Tracing Transmission of Sin Nombre Virus and Discovery of Infection in Multiple Rodent Species.

Sin Nombre orthohantavirus (SNV), a negative-sense, single-stranded RNA virus that is carried and transmitted by the North American deer mouse Peromyscus maniculatus, can cause infection in humans through inhalation of aerosolized excreta from infected rodents. This infection can lead to hantavirus cardiopulmonary syndrome (HCPS), which has an ∼36% case-fatality rate. We used reverse transcriptase quantitative PCR (RT-qPCR) to confirm SNV infection in a patient and identified SNV in lung tissues in wild-caught rodents from potential sites of exposure. Using viral whole-genome sequencing (WGS), we identified the likely site of transmission and discovered SNV in multiple rodent species not previously known to carry the virus. Here, we report, for the first time, the use of SNV WGS to pinpoint a likely site of human infection and identify SNV simultaneously in multiple rodent species in an area of known host-to-human transmission. These results will impact epidemiology and infection control for hantaviruses by tracing zoonotic transmission and investigating possible novel host reservoirs. IMPORTANCE Orthohantaviruses cause severe disease in humans and can be lethal in up to 40% of cases. Sin Nombre orthohantavirus (SNV) is the main cause of hantavirus disease in North America. In this study, we sequenced SNV from an infected patient and wild-caught rodents to trace the location of infection. We also discovered SNV in rodent species not previously known to carry SNV. These studies demonstrate for the first time the use of virus sequencing to trace the transmission of SNV and describe infection in novel rodent species.

The 1993 Hantavirus Pulmonary Syndrome Outbreak and Lessons for Today.

While grappling with the implications of the current COVID-19 pandemic, we have perhaps overlooked recent history dealing with previous outbreaks. In the spring of 1993, America was presented with an outbreak of Hantavirus Pulmonary Syndrome caused by the Sin Nombre virus. This article recounts the investigation into this disease and discusses the spectrum of issues that medical communities must face as it deals with a mysterious outbreak.

"Super-Spreaders" and Person-to-Person Transmission of Andes Virus in Argentina.

BACKGROUND: From November 2018 through February 2019, person-to-person transmission of Andes virus (ANDV) hantavirus pulmonary syndrome occurred in Chubut Province, Argentina, and resulted in 34 confirmed infections and 11 deaths. Understanding the genomic, epidemiologic, and clinical characteristics of person-to-person transmission of ANDV is crucial to designing effective interventions. METHODS: Clinical and epidemiologic information was obtained by means of patient report and from public health centers. Serologic testing, contact-tracing, and next-generation sequencing were used to identify ANDV infection as the cause of this outbreak of hantavirus pulmonary syndrome and to reconstruct person-to-person transmission events. RESULTS: After a single introduction of ANDV from a rodent reservoir into the human population, transmission was driven by 3 symptomatic persons who attended crowded social events. After 18 cases were confirmed, public health officials enforced isolation of persons with confirmed cases and self-quarantine of possible contacts; these measures most likely curtailed further spread. The median reproductive number (the number of secondary cases caused by an infected person during the infectious period) was 2.12 before the control measures were enforced and decreased to 0.96 after the measures were implemented. Full genome sequencing of the ANDV strain involved in this outbreak was performed with specimens from 27 patients and showed that the strain that was present (Epuyén/18-19) was similar to the causative strain (Epilink/96) in the first known person-to-person transmission of hantavirus pulmonary syndrome caused by ANDV, which occurred in El Bolsón, Argentina, in 1996. Clinical investigations involving patients with ANDV hantavirus pulmonary syndrome in this outbreak revealed that patients with a high viral load and liver injury were more likely than other patients to spread infection. Disease severity, genomic diversity, age, and time spent in the hospital had no clear association with secondary transmission. CONCLUSIONS: Among patients with ANDV hantavirus pulmonary syndrome, high viral titers in combination with attendance at massive social gatherings or extensive contact among persons were associated with a higher likelihood of transmission. (Funded by the Ministerio de Salud y Desarrollo Social de la Nación Argentina and others.).

Hantavirus pulmonary syndrome outbreaks associated with climate variability in Northwestern Argentina, 1997-2017.

