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[Hantavirus pulmonary syndrome (Rio Mamore Virus) in the Peruvian Amazon region].
Abstract
Hantavirus infection is a viral zoonotic infection borne by rodents which most letal form clinical is the Hantavirus Pulmonary Syndrome (SPH, Spanish abbreviation). The Mamore River variant originates in South America and was found in rodents without any association to human diseases. Two cases of SPH were identified in the Peruvian Amazon region in November 2011. In both cases, a molecular diagnostic testing was conducted by the Instituto Nacional de Salud from Peru. A phylogenetic analysis of a viral genome fragment and a histopathological evaluation were conducted. Both patients developed adult respiratory distress syndrome and refractory shock. A patient died and another one recovered 12 days later.
... Esse resultado mostrou-se diferente de outros estudos, que identificaram maior concentração de casos no período de seca, com maior população de roedores no bioma Cerrado; ou, ainda, no bioma Mata Atlântica, onde a maior frequência de registros foi entre os meses de setembro e dezembro. 27,28 O número de casos suspeitos tem aumentado em cada ano no estado, sem refletir no aumento do número de casos confirmados, porém com aumento na letalidade. A taxa de letalidade foi superior àquela encontrada em estudo brasileiro realizado no bioma Cerrado e também superior à taxa de letalidade por hantavirose no Brasil no último ano. ...
... 19 A alta letalidade pode estar associada às variantes do hantavírus que apresentam diferentes virulências. 18,28 Esta foi uma das limitações do presente estudo, pois não foi realizada a identificação dos diferentes genótipos do agente etiológico. ...
OBJECTIVE:
to describe the epidemiological and clinical profile of hantavirus infection and to analyze factors associated with case-fatality in Goiás, Brazil.
METHODS:
this was a cross-sectional study on case fatality due to hantavirus infection from 2007 to 2013 using data from the Notifiable Diseases Information System (SINAN) for Goiás State. Logistic regression analysis was performed to estimate odds ratios (OR) with 95% confidence intervals (95%CI).
RESULTS:
1,171 suspected cases were reported, of which 73 (6.2%) were confirmed. Among the confirmed cases, greater frequency was found among males (n=50), fever was the most common symptom (n=70), and there was a high proportion of hospitalization (n=68). The case-fatality rate was 57.5% . The following factors were associated with death: acute respiratory failure (ARF) (OR=3.6; 95%CI 1.2;10.6), hemoconcentration (OR=3.3; 95%CI 1.1;7.9) and not using a mechanical ventilator (OR=3.4; 95%CI 1.3;9.1). After adjustment, the ARF was still associated with death (OR=3.4; 95%CI 1.0;11.6).
CONCLUSION:
the case-fatality rate was high, primarily associated with respiratory failure.
... More than 30 hantaviruses have been reported in the Western Hemisphere with more frequent cases registered in the southern cone (Argentina, Chile, Uruguay, Paraguay, Bolivia, and Brazil). 56,57 However, there was an important outbreak in 2000 in Panama, 58 and some rare events have been described in Peru, 59 Venezuela, 60 and French Guiana. 61 ...
