Antonio Utrera - Academia.edu (original) (raw)
Papers by Antonio Utrera
American Journal of Tropical Medicine and Hygiene, May 1, 1997
Specific rodent species are principal hosts for each of the well-characterized members of the vir... more Specific rodent species are principal hosts for each of the well-characterized members of the virus family Arenaviridae. Guanarito virus (Arenaviridae) is the etiologic agent of Venezuelan hemorrhagic fever. A previous study on the epidemiology of Venezuelan hemorrhagic fever revealed extensive arenavirus infection (presumed to be caused by Guanarito virus) in two rodent species. Sigmodon alstoni and Zygodontomys brevicauda, collected from the region of Venezuela in which the disease is endemic. In the present study, four arenavirus isolates recovered from the Municipality of Guanarito (two isolates each from S. alstoni and Z. brevicauda) were characterized to learn more about the natural rodent host relationships of Guanarito virus. Serologic tests and analyses of nucleocapsid protein gene sequence data indicated that the two isolates from Z. brevicauda are strains of Guanarito virus and that the two isolates from S. alstoni are representatives of a novel New World arenavirus (proposed name Pirital) that is antigenically and phylogenetically distinct from all known New World arenaviruses. The results of the present study provide further evidence that the cane mouse Z. brevicauda is a natural host of Guanarito virus and suggest that the cotton rat S. alstoni is the natural reservoir host of Pirital but not Guanarito virus.
Vector-borne and Zoonotic Diseases, Jun 1, 2011
... En tal sentido, en Venezuela durante las últimas dos décadas, se han realizado esfuerzos para... more ... En tal sentido, en Venezuela durante las últimas dos décadas, se han realizado esfuerzos para determinar la importancia de paisajes y hábitat con el propósito de mantener y ... Metodología para evaluar fauna silvestre / Utrera ... Impacto humano sobre los hábitat de Venezuela. ...
Journal of Clinical Microbiology, 1996
Twenty samples from cases of rabies in humans and domestic animals diagnosed in Venezuela between... more Twenty samples from cases of rabies in humans and domestic animals diagnosed in Venezuela between 1990 and 1994 and one sample from a vampire bat collected in 1976 were characterized by reactivity to monoclonal antibodies against the viral nucleoprotein and by patterns of nucleotide substitution in the nucleoprotein gene. Three antigenic variants were found: 1, 3, and 5. Antigenic variant 1 included all samples from dogs and humans infected by contact with rabid dogs. Unique substitutions permitted identification of two separate outbreaks of dog rabies in the Maracaibo Depression and Los Llanos region and in the Andean region of Venezuela. Samples from the vampire bat and two head of cattle were characterized as antigenic variant 3 and showed a nucleotide sequence homology of 96 to 98% to each other and to samples of vampire bat-associated rabies throughout Latin America. Ten of the remaining 12 samples were characterized as antigenic variant 5. Genetic studies indicated that 11 of ...
The American Journal of Tropical Medicine and Hygiene, 1999
The objective of this study was to elucidate the natural rodent host relationships of Guanarito a... more The objective of this study was to elucidate the natural rodent host relationships of Guanarito and Pirital viruses (family Arenaviridae) in the plains of central Venezuela. Ninety-two arenavirus isolates from 607 animals, representing 10 different rodent species, were characterized to the level of serotype. The 92 isolates comprised 19 Guanarito virus strains and 73 Pirital virus strains. The 19 Guanarito virus isolates were from Zygodontomys brevicauda; 72 (98.6%) of the 73 Pirital virus isolates were from Sigmodon alstoni. These results indicate that the natural rodent associations of these 2 sympatric arenaviruses are highly specific and that Z. brevicauda and S. alstoni are the principal rodent hosts of Guanarito and Pirital viruses, respectively.
