Role of Mus musculus in the transmission of several pathogens in poultry farms.

This study aimed to analyze the role of Mus musculus as a host of Leptospira spp., lymphocytic choriomeningitis virus (LCMV) and Toxoplasma gondii, in poultry farms of Buenos Aires province, Argentina, and to assess the potential risk of transmission to humans and domestic or breeding animals. Samplings were performed between 2009 and 2011 (S1) and during 2016 (S2). In S1, we studied the prevalence of infection for Leptospira spp. and LCMV, whereas, in S2, we studied the prevalence of infection for Leptospira spp. and T. gondii. In S1, we found an overall Leptospira spp. prevalence in M. musculus of 18% (14/79) and no positive serum samples for LCMV (0/166). In S2, we detected no positive individuals for Leptospira spp. (0/56) and an overall T. gondii seroprevalence of 3.6% (2/56). The probability of Leptospira spp. infection in M. musculus was higher in reproductively active individuals and in samplings subsequent to months with high accumulated precipitation. Our results suggest that, in the poultry farms studied, the presence of M. musculus may be a risk factor in the transmission of Leptospira spp. and T. gondii to humans and domestic animals. The management of farms should include biosecurity measures for farm workers and more effective rodent control.

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.

Estimating hantavirus risk in southern Argentina: a GIS-based approach combining human cases and host distribution.

We use a Species Distribution Modeling (SDM) approach along with Geographic Information Systems (GIS) techniques to examine the potential distribution of hantavirus pulmonary syndrome (HPS) caused by Andes virus (ANDV) in southern Argentina and, more precisely, define and estimate the area with the highest infection probability for humans, through the combination with the distribution map for the competent rodent host (Oligoryzomys longicaudatus). Sites with confirmed cases of HPS in the period 1995-2009 were mostly concentrated in a narrow strip (~90 km × 900 km) along the Andes range from northern Neuquén to central Chubut province. This area is characterized by high mean annual precipitation (~1,000 mm on average), but dry summers (less than 100 mm), very low percentages of bare soil (~10% on average) and low temperatures in the coldest month (minimum average temperature -1.5 °C), as compared to the HPS-free areas, features that coincide with sub-Antarctic forests and shrublands (especially those dominated by the invasive plant Rosa rubiginosa), where rodent host abundances and ANDV prevalences are known to be the highest. Through the combination of predictive distribution maps of the reservoir host and disease cases, we found that the area with the highest probability for HPS to occur overlaps only 28% with the most suitable habitat for O. longicaudatus. With this approach, we made a step forward in the understanding of the risk factors that need to be considered in the forecasting and mapping of risk at the regional/national scale. We propose the implementation and use of thematic maps, such as the one built here, as a basic tool allowing public health authorities to focus surveillance efforts and normally scarce resources for prevention and control actions in vast areas like southern Argentina.

Prevalence of antibody to hantaviruses in humans and rodents in the Caribbean region of Colombia determined using Araraquara and Maciel virus antigens.

We tested sera from 286 agricultural workers and 322 rodents in the department of Córdoba, northeastern Colombia, for antibodies against two hantaviruses. The sera were analysed by indirect ELISA using the lysate of Vero E6 cells infected with Maciel virus (MACV) or the N protein of Araraquara virus (ARAV) as antigens for the detection of antibodies against hantaviruses. Twenty-four human sera were IgG positive using one or both antigens. We detected anti-MACV IgG antibodies in 10 sera (3.5%) and anti-ARAV antibodies in 21 sera (7.34%). Of the 10 samples that were positive for MACV, seven (70%) were cross-reactive with ARAV; seven of the 21 ARAV-positive samples were cross-reactive with MACV. Using an ARAV IgM ELISA, two of the 24 human sera (8.4%) were positive. We captured 322 rodents, including 210 Cricetidae (181 Zygodontomys brevicauda, 28 Oligoryzomys fulvescens and 1 Oecomys trinitatis), six Heteromys anomalus (Heteromyidae), one Proechimys sp. (Echimyidae) and 105 Muridae (34 Rattus rattus and 71 Mus musculus). All rodent sera were negative for both antigens. The 8.4% detection rate of hantavirus antibodies in humans is much higher than previously found in serosurveys in North America, suggesting that rural agricultural workers in northeastern Colombia are frequently exposed to hantaviruses. Our results also indicate that tests conducted with South American hantavirus antigens could have predictive value and could represent a useful alternative for the diagnosis of hantavirus infection in Colombia.