Community-acquired pneumonia (CAP) is associated with significant morbidity and mortality in Latin America and the Caribbean (LAC) region. Poverty, socioeconomic factors, and malnutrition influence the incidence and outcome of CAP in LAC. In LAC, Streptococcus pneumoniae is the most frequent microorganism responsible for CAP, (incidence: 24-78%); the incidence of atypical microorganisms is similar to other regions of the world. Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) is a growing problem in the LAC region, with the Caribbean being the second most affected area worldwide after Sub-Saharan Africa. Pneumococcal pneumonia remains the most common cause of CAP in HIV-infected patients, but Pneumocystis jirovecii and tuberculosis (TB) are also common in this population. The heterogeneity of the health care systems and social inequity between different countries in LAC, and even between different settings inside the same country, is a difficult issue. TB, including multidrug-resistant TB, is several times more common in South American and Central American countries compared with North America. Furthermore, hantaviruses circulating in the Americas (new world hantaviruses) generate a severe respiratory disease called hantavirus pulmonary syndrome, with an associated mortality as high as 50%. More than 30 hantaviruses have been reported in the Western Hemisphere, with more frequent cases registered in the southern cone (Argentina, Chile, Uruguay, Paraguay, Bolivia, and Brazil). Respiratory viruses (particularly influenza) remain an important cause of morbidity and mortality, particularly in the elderly. Low rates of vaccination (against influenza as well as pneumococcus) may heighten the risk of these infections in low- and middle-income countries. © Thieme Medical Publishers333 Seventh Avenue, New York, NY 10001, USA
... DNA microarray technology has previously been used to detect some groups of arboviruses and viruses transmitted by small mammals, specially viruses pathogenic to humans within the families Togaviridae, Flaviviridae, Bunyaviridae and Arenaviridae, [43][44][45][46][47][48]. However, it is well known that non-pathogenic viruses can easily become emergent viruses; for example, Rio Mamore virus was previously considered non-pathogenic to humans, but recent fatal hantavirus pulmonary syndrome cases associated with this virus have been reported in Peru, French Guiana and Brazil [49][50][51]. Therefore, pathogenic and non-pathogenic viruses should be included in surveillance systems, which is why we included all viruses transmitted by small mammals and arthropods, regardless of whether they are pathogenic or non-pathogenic to humans, in the SMAvirusChip platform. ...
Viruses transmitted by small mammals and arthropods serve as global threats to humans. Most emergent and re-emergent viral agents are transmitted by these groups; therefore, the development of high-throughput screening methods for the detection and surveillance of such viruses is of great interest. In this study, we describe a DNA microarray platform that can be used for screening all viruses transmitted by small mammals and arthropods (SMAvirusChip) with nucleotide sequences that have been deposited in the GenBank. SMAvirusChip was designed with more than 15,000 oligonucleotide probes (60-mers), including viral and control probes. Two SMAvirusChip versions were designed: SMAvirusChip v1 contains 4209 viral probes for the detection of 409 viruses, while SMAvirusChip v2 contains 4943 probes for the detection of 416 viruses. SMAvirusChip was evaluated with 20 laboratory reference-strain viruses. These viruses could be specifically detected when alone in a sample or when artificially mixed within a single sample. The sensitivity of SMAvirusChip was evaluated using 10-fold serial dilutions of dengue virus (DENV). The results showed a detection limit as low as 2.6E3 RNA copies/mL. Additionally, the sensitivity was one log10 lower (2.6E2 RNA copies/mL) than quantitative real-time RT-PCR and sufficient to detect viral genomes in clinical samples. The detection of DENV in serum samples of DENV-infected patients (n = 6) and in a whole blood sample spiked with DENV confirmed the applicability of SMAvirusChip for the detection of viruses in clinical samples. In addition, in a pool of mosquito samples spiked with DENV, the virus was also detectable. SMAvirusChip was able to specifically detect viruses in cell cultures, serum samples, total blood samples and a pool of mosquitoes, confirming that cellular RNA/DNA did not interfere with the assay. Therefore, SMAvirusChip may represent an innovative surveillance method for the rapid identification of viruses transmitted by small mammals and arthropods.
... Subsequently, strains of RIOMV, were isolated from O. microtis, one designated HTN-007 in Peru (Powers et al., 1999) and two strains in Brazilian Amazon, RIOMV-3 and RIOMV-4 recovered from O. microtis and uncharacterized species rodents of the genus Oligoryzomys, respectively (Firth et al., 2012). The HPS cases associated with RIOMV have been reported: two cases in the Peruvian Amazon region (Casapía et al., 2012) and one in French Guiana, named Maripa virus (Matheus et al., 2012). Recently, we detect a strain of RIOMV detected in a fatal HPS case in Brazil . ...
