Hantavirus infection in the United States: epizootiology and epidemiology

Multiple species of murid and arvicolid (microtine) rodents serve as the reservoir hosts of hantaviruses, the etiologic agents of hemorrhagic fever with renal syndrome. Three antigenically distinct hantaviruses have been isolated from Rattus norvegicus, Mus musculus, and Microtus pennsylvanicus captured in the United States, and serologic evidence of a hantavirus enzootic has been found in several other indigenous rodent species. In residential districts of port cities such as Baltimore, nearly 50% of Norway rats are infected with viruses that are serologically indistinguishable from disease-causing Hantavirus strains isolated from rats in the Far East. Despite the widespread distribution of Hantavirus-infected rodents, confirmed cases of hemorrhagic fever with renal syndrome have not been recognized in the United States. Moreover, the overall risk of hantavirus infection in humans in the United States is low, even among individuals who have frequent exposure to commensal and wild rodents. Studies are needed to define the clinical spectrum of hantavirus infection in humans in the United States.     

Serological evidence of hantavirus infections in Malaysia

Hantaviruses are primarily rodent-borne and transmission is by inhalation of virus-contaminated aerosols of rodent excreta, especially urine and saliva. The genus Hantavirus, family Bunyaviridae, comprises at least 14 serotypes and the symptoms of clinical illness range from mild fever to severe hemorrhagic manifestations with renal complications. Many countries in Southeast Asia are unaware of the importance of hantavirus infections and give them low priority. Malaysia, like other countries in the region, has conducted very few studies on the epidemiology of hantaviruses - and even these were conducted in the 1980s. Using a more extensive range of hantavirus antigens, we conducted a seroprevalence study of rodents and humans and found further evidence of hantavirus infections. Moreover, the data from the antibody profiles strongly suggest the presence of different hantaviruses at the study sites.     

Hantavirus ecology in rodent populations in three protected areas of Argentina

In this study, we identified hantavirus genotypes and their reservoirs and evaluated the spatial and temporal distribution of the virus in rodent population in three protected areas of Argentina over 3 years (2007-2010). A total of 837 rodents were captured with an effort of 22 117 trap-nights. We detected the genotype Lechiguanas in Oligoryzomys nigripes and O. flavescens and Pergamino in Akodon azarae. There was no correlation between seroprevalence and trap success of the host. The proportion of seropositive males was significantly higher than the proportion of seropositive females. The total length of seropositives was higher than that of seronegatives in each host species. Seropositive individuals were observed in warm months and not in cold months, which suggests an infection cycle. This investigation confirms that protected areas of central east Argentina are places with a variety of sylvan rodents species associated with different hantavirus genotypes where reservoirs are numerically dominant. Although there was more than one known reservoir of hantavirus, only one species had antibodies in each area. This can be explained because the transmission of the virus does need not only the presence of a rodent species but also a threshold density. Longevity of even a small proportion of the host population in cold months may provide a trans-seasonal mechanism for virus persistence. The seroprevalence detected was higher than the one found before in rodent populations of Argentina, and this explains the appearance of human cases in two of these three areas.     

Hantavirus infection prevalence in wild rodents and human anti-hantavirus serological profiles from different geographic areas of South Brazil

Abstract. Paraná state presents the fourth highest number of accumulated cases of hantavirus pulmonary syndrome in Brazil. To map the risk areas for hantavirus transmission we carried out a study based on rodent trapping and determined the anti-hantavirus seroprevalence in these animals and in the inhabitants of these localities. Overall seroprevalence in rodents and humans were 2.5% and 2.4%, respectively. Eighty-two percent of the seropositive rodents were genetically analyzed. Phylogenetic analyses revealed that hantaviruses from rodent samples cluster with Araucária (Juquitiba-like) or Jaborá hantavirus genotypes. The Jaborá strain was identified in Akodon serrensis and Akodon montensis, whereas the Araucária strain was detected in Oligoryzomys nigripes, Oxymycterus judex, A. montensis, and Akodon paranaensis, with the latter species being identified for the first time as a natural host. These findings expose the complex relationships between virus and reservoirs in Brazil, which could have an impact on hantavirus transmission dynamics in nature and human epidemiology.     

