 2005–2020 were analyzed to evaluate the effect of rabies control in China in recent years. A total of 24,319 human rabies cases were recorded in 2097 counties in 321 cities of 31 provinces in mainland China. Only 202 cases, located in 143 counties, were recorded in 2020, compared with 3305 cases in 992 counties in 2007; however, rabies was still relatively severe in Hunan Province even in 2020. Peak periods occurred in July–November; August was often the month with the most cases. Guizhou, Hunan, Guangdong, and Guangxi Provinces, in the central and southern regions, accounted for 50.0% of the cases in 2005–2020. Cases occurred almost exclusively in rural areas with 96.7% versus 3.3% in urban areas. A paradoxical relative expansion from southern, eastern, and central towards southwestern, northwestern, northern, and northeastern regions was observed along with the overall reduction of cases. Some regions witnessed complete elimination. The male-to-female ratio was 2.33:1; 66.8% of all cases were reported in the 0–10 (13.8%) and 41–70 (53.0%) age groups. Farmers (68.3%), followed by students (12.2), and diaspora children (6.5%) were most frequently involved. Our results provide objective information for the improvement of rabies prevention and control efforts. This will aid policymakers in China and elsewhere achieve the “Zero human deaths from dog-mediated rabies by 2030” global goal.

Objective To formulate a catalogue of alien vectors and pathogenic organisms for early warning and effective prevention of alien species invasion. Methods The authors searched literature, online databases, and published catalogues for alien vectors and pathogens that can seriously threaten the health of human and animals and agricultural and ecological security. They were evaluated for the risk of invasion to China by using a suitable habitat prediction model and a comprehensive evaluation system of multiple indicators. Candidate species with the potential of invasion were included in this catalogue. Results A total of 304 alien species were screened out and listed in this catalogue for China,including 69 vectors and 235 pathogenic organisms. Among them, 275 species（47 vectors and 228 pathogens） had high probability of invading China. Conclusion This catalogue can be used as an early warning directory to prevent alien vectors and pathogenic organisms from invading China, which provides a reference for relevant departments to formulate preventive management strategies and measures.

IntroductionIn 2019, China experienced massive dengue outbreaks with high incidence and expanded outbreak areas. The study aims to depict dengue’s epidemiology and evolutionary dynamics in China and explore the possible origin of these outbreaks.MethodsRecords of confirmed dengue cases in 2019 were obtained from the China Notifiable Disease Surveillance System. The sequences of complete envelope gene detected from the outbreak provinces in China in 2019 were retrieved from GenBank. Maximum Likelihood trees were constructed to genotype the viruses. The median-joining network was used to visualize fine-scale genetic relationships. Four methods were used to estimate the selective pressure.ResultsA total of 22,688 dengue cases were reported, 71.4% of which were indigenous cases and 28.6% were imported cases (including from abroad and from other domestic provinces). The abroad cases were predominantly imported from Southeast Asia countries (94.6%), with Cambodia (3,234 cases, 58.9%), and Myanmar (1,097 cases, 20.0%) ranked as the top two. A total of 11 provinces with dengue outbreaks were identified in the central-south of China, of which Yunnan and Guangdong provinces had the highest number of imported and indigenous cases. The primary source of imported cases in Yunnan was from Myanmar, while in the other ten provinces, the majority of imported cases were from Cambodia. Guangdong, Yunnan and Guangxi provinces were China’s primary sources of domestically imported cases. Phylogenetic analysis of the viruses in outbreak provinces revealed three genotypes: (I, IV, and V) in DENV 1, Cosmopolitan and Asian I genotypes in DENV 2, and two genotypes (I and III) in DENV 3. Some genotypes concurrently circulated in different outbreak provinces. Most of the viruses were clustered with those from Southeast Asia. Haplotype network analysis showed that Southeast Asia, possibly Cambodia and Thailand, was the respective origin of the viruses in clade 1 and 4 for DENV 1. Positive selection was detected at codon 386 in clade 1.ConclusionDengue importation from abroad, especially from Southeast Asia, resulted in the dengue epidemic in China in 2019. Domestic transmission between provinces and positive selection on virus evolution may contribute to the massive dengue outbreaks.