Prevalence of antibody to hantaviruses in humans and rodents in the Caribbean region of Colombia determined using Araraquara and Maciel virus antigens

We tested sera from 286 agricultural workers and 322 rodents in the department of Córdoba, northeastern Colombia, for antibodies against two hantaviruses. The sera were analysed by indirect ELISA using the lysate of Vero E6 cells infected with Maciel virus (MACV) or the N protein of Araraquara virus (ARAV) as antigens for the detection of antibodies against hantaviruses. Twenty-four human sera were IgG positive using one or both antigens. We detected anti-MACV IgG antibodies in 10 sera (3.5%) and anti-ARAV antibodies in 21 sera (7.34%). Of the 10 samples that were positive for MACV, seven (70%) were cross-reactive with ARAV; seven of the 21 ARAV-positive samples were cross-reactive with MACV. Using an ARAV IgM ELISA, two of the 24 human sera (8.4%) were positive. We captured 322 rodents, including 210 Cricetidae (181 Zygodontomys brevicauda, 28 Oligoryzomys fulvescens and 1 Oecomys trinitatis), six Heteromys anomalus (Heteromyidae), one Proechimys sp. (Echimyidae) and 105 Muridae (34 Rattus rattus and 71 Mus musculus). All rodent sera were negative for both antigens. The 8.4% detection rate of hantavirus antibodies in humans is much higher than previously found in serosurveys in North America, suggesting that rural agricultural workers in northeastern Colombia are frequently exposed to hantaviruses. Our results also indicate that tests conducted with South American hantavirus antigens could have predictive value and could represent a useful alternative for the diagnosis of hantavirus infection in Colombia.

Temporal and spatial host abundance and prevalence of Andes hantavirus in southern Argentina.

Andes virus (AND) is a hantavirus hosted by the sigmodontine rodent Oligoryzomys longicaudatus in southern Argentina, where it is responsible for most cases of hantavirus pulmonary syndrome (HPS). Our study provides data about the spatial variation in abundance of the rodent host of AND hantavirus. We report results of a longitudinal study performed in a locality of the Andean region of Chubut Province. From November 2003 (spring) to July 2006 (winter), O. longicaudatus was the most common species captured (63%) and it showed significant differences in abundance among habitats and seasons. Most antibody-positive rodents were O. longicaudatus (9.2%), followed by A. longipilis (3.6%) and A. olivaceus (1.5%). The highest number of antibody-positive animals was observed for males that belonged to the heaviest mass classes. Antibody-positive O. longicaudatus were more abundant in brush habitats. We found low richness of rodents and abundance of O. longicaudatus in areas affected by anthropogenic activity. The infection seems to be regionally persistent, but the risk to humans in a landscape would be localized. To develop accurate models for predicting HPS outbreaks, further research is needed to characterize rodent movement patterns across the landscape.

Epidemiología de las infecciones por arena y hantavirus del nuevo mundo / Epidemiology of arenavirus and hantavirus infections in the new world

En la última década el reconocimiento de un número de brotes o casos aislados de fiebres hemorrágicas virales (FHV) ha alertado sobre la amenaza de estas enfermedades como potenciales infecciones emergentes. El concepto de FHV resulta relativamente moderno, si se considera que muchas de las enfermedades que agrupamos bajo este síndrome eran claramente conocidas por el hombre desde muchos siglos atrás (1). Su carácter de infecciones emergentes es, sin duda, verdadero si se tiene en cuenta que su reconocimiento se ha incrementado significativamente. Observadas, sin embargo, desde el ángulo de los agentes que las producen, el concepto de “nuevo” no es tal: los virus causantes de estas enfermedadeses probable que sean más antiguos que nuestra propia especie humana.

Truncated hantavirus nucleocapsid proteins for serotyping Sin Nombre, Andes, and Laguna Negra hantavirus infections in humans and rodents.