Hantaviruses are the etiologic agents of Hemorrhagic Fever with Renal Syndrome (HFRS) in Old World, and Hantavirus Pulmonary Syndrome (HPS)/Hantavirus Cardiopulmonary Syndrome (HCPS), in the New World. Serological methods are the most common approach used for laboratory diagnosis of HCPS, however theses methods do not allow the characterization of viral genotypes. The polymerase chain reaction (PCR) has been extensively used for diagnosis of viral infections, including those caused by hantaviruses, enabling detection of few target sequence copies in the sample. However, most studies proposed methods of PCR with species-specific primers. This study developed a simple and reliable diagnostic system by RT-PCR for different hantavirus detection. Using new primers set, we evaluated human and rodent hantavirus positive samples of various regions from Brazil. Besides, we performed computational analyzes to evaluate the detection of other South American hantaviruses. The diagnostic system by PCR proved to be a sensible and simple assay, allowing amplification of Juquitiba virus, Araraquara virus, Laguna Negra virus, Rio Mamore virus and Jabora virus, beyond of the possibility of the detecting Andes, Anajatuba, Bermejo, Choclo, Cano Delgadito, Lechiguanas, Maciel, Oran, Pergamino and Rio Mearim viruses. The primers sets designed in this study can detect hantaviruses from almost all known genetics lineages in Brazil and from others South America countries and also increases the possibility to detect new hantaviruses. These primers could easily be used both in diagnosis of suspected hantavirus infections in humans and also in studies with animals reservoirs.
Copyright © 2015. Published by Elsevier B.V.
... Wild ruminants in the study area were the following species: hunted red deer (Cervus elaphus), roe deer (Capreolus capreolus), chamois (Rupicapra rupicapra), and protected Alpine ibex (Capra ibex). Although B. abortus and B. suis have been reported in numerous wildlife species (3), B. melitensis has rarely been isolated from wildlife, and only sporadic cases of infection have been reported in Europe, in chamois and Alpine ibex in the Alps (4,5) and in Iberian ibex (Capra pyrenaica hispanica) in the Pyrenees (6). These cases were considered to be caused by spillover from domestic ruminants, which suggests that these wild species are unable to sustain the infection (3). ...
... Two additional cases of HPS were reported that year near the city of Iquitos; both were clinically characterized by fever, malaise, abdominal pain, watery diarrhea, coughing, cyanosis and severe acute respiratory failure, which evolved to renal failure and refractory shock. In both patients the causative agent was confirmed by molecular tests, which demonstrated 96% similarity with the RIOM variant previously detected in Oligoryzomys microtis in the same location [29]. ...
Hantaan virus was discovered in Korea during the 1970s while other similar viruses were later reported in Asia and Europe. There was no information about hantavirus human infection in the Americas until 1993 when an outbreak was described in the United States. This event promoted new studies to find hantaviruses in the Americas. At first, many studies were conducted in Brazil, Argentina, Chile, Uruguay and Paraguay, while other Latin American countries began to report the presence of these agents towards the end of the 20th century. More than 30 hantaviruses have been reported in the Western Hemisphere with more frequent cases registered in the southern cone (Argentina, Chile, Uruguay, Paraguay, Bolivia and Brazil). However there was an important outbreak in 2000 in Panama and some rare events have been described in Peru, Venezuela and French Guiana. Since hantaviruses have only recently emerged as a potential threat in the tropical zones of the Americas, this review compiles recent hantavirus reports in Central America, the Caribbean islands and the northern region of South America. These studies have generated the discovery of new hantaviruses and could help to anticipate the presentation of possible future outbreaks in the region.
... In November 2011, two cases of HCPS were identified in the Peruvian Amazon region; one patient died and the other one recovered 12 days later (Casapia et al., 2012). The phylogenetic analysis of a viral genome fragment from an infected O. microtis, with 210 nucleotides from the S segment, showed high homology (96%) with the same genomic region of a RIOMV virus previously identified in the same rodent from Iquitos (Powers et al., 1999). ...