The American Journal of Tropical Medicine and Hygiene, 1997
Specific rodent species are principal hosts for each of the well-characterized members of the vir... more Specific rodent species are principal hosts for each of the well-characterized members of the virus family Arenaviridae. Guanarito virus (Arenaviridae) is the etiologic agent of Venezuelan hemorrhagic fever. A previous study on the epidemiology of Venezuelan hemorrhagic fever revealed extensive arenavirus infection (presumed to be caused by Guanarito virus) in two rodent species. Sigmodon alstoni and Zygodontomys brevicauda, collected from the region of Venezuela in which the disease is endemic. In the present study, four arenavirus isolates recovered from the Municipality of Guanarito (two isolates each from S. alstoni and Z. brevicauda) were characterized to learn more about the natural rodent host relationships of Guanarito virus. Serologic tests and analyses of nucleocapsid protein gene sequence data indicated that the two isolates from Z. brevicauda are strains of Guanarito virus and that the two isolates from S. alstoni are representatives of a novel New World arenavirus (proposed name Pirital) that is antigenically and phylogenetically distinct from all known New World arenaviruses. The results of the present study provide further evidence that the cane mouse Z. brevicauda is a natural host of Guanarito virus and suggest that the cotton rat S. alstoni is the natural reservoir host of Pirital but not Guanarito virus.
Virus Research, 1997
Rodents collected from the Venezuelan llanos (plains) during field studies of viral hemorrhagic f... more Rodents collected from the Venezuelan llanos (plains) during field studies of viral hemorrhagic fever were tested for evidence of hantavirus infection. Hantavirus antibody was found in one (7.7%) of 13 Oryzomys bicolor, one (3.4%) of 29 Rattus rattus, 10 (6.0%) of 166 Sigmodon alstoni and one (2.2%) of 45 Zygodontomys brevicauda. Hantavirusspecific RNA was detected in lung tissues from four antibody-positive rodents: two S. alstoni from Portuguesa State and one S. alstoni each from Cojedes and Barinas States. A hantavirus isolate (herein identified as VHV-574) was recovered from lung tissue from a hantavirus RNA-positive S. alstoni collected from Portuguesa State. The results of serological tests and analyses of small and medium RNA segment nucleotide sequence data indicated that VHV-574 represents a novel hantavirus (proposed name 'Carlo Delgadito') that is distinct from all previously characterized hantaviruses. The results of analyses of nucleotide sequence data from the four hantavirus RNA-positive S. alstoni suggested that Carlo Delgadito virus is widely distributed in the Venezuelan llanos.
Virology, 2000
Despite intensive surveillance, Venezuelan hemorrhagic fever (VHF), caused by Guanarito (GTO) vir... more Despite intensive surveillance, Venezuelan hemorrhagic fever (VHF), caused by Guanarito (GTO) virus, has been detected in only a small region of western Venezuela. To determine whether VHF is associated with a particular regional GTO virus strain(s), 29 isolates from rodents and humans throughout the surrounding regions were analyzed by partial sequencing of the nucleocapsid protein gene. Phylogenetic trees delineated nine distinct GTO genotypes that differ by 4-17% in nucleotides and up to 9% in amino acid sequences; most appeared to be restricted to discrete geographic regions, although a few genotypes were isolated in several locations. Each genotype included at least one strain recovered from a rodent, but only two genotypes were isolated from VHF cases. The presence outside of the endemic/epidemic region of two genotypes isolated also from VHF cases suggests that human pathogenic viruses occur outside of the endemic zone, but do not frequently infect people and/or cause apparent disease there. VHF does not appear to be associated with a GTO virus genotype that is restricted to a certain rodent species. When quasispecies diversity was examined, rodent isolates had higher sequence variation than human isolates. One rodent isolate included a mixture of two phylogenetically distinct genotypes, suggesting a dual infection.
Journal of Mammalogy, 2000
We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal... more We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal assemblages in agricultural and pastoral areas on the western llanos of Venezuela. Among 34 sites sampled, species richness, diversity, population densities, and relative contribution to the assemblage by 10 rodent and 3 marsupial species varied by habitat or land-use category, major vegetative formation, and (within agricultural systems) crop species. Most habitat types, especially relatively uniform areas of mechanized agriculture, were numerically dominated by 2 rodents, Sigmodon alstoni and Zygodontomys brevicauda. Subsistence agriculture plots were more variable and had the highest species richness and diversity. Peridomestic habitats were dominated by Rattus rattus. In contrast to findings in agroecosystems in the United States and Argentina, relative densities were not lower in crop fields than in adjacent borders nor were there differences in the structure of the rodent assemblages. Captures of Heteromys anomalus, Oecomys speciosus, and Oecomys trinitatus document range extensions for these species on the western llanos.