Background Global connectivity and environmental change pose continuous threats to dengue invasions from worldwide to China. However, the intrinsic relationship on introduction and outbreak risks of dengue driven by the landscape features are still unknown. This study aimed to map the patterns on source-sink relation of dengue cases and assess the driving forces for dengue invasions in China. Methods We identified the local and imported cases (2006–2020) and assembled the datasets on environmental conditions. The vector auto-regression model was applied to detect the cross-relations of source-sink patterns. We selected the major environmental drivers via the Boruta algorithm to assess the driving forces in dengue outbreak dynamics by applying generalized additive models. We reconstructed the internal connections among imported cases, local cases, and external environmental drivers using the structural equation modeling. Results From 2006 to 2020, 81,652 local dengue cases and 12,701 imported dengue cases in China were reported. The hotspots of dengue introductions and outbreaks were in southeast and southwest China, originating from South and Southeast Asia. Oversea-imported dengue cases, as the Granger-cause, were the initial driver of the dengue dynamic; the suitable local bio-socioecological environment is the fundamental factor for dengue epidemics. The Bio8 [odds ratio ( OR) = 2.11, 95% confidence interval ( CI) : 1.67–2.68], Bio9 ( OR = 291.62, 95% CI : 125.63–676.89), Bio15 ( OR = 4.15, 95% CI : 3.30–5.24), normalized difference vegetation index in March ( OR = 1.27, 95% CI : 1.06–1.51) and July ( OR = 1.04, 95% CI : 1.00–1.07), and the imported cases are the major drivers of dengue local transmissions ( OR = 4.79, 95% CI : 4.34–5.28). The intermediary effect of an index on population and economic development to local cases via the path of imported cases was detected in the dengue dynamic system. Conclusions Dengue outbreaks in China are triggered by introductions of imported cases and boosted by landscape features and connectivity. Our research will contribute to developing nature-based solutions for dengue surveillance, mitigation, and control from a socio-ecological perspective based on invasion ecology theories to control and prevent future dengue invasion and localization. Graphical Abstract

The development of a vaccine to prevent congenital human cytomegalovirus (HCMV) disease is a public health priority. We tested rhesus CMV (RhCMV) prototypes of HCMV vaccine candidates in a seronegative macaque oral challenge model. Immunogens included a recombinant pentameric complex (PC; gH/gL/pUL128/pUL130/pUL131A), a postfusion gB ectodomain, and a DNA plasmid that encodes pp65-2. Immunization with QS21-adjuvanted PC alone or with the other immunogens elicited neutralizing titers comparable to those elicited by RhCMV infection. Similarly, immunization with all 3 immunogens elicited pp65-specific cytotoxic T-cell responses comparable to those elicited by RhCMV infection. RhCMV readily infected immunized animals and was detected in saliva, blood, and urine after challenge in quantities similar to those in placebo-immunized animals. If HCMV evades vaccine-elicited immunity in humans as RhCMV evaded immunity in macaques, a HCMV vaccine must elicit immunity superior to, or different from, that elicited by the prototype RhCMV vaccine to block horizontal transmission.

目的分析2020-2021年我国12个省（自治区、直辖市）媒介伊蚊生态学监测结果,为媒介伊蚊传播疾病风险评估、预测预警及控制提供科学依据。方法收集我国12个省（自治区、直辖市）媒介伊蚊专项调查点媒介伊蚊幼蚊及成蚊密度调查资料,利用SPSS 18.0软件进行统计分析。结果 2020-2021年海南、浙江和湖南省平均布雷图指数（BI）＞10.00,广西壮族自治区（广西）、云南、河南和山东省平均BI＞5.00;广西、广东、海南和山东省（自治区）平均诱蚊诱卵指数（MOI）＞5.00;河南、湖北和山东省平均帐诱指数≥2.00只/（顶·h）,广西、广东、海南、云南、福建和湖南省（自治区）平均帐诱指数＞1.00只/（顶·h）。Ⅰ类省份[广东、海南、广西、福建、云南和浙江省（自治区）]与其他类型省份平均BI、MOI和帐诱指数比较差别无统计学意义（t=0.766、1.030、-0.745,均P＞0.05）。2020-2021年,除广东、广西、云南、山东省（自治区）平均BI高于2017-2019三年平均水平外,其他省份BI均低于这3年的平均水平。媒介伊蚊在广东、海南、广西、云南4省（自治区）调查点全年有活动,在福建、浙江和湖北等省（自治区）3-12月有活动,在重庆、山东和河南等省（直辖市）4-11月有活动,在江西省4-12月有活动。BI和MOI研究结果在云南、广西和湖北省（自治区）存在一定差别。研究期内,发生登革热暴发和本地病例的地区媒介伊蚊BI均＞5.00,云南省瑞丽市、广西梧州市岑溪市及广东省中山市三角镇BI＞10.00;广西岑溪市帐诱指数＞2.00只/（顶·h）。结论 2020-2021年我国出现登革热本地病例省份媒介伊蚊平均密度较高,不同地区媒介伊蚊密度差异存在时空异质性。建议我国登革热本地传播地区适当调整媒介伊蚊监测时间,继续加强媒介伊蚊监测和风险评估,系统梳理媒介伊蚊生态学调查结果,为我国媒介伊蚊监测方案修订完善及媒介伊蚊传播疾病暴发控制提供科学依据。