BACKGROUND: Rodent-borne hantaviruses (genus Orthohantavirus) are the etiologic agents causing two human diseases: hemorrhagic fever with renal syndrome (HFRS) in Euroasia; and hantavirus pulmonary syndrome (HPS) in North and South America. In South America fatality rates of HPS can reach up to 35%-50%. The transmission of pathogenic hantaviruses to humans occurs mainly via inhalation of aerosolized excreta from infected rodents. Thus, the epidemiology of HPS is necessarily linked to the ecology of their rodent hosts and the contact with a human, which in turn may be influenced by climatic variability. Here we examined the relationship between climatic variables and hantavirus transmission aim to develop an early warning system of potential hantavirus outbreaks based on ecologically relevant climatic factors. METHODOLOGY AND MAIN FINDINGS: We compiled reported HPS cases in northwestern Argentina during the 1997-2017 period and divided our data into biannual, quarterly, and bimestrial time periods to allow annual and shorter time delays to be observed. To evaluate the relationship of hantavirus transmission with mean temperature and precipitation we used dynamic regression analysis. We found a significant association between HPS incidence and lagged rainfall and temperature with a delay of 2 to 6 months. For the biannual and quarterly models, hantavirus transmission was positively associated with lagged rainfall and temperature; whereas the bimestrial models indicate a direct relationship with the rainfall but inverse for temperature in the second lagged period. CONCLUSIONS/SIGNIFICANCE: This work demonstrates that climate variability plays a significant role in the transmission of hantavirus in northwestern Argentina. The model developed in this study provides a basis for the forecast of potential HPS outbreaks based on climatic parameters. Our findings are valuable for the development of public health policies and prevention strategies to mitigate possible outbreaks. Nonetheless, a surveillance program on rodent population dynamics would lead to a more accurate forecast of HPS outbreaks.

Mechanisms of Hantavirus Transmission in Oligoryzomys longicaudatus.

The cricetid rodent Oligoryzomys longicaudatus is the species host of Andes virus (ANDV) which causes hantavirus pulmonary syndrome in southern Argentina and Chile. Population density, behavioral interactions, and spacing patterns are factors that affect viral transmission among wild rodents. We predict that the highest prevalence of hantavirus antibody positive would be found among wounded, reproductive males and that, at high population densities, wounded, reproductive males would be dispersers rather than resident individuals. The study was conducted seasonally from October (spring) 2011 to October (spring) 2013 in a shrubland habitat of Cholila, Argentina. During each trapping session, we classified captured O. longicaudatus as resident or disperser individuals, estimated population density, and recorded wounds as an indicator of aggression among individuals. We obtained blood samples from each individual for serological testing. We used generalized linear models to test the statistical significance of association between antibody prevalence, and sex, resident/dispersal status, wounds and trapping session. The highest proportion of seropositive O. longicaudatus individuals was among wounded reproductive males during periods of the greatest population density, and the characteristics of seroconverted individuals support that transmission is horizontal through male intrasexual competition. A positive association between dispersing individuals and hantavirus antibody was detected at high population density. Our study design allowed us to obtain data on a large number of individuals that are seroconverted, enabling a better understanding of the ecology and epidemiology of the ANDV host system.

Spatiotemporal Dynamics of Hantavirus Cardiopulmonary Syndrome Transmission Risk in Brazil.

BACKGROUND: Hantavirus disease in humans is rare but frequently lethal in the Neotropics. Several abundant and widely distributed Sigmodontinae rodents are the primary hosts of Orthohantavirus and, in combination with other factors, these rodents can shape hantavirus disease. Here, we assessed the influence of host diversity, climate, social vulnerability and land use change on the risk of hantavirus disease in Brazil over 24 years. METHODS: Landscape variables (native forest, forestry, sugarcane, maize and pasture), climate (temperature and precipitation), and host biodiversity (derived through niche models) were used in spatiotemporal models, using the 5570 Brazilian municipalities as units of analysis. RESULTS: Amounts of native forest and sugarcane, combined with temperature, were the most important factors influencing the increase of disease risk. Population at risk (rural workers) and rodent host diversity also had a positive effect on disease risk. CONCLUSIONS: Land use change-especially the conversion of native areas to sugarcane fields-can have a significant impact on hantavirus disease risk, likely by promoting the interaction between the people and the infected rodents. Our results demonstrate the importance of understanding the interactions between landscape change, rodent diversity, and hantavirus disease incidence, and suggest that land use policy should consider disease risk. Meanwhile, our risk map can be used to help allocate preventive measures to avoid disease.