5株鼠样品中分离汉坦病毒毒株S基因序列比较与分析

目的 了解近年来从宁波口岸捕获的鼠类样品中分离的5个汉坦病毒株遗传学差异。方法 利用RT-PCR方法,对5个汉坦病毒株S基因全长进行扩增、克隆和测序,并将这5个毒株的S基因序列分别与GenBank登录的20个汉坦病毒感毒株进行比较分析。结果 DX1507株和DX1408株S基因核苷酸序列长度为1766 bp与汉城型(SEOV)病毒株 Rn-DH27同源性最为接近,LJ1112株S基因核苷酸序列长度为1772 bp与汉城型(SEOV)病毒株Cherwell同源性最为接近,DX0903株和BL1402株S基因核苷酸序列长度为1725 bp与大别山型(DABV)病毒株 Yongjia-Nc-95和Yongjia-Nc-38同源性最为接近。结论 宁波口岸分离到的汉坦病毒株分别为汉城型和大别山型,对宁波口岸开展汉坦病毒传播防控有重要意义。     

Distribution of hantavirus foci in Belgium

During 1999 and 2000, we performed rodent captures on 15 sites all over Belgium to evaluate the presence of hantaviruses in local rodent populations. Viral antibody and RNA detection was performed by ELISA/focus reduction neutralisation test and RT-PCR, respectively. We found hantavirus-positive rodents on 13 out of 15 trapping sites and 3 rodent species were found positive for hantavirus infection. Apart from Puumala virus that was carried by Clethrionomys glareolus, 2 additional rodent species, Microtus arvalis and Apodemus sylvaticus, were found antibody- and/or RNA-positive.     

Genetic evidence of hantavirus infections in wild rodents from northwestern Colombia

This report builds on recent serological evidence for the presence of hantavirus in northern Colombia by providing sequence-specific and phylogenetic data of hantavirus infections in wild rodents. From August 2007 to August 2008, 354 rodent specimens representing four families were collected in the northwestern Antioquia region of Colombia. Antibodies reactive to Sin Nombre virus and Maciel virus antigens by IgG enzyme-linked immunosorbent assay were found in 15 of 109 (14%) Cherries cane rats (Zygodontomys cherriei), the only sigmodontinae rodents captured. Lung tissue samples from 11 of the 15 seropositive rodents were RT-polymerase chain reaction positive for hantavirus RNA, using primers for the S and M genome segments. Eight of these amplicons were sequenced and phylogenetic analyses indicated RNA of a hantavirus closely related to Calabazo virus, previously found in Panama. This is the first report of the genetic characterization of a hantavirus in rodents in Colombia.     

2017-2020年湖北省荆州市肾综合征出血热宿主动物监测分析北大核心CSCD

目的总结荆州市2017-2020年肾综合征出血热(HFRS)宿主动物监测结果,为该市HFRS科学防控提供依据。方法在全市8个县(市、区)开展HFRS宿主动物监测。在春季(4-5月)和秋季(9—10月)采用夹夜法分别于室内、野外布放鼠夹。室内及野外选取荆州市常见生境。对捕获鼠进行鉴定,无菌取鉴定鼠肺,利用实时荧光定量PCR(RT-PCR)检测鼠肺汉坦病毒并分型。结果 2017-2020年荆州市平均鼠密度4.83%(1 106/22 910),鼠汉坦病毒阳性率9.83%(58/590)。鼠密度居前3位的地区分别为江陵县(9.61%)、沙市区(6.44%)和石首市(4.92%)。鼠汉坦病毒阳性率由高到低依次为沙市区(17.31%,27/156)、江陵县(8.51%,16/188)、监利县(8.42%,8/95)和洪湖市(7.29%,7/96),其它地区捕获鼠未检出汉坦病毒。春季鼠密度为5.47%(578/10 566)。其中室内生境鼠密度6.15%(146/2 374),鼠汉坦病毒阳性率1.89%(1/53),阳性鼠为厨房捕获小家鼠;野外生境鼠密度5.27%(432/8 192),鼠汉坦病毒阳性率11.76%(16/136),阳性鼠以小麦田和虾稻田捕获黑线姬鼠、褐家鼠为主。秋季鼠密度为4.28%(528/12 344)。其中室内生境鼠密度6.06%(198/3 269),鼠汉坦病毒阳性率0.78%(1/129),阳性鼠为杂物间捕获黄胸鼠;野外生境鼠密度3.64%(330/9 075),鼠汉坦病毒阳性率14.71%(40/272),阳性鼠以蔬菜田、虾田、虾稻田、稻田捕获黑线姬鼠和褐家鼠为主。捕获黑线姬鼠均携带HNTV型汉坦病毒;褐家鼠、小家鼠、黄胸鼠携带SEOV型汉坦病毒。结论荆州市HFRS宿主动物以野外捕获黑线姬鼠、褐家鼠为主,分别携带HNTV型、SEOV型汉坦病毒。江陵县、沙市区鼠密度及鼠汉坦病毒阳性率均较高。     

A case-control study after a hantavirus infection outbreak in the south of Belgium: who is at risk?