Boletín Científico Centro de Museos Museo de Historia Natural
Desde agosto de 2006 hasta agosto de 2007 evaluamos la distribución de la nutria neotropical en l... more Desde agosto de 2006 hasta agosto de 2007 evaluamos la distribución de la nutria neotropical en la cuenca alta y media del río La Vieja; determinamos su extensión de presencia por medio de encuestas y el área de ocupación actual mediante visitas a campo. Décadas atrás la nutria presentaba una distribución continua en todos los ríos de la cuenca desde 950 m hasta 2432 msnm, con un área de extensión de presencia de 4895 ha; actualmente la nutria presenta distribución continua sólo en el cauce principal del río La Vieja y su población se ha fragmentado en los ríos Quindío, Barragán, Espejo, Roble y Barbas, con un área de ocupación de 2569 ha, lo que corresponde a 52,5% del área de su extensión de presencia original. También se presenta una disminución de su distribución altitudinal de 901 m. Tal disminución se debe probablemente a la reducción del hábitat por factores antrópicos tales como contaminación de los cauces, tala de bosques ribereños, minería de material de arrastre, pesca co...
Interciencia, Jul 1, 2007
Interciencia, Jul 1, 2007
Vector-Borne and Zoonotic Diseases, 2011
Emerging Infectious Diseases, 2011
Biological conservation, 1992
Intensive hunting in the first part of this century placed the Orinoco crocodile Crocodylus inter... more Intensive hunting in the first part of this century placed the Orinoco crocodile Crocodylus intermedius in immediate danger of extinction, We studied the potential for enhancing populations through captive rearing. In an area of 35000 m 2 seven enclosures were developed with six earthen and eight concrete ponds. In two years' operation a hatching rate of 72.4% and a hatchling survival rate of 42% were obtained. In the first year males attained an average total length of 745 mm and females 620 mm. In the second year average total length was 1362 mm and 1111 ram, respectively. Seasonal changes in growth and the influence of climatic conditions in mortality are discussed. Captive breeding and rearing appears to be an appropriate conservation strategy for this species.
Virus research, 2004
Oryzomine rodents in the southeastern United States, Panama, and southern South America are natur... more Oryzomine rodents in the southeastern United States, Panama, and southern South America are natural hosts of 6 of the 13 viruses known to cause hantavirus pulmonary syndrome. The purpose of this study was to extend our knowledge of the geographical distribution and ...
The objective of this study was to elucidate the natural rodent host relationships of Guanarito a... more The objective of this study was to elucidate the natural rodent host relationships of Guanarito and Pirital viruses (family Arenaviridae) in the plains of central Venezuela. Ninety-two arenavirus isolates from 607 animals, representing 10 different rodent species, were characterized to the level of serotype. The 92 isolates comprised 19 Guanarito virus strains and 73 Pirital virus strains. The 19 Guanarito virus isolates were from Zygodontomys brevicauda; 72 (98.6%) of the 73 Pirital virus isolates were from Sigmodon alstoni. These results indicate that the natural rodent associations of these 2 sympatric arenaviruses are highly specific and that Z. brevicauda and S. alstoni are the principal rodent hosts of Guanarito and Pirital viruses, respectively.
Journal of Mammalogy, 2000
We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal... more We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal assemblages in agricultural and pastoral areas on the western llanos of Venezuela. Among 34 sites sampled, species richness, diversity, population densities, and relative contribution to the assemblage by 10 rodent and 3 marsupial species varied by habitat or land-use category, major vegetative formation, and (within agricultural systems) crop species. Most habitat types, especially relatively uniform areas of mechanized agriculture, were numerically dominated by 2 rodents, Sigmodon alstoni and Zygodontomys brevicauda. Subsistence agriculture plots were more variable and had the highest species richness and diversity. Peridomestic habitats were dominated by Rattus rattus. In contrast to findings in agroecosystems in the United States and Argentina, relative densities were not lower in crop fields than in adjacent borders nor were there differences in the structure of the rodent assemblages. Captures of Heteromys anomalus, Oecomys speciosus, and Oecomys trinitatus document range extensions for these species on the western llanos.