目的 探究北京市平谷区恙虫病发病与土地利用的相关性。方法 应用eCognition V9.0.1软件的多尺度分割和随机森林算法分别对平谷区累计发病数较多的5个镇（王辛庄镇、大兴庄镇、金海湖镇、南独乐河镇和山东庄镇）2016、2018和2021年的遥感影像数据进行地物提取和分类，ArcGIS 10.7软件统计每年各个乡镇土地类别的面积，分别通过构建折线图和Spearman秩相关分析探索地物面积与恙虫病发病率的关联。结果 北京市平谷区5个镇3年遥感影像的总体分类精度均＞80%,Kappa系数为0.600～0.800。Spearman秩相关分析显示，2016、2018年，平谷区5个镇恙虫病发病率与绿地面积占非林地面积的比值呈正相关（r=0.576,P=0.082），而2018、2021年发病率与地物面积占比无相关性。按镇来看，南独乐河镇和山东庄镇的恙虫病发病率与裸土/非林地呈负相关（均r=-1.000，均P＜0.010），与绿地/非林地呈正相关（r=1.000,P＜0.010），与荒地/非林地呈负相关（r=-1.000,P＜0.010），但金海湖镇的发病率与荒地/非林地呈正相关（r=1.000,P＜0.010）。按不同年份来看，2016年5个镇的恙虫病发病率与建筑/非林地呈负相关（r=-0.900,P=0.037）,2018年发病率与水体/非林地呈负相关（r=-0.900,P=0.037）,2021年发病率与水体/非林地呈正相关（r=0.900,P=0.037）。结论 2016、2018年北京市平谷区恙虫病发病率与绿地面积占非林地面积的比值呈正相关，而2018、2021年二者无相关性。不同镇和不同年份的相关性结果不同。

Dengue fever occurs throughout mainland China, except in the Tibet Autonomous Region. During 2005–2020, there were 12,701 imported cases and 81,653 indigenous cases recorded. The indigenous cases were mainly clustered in Guangdong (74.0%) and Yunnan provinces (13.7%). Indigenous dengue fever is a seasonal illness in mainland China, manifesting predominantly in summer and autumn. Indigenous dengue fever cases tend to peak every 5years and have shown a substantial increase during the period 2005–2020. During the study period, indigenous dengue fever occurred more than ten times in each of the seven counties of Guangdong Province. Indigenous dengue fever has spread from low to high latitudes; that is, from the southwestern, southern, and southeastern areas to the central and northern regions, and from border ports and cities to rural areas. Aedes aegypti has become widespread in Yunnan Province but has diminished in Guangxi, Guangdong, and Hainan provinces in recent years. Aedes albopictus is distributed throughout mainland China, spanning 25 provinces and municipalities. To maintain effective public health prevention and control, it is important to monitor dengue occurrence, provide dengue classification guidance, and ensure sustainable vector management of Aedes.

目的了解云南省登革热流行及聚集特征,为今后针对性防控措施的制定和完善提供依据。方法从中国疾病预防控制信息系统收集云南省2013-2020年报告的登革热病例数据,利用ArcMap 10.7软件绘制分布地图、SaTScan v9.3软件进行空间扫描分析。结果 2013-2020年,云南省106个县（区）累计报告登革热病例14 031例,其中本地病例11 505例、境外输入病例2 507例、省外输入病例19例;疫情呈"锯齿状"升高态势。总体疫情扫描探测出2个一级聚类区和2个二级聚类区（均P＜0.05）,一级聚类区为景洪市[对数似然比（LLR）=22 647.97]和瑞丽市（LLR=10 125.08）,二级聚类区为勐腊县（LLR=1 167.76）和耿马县（LLR=1 061.22）。2013、2015、2017和2019年均扫描探测出一级聚类区。本地病例出现在边境10个县,境外输入病例主要来源于东南亚和非洲国家,缅甸、柬埔寨和老挝是主要来源国。上半年以输入病例为主、下半年以本地病例为主,7月开始上升,8-10月达高峰期,11月开始下降。发病数男女性别比为1∶0.88,15～60岁年龄组占79.78%,发病前5位人群构成分别为商业服务人员（20.95%）、农民（20.52%）、家务及待业人员（11.17%）、离退人员（8.97%）和学生（7.31%）。结论云南省登革热疫情形势严峻,亟待做好输入病例管控、媒介伊蚊监测及控制工作,为登革热可持续控制提供保障。