Exotic Pinus radiata Plantations do not Increase Andes Hantavirus Prevalence in Rodents.

Andes south virus (ANDV) is the etiologic agent of hantavirus cardiopulmonary syndrome (HCPS) in Chile and southern Argentina. Farm and forestry workers have been identified as a group at high risk of acquiring HCPS caused by ANDV due to their close exposure to rodents or their secretions in rural areas. Therefore, investigation on the effect of landscape composition on ANDV in wild rodents becomes relevant for disease prevention and control. In this study, we analyzed the influence of Monterey pine (Pinus radiata) plantations, an important monoculture in the global forest industry, on small mammal assemblage and on ANDV seroprevalence and abundance of seropositive rodents from central Chile. Small mammals were sampled seasonally during 2 years in native forests, adult pine plantations and young pine plantations. A total of 1630 samples from seven rodent species were analyzed for antibody detection. ANDV seroprevalence and abundance of seropositive rodents were significantly higher in the native forest compared to pine plantations. Furthermore, Monterey pine plantations decrease the abundance and relative abundance of Oligoryzomys longicaudatus (the principal reservoir of ANDV) and do not change sex ratio and distribution of age classes of this rodent species, which are variables that are important for ANDV transmission. Our findings indicate that Monterey pine plantations would not pose a higher risk of human exposure to ANDV compared to the temperate native forest. Our results can be useful for hantavirus risks assessment in human-dominated areas where ANDV is endemic.

A 19 Year Analysis of Small Mammals Associated with Human Hantavirus Cases in Chile.

Small mammals present in areas where hantavirus cardiopulmonary syndrome (HCPS) cases had occurred in central and southern Chile were captured and analyzed to evaluate the abundance of rodents and seroprevalence rates of antibodies to Andes orthohantavirus (ANDV). Sampling areas ranged from the Coquimbo to Aysén regions (30-45° S approx.) regions. Ninety-two sites in peridomestic and countryside areas were evaluated in 19 years of sampling. An antibody against ANDV was detected by strip immunoassay in 58 of 1847 specimens captured using Sherman traps. Of the eleven species of rodents sampled, Abrothrix olivacea, Oligoryzomys longicaudatus and Abrothrix hirta were the most frequently trapped. O. longicaudatus had the highest seropositivity rate, and by logistic regression analysis, O. longicaudatus of at least 60 g had 80% or higher probability to be seropositive. Sex, age and wounds were significantly related to seropositivity only for O. longicaudatus. Across administrative regions, the highest seropositivity was found in the El Maule region (34.8-36.2° S), and the highest number of HCPS cases was registered in the Aysén region. Our results highlight the importance of long term and geographically extended studies, particularly for highly fluctuating pathogens and their reservoirs, to understand the implications of the dynamics and transmission of zoonotic diseases in human populations.

Development and Characterization of a Sin Nombre Virus Transmission Model in Peromyscus maniculatus.

In North America, Sin Nombre virus (SNV) is the main cause of hantavirus cardiopulmonary syndrome (HCPS), a severe respiratory disease with a fatality rate of 35⁻40%. SNV is a zoonotic pathogen carried by deer mice (Peromyscus maniculatus), and few studies have been performed examining its transmission in deer mouse populations. Studying SNV and other hantaviruses can be difficult due to the need to propagate the virus in vivo for subsequent experiments. We show that when compared with standard intramuscular infection, the intraperitoneal infection of deer mice can be as effective in producing SNV stocks with a high viral RNA copy number, and this method of infection provides a more reproducible infection model. Furthermore, the age and sex of the infected deer mice have little effect on viral replication and shedding. We also describe a reliable model of direct experimental SNV transmission. We examined the transmission of SNV between deer mice and found that direct contact between deer mice is the main driver of SNV transmission rather than exposure to contaminated excreta/secreta, which is thought to be the main driver of transmission of the virus to humans. Furthermore, increases in heat shock responses or testosterone levels in SNV-infected deer mice do not increase the replication, shedding, or rate of transmission. Here, we have demonstrated a model for the transmission of SNV between deer mice, the natural rodent reservoir for the virus. The use of this model will have important implications for further examining SNV transmission and in developing strategies for the prevention of SNV infection in deer mouse populations.