Puumala is the most common hantavirus serotype in Europe and is spread mainly by the red bank vole. Between 1 July 1992 and 31 January 1994, an outbreak of Puumala virus-induced nephropathia epidemica (NE) occurred in the Belgian Ardennes. Serologically confirmed cases (n = 41) were compared with two groups of asymptomatic seronegative controls. Risks identified included sighting of living rodents, exposure to rodent droppings, and trapping rodents during the 4 weeks preceding onset of symptoms. Activities during this 4-week period that presented the greatest risk were woodcutting, reopening of a nonaerated room, and strenuous physical effort. This is the first case-control study on risk factors for NE in Europe. In comparison with the American form of hantavirus pulmonary syndrome, which is spread by deer mice, professional activity appears to be a more important risk factor for acquisition of hantavirus in Europe.     

山东部分地区鼠体外寄生螨种类调查

目的调查山东地区鼠体外寄生虫分布及种类组成情况。方法在山东省的济南、济宁、泰安、枣庄、菏泽等5地市采用笼日法捕鼠,分离鼠体外寄生螨并分类。结果共捕获鼠类186只,采获鼠体外寄生螨723只,分属5科7属11种。其中恙螨451只,占62.38%,分属l科3属5种;革螨272只,占37.62%,分属4科4属6种。恙螨的优势种为小盾纤恙螨(258只)和居中纤恙螨(77只);革螨的优势种为柏氏禽刺螨(132只)和厩真厉螨(41只)。黑线姬鼠体外的优势种为小盾纤恙螨、须纤恙螨和柏氏禽刺螨、厩真厉螨;东方田鼠体外主要为小盾纤恙螨;小家鼠和大仓鼠体外以柏氏禽刺螨和居中纤恙螨为主;褐家鼠体外以柏氏禽刺螨和格氏血厉螨为主。结论通过本次对山东部分地区鼠体外寄生虫分布及种类组成调查;为该地区进一步研究鼠类传染病提供了依据。     

Multiple co-infections of rodents with hantaviruses, Leptospira, and Babesia in Croatia

Hantaviruses, Leptospira spp., and Babesia spp. are rodent-borne pathogens present worldwide. We studied multiple co-infections of small rodents in Croatia with all three pathogens. Twenty-eight Apodemus flavicollis and 16 Myodes glareolus were tested for the presence of hantavirus RNA by real-time RT-PCR, Leptospira strains by renoculture method and Babesia DNA by PCR. Anti-hantavirus antibodies and anti-Leptospira antibodies were detected by serological methods. Very high infection rates with each pathogen were found in A. flavicollis: 20 of 28 rodents (71%) were infected with Dobrava virus, 13 rodents (46%) were infected with Leptospira, and 5 rodents (18%) were infected with Babesia. Multiple co-infections with all three pathogens were found in 3 of 28 (11%) A. flavicollis animals, suggesting that the same rodent host can be infected with several pathogens at the same time. Dual infections with both hantaviruses and Leptospira were found in 7 of 44 rodents (16%), with hantaviruses and Babesia in 2 rodents (5%), and double infection with both Leptospira and Babesia were found in 1 rodent (2%). Since hantaviruses, Leptospira, and Babesia have similar geographical distributions, it is to be expected that in other parts of the world multiple co-infections, representing a serious threat to public health, can be found.     