目的通过现场调查和实验室研究,了解北京市平谷区恙虫病疫源地宿主和媒介生物种类、季节规律及病原基因分型,为恙虫病防控提供依据。方法每月在野外布放鼠夹,连续1年,捕获小型兽类梳捡体表恙螨,分析小兽及体表恙螨数量、种类构成、季节消长和空间分布规律。解剖小兽,取肝、脾样本,提取组织DNA,采用巢式PCR扩增检测恙虫病东方体56 kDa基因核酸片段,通过核酸序列比对确定恙虫病东方体基因分型并计算阳性率。结果2018年9月至2019年8月共捕获小兽7种734只,其中黑线姬鼠和小家鼠分别占65.26%和30.52%,为该地优势鼠种。小兽肝、脾检出Shimokoshi、Kawasaki和Japan Gilliam 3个恙虫病东方体基因型,以前2型为主。小兽恙虫病东方体阳性率为10.90%。小家鼠和黑线姬鼠阳性率分别为14.86%和9.30%,是该地主要宿主动物。从小兽体表捡获恙螨10种31 321只,亚须纤恙螨、临淮岗纤恙螨和小盾纤恙螨分别占84.79%、6.49%和3.63%。其中小盾纤恙螨的季节消长与病例发病季节基本一致,应为该疫源地主要传播媒介。它只分布在平谷区的山区和山前过渡地带。结论平谷区恙虫病疫源地野外以黑线姬鼠和小家鼠为主要宿主,小盾纤恙螨可能为主要传播媒介,恙虫病东方体存在至少3个基因型。本次调查明确了平谷区恙虫病疫源地的基本要素,为恙虫病防控提供了依据,但其他种类恙螨媒介作用还需开展进一步研究。

Rhesus cytomegalovirus (RhCMV) infection of rhesus macaques (Macaca mulatta) is a valuable nonhuman primate model of human CMV (HCMV) persistence and pathogenesis. In vivo studies predominantly use tissue culture-adapted variants of RhCMV that contain multiple genetic mutations compared to wild-type (WT) RhCMV. In many studies, animals have been inoculated by nonnatural routes (e.g., subcutaneous, intravenous) that do not recapitulate disease progression via the normative route of mucosal exposure. Accordingly, the natural history of RhCMV would be more accurately reproduced by infecting macaques with strains of RhCMV that reflect the WT genome using natural routes of mucosal transmission. Here, we tested two WT-like RhCMV strains, UCD52 and UCD59, and demonstrated that systemic infection and frequent, high-titer viral shedding in bodily fluids occurred following oral inoculation. RhCMV disseminated to a broad range of tissues, including the central nervous system and reproductive organs. Commonly infected tissues included the thymus, spleen, lymph nodes, kidneys, bladder, and salivary glands. Histological examination revealed prominent nodular hyperplasia in spleens and variable levels of lymphoid lymphofollicular hyperplasia in lymph nodes. One of six inoculated animals had limited viral dissemination and shedding, with commensurately weak antibody responses to RhCMV antigens. These data suggest that long-term RhCMV infection parameters might be restricted by local innate factors and/or de novo host immune responses in a minority of primary infections. Together, we have established an oral RhCMV infection model that mimics natural HCMV infection. The virological and immunological parameters characterized in this study will greatly inform HCMV vaccine designs for human immunization. IMPORTANCE Human cytomegalovirus (HCMV) is globally ubiquitous with high seroprevalence rates in all communities. HCMV infections can occur vertically following mother-to-fetus transmission across the placenta and horizontally following shedding of virus in bodily fluids in HCMV-infected hosts and subsequent exposure of susceptible individuals to virus-laden fluids. Intrauterine HCMV has long been recognized as an infectious threat to fetal growth and development. Since vertical HCMV infections occur following horizontal HCMV transmission to the pregnant mother, the nonhuman primate model of HCMV pathogenesis was used to characterize the virological and immunological parameters of infection following primary mucosal exposures to rhesus cytomegalovirus.