... The IgG prevalence in humans in Loreto tested during 2007-2010 was low (1.7%) (3). Nevertheless, 4 cases (3 fatal) of human hantavirus infection were reported in 2011 in this region, 2 from Rio Mamoré and 2 from Seoul virus (4,5). To expand the knowledge base on hantaviruses in Peru, we conducted an investigation of rodents in a previously unexplored area of Peru's southern Amazon Basin. ...
We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.
In the last decades, South American hemorrhagic fevers (HFs) caused by hantaviruses and arenaviruses have emerged. Hantaviruses in the Americas cause hantavirus pulmonary syndrome (HPS) in humans; the primary reservoirs of these viruses are rodents of the Sigmodontinae subfamily. The genus Hantavirus belongs to the Bunyaviridae family; hantaviruses comprise a single-stranded RNA genome of negative polarity and are tri-segmented, located in a helical capsid. The three RNA segments, L, M, and S, have different sizes and functions. Except for Ecuador, in all of South America, cases of hantavirus pulmonary syndrome have been diagnosed. The fatality rate of hantaviruses is about 15–30%. Hantavirus disease has become an emerging health problem in Central and South America, with more than 43 genotypes reported. There are several hantaviruses distributed in the Americas: Sin Nombre virus (SNV; United States), Black Creek Canal (United States), Choclo (Panama), Calabazo (Panama), Maripa (French Guiana), Andes (Argentina, Chile, Uruguay), Bermejo (Argentina), Laguna Negra (Paraguay, Bolivia), Mamore (Bolivia), Lechiguanas (Argentina), Juquitiba (Brazil), Sabia (Brazil), and Araraquara (Brazil) between others. Hantavirus hemorrhagic fever describes a life-threatening clinical syndrome characterized by an insidious onset of nonspecific signs followed by hemorrhagic manifestations and shock. A combination of capillary leak syndrome and hemorrhagic diathesis also characterizes hemorrhagic fever syndrome. Hantaviruses have clinical manifestations and histopathological findings similar to other hemorrhagic fevers such as dengue, Zika, yellow fever, malaria, encephalitis, leptospirosis, and rickettsiosis. Those etiology diversities make a problematic differential diagnosis. Given the diversity of rodent species in the Americas region, it is possible to predict that more viruses will be discovered, and some will cause human diseases with a high impact on public health. This chapter aims to show the public health importance of hantavirus hemorrhagic fevers in Colombia and South America.
This study shows an experimental spillover infection of Sigmodontinae rodents with Rio Mamore hantavirus (RIOMV). Necromys lasiurus and Akodon sp were infected with 103 RNA copies of RIOMV by intraperitoneal administration. The viral genome was detected in heart, lung, and kidney tissues 18 days after infection (ai), and viral excretion in urine and faeces began at four and six ai, respectively. These results reveal that urine and faeces of infected rodents contain the virus for at least 18 days. It is possible that inhaled aerosols of these excreta could transmit hantavirus to humans and other animals.
The results of a previous study suggested that Cherrie's cane rat (Zygodontomys cherriei) is the principal host of Necoclí virus (family Bunyaviridae, genus Hantavirus) in Colombia. Bayesian analyses of complete nucleocapsid protein gene sequences and complete glycoprotein precursor gene sequences in this study confirmed that Necoclí virus is phylogenetically closely related to Maporal virus, which is principally associated with the delicate pygmy rice rat (Oligoryzomys delicatus) in western Venezuela. In pairwise comparisons, nonidentities between the complete amino acid sequence of the nucleocapsid protein of Necoclí virus and the complete amino acid sequences of the nucleocapsid proteins of other hantaviruses were ≥8.7%. Likewise, nonidentities between the complete amino acid sequence of the glycoprotein precursor of Necoclí virus and the complete amino acid sequences of the glycoprotein precursors of other hantaviruses were ≥11.7%. Collectively, the unique association of Necoclí virus with Z. cherriei in Colombia, results of the Bayesian analyses of complete nucleocapsid protein gene sequences and complete glycoprotein precursor gene sequences, and results of the pairwise comparisons of amino acid sequences strongly support the notion that Necoclí virus represents a novel species in the genus Hantavirus. Further work is needed to determine whether Calabazo virus (a hantavirus associated with Z. brevicauda cherriei in Panama) and Necoclí virus are conspecific.