Sin Nombre virus (SNV), Andes virus (ANDV), and Laguna Negra virus (LANV) have been known as the dominant causative agents of hantavirus pulmonary syndrome (HPS). ANDV and LANV, with different patterns of pathogenicity, exist in a sympatric relationship. Moreover, there is documented evidence of person-to-person transmission of ANDV. Therefore, it is important in clinical medicine and epidemiology to know the serotype of a hantavirus causing infection. Truncated SNV, ANDV, and LANV recombinant nucleocapsid proteins (trNs) missing 99 N-terminal amino acids (trN100) were expressed using a baculovirus system, and their applicability for serotyping SNV, ANDV, and LANV infection by the use of enzyme-linked immunosorbent assays (ELISA) was examined. HPS patient sera and natural-reservoir rodent sera infected with SNV, ANDV, and LANV showed the highest optical density (OD) values for homologous trN100 antigens. Since even patient sera with lower IgM and IgG antibody titers were serotyped, the trN100s are therefore considered useful for serotyping with early-acute-phase sera. In contrast, assays testing whole recombinant nucleocapsid protein antigens of SNV, ANDV, and LANV expressed in Escherichia coli detected homologous and heterologous antibodies equally. These results indicated that a screening ELISA using an E. coli-expressed antigen followed by a serotyping ELISA using trN100s is useful for epidemiological surveillance in regions where two or more hantavirus species cocirculate.

Hantavirus pulmonary syndrome in northwestern Argentina: circulation of Laguna Negra virus associated with Calomys callosus.

The purpose of this study was to characterize the hantaviruses circulating in northwestern Argentina. Human and rodent studies were conducted in Yuto, where most cases of hantavirus pulmonary syndrome (HPS) occur. Partial virus genome sequences were obtained from the blood of 12 cases of HPS, and from the lungs of 4 Calomys callosus and 1 Akodon simulator. Phylogenetic analysis showed that three genotypes associated with HPS circulate in Yuto. Laguna Negra (LN) virus, associated with C. laucha in Paraguay, was identified for the first time in Argentina; it was recovered from human cases and from C. callosus samples. The high sequence identity between human and rodent samples implicated C. callosus as the primary rodent reservoir for LN virus in Yuto. The genetic analysis showed that the Argentinian LN virus variant differed 16.8% at the nucleotide level and 2.9% at the protein level relative to the Paraguayan LN virus. The other two hantavirus lineages identified were the previously known Bermejo and Oran viruses.

Hantavirus pulmonary syndrome in Latin America.

PURPOSE OF REVIEW: Since the identification of hantavirus pulmonary syndrome in the United States in 1993, Latin America has been the region of the world where more hantaviruses have been identified, associated with human disease or not. This update shows the advances in the study of hantaviruses in several countries of the region and the problems that are still unresolved. RECENT FINDINGS: Clinical findings in Chile have shown differences in the classical description of hantavirus pulmonary syndrome in the United States. Hemorrhage was observed in 64% of the cases and alteration in renal function in 48%. The classification of cases in mild, self-limited forms and severe forms has a prognostic value, with statistically significant differences between survivors and nonsurvivors. Epidemiological studies have shown noticeable differences in seroprevalence of antibodies against hantaviruses in humans, ranging from about 1% to more than 40% according to geographical and ethnical differences. Risk factors continue to be related to rural activities and peridomestic sites. Rodent studies have allowed the identification of putative reservoirs of hantaviruses in Uruguay, Brazil and Argentina and detected antibodies in several rodent species not previously reported in Paraguay and Panama. An Andes virus gene-based hantavirus pulmonary syndrome vaccine is currently under study. SUMMARY: Progress in research on hantaviruses has been continuous but slow. The complex picture of the viruses, the rodent reservoirs and the clinical forms of the disease mean researchers are faced with the great challenge of properly clarifying the genetic and pathogenic relationships between hantaviruses in the Americas.

La atención y el tratamiento de los niños con síndrome pulmonar por Hantavirus / The attention and the treatment of the children with syndrome pulmonary by hantavirus

El sindrome pulmonar por hantavirus (SPH) es una enfermedad emergentes en niños y adolecentes que debe ser considerada en las áreas endémicas. La definición de caso sospechoso de los Centros para Control y Prevención de Enfermedades ha sido ajustada según los hallazgos clínicos en los casos regisitrados en el Gran La Plata (Provincia de Buenos Aires,Argentina). El tratamiento de SPH se basa en aporte hidroelectrolítico, asistencia respiratoria y control hemodinámico dado que no se dispone de terapéutica especifica efectiva. Se describen la asistencia y el tratamiento en tres escenarios diferentes: Sala/Servicio de emergencia o Guardia Médica; traslado en ambulancia y Unidad de Cuidados Intensivos Pediátricos según la condición clínica del paciente en cada uno

La atención y el tratamiento de los niños con síndrome pulmonar por Hantavirus / The attention and the treatment of the children with syndrome pulmonary by hantavirus

El sindrome pulmonar por hantavirus (SPH) es una enfermedad emergentes en niños y adolecentes que debe ser considerada en las áreas endémicas. La definición de caso sospechoso de los Centros para Control y Prevención de Enfermedades ha sido ajustada según los hallazgos clínicos en los casos regisitrados en el Gran La Plata (Provincia de Buenos Aires,Argentina). El tratamiento de SPH se basa en aporte hidroelectrolítico, asistencia respiratoria y control hemodinámico dado que no se dispone de terapéutica especifica efectiva. Se describen la asistencia y el tratamiento en tres escenarios diferentes: Sala/Servicio de emergencia o Guardia Médica; traslado en ambulancia y Unidad de Cuidados Intensivos Pediátricos según la condición clínica del paciente en cada uno

Comparison of three diagnostic techniques for the detection of leptospires in the kidneys of wild house mice (Mus musculus)

Foram capturados 41 camundongos (Mus musculus) na região urbana, próximo à ferrovia da cidade de Santa Fé, Argentina. Os rins de cada animal capturado foram removidos para estudos bacteriológicos e histológicos. Um dos rins foi imerso em meio semi-sólido de Fletcher para isolamento de leptospiras, as quais foram serologicamente tipificadas. O outro rim foi microscopicamente examinado por coloração de cortes histológicos pela hematoxilina-eosina, impregnação pela prata e imunohistoquímica. Leptospiras pertencentes ao serogrupo Ballum foram isoladas em 16 (39%) das 41 amostras availadas. A presença do agente foi observada em 18 (44%) e 19 (46%) das 41 amostras avaliadas por impregnação pela prata e imunohistoquímica, respectivamente. Leptospiras foram detectadas em grande numero na superfície apical das células epiteliais e no lumen dos túbulos medulares e foram menos frequentemente encontradas na superficie apical de células epiteliais ou no lúmen dos túbulos corticais, o que é considerado achado raro em animais portadores. Lesões microscópicas consistindo de nefrite mononuclear intersticial focal, atrofia glomerular e descamação das células tubulares epiteliais foram observadas em 13 dos 19 animais infectados e em 10 dos 22 animais não infectados. Não houve diferença estatisticamente significativa entre presença de lesões em animais infectados e não infectados (P=0,14). As três técnicas empregadas, isolamento, impregnação pela prata e imunohistoquímica, apresentaram alta concordância (k 0,85) e não apresentaram diferenças estatisticamente significativas (P>0,05). Esse trabalho descreve a presença incomum de leptospira em rins de animais portadores, porém com esse estudo não foi possível estabelecer uma relação entre lesões e presença de leptospira.

Identifying rodent hantavirus reservoirs, Brazil.

We describe the genetic analysis of samples from hantavirus pulmonary syndrome (HPS) patients from southern and southeastern states of Brazil and rodents captured at the presumed site of infection of these patients. A total of 65 samples that were antibody-positive for Sin Nombre or Laguna Negra virus by enzyme-linked immunosorbent assay were processed by nested reverse transcription-polymerase chain reaction (RT-PCR) by using several primer combinations in the M and S genome segments. PCR products were amplified and sequenced from samples from 11 HPS patient and 7 rodent samples. Phylogenetic analysis of nucleotide sequence differences showed the cocirculation of Araraquara and Juquitiba-like viruses, previously characterized from humans. Our genetic data indicate that Araraquara virus is associated with Bolomys lasiurus (hairy-tailed Bolo mouse) and the Juquitiba-like virus is associated with Oligoryzomys nigripes (black-footed pigmy rice rat).

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.

[Study of Hantavirus seoul in a human and rodent population from a marginal area in Buenos Aires City]. / Estudio de Hantavirus seoul en una población humana y de roedores en un asentamiento precario de la ciudad de Buenos Aires.

A sero-epidemiological survey was conducted to detect evidence of the circulation of Hantavirus seoul. This virus of worldwide distribution is associated with hemorrhagic fever with renal syndrome. A total of 106 samples from people who live in a marginal area in Buenos Aires City and 29 Rattus norvegicus captured in the surroundings of their houses were tested for specific antibodies. Thirty five samples from hypertensive patients undergoing a follow up health program, living in the same neighbourhood, were also tested. The antibody prevalence in rodents was 31% while no evidence of infection was found in the human samples.

Estudio de Hantavirus seoul en una población humana y de roedores en un asentamiento precario de la ciudad de Buenos Aires / Study of Hantavirus seoul in a human and rodent population from a marginal area in Buenos Aires City

Se realizó un estudio seroepidemiológico transversal para determinar la circulación de Hantavirus seoul, de distribución mundial y asociado con fiebre hemorrágica con síndrome renal (FHSR), en una población humana (n: 106) de un asentamiento precario de la ciudad de Buenos Aires y en población de Rattus norvegicus, (n: 29) capturados en el perodomicilio. Se estudiaron además 35 personas, con igual relación epidemiológica, que eran asistidas por hipertensión arterial. La seroprevalencia de anticuerpos antihantavirus en los roedores fue del 31% mientras que no se encontraron indicios serológicos de infección en los humanos.(AU) Se realizó un estudio seroepidemiológico transversal para determinar la circulación de Hantavirus seoul, de distribución mundial y asociado con fiebre hemorrágica con síndrome renal (FHSR), en una población humana (n: 106) de un asentamiento precario de la ciudad de Buenos Aires y en una población de Rattus norvegicus, (n: 29) capturados en el peridomicilio. Se estudiaron además 35 personas, con igual relación epidemiológica, que eran asistidas por hipertensión arterial. La seroprevalencia de anticuerpos antihantavirus en los roedores fue del 31% mientras que no se encontraron indicios serológicos de infección en los humanos.(AU)

Estudio de Hantavirus seoul en una población humana y de roedores en un asentamiento precario de la ciudad de Buenos Aires. / [Study of Hantavirus seoul in a human and rodent population from a marginal area in Buenos Aires City]

A sero-epidemiological survey was conducted to detect evidence of the circulation of Hantavirus seoul. This virus of worldwide distribution is associated with hemorrhagic fever with renal syndrome. A total of 106 samples from people who live in a marginal area in Buenos Aires City and 29 Rattus norvegicus captured in the surroundings of their houses were tested for specific antibodies. Thirty five samples from hypertensive patients undergoing a follow up health program, living in the same neighbourhood, were also tested. The antibody prevalence in rodents was 31

while no evidence of infection was found in the human samples.

Estudio de Hantavirus seoul en una población humana y de roedores en un asentamiento precario de la ciudad de Buenos Aires / Study of Hantavirus seoul in a human and rodent population from a marginal area in Buenos Aires City

Se realizó un estudio seroepidemiológico transversal para determinar la circulación de Hantavirus seoul, de distribución mundial y asociado con fiebre hemorrágica con síndrome renal (FHSR), en una población humana (n: 106) de un asentamiento precario de la ciudad de Buenos Aires y en población de Rattus norvegicus, (n: 29) capturados en el perodomicilio. Se estudiaron además 35 personas, con igual relación epidemiológica, que eran asistidas por hipertensión arterial. La seroprevalencia de anticuerpos antihantavirus en los roedores fue del 31% mientras que no se encontraron indicios serológicos de infección en los humanos.(AU) Se realizó un estudio seroepidemiológico transversal para determinar la circulación de Hantavirus seoul, de distribución mundial y asociado con fiebre hemorrágica con síndrome renal (FHSR), en una población humana (n: 106) de un asentamiento precario de la ciudad de Buenos Aires y en una población de Rattus norvegicus, (n: 29) capturados en el peridomicilio. Se estudiaron además 35 personas, con igual relación epidemiológica, que eran asistidas por hipertensión arterial. La seroprevalencia de anticuerpos antihantavirus en los roedores fue del 31% mientras que no se encontraron indicios serológicos de infección en los humanos.