American Journal of Tropical Medicine and Hygiene, May 1, 1997
Specific rodent species are principal hosts for each of the well-characterized members of the vir... more Specific rodent species are principal hosts for each of the well-characterized members of the virus family Arenaviridae. Guanarito virus (Arenaviridae) is the etiologic agent of Venezuelan hemorrhagic fever. A previous study on the epidemiology of Venezuelan hemorrhagic fever revealed extensive arenavirus infection (presumed to be caused by Guanarito virus) in two rodent species. Sigmodon alstoni and Zygodontomys brevicauda, collected from the region of Venezuela in which the disease is endemic. In the present study, four arenavirus isolates recovered from the Municipality of Guanarito (two isolates each from S. alstoni and Z. brevicauda) were characterized to learn more about the natural rodent host relationships of Guanarito virus. Serologic tests and analyses of nucleocapsid protein gene sequence data indicated that the two isolates from Z. brevicauda are strains of Guanarito virus and that the two isolates from S. alstoni are representatives of a novel New World arenavirus (proposed name Pirital) that is antigenically and phylogenetically distinct from all known New World arenaviruses. The results of the present study provide further evidence that the cane mouse Z. brevicauda is a natural host of Guanarito virus and suggest that the cotton rat S. alstoni is the natural reservoir host of Pirital but not Guanarito virus.
Vector-borne and Zoonotic Diseases, Jun 1, 2011
... En tal sentido, en Venezuela durante las últimas dos décadas, se han realizado esfuerzos para... more ... En tal sentido, en Venezuela durante las últimas dos décadas, se han realizado esfuerzos para determinar la importancia de paisajes y hábitat con el propósito de mantener y ... Metodología para evaluar fauna silvestre / Utrera ... Impacto humano sobre los hábitat de Venezuela. ...
Journal of Clinical Microbiology, 1996
Twenty samples from cases of rabies in humans and domestic animals diagnosed in Venezuela between... more Twenty samples from cases of rabies in humans and domestic animals diagnosed in Venezuela between 1990 and 1994 and one sample from a vampire bat collected in 1976 were characterized by reactivity to monoclonal antibodies against the viral nucleoprotein and by patterns of nucleotide substitution in the nucleoprotein gene. Three antigenic variants were found: 1, 3, and 5. Antigenic variant 1 included all samples from dogs and humans infected by contact with rabid dogs. Unique substitutions permitted identification of two separate outbreaks of dog rabies in the Maracaibo Depression and Los Llanos region and in the Andean region of Venezuela. Samples from the vampire bat and two head of cattle were characterized as antigenic variant 3 and showed a nucleotide sequence homology of 96 to 98% to each other and to samples of vampire bat-associated rabies throughout Latin America. Ten of the remaining 12 samples were characterized as antigenic variant 5. Genetic studies indicated that 11 of ...
The American Journal of Tropical Medicine and Hygiene, 1999
The objective of this study was to elucidate the natural rodent host relationships of Guanarito a... more The objective of this study was to elucidate the natural rodent host relationships of Guanarito and Pirital viruses (family Arenaviridae) in the plains of central Venezuela. Ninety-two arenavirus isolates from 607 animals, representing 10 different rodent species, were characterized to the level of serotype. The 92 isolates comprised 19 Guanarito virus strains and 73 Pirital virus strains. The 19 Guanarito virus isolates were from Zygodontomys brevicauda; 72 (98.6%) of the 73 Pirital virus isolates were from Sigmodon alstoni. These results indicate that the natural rodent associations of these 2 sympatric arenaviruses are highly specific and that Z. brevicauda and S. alstoni are the principal rodent hosts of Guanarito and Pirital viruses, respectively.