Neglected Infectious Diseases (NID) affect more than one billion people worldwide, and are associated with poverty, geographic isolation of populations, social stigma, lack of precise data on estimates on both the global and local burden of disease (underreporting of the diseases), inadequate financial and political resources to effective control measures, lack of lobbying on behalf of the most vulnerable population, as well as scarce drug and diagnostic methods development. In this article we describe the relationship between NID, poverty and inequality, we propose a new concept of disease in the tropics, expanding the list of diseases that share characteristics with NID in the Peruvian context, discuss the limited availability of drugs and diagnostic tests to properly deal with these diseases, as well as highlight the contributions by the Peruvian National Institute of Health, and as final thoughts, we state that the solution for the prevention and control of NID must include an integrated approach, including the social determinants of health in the context of the fight against poverty and inequality.
Rio Mamoré virus is an etiological agent of hantavirus pulmonary syndrome in South America. The purpose of this study was to determine whether Rio Mamoré virus strain HTN-007 in Syrian golden hamsters is pathogenic. None of 37 adult hamsters infected by intramuscular injection of HTN-007, including 10 animals killed on Day 42 or 43 post-inoculation, exhibited any symptom of disease. Histological abnormalities included severe or moderately severe pneumonitis in 6 (46.2%) of the 13 animals killed on Day 7 or 10 post-inoculation. The primary target of infection in lung was the endothelium of the microvasculature. Collectively, these results indicate that Rio Mamoré virus strain HTN-007 in adult Syrian golden hamsters can cause a nonlethal disease that is pathologically similar to hantavirus pulmonary syndrome.
In this study we analyze population dynamics of hantavirus rodent hosts and prevalence of infection over a 2-year period in Southern Brazil, a region with a high incidence of hantavirus pulmonary syndrome. The 14 small mammal species captured were composed of 10 rodents and four marsupials, the six most abundant species being Akodon serrensis, Oxymycterus judex, Akodon montensis, Akodon paranaensis, Oligoryzomys nigripes, and Thaptomys nigrita. These species displayed a similar pattern with increasing population sizes in fall/winter caused by recruitment and both, increase in reproductive activity and higher hantavirus prevalence in spring/summer. Specific associations between A. montensis/Jaborá Virus (JABV) and O. nigripes/Juquitiba-like Virus (JUQV-like) were established and spillover infections between A. paranaensis/JABV, A. serrensis/JABV, and A. paranaensis/JUQV-like. Spillover infection in secondary hosts seems to play an important role in maintaining JABV and JUQV-like in the hantavirus sylvatic cycle mainly during periods of low prevalence in primary hosts.
Several species of the genus Oligoryzomys are natural hosts of different hantavirus genotypes affecting humans. The systematics of the genus is confusing, which complicates the identification of the rodent host and hence the potential endemic areas of hantavirus pulmonary syndrome. In this study, we analyse molecular data to infer phylogenetic relationships among Central and South American specimens of Oligoryzomys, and compare our results with previously published data on karyotypic, geographic distribution and host–virus associations to solve contradictory taxonomic reports. We identified 25 clades, each one corresponding to a different putative species. The phylogenetic trees show that Oligoryzomys longicaudatus is strongly related to the Oligoryzomys flavescens complex, which comprises four clades; Oligoryzomys nigripes is related to Oligoryzomys stramineus, Oligoryzomys vegetus is related to Oligoryzomys fulvescens from Central America, and Oligoryzomys brendae is the sister species of Oligoryzomys aff. destructor. We identified the following rodent host–hantavirus genotype relationships: O. longicaudatus–Andes; O. flavescens ‘West'–Bermejo; O. flavescens ‘East'–Lechiguanas; O. nigripes–Juquitiba; Oligoryzomys microtis–Rio Mamore and Rio Mamore-3; Oligoryzomys chacoensis–Oran; Oligoryzomys costaricencis–Choclo; Oligoryzomys delicatus–Maporal; Oligoryzomys utiaritensis–Castelo dos Sonhos; Oligoryzomys sp. RT2012–Rio Mamore-4; Oligoryzomys sp. (and not Oligoryzomys fornesi)–Anajatuba. This work, besides contributing to the development of prevention programmes for hantavirus epidemiology in Latin America, represents a comprehensive update of the systematics of the genus Oligoryzomys. © 2014 The Linnean Society of London
Introducción: El síndrome cardiopulmonar por hantavirus (SCPH) es una enfermedad infecciosa aguda, caracterizada por insuficiencia cardio-respiratoria súbita y alta mortalidad, causada por un virus ARN del género Hantavirus, familia Bunyaviridae. Un 15% de los casos chilenos ha sido pesquisado en la Araucanía. Objetivo: Conocer en casos fatales de SCPH, sus características clínicas y morfológicas. Material y Método: Estudio descriptivo-retrospectivo de siete casos fatales con examen postmortem, de SCPH, atendidos entre 1997 y 2009 en el Hospital Regional de Temuco. Resultados: Los casos fueron principalmente pacientes jóvenes, rurales, con un cuadro de compromiso respiratorio progresivo, con leucocitosis, trombopenia e infiltrado pulmonar intersticial bilateral. Los principales hallazgos histopatológicos fueron un acentuado edema pulmonar intra-alveolar e intersticial, con escaso daño epitelial e infiltrado mono-nuclear y leve edema miocárdico con infiltrado mononu-clear. Conclusiones: Los antecedentes epidemiológicos, clínicos y laboratorio permiten sospechar SCPH. En los casos fatales la autopsia permite diferenciar el SCPH de otras patologías similares y aporta tejidos para confirmar el diagnóstico.
While human illness associated with hantavirus infection has been documented in many countries of South America, evidence for hantavirus transmission in Peru has been limited to the isolation of Rio Mamore virus from a pigmy mouse rat (Oligoryzomys microtis) in the Amazon city of Iquitos. To address the possibility of human hantavirus exposure in the region, we screened febrile patients reporting to health clinics in Iquitos from 2007 to 2010 for serological evidence of recent hantavirus infection. In addition, we conducted a serological survey for hantavirus-reactive IgG among healthy participants residing in Iquitos and rural areas surrounding the city. Through the febrile surveillance study, we identified 15 participants (0.3%; 15/5174) with IgM reactive to hantavirus (Andes virus) antigen, all with relatively mild, self-limited illness. From the cross-sectional serosurvey we found that 1.7% (36/2063) of residents of the Iquitos area had serum IgG reactive to one or more hantaviruses, with a higher prevalence in the urban population (2.2%, compared to 1.1% in rural areas). These results suggest that human infection with hantavirus has occurred in Peru.
A mysterious respiratory illness with high mortality was recently reported in the southwestern United States. Serologic studies implicated the hantaviruses, rodent-borne RNA viruses usually associated elsewhere in the world with hemorrhagic fever with renal syndrome. A genetic detection assay amplified hantavirus-specific DNA fragments from RNA extracted from the tissues of patients and deer mice (Peromyscus maniculatus) caught at or near patient residences. Nucleotide sequence analysis revealed the associated virus to be a new hantavirus and provided a direct genetic link between infection in patients and rodents.
Hantavirus pulmonary syndrome (HPS) is a severe respiratory illness identified in 1993. Since its identification, the Centers for Disease Control and Prevention has obtained standardized information about and maintained a registry of all laboratory-confirmed HPS cases in the United States. During 1993-2009, a total of 510 HPS cases were identified. Case counts have varied from 11 to 48 per year (case-fatality rate 35%). However, there were no trends suggesting increasing or decreasing case counts or fatality rates. Although cases were reported in 30 states, most cases occurred in the western half of the country; annual case counts varied most in the southwestern United States. Increased hematocrits, leukocyte counts, and creatinine levels were more common in HPS case-patients who died. HPS is a severe disease with a high case-fatality rate, and cases continue to occur. The greatest potential for high annual HPS incidence exists in the southwestern United States.
Hantavirus cardiopulmonary syndrome (HCPS) is an acute infectious disease characterized by sudden cardiorespiratory failure and high mortality, caused by a RNA virus of the genus Hantavirus, family Bunyaviridae, 15% of Chilean cases have been detected in the Araucania Region.
To determine in fatal cases of HCPS, clinical and morphological characteristics.
Descriptive-retrospective analysis of seven fatal cases with postmortem study of HCPS, attended between 1997 and 2009 at the Hospital of Temuco, Chile.
Cases were young patients from rural areas, and presented as an illness of progressive respiratory failure, with leukocytosis, thrombocytopenia and bilateral interstitial pulmonary infiltrates. Main morphological findings were marked intersticial and intraalveolar pulmonary edema, with minimal epithelial injury and mononuclear cell intersticial infiltrate and mild edematous intersticial inflamatory process.
Epidemiological, clinical and laboratory background allow to suspect HCPS. In fatal cases, the autopsy makes possible to discard other similar pathologies and provide tissue for confirmation of the disease.
Hantavirus HTN.007 was originally isolated from a small-eared pygmy rice rat (Oligoryzomys microtis) captured in northeastern Peru. The results of analyses of nucleotide and amino acid sequence data in this study indicated that HTN.007 is a strain of Rio Mamoré virus (RIOMV) which is enzootic in small-eared pygmy rice rat populations in Bolivia. As such, the results of this study extend our knowledge of the geographical range of RIOMV and support the notion that the small-eared pygmy rice rat is the principal host of RIOMV.
Hantaviruses are globally important human pathogens that cause hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. Capillary leakage is central to hantaviral diseases, but how it develops, has remained unknown. It has been hypothesized that the pathogenesis of hantavirus infection would be a complex interplay between direct viral effects and immunopathological mechanisms. Both of these were studied in the so far best model of mild hemorrhagic fever with renal syndrome, i.e. cynomolgus macaques infected with wild-type Puumala hantavirus. Viral RNA detected by in situ hybridization and nucleocapsid protein detected by immunohistochemical staining were observed in kidney, spleen and liver tissues. Inflammatory cell infiltrations and tubular damage were found in the kidneys, and these infiltrations contained mainly CD8-type T-cells. Importantly, these results are consistent with those obtained from patients with hantaviral disease, thus showing that the macaque model of hantavirus infection mimics human infection also on the tissue level. Furthermore, both the markers of viral replication and the T-cells appeared to co-localize in the kidneys to the sites of tissue damage, suggesting that these two together might be responsible for the pathogenesis of hantavirus infection.
In the spring of 1993, hantavirus pulmonary syndrome (HPS) “emerged” in the southwestern United States, where a multiagency
investigation led to the rapid description of this new clinical entity and its etiology. Analysis of the first 100 US cases
identified showed that the disease was distributed in 21 states, had gone unrecognized since at least 1959, and had a distinct
spring-early summer seasonality. Of the infected persons, 54% were male; 63% were Caucasian, 35% were Native American, and
2% were African American. The average age of case-patients was 34.9 years, and 8 were children or adolescents aged ⩽16 years.
The overall case-fatality rate was 52%. There was a 91% concordance among serologic, immunohistochemical, and molecular results.
HPS in the United States is caused by at least three newly described pathogenic hantaviruses, each of which has a distinct
rodent host, and cases of HPS have been recently recognized in Canada and South America. National surveillance of this sporadic
disease remains essential for further defining the epidemiology and clinical spectrum.
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.
Human hantavirus disease occurs throughout much of South America. The rodent hosts and the specific etiologic agent(s) are largely unknown, but many reported cases occurred within the habitation ranges of oryzomine rodents (rice rats). We have identified a genetically novel hantavirus (Rio Mamore virus [RM]) of the pygmy rice rat Oligoryzomys microtis in Bolivia. The complete sequence of the small (S) genome and the partial sequence of the medium (M) genome are described. This virus is closely related to the newly identified human pathogen Andes virus from Patagonia. To facilitate improved diagnosis of hantavirus infections in South America, we have expressed the complete nucleocapsid protein of RM in Escherichia coli and affinity-purified it for use in an ELISA and Western blot assays for antibodies to RM.
Although hantavirus pulmonary syndrome (HPS) was discovered in North America in 1993, more recent investigations have shown that the disease is a much larger problem in South America, where a greater number of cases and HPS-associated viruses have now been detected. Here we describe the genetic investigation of three fatal HPS cases from Brazil, including a 1995 case in Castelo dos Sonhos (CAS) in the state of Mato Grosso and two 1996 cases in the counties of Araraquara (ARA) and Franca (FRA), in the state of São Paulo. Reverse transcription-polymerase chain reaction (RT-PCR) products representing fragments of the hantavirus N, G1, and G2 coding regions were amplified from patient acute-phase serum samples, and the nucleotide (nt) sequences (394, 259, and 139 nt, respectively) revealed high deduced amino acid sequence identity between ARA and FRA viruses (99.2%, 96.5%, and 100%, respectively). However, amino acid differences of up to 14.0% were observed when ARA and FRA virus sequences were compared with those of the geographically more distant CAS virus. Analysis of a 643-nt N coding region and a 1734-nt predominantly G2-encoding region of ARA and CAS virus genomes confirmed that these Brazilian viruses were distinct and monophyletic with previously characterized Argentinean hantaviruses, and suggested that Laguna Negra (LN) virus from Paraguay was ancestral to both the Brazilian and Argentinean viruses. The phylogenetic tree based on the N coding fragment also placed LN in a separate clade with Rio Mamore virus from Bolivia. At the amino acid level, ARA and CAS viruses appeared more closely related to the Argentinean viruses than they were to each other. Similarly, analysis of the diagnostic 139-nt G2 fragment showed that the Juquitiba virus detected in a 1993 fatal HPS case close to São Paulo city, Brazil was closer to Argentinean viruses than to ARA or CAS viruses. These data indicate that at least three different hantavirus genetic lineages are associated with Brazilian HPS cases.
Hantaviruses are enveloped RNA viruses that persistently infect rodent hosts without ill-effect. The host persistently excretes virus in urine and saliva. Man becomes infected from the rodents when one enters the ecological niche of the other. There are two major clinical presentations--haemorrhagic fever with renal syndrome, found worldwide in various forms and hantavirus pulmonary syndrome, found only in the Americas. This review examines the virology, epidemiology and pathogenesis of these emerging pathogens.
In August 2002, two cases of hantavirus pulmonary syndrome (HPS) were confirmed in Mineros and Concepcion, within the Santa Cruz Department of Bolivia. Extensive alteration of the native ecosystem, from dense forest to pasture or sugarcane, had occurred in both regions. An ecologic assessment of reservoir species associated with the human disease identified a single hantavirus antibody-positive Oligoryzomys microtis from Mineros and three hantavirus antibody-positive Calomys callosus from Concepcion. In Mineros, the virus from the O. microtis was 90% similar to sequences published for Rio Mamore virus. Viral nucleotide sequences from two C. callosus were 87-88% similar to the sequence of Laguna Negra virus. The viral sequence from the C. callosus was 99% identical to viral sequences obtained from the HPS patient in this area, implicating C. callosus as the host and Laguna Negra virus as the agent responsible for the HPS case near Concepcion.
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