An Overview of Zoonotic Disease Outbreaks and its Forensic Management Over Time.

Most emerging or re-emerging infections are vector-borne or zoonotic and can be disseminated worldwide by infected humans or animals. They are a major public health problem and cause a great impact on economy. Zoonotic outbreaks began to be characterized in the 90s, after the creation of Europol and the FBI. Such investigations are carried by forensic pathologists and other specialists to determine whether an outbreak is natural or deliberate. This review will discuss ten zoonotic outbreaks nonrelated to wars focusing on forensic management. In conclusion, some points should be highlighted in the management of a zoonotic outbreak: (i) its diagnosis and detection by forensic pathologists and the coordination of efforts between other specialists are key factors; (ii) communication guidelines and an efficient healthcare system are crucial for any emergency response; (iii) biosafety of all specialists involved must be guaranteed.

Species diversity concurrently dilutes and amplifies transmission in a zoonotic host-pathogen system through competing mechanisms.

In this era of unprecedented biodiversity loss and increased zoonotic disease emergence, it is imperative to understand the effects of biodiversity on zoonotic pathogen dynamics in wildlife. Whether increasing biodiversity should lead to a decrease or increase in infection prevalence, termed the dilution and amplification effects, respectively, has been hotly debated in disease ecology. Sin Nombre hantavirus, which has an ∼35% mortality rate when it spills over into humans, occurs at a lower prevalence in the reservoir host, the North American deermouse, in areas with higher small mammal diversity-a dilution effect. However, the mechanism driving this relationship is not understood. Using a mechanistic mathematical model of infection dynamics and a unique long-term, high-resolution, multisite dataset, it appears that the observed dilution effect is a result of increasing small-mammal diversity leading to decreased deermouse population density and, subsequently, prevalence (a result of density-dependent transmission). However, once density is taken into account, there is an increase in the transmission rate at sites with higher diversity-a component amplification effect. Therefore, dilution and amplification are occurring at the same time in the same host-pathogen system; there is a component amplification effect (increase in transmission rate), but overall a net dilution because the effect of diversity on reservoir host population density is stronger. These results suggest we should focus on how biodiversity affects individual mechanisms that drive prevalence and their relative strengths if we want to make generalizable predictions across host-pathogen systems.

Climate change and sugarcane expansion increase Hantavirus infection risk.

Hantavirus Cardiopulmonary Syndrome (HCPS) is a disease caused by Hantavirus, which is highly virulent for humans. High temperatures and conversion of native vegetation to agriculture, particularly sugarcane cultivation can alter abundance of rodent generalist species that serve as the principal reservoir host for HCPS, but our understanding of the compound effects of land use and climate on HCPS incidence remains limited, particularly in tropical regions. Here we rely on a Bayesian model to fill this research gap and to predict the effects of sugarcane expansion and expected changes in temperature on Hantavirus infection risk in the state of São Paulo, Brazil. The sugarcane expansion scenario was based on historical data between 2000 and 2010 combined with an agro-environment zoning guideline for the sugar and ethanol industry. Future evolution of temperature anomalies was derived using 32 general circulation models from scenarios RCP4.5 and RCP8.5 (Representative greenhouse gases Concentration Pathways adopted by IPCC). Currently, the state of São Paulo has an average Hantavirus risk of 1.3%, with 6% of the 645 municipalities of the state being classified as high risk (HCPS risk ≥ 5%). Our results indicate that sugarcane expansion alone will increase average HCPS risk to 1.5%, placing 20% more people at HCPS risk. Temperature anomalies alone increase HCPS risk even more (1.6% for RCP4.5 and 1.7%, for RCP8.5), and place 31% and 34% more people at risk. Combined sugarcane and temperature increases led to the same predictions as scenarios that only included temperature. Our results demonstrate that climate change effects are likely to be more severe than those from sugarcane expansion. Forecasting disease is critical for the timely and efficient planning of operational control programs that can address the expected effects of sugarcane expansion and climate change on HCPS infection risk. The predicted spatial location of HCPS infection risks obtained here can be used to prioritize management actions and develop educational campaigns.