The American Journal of Tropical Medicine and Hygiene, 1997
Specific rodent species are principal hosts for each of the well-characterized members of the vir... more Specific rodent species are principal hosts for each of the well-characterized members of the virus family Arenaviridae. Guanarito virus (Arenaviridae) is the etiologic agent of Venezuelan hemorrhagic fever. A previous study on the epidemiology of Venezuelan hemorrhagic fever revealed extensive arenavirus infection (presumed to be caused by Guanarito virus) in two rodent species. Sigmodon alstoni and Zygodontomys brevicauda, collected from the region of Venezuela in which the disease is endemic. In the present study, four arenavirus isolates recovered from the Municipality of Guanarito (two isolates each from S. alstoni and Z. brevicauda) were characterized to learn more about the natural rodent host relationships of Guanarito virus. Serologic tests and analyses of nucleocapsid protein gene sequence data indicated that the two isolates from Z. brevicauda are strains of Guanarito virus and that the two isolates from S. alstoni are representatives of a novel New World arenavirus (proposed name Pirital) that is antigenically and phylogenetically distinct from all known New World arenaviruses. The results of the present study provide further evidence that the cane mouse Z. brevicauda is a natural host of Guanarito virus and suggest that the cotton rat S. alstoni is the natural reservoir host of Pirital but not Guanarito virus.
Virus Research, 1997
Rodents collected from the Venezuelan llanos (plains) during field studies of viral hemorrhagic f... more Rodents collected from the Venezuelan llanos (plains) during field studies of viral hemorrhagic fever were tested for evidence of hantavirus infection. Hantavirus antibody was found in one (7.7%) of 13 Oryzomys bicolor, one (3.4%) of 29 Rattus rattus, 10 (6.0%) of 166 Sigmodon alstoni and one (2.2%) of 45 Zygodontomys brevicauda. Hantavirusspecific RNA was detected in lung tissues from four antibody-positive rodents: two S. alstoni from Portuguesa State and one S. alstoni each from Cojedes and Barinas States. A hantavirus isolate (herein identified as VHV-574) was recovered from lung tissue from a hantavirus RNA-positive S. alstoni collected from Portuguesa State. The results of serological tests and analyses of small and medium RNA segment nucleotide sequence data indicated that VHV-574 represents a novel hantavirus (proposed name 'Carlo Delgadito') that is distinct from all previously characterized hantaviruses. The results of analyses of nucleotide sequence data from the four hantavirus RNA-positive S. alstoni suggested that Carlo Delgadito virus is widely distributed in the Venezuelan llanos.
Virology, 2000
Despite intensive surveillance, Venezuelan hemorrhagic fever (VHF), caused by Guanarito (GTO) vir... more Despite intensive surveillance, Venezuelan hemorrhagic fever (VHF), caused by Guanarito (GTO) virus, has been detected in only a small region of western Venezuela. To determine whether VHF is associated with a particular regional GTO virus strain(s), 29 isolates from rodents and humans throughout the surrounding regions were analyzed by partial sequencing of the nucleocapsid protein gene. Phylogenetic trees delineated nine distinct GTO genotypes that differ by 4-17% in nucleotides and up to 9% in amino acid sequences; most appeared to be restricted to discrete geographic regions, although a few genotypes were isolated in several locations. Each genotype included at least one strain recovered from a rodent, but only two genotypes were isolated from VHF cases. The presence outside of the endemic/epidemic region of two genotypes isolated also from VHF cases suggests that human pathogenic viruses occur outside of the endemic zone, but do not frequently infect people and/or cause apparent disease there. VHF does not appear to be associated with a GTO virus genotype that is restricted to a certain rodent species. When quasispecies diversity was examined, rodent isolates had higher sequence variation than human isolates. One rodent isolate included a mixture of two phylogenetically distinct genotypes, suggesting a dual infection.
Journal of Mammalogy, 2000
We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal... more We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal assemblages in agricultural and pastoral areas on the western llanos of Venezuela. Among 34 sites sampled, species richness, diversity, population densities, and relative contribution to the assemblage by 10 rodent and 3 marsupial species varied by habitat or land-use category, major vegetative formation, and (within agricultural systems) crop species. Most habitat types, especially relatively uniform areas of mechanized agriculture, were numerically dominated by 2 rodents, Sigmodon alstoni and Zygodontomys brevicauda. Subsistence agriculture plots were more variable and had the highest species richness and diversity. Peridomestic habitats were dominated by Rattus rattus. In contrast to findings in agroecosystems in the United States and Argentina, relative densities were not lower in crop fields than in adjacent borders nor were there differences in the structure of the rodent assemblages. Captures of Heteromys anomalus, Oecomys speciosus, and Oecomys trinitatus document range extensions for these species on the western llanos.