云南省曲靖市汉坦病毒宿主动物调查

目的了解云南省曲靖市肾综合征出血热(HFRS)宿主动物及疫源地分布特点,为防治HFRS提供科学依据。方法在居民区用鼠笼法捕鼠,捕获鼠类经分类鉴定,解剖取肺组织,用直接免疫荧光试验(DFA)检测汉坦病毒抗原。结果 2009年5~9月,在云南省曲靖市宣威、沾益、麒麟、马龙、陆良、会泽、罗平、师宗、富源县(市、区)共捕获鼠类6种643只,褐家鼠、黄胸鼠、小家鼠、斯氏家鼠、大足鼠和树鼩构成比依次为47.28%、44.63%、5.13%、1.56%、1.24%、0.16%,褐家鼠和黄胸鼠为优势种;用DFA法检查鼠肺组织643份,阳性12份,阳性率1.87%;阳性鼠种为褐家鼠(2.63%,8/304)、黄胸鼠(1.05%,3/287)和小家鼠(3.03%,1/33)。结论曲靖市广泛存在以褐家鼠为主要宿主的家鼠型HFRS疫源地,今后应加强本病的监测和防制工作。     

Emerging Zoonoses: Hantavirus-Infektionen

Among the emerging viruses, hantaviruses are being focused on more and more due to their increasing number and worldwide distribution. Transmission occurs via inhalation of aerosolized infected rodent excreta. The symptoms and course of disease vary with the infecting hantavirus species. The distribution of the different hantavirus species correlates with the geographical distribution of the virus-type-specific rodent host. Hantaviruses in Europe and Asia cause hemorrhagic fever with renal syndrome (HFRS). Infection with Puumala, the prevalent virus type in Germany, results in a more moderate form of HFRS, nephropathia epidemica. Infections with virus species on the American continents lead to a clinical picture with predominantly pulmonary pathology (hantaviral pulmonary syndrome). No specific antiviral therapy or approved vaccines are available for any hantavirus species. Controlling the rodent populations and avoiding contact with rodent excrement are the only measures that can be undertaken to contain and prevent infection.     

Genetic characterization of hantaviruses associated with sigmodontine rodents in an endemic area for hantavirus pulmonary syndrome in southern Brazil

An ecological assessment of reservoir species was conducted in a rural area (Jaborá) in the mid-west of the state of Santa Catarina in southern Brazil, where hantavirus pulmonary syndrome is endemic, to evaluate the prevalence of hantavirus infection in wild rodents. Blood and tissue samples were collected from 507 rodents during seven field trips from March 2004 to April 2006. Some of the animals were karyotyped to confirm morphological identification. Phylogenetic reconstructions of rodent specimens, based on the mitochondrial DNA cytochrome b gene sequences, were also obtained. Hantavirus antibody was found in 22 (4.3%) of the 507 rodents: 5 Akodon montensis, 2 Akodon paranaensis, 14 Oligoryzomys nigripes, and 1 Sooretamys angouya. Viral RNAs detected in O. nigripes and A. montensis were amplified and sequenced. O. nigripes virus genome was 97.5% (nt) and 98.4% (nt) identical to sequences published for Araucaria (Juquitiba-like) virus based on N and G2 fragment sequences. Viral sequences from A. montensis strain showed 89% and 88% nucleotide identities in a 905-nt fragment of the nucleocapsid (N) protein-coding region of the S segment when it was compared with two other Akodontine rodent-associated viruses from Paraguay, A. montensis and Akodon cursor, respectively. Phylogenetic analysis showed the cocirculation of two genetic hantavirus lineages in the state of Santa Catarina, one from O. nigripes and the other from A. montensis, previously characterized in Brazil and Paraguay, respectively. The hantavirus associated with A. montensis, designed Jaborá virus, represents a distinct phylogenetic lineage among the Brazilian hantaviruses.     

我国东北部分地区宿主动物感染汉坦病毒的分子流行病学调查

目的了解我国东北部分地区宿主动物携带汉坦病毒状况及其型别。方法采用夹夜法捕鼠，针对不同型别汉坦病毒M片段设计引物，应用RT—PCR检测带毒状况，阳性标本测序，对M片段变异大的标本再进行S片段的扩增测序，获得序列用clustalX（1．83）和Phylip3．63进行分析。结果共捕获鼠类宿主220只，平均阳性率为3．64％，不同鼠种间阳性率差别有统计学意义。其中从棕背鼠平鼠Jilin-54、Jilin-59检测到汉滩型汉坦病毒，从褐家鼠Jilin-99、Ji—lin-106标本中检测到汉城型汉坦病毒。而从大林姬鼠HU-32、Jilin—AP10和HLJ-47中得到的汉坦病毒M片段均与HTNV原型株76-118同源性最高（95．35％～97．42％）；来源吉林（毗邻俄罗斯远东地区）大林姬鼠的Jilin-AP06的汉坦病毒M片段与我国病人分离株B78、H5同源性最高（97.25％～95.33％），与来源俄罗斯远东地区大林姬鼠的Amur类汉坦病毒AP111株同源性为93．48％，与来自吉林大林姬鼠的Jilin93同源性为80．80％，与76-118同源性为80.80％，与朝鲜大林姬鼠分离株Soochong-1同源性为88.24％。Jilin-AP06S片段同其他株的同源性与M片段的结果一致。结论我国东北部分地区宿主动物携带汉坦病毒的型别多样，我国大林姬鼠中存在Amur类病毒感染。     

黑龙江口岸地区鼠类动物中汉坦病毒感染情况调查

目的 了解黑龙江省中俄边境11个口岸鼠类宿主动物携带汉坦病毒(Hantavirus,HV)状况及其分子流行病学特征。方法 采用夹夜法和鼠笼法捕获鼠类,应用巢式PCR方法对鼠肺样本进行检测,对阳性样本测序并分型,获得序列用MEGA6进行分析。结果 此次调查共捕获鼠类动物346只,经鉴定隶属3科9属11种。检测出汉坦病毒核酸阳性样本17份,平均带毒率为4.90 %,包括汉滩型病毒(Hantaan virus, HNTV)6例,汉城型病毒(Seoul virus, SEOV) 11例,首次在黑龙江口岸东方田鼠中检测到1例SEO型HV。进化分析表明,6株HNT型HV均与HNT型HV原型株76-118亲缘性较远(86.82%~88.43%),分别与HNT型HV株BAO14、HXZ244同源性最高;11株SEO型HV分别与SEO型HV株Gongzhuling97、北京株BjHD01、越南株HaiPhong3-11同源性最高。结论 黑龙江中俄边境口岸宿主动物感染汉坦病毒至少2个类型,相对较高的感染率提示着中俄边境地区开展肾综合征出血热监测和防控的迫切性。     

Phylogenetic and geographical relationships of hantavirus strains in eastern and western Paraguay

Recently, we reported the discovery of several potential rodent reservoirs of hantaviruses in western (Holochilus chacarius) and eastern Paraguay (Akodon montensis, Oligoryzomys chacoensis, and O. nigripes). Comparisons of the hantavirus S- and M-segments amplified from these four rodents revealed significant differences from each another and from other South American hantaviruses. The ALP strain from the semiarid Chaco ecoregion clustered with Leguna Negra and Rio Mamore (LN/RM), whereas the BMJ-NEB strain from the more humid lower Chaco ecoregion formed a clade with Oran and Bermejo. The other two strains, AAI and IP37/38, were distinct from known hantaviruses. With respect to the S-segment sequence, AAI from eastern Paraguay formed a clade with ALP/LN/RM, but its M-segment clustered with Pergamino and Maciel, suggesting a possible reassortment. AAI was found in areas experiencing rapid land cover fragmentation and change within the Interior Atlantic Forest. IP37/38 did not show any strong association with any of the known hantavirus strains.     

Isolation and genetic characterization of a hantavirus (Bunyaviridae: Hantavirus) from a rodent, Oligoryzomys microtis (Muridae), collected in northeastern Peru.

This paper describes the isolation and partial genetic characterization of a hantavirus from a pygmy rice rat, Oligoryzomys microtis, collected within the urban area of Iquitos, Loreto Department, Peru. The virus, designated HTN-007, exhibited the highest degree of genetic similarity to Rio Mamore virus, which was originally described from the same rodent species in eastern Bolivia. Comparison of small and medium segment nucleotide sequence data from HTN-007 and Rio Mamore virus revealed 87% and 85% sequence identity, respectively. Based on these analyses, HTN-007 appears to be a variant of Rio Mamore virus. As such, it represents the first successful isolation of Rio Mamore virus and the first evidence for the existence of a hantavirus in Peru. Serologic studies done by immunofluorescence on blood samples of 56 O. microtis trapped at the collection site indicated that 21.4% had antibodies to hantavirus. In view of the proximity of this rodent species to humans and the close phylogenetic relationship of Rio Mamore virus to hantaviruses that have been associated with human disease, Rio Mamore virus may be a hantavirus of some public health importance in tropical South America.