VIAL CLARO, PABLO AGUSTIN
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VIAL CLARO, PABLO AGUSTIN
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pvial@udd.cl
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17339613100

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Serological assays for the detection of human Andes hantavirus infections based on its yeast-expressed nucleocapsid protein

2006-01-01 , Schmidt, Jonas , Meisel, Helga , Capria, Silvana G. , Petraityte, Rasa , Lundkvist, Åke , Hjelle, Brian , VIAL CLARO, PABLO AGUSTIN , Padula, Paula , Krüger, Detlev H. , Ulrich, Rainer

Background: The objective of the study was to develop and evaluate IgM and IgG ELISAs and an IgG Western blottest for the serological detection of human infections with Andes virus (ANDV), the major cause of hantavirus cardiopulmonary syndrome (HCPS) in South America. Methods: The entire nucleocapsid (N) protein-encoding sequence of ANDV (strain AH-1) was cloned and expressed in the yeast Saccharomyces cerevisiae. The polyhistidine-tagged recombinant N (rN) protein of ANDV was purified by nickel-chelation chromatography and characterized by its reactivity with different N-specific monoclonal antibodies. To detect an antibody response directed against ANDV in humans, indirect IgM and IgG ELISAs and an IgG Western blot test based on ANDV rN antigen were developed. The evaluation of the tests was performed using a negative serum panel and 63 blinded sera from Argentina and Chile, containing acute-phase and convalescent sera from HCPS patients. Results: The specificities and sensitivities for the IgM and IgG ELISAs were demonstrated to be very high. The IgG ELISA data were confirmed by the IgG Western blot assay based on the same rN antigen. Almost all anti-ANDV-positive sera reacted to higher endpoint titers with N protein of ANDV than with those of Sin Nombre, Laguna Negra or Puumala virus. The cross-reactivity of anti-ANDV-N IgG-positive sera to rN proteins of other hantaviruses was found to be increased with time after the onset of HCPS. Conclusion: The high sensitivity of the novel assays should facilitate early diagnosis of ANDV infections and might contribute to a successful treatment of HCPS patients. Copyright © 2006 S. Karger AG.

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Hantavirus prevalence in the IX Region of Chile

2003-07-01 , Frey, Marlis Täger , VIAL CLARO, PABLO AGUSTIN , Castillo, Constanza H. , Godoy, Paula M. , Hjelle, Brian , Ferrés, Marcela G.

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

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Incubation period of hantavirus cardiopulmonary syndrome

2006-01-01 , VIAL CLARO, PABLO AGUSTIN , Valdivieso, Francisca , Mertz, Gregory , Castillo, Constanza , Belmar, Edith , DELGADO BECERRA, OROZIMBA IRIS , Tapia, Mauricio , Ferrés, Marcela

The potential incubation period from exposure to onset of symptoms was 7-39 days (median 18 days) in 20 patients with a defined period of exposure to Andes virus in a high-risk area. This period was 14-32 days (median 18 days) in 11 patients with exposure for ≤48 hours.

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Peridomestic small mammals associated with confirmed cases of human hantavirus disease in Southcentral Chile

2004-01-01 , Torres-Pérez, Fernando , Navarrete-Droguett, Jorge , Aldunate, Rebeca , Yates, Terry L. , Mertz, Gregory J. , VIAL CLARO, PABLO AGUSTIN , Ferrés, Marcela , Marquet, Pablo A. , Palma, R. Eduardo

Cases of human hantavirus disease have been reported in Chile since 1995, most of them in people living in rural and periurban areas. We conducted a peridomestic study of small mammals to evaluate the relationships between the presence of rodents with antibodies to Andes virus confirmed human cases of hantavirus pulmonary syndrome in southcentral Chile. The results of 20 sampled sites, which involved the capture of 272 mice over ah 18-month period, showed the occurrence of 10 small mammal species, of which Oligoryzomys longicaudatus was the only sero-positive species for hantavirus, with an intra-specific serologic rate of 10.4%.

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