Boletín Científico Centro de Museos Museo de Historia Natural
Desde agosto de 2006 hasta agosto de 2007 evaluamos la distribución de la nutria neotropical en l... more Desde agosto de 2006 hasta agosto de 2007 evaluamos la distribución de la nutria neotropical en la cuenca alta y media del río La Vieja; determinamos su extensión de presencia por medio de encuestas y el área de ocupación actual mediante visitas a campo. Décadas atrás la nutria presentaba una distribución continua en todos los ríos de la cuenca desde 950 m hasta 2432 msnm, con un área de extensión de presencia de 4895 ha; actualmente la nutria presenta distribución continua sólo en el cauce principal del río La Vieja y su población se ha fragmentado en los ríos Quindío, Barragán, Espejo, Roble y Barbas, con un área de ocupación de 2569 ha, lo que corresponde a 52,5% del área de su extensión de presencia original. También se presenta una disminución de su distribución altitudinal de 901 m. Tal disminución se debe probablemente a la reducción del hábitat por factores antrópicos tales como contaminación de los cauces, tala de bosques ribereños, minería de material de arrastre, pesca co...
Interciencia, Jul 1, 2007
Interciencia, Jul 1, 2007
Vector-Borne and Zoonotic Diseases, 2011
Emerging Infectious Diseases, 2011
Biological conservation, 1992
Intensive hunting in the first part of this century placed the Orinoco crocodile Crocodylus inter... more Intensive hunting in the first part of this century placed the Orinoco crocodile Crocodylus intermedius in immediate danger of extinction, We studied the potential for enhancing populations through captive rearing. In an area of 35000 m 2 seven enclosures were developed with six earthen and eight concrete ponds. In two years' operation a hatching rate of 72.4% and a hatchling survival rate of 42% were obtained. In the first year males attained an average total length of 745 mm and females 620 mm. In the second year average total length was 1362 mm and 1111 ram, respectively. Seasonal changes in growth and the influence of climatic conditions in mortality are discussed. Captive breeding and rearing appears to be an appropriate conservation strategy for this species.
Virus research, 2004
Oryzomine rodents in the southeastern United States, Panama, and southern South America are natur... more Oryzomine rodents in the southeastern United States, Panama, and southern South America are natural hosts of 6 of the 13 viruses known to cause hantavirus pulmonary syndrome. The purpose of this study was to extend our knowledge of the geographical distribution and ...
The objective of this study was to elucidate the natural rodent host relationships of Guanarito a... more The objective of this study was to elucidate the natural rodent host relationships of Guanarito and Pirital viruses (family Arenaviridae) in the plains of central Venezuela. Ninety-two arenavirus isolates from 607 animals, representing 10 different rodent species, were characterized to the level of serotype. The 92 isolates comprised 19 Guanarito virus strains and 73 Pirital virus strains. The 19 Guanarito virus isolates were from Zygodontomys brevicauda; 72 (98.6%) of the 73 Pirital virus isolates were from Sigmodon alstoni. These results indicate that the natural rodent associations of these 2 sympatric arenaviruses are highly specific and that Z. brevicauda and S. alstoni are the principal rodent hosts of Guanarito and Pirital viruses, respectively.
Journal of Mammalogy, 2000
We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal... more We used mark-recapture and removal trapping during 37 months to examine structure of small-mammal assemblages in agricultural and pastoral areas on the western llanos of Venezuela. Among 34 sites sampled, species richness, diversity, population densities, and relative contribution to the assemblage by 10 rodent and 3 marsupial species varied by habitat or land-use category, major vegetative formation, and (within agricultural systems) crop species. Most habitat types, especially relatively uniform areas of mechanized agriculture, were numerically dominated by 2 rodents, Sigmodon alstoni and Zygodontomys brevicauda. Subsistence agriculture plots were more variable and had the highest species richness and diversity. Peridomestic habitats were dominated by Rattus rattus. In contrast to findings in agroecosystