Assessment of person-to-person transmission of hantavirus pulmonary syndrome in a Chilean hospital setting

Person-to-person transmission of Andes hantavirus among healthcare workers was reported in Argentina for the first time in 1996. To determine whether such transmission of the virus occurred during a 1997 outbreak of hantavirus pulmonary syndrome (HPS) in southern Chile due to Andes virus, we conducted a serological and epidemiological study in the Coyhaique Regional Hospital, where the majority of HPS patients were admitted. Workers in every department of the hospital were evaluated for immunoglobulin G (IgG) and IgM hantavirus antibodies using the enzyme-linked immunosorbent assay (ELISA). A standardized questionnaire was used to determine the type and extent of exposure to HPS patients, as well as other potential risk factors and previous febrile respiratory illnesses requiring hospitalization. Less than half (44%) reported always using gloves when touching patients or their secretions; respiratory protection was not used. Of the 319 participants (87·9% of those eligible), 12 (3·7%) had IgG antibodies. This finding is consistent with the antibody prevalence in the community in which the participants lived. Of the 12 positive healthcare workers, six reported contact with HPS patients. A similar exposure was found in those who tested negative [6/140 (4%) compared to 6/179 (3%), P=0·66]. There was no significant difference in the types of hospital activities performed or the number of hospitalizations for febrile respiratory illnesses between antibody-positive and antibody-negative individuals. These data suggest that there was no person-to-person transmission among healthcare workers during a recent outbreak of HPS in Southern Chile in 1997, despite the inconsistent use of any precautions against transmission.     

Person-to-Person Household and Nosocomial Transmission of Andes Hantavirus,Southern Chile, 2011

Andes hantavirus (ANDV) causes hantavirus cardiopulmonary syndrome in Chile and is the only hantavirus for which person-to-person transmission has been proven. We describe an outbreak of 5 human cases of ANDV infection in which symptoms developed in 2 household contacts and 2 health care workers after exposure to the index case-patient. Results of an epidemiologic investigation and sequence analysis of the virus isolates support person-to-person transmission of ANDV for the 4 secondary case-patients, including nosocomial transmission for the 2 health care workers. Health care personnel who have direct contact with ANDV case-patients or their body fluids should take precautions to prevent transmission of the virus. In addition, because the incubation period of ANDV after environmental exposure is longer than that for person-to-person exposure, all persons exposed to a confirmed ANDV case-patient or with possible environmental exposure to the virus should be monitored for 42 days for clinical symptoms.     

Person-to-person transmission of Andes virus

Despite the fact that rodents are considered to be the infectious source of hantavirus for humans, another route of transmission was demonstrated. Andes virus (ANDV) has been responsible for most of the cases recorded in Argentina. Person-to-person transmission of ANDV Sout lineage was described during an outbreak of hantavirus pulmonary syndrome in southwest Argentina. In this study, we analyzed 4 clusters that occurred in 2 disease-endemic areas for different ANDV lineages. We found new evidence of interhuman transmission for ANDV Sout lineage and described the first event in which another lineage, ANDV Cent BsAs, was implicated in this mechanism of transmission. On the basis of epidemiologic and genetic data, we concluded that person-to-person spread of the virus likely took place during the prodromal phase or shortly after it ended, since close and prolonged contact occurred in the events analyzed here, and the incubation period was 15-24 days.     

Clusters of hantavirus infection, southern Argentina

Person-to-person transmission of a hantavirus was first confirmed during a 1996 outbreak of hantavirus pulmonary syndrome in southern Argentina, where Andes virus is endemic. To identify other episodes of secondary transmission, we reviewed reports of 51 cases of hantavirus infection from this region (November 1993-June 2005). Nine clusters involving 20 cases (39.2%) were found. Two patients, who had symptoms 3 weeks after they shared risks for rodent exposure, were considered a cluster. The other 8 clusters each began with an index case, which was almost always fatal, followed 19-40 days later by the illness of at least 1 person who had close and prolonged contact with the index case-patient. Person-to-person transmission was considered the probable source of these 8 clusters. The probability of initiating secondary cases was 41% for patients who died versus 4% for those who survived (p = 0.005). Interpersonal transmission of Andes virus infection should be considered even when rodent exposure cannot be definitively excluded.     

Hantavirus infections in Greece--an update

Hantaviruses are emerging viruses spread worldwide and cause hemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome (HPS). Two pathogenic hantaviruses are present in Greece: Dobrava/Belgrade virus (DOBV) and Puumala virus (PUUV). The predominant one is DOBV, carried in Greece by the rodent Apodemus flavicollis. Most human infections are sporadic, but epidemic outbreaks were also described. The severity of the disease ranges from a mild or moderate form to severe and fatal cases. Several endemic foci for HFRS have been identified. Phylogenetic analysis of hantavirus sequences revealed a stable geographical distribution.     