Exposure Characteristics of Hantavirus Pulmonary Syndrome Patients, United States, 1993-2015.

Those at highest risk are persons in occupations with potential for rodent exposure and American Indian women 40--64 years of age.

[Hantavirus pulmonary syndrome in Buenos Aires, 2009-2014]. / Síndrome pulmonar por hantavirus en Buenos Aires, 2009-2014.

Andes virus is the causative agent of hantavirus pulmonary syndrome (HPS) in Argentina and neighboring countries. In our country four different areas are affected: Northwest, Southwest, Central and Northeast, where distinct Andes virus genotypes were characterized. Three genotypes were described in Buenos Aires province (Central area): AND-Buenos Aires, AND-Lechiguanas and AND-Plata. In this work, we considered all HPS cases confirmed by ELISA and real time RT-PCR during the period 2009-2014 in Buenos Aires province. The annual distribution, fatality rate and geographic distribution were analyzed. We also analyzed the genotypes involved by RT-PCR and nucleotide sequencing. Finally we evaluated epidemiological data in order to establish the route of transmission. We analyzed 1386 suspect cases of hantavirus infection from Buenos Aires province and we confirmed 88 cases of Hantavirus Pulmonary Syndrome during 2009-2014. The overall average was 14.3 cases per year. The occurrence of a HPS outbreak was confirmed in Buenos Aires province during 2013, showing a 3 fold increase in case number compared to the annual average between 2009 and 2012, tending to normalize during 2014. The overall lethality was 25.6%, with a maximum value of 45.5% in 2011. Genotype analysis was performed in 30.7% of confirmed cases, AND-BsAs show the highest incidence, it was characterized in 72% of the studied cases. Epidemiological data and results of viral genome comparison strongly suggest person-to-person transmission in the three clusters of two cases described in our study.

Síndrome pulmonar por hantavirus en Buenos Aires, 2009-2014 / Hantavirus pulmonary syndrome in Buenos Aires, 2009-2014

El virus Andes es el agente causante del síndrome pulmonar por hantavirus en Argentina y países limítrofes. Existen varios genotipos característicos en las cuatro regiones endémicas del país. En la provincia de Buenos Aires, zona central, co-circulan tres genotipos: AND-BsAs, AND-Lechiguanas y AND-Plata. A partir de los casos confirmados por ELISA y PCR en tiempo real durante el período 2009-2014 en Buenos Aires, se evaluó la distribución anual, la letalidad y la distribución geográfica dentro de la provincia; mediante RT-PCR y secuenciación nucleotídica se analizaron los genotipos implicados. También se estudió la evidencia epidemiológica para determinar la ruta de infección en casos agrupados. Se analizaron 1386 muestras de casos sospechosos de la provincia de Buenos Aires, confirmándose 88 casos de Síndrome Pulmonar por Hantavirus durante el período 2009-2014. El promedio general fue de 14.3 casos por año. El análisis del genotipo viral se realizó en el 30.7% de los casos confirmados, AND-BsAs fue el de mayor incidencia, caracterizado en el 72% de los casos estudiados. Se confirmó la ocurrencia de un brote de síndrome pulmonar por hantavirus Buenos Aires durante el año 2013, con un registro de casos 3 veces mayor respecto al promedio anual del período 2009-2012, con tendencia a normalizarse durante 2014. La letalidad general fue del 25.6%, con un valor máximo de 45.5% en 2011. Se evaluaron los datos epidemiológicos y los resultados obtenidos del análisis de comparación de genomas virales en 3 agrupamientos de 2 casos cada uno, sugiriendo fuertemente transmisión persona a persona.

Andes virus is the causative agent of hantavirus pulmonary syndrome (HPS) in Argentina and neighboring countries. In our country four different areas are affected: Northwest, Southwest, Central and Northeast, where distinct Andes virus genotypes were characterized. Three genotypes were described in Buenos Aires province (Central area): AND-Buenos Aires, AND-Lechiguanas and AND-Plata. In this work, we considered all HPS cases confirmed by ELISA and real time RT-PCR during the period 2009-2014 in Buenos Aires province. The annual distribution, fatality rate and geographic distribution were analyzed. We also analyzed the genotypes involved by RT-PCR and nucleotide sequencing. Finally we evaluated epidemiological data in order to establish the route of transmission. We analyzed 1386 suspect cases of hantavirus infection from Buenos Aires province and we confirmed 88 cases of Hantavirus Pulmonary Syndrome during 2009-2014. The overall average was 14.3 cases per year. The occurrence of a HPS outbreak was confirmed in Buenos Aires province during 2013, showing a 3 fold increase in case number compared to the annual average between 2009 and 2012, tending to normalize during 2014. The overall lethality was 25.6%, with a maximum value of 45.5% in 2011. Genotype analysis was performed in 30.7% of confirmed cases, AND-BsAs show the highest incidence, it was characterized in 72% of the studied cases. Epidemiological data and results of viral genome comparison strongly suggest person-to-person transmission in the three clusters of two cases described in our study.

Daily Movements and Microhabitat Selection of Hantavirus Reservoirs and Other Sigmodontinae Rodent Species that Inhabit a Protected Natural Area of Argentina.

Abundance, distribution, movement patterns, and habitat selection of a reservoir species influence the dispersal of zoonotic pathogens, and hence, the risk for humans. Movements and microhabitat use of rodent species, and their potential role in the transmission of hantavirus were studied in Otamendi Natural Reserve, Buenos Aires, Argentina. Movement estimators and qualitative characteristics of rodent paths were determined by means of a spool and line device method. Sampling was conducted during November and December 2011, and March, April, June, October, and December 2012. Forty-six Oxymycterus rufus, 41 Akodon azarae, 10 Scapteromys aquaticus and 5 Oligoryzomys flavescens were captured. Movement patterns and distances varied according to sex, habitat type, reproductive season, and body size among species. O. flavescens, reservoir of the etiologic agent of hantavirus pulmonary syndrome in the region, moved short distances, had the most linear paths and did not share paths with other species. A. azarae had an intermediate linearity index, its movements were longer in the highland grassland than in the lowland marsh and the salty grassland, and larger individuals traveled longer distances. O. rufus had the most tortuous paths and the males moved more during the non-breeding season. S. aquaticus movements were associated with habitat type with longer distances traveled in the lowland marsh than in the salty grassland. Hantavirus antibodies were detected in 20% of A. azarae and were not detected in any other species. Seropositive individuals were captured during the breeding season and 85% of them were males. A. azarae moved randomly and shared paths with all the other species, which could promote hantavirus spillover events.

Assessing prevention measures and Sin Nombre hantavirus seroprevalence among workers at Yosemite National Park.

BACKGROUND: During 2012, a total of 10 overnight visitors to Yosemite National Park (Yosemite) became infected with a hantavirus (Sin Nombre virus [SNV]); three died. SNV infections have been identified among persons with occupational exposure to deer mice (Peromyscus maniculatus). METHODS: We assessed SNV infection prevalence, work and living environments, mice exposures, and SNV prevention training, knowledge, and practices among workers of two major employers at Yosemite during September-October, 2012 by voluntary blood testing and a questionnaire. RESULTS: One of 526 participants had evidence of previous SNV infection. Participants reported frequently observing rodent infestations at work and home and not always following prescribed safety practices for tasks, including infestation cleanup. CONCLUSION: Although participants had multiple exposures to deer mice, we did not find evidence of widespread SNV infections. Nevertheless, employees working around deer mice should receive appropriate training and consistently follow prevention policies for high-risk activities.

[Conditions for the transmission of Hantavirus in Rio Negro, Argentina]. / Condiciones para la transmision del hantavirus en zona andina de Río Negro, Argentina.

Hantavirus Pulmonary Syndrome (HPS) is a disease of viral etiology that affects humans causing severe acute respiratory symptoms. In Patagonia the disease is caused by the Andes Virus (AND) and transmitted by the rodent Oligoryzomys longicaudatus. The aim of this study was to identify those human activities that increase the risk of exposure to rodents, what we call "contagious scenarios". A retrospective study was performed with data obtained from cases in Rio Negro, which included clinic-epidemiological records and ecological/environmental assessment reports. The following variables were considered: age, sex, season, percentage of urbanization, geographic location, human settlements in rodent infested areas, probable source of exposure, type of activity and level of sanitary development. In total 32 cases were studied. Exposure was verified in 18 (56.2 %) cases in rural areas and 10 cases (31.3%) in small rural towns. In relation to anthropogenic environment, 24 (75%) cases were reported in developed settlements and 8 cases (25%) were related to slightly modified areas. Major exposition in El Bolson identified 8 cases of indoor activities of the total 18 reported in the area (44.5%), while in Bariloche 8 (57.1%) cases out of 14 were reported in outdoor surroundings. In general, activities that generated greater risk were work-related, accounting for 23 (71.9%) cases while 7 were related to recreational activities (28.1%). The identification of "contagious scenarios" at local level provided information for an effective application of available resources in terms of prevention and sanitary education.

Condiciones para la transmision del hantavirus en zona andina de Río negro, Argentina

El Síndrome Pulmonar por Hantavirus (SPH) es una enfermedad de etiología viral que causa en el hombre un cuadro respiratorio grave. En Patagonia, la enfermedad es causada por el virus Andes Sur (AND), transmitido por el roedor Oligoryzomys longicaudatus. El objetivo del presente trabajo fue identificar las actividades del hombre que favorecen su exposición a roedores, denominados escenarios de contagio. Se realizó un estudio retrospectivo a partir de información recolectada en investigaciones de casos ocurridos en Río Negro, mediante Fichas Clínico-Epidemiológicas e informes de evaluación ecológico/ambiental. Se definieron como variables a ser consideradas: edad, sexo, época del año, grado de urbanización, localización geográfica, integración del hombre al hábitat de roedores, fuente probable de exposición, actividad humana y nivel de saneamiento. Se estudiaron 32 casos. La exposición rural se verificó en 18 (56.2%) de los casos y 10 (31.3%) en paraje rural (grupo de viviendas en zona rural). En relación al ambiente antropogénico 24 (75%) resultaron en ambientes modificados por el hombre y 8 (25%) en áreas poco modificadas. El sitio de exposición de mayor importancia en El Bolsón fue el interior de edificaciones en 8 de los 18 casos allí registrados (44.5%), mientras que en Bariloche fueron ambientes de exterior con 8/14 (57.1%) casos. La actividad de riesgo fue laboral en 23 (71.9%) de los casos y recreacional en 7 (28.1%). Determinar los escenarios de contagio a nivel local ha aportado información para aplicar todos los recursos disponibles en materia de prevención y educación sanitaria.

Hantavirus Pulmonary Syndrome (HPS) is a disease of viral etiology that affects humans causing severe acute respiratory symptoms. In Patagonia the disease is caused by the Andes Virus (AND) and transmitted by the rodent Oligoryzomys longicaudatus. The aim of this study was to identify those human activities that increase the risk of exposure to rodents, what we call "contagious scenarios". A retrospective study was performed with data obtained from cases in Rio Negro, which included clinic-epidemiological records and ecological/environmental assessment reports. The following variables were considered: age, sex, season, percentage of urbanization, geographic location, human settlements in rodent infested areas, probable source of exposure, type of activity and level of sanitary development. In total 32 cases were studied. Exposure was verified in 18 (56.2 %) cases in rural areas and 10 cases (31.3%) in small rural towns. In relation to anthropogenic environment, 24 (75%) cases were reported in developed settlements and 8 cases (25%) were related to slightly modified areas. Major exposition in El Bolson identified 8 cases of indoor activities of the total 18 reported in the area (44.5%), while in Bariloche 8 (57.1%) cases out of 14 were reported in outdoor surroundings. In general, activities that generated greater risk were work-related, accounting for 23 (71.9%) cases while 7 were related to recreational activities (28.1%). The identification of "contagious scenarios" at local level provided information for an effective application of available resources in terms of prevention and sanitary education.