Hantavirus infection in humans and rodents, northwestern Argentina

We initiated a study to elucidate the ecology and epidemiology of hantavirus infections in northern Argentina. The northwestern hantavirus pulmonary syndrome (HPS)-endemic area of Argentina comprises Salta and Jujuy Provinces. Between 1997 and 2000, 30 HPS cases were diagnosed in Jujuy Province (population 512,329). Most patients had a mild clinical course, and the death rate (13.3%) was low. We performed a serologic and epidemiologic survey in residents of the area, in conjunction with a serologic study in rodents. The prevalence of hantavirus antibodies in the general human population was 6.5%, one of the highest reported in the literature. No evidence of interhuman transmission was found, and the high prevalence of hantavirus antibody seemed to be associated with the high infestation of rodents detected in domestic and peridomestic habitats.     

Hantavirus infection in children in Argentina.

Clinical hantavirus infection was diagnosed in five Argentine children ages 5 to 11 years by immunoglobulin M (IgM)- capture enzyme-linked immunosorbent assay using Sin Nombre virus (SNV) antigens. Death in three of the children was associated with absence of detectable IgG to SNV antigens. An additional two cases in healthy children were studied: one, a breast-fed 15-month-old whose mother died of suspected hantavirus pulmonary syndrome (HPS) 8 months previously, had hantavirus IgG (> 1:6400); a second, whose mother survived HPS during month three of pregnancy, apparently had maternal antibodies no longer detectable 1 year after birth.     

汉坦病毒肺综合征人-人传播的研究进展

啮齿动物是汉坦病毒(HV)的主要传染源,但近几年在南美HV肺综合征(HPS)流行中,经流行病学和病毒学研究证实,HPS可引起人-人直接传播,传播途径是通过与患者的直接接触及气溶胶传播。直接接触可发生在医院内、家庭成员及共同旅行者中。患者呼吸道分泌物污染空气也可引起人-人传播。     

浙江省慈溪市啮齿动物中汉坦病毒分子流行病学研究

目的 研究浙江省慈溪市啮齿动物中汉坦病毒(HV)流行情况及病毒型别.方法 采用间接免疫荧光法(IFA)检测鼠肺中HV抗原;用逆转录聚合酶链反应(RT-PCR)法扩增阳性样品中HV的部分S片段;构建系统发生树进行系统发生分析及分型.结果 在慈溪市肾综合征出血热(HFRS)疫点共捕获啮齿动物243只,在7份鼠肺样品中检测到HV抗原,其中4只为褐家鼠,3只为黄胸鼠,病毒携带率为2.88%.用汉城型病毒(SEOV)特异性引物从6份HV抗原阳性样品中扩增出部分S片段(620～999 nt)并测定了序列.对扩增出的部分S片段核苷酸序列分析表明,6株病毒与现有的SEOV有最高的同源性,均为SEOV.用部分S片段核苷酸序列所构建的系统进化树显示,6株病毒构成两个单元支,其中由褐家鼠携带的3株病毒与BjHD01株病毒的亲缘关系最近,分在同一分支,由黄胸鼠携带的3株病毒构成另一分支,与L99、R22及Hb8610株的亲缘关系较近.结论 慈溪市的褐家鼠与黄胸鼠分别携带一种不同亚型的SEOV,表现出SEOV在同一地区的遗传多样性,并支持宿主与汉坦病毒共进化的理论.     

Andes virus infections in the rodent reservoir and in humans vary across contrasting landscapes in Chile

Hantavirus cardiopulmonary syndrome (HCPS) is an emerging infectious disease first reported in Chile in 1995. Andes hantavirus (ANDV) is responsible for the more than 500 cases of HCPS reported in Chile. Previous work showed that ANDV is genetically differentiated in Chile across contrasting landscapes. To determine whether the reservoir rodent (Oligoryzomys longicaudatus) populations are also geographically segregated, we conducted range-wide spatial genetic analyses of O. longicaudatus in Chile using the mitochondrial DNA cytochrome b gene. Given that landscape structure influences the incidence of hantavirus infections, we also tested 772 O. longicaudatus specimens for antibodies to ANDV captured during the period 2000–2006. Population genetic analyses of O. longicaudatus are largely congruent with those reported for ANDV, with the host primarily differentiated according to three defined ecoregions, Mediterranean, Valdivian rain forest and North Patagonian rain forest. Significant differences in the relative prevalence of anti-ANDV antibodies in rodent samples also were found across the three ecoregions. We relate these results to the number of reported human HCPS cases in Chile, and discuss the importance of landscape differences in light of ANDV transmission to humans and among rodent populations.     

Pathogenic hantaviruses, northeastern Argentina and eastern Paraguay

We describe the first, to our knowledge, cases of han-tavirus pulmonary syndrome in northeastern Argentina and eastern Paraguay. Andes and Juquitiba (JUQ) viruses were characterized. JUQV was also confirmed in 5 Oligoryzomys nigripes reservoir species from Misiones. A novel Akodon-borne genetic hantavirus lineage was detected in 1 rodent from the Biologic Reserve of Limoy.     

Outbreak of hantavirus pulmonary syndrome, Los Santos, Panama, 1999-2000

An outbreak of hantavirus pulmonary syndrome occurred in the province of Los Santos, Panama, in late 1999 and early 2000. Eleven cases were identified; 9 were confirmed by serology. Three cases were fatal; however, no confirmed case-patient died. Case-neighborhood serologic surveys resulted in an overall hantavirus antibody prevalence of 13% among household and neighborhood members from the outbreak foci. Epidemiologic investigations did not suggest person-to-person transmission of hantavirus infection. By use of Sin Nombre virus antigen, hantavirus antibodies were detected in Oligoryzomys fulvescens and Zygodontomys brevicauda cherriei. This outbreak resulted in the first documented cases of human hantavirus infections in Central America.     

Hantavirus prevalence in the IX Region of Chile

An epidemiologic and seroprevalence survey was conducted (n=830) to assess the proportion of persons exposed to hantavirus in IX Region Chile, which accounts for 25% of reported cases of hantavirus cardiopulmonary syndrome. This region has three geographic areas with different disease incidences and a high proportion of aboriginals. Serum samples were tested for immunoglobulin (Ig) G antibodies by enzyme-linked immunosorbent assay against Sin Nombre virus N antigen by strip immunoblot assay against Sin Nombre, Puumala, Río Mamoré, and Seoul N antigens. Samples from six patients were positive for IgG antibodies reactive with Andes virus; all patients lived in the Andes Mountains. Foresting was also associated with seropositivity; but not sex, age, race, rodent exposure, or farming activities. Exposure to hantavirus varies in different communities of IX Region. Absence of history of pneumonia or hospital admission in persons with specific IgG antibodies suggests that infection is clinically inapparent.     

湖南省啮齿动物携带汉坦病毒的分子流行病学研究

目的研究湖南省啮齿动物中汉坦病毒(HV)流行情况及病毒型别。方法采用IFA法检测鼠肺中HV抗原;用RT-PCR法扩增阳性标本中HV的部分S和M片段;构建系统发生树进行系统发生分析及分型。结果在湖南省HV流行的地区共捕获啮齿动物344只,其中6份标本HV抗原阳性,病毒携带率为1.74%。对扩增出的部分S与M片段的核苷酸序列分析表明,5份标本中的病毒为汉城型HV(SEOV),1份为汉滩型HV(HTNV)。用S(620～990 nt)与M片段G2区(2001～2301 nt)核苷酸序列所构建的系统进化树显示,湘乡褐家鼠、黄胸鼠及黄毛鼠携带的病毒均为SEOV的S4亚型;宁远褐家鼠携带的病毒为SEOV的一个新亚型;石门小家鼠携带的病毒为HTNV的H4亚型。结论湖南省为混合型HV疫区,以汉城病毒为主,并具有宿主多样性。     

吉林省珲春市3株肾综合征出血热汉城型病毒的分离与鉴定

目的对2006年吉林省珲春市采集的鼠肺标本进行病毒分离与鉴定。方法采集鼠肺组织活体标本132份，用免疫荧光法筛检出阳性标本20份，用VeroE6细胞培养分离病毒，对病毒分离株进行血清学（EUSA和IFA方法）、分子生物学（RT-PCR）鉴定。结果本实验共筛检出阳性标本20份，分离到3株病毒，分离率为15％，分别命名为H156、H158、H162。结论在珲春市采集的褐家鼠标本中分离到3株病毒，经血清学和分子生物学鉴定为汉坦病毒汉城型，这是在珲春市首次分离到汉城型病毒。     

An outbreak of hantavirus pulmonary syndrome, Chile, 1997.

An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area.     

3株肾综合征出血热病毒的分离和鉴定

目的了解浙江省肾综合征出血热（HFRS）流行特点及汉坦病毒（HV）型别，为防治提供科学依据。方法鼠肺HV抗原检测采用直接免疫荧光法（DFA），病毒分离采用阳性鼠肺研磨液接种幼龄长爪沙鼠，再经vero-E6细胞传代，用单克隆抗体DFA定毒株及分型。结果从捕自浙江省龙泉地区的8份阳性鼠肺中分离到3株HV，经DFA鉴定均为汉滩型（Ⅰ型）病毒，3株病毒在Vero-E6细胞中的感染滴度为10^4.75～10^5.25CCID50／ml。结论从鼠类肺组织中分离到3株汉滩型HV，毒株均能在Vero-E6细胞中较好增殖，有可能成为HFRS疫苗后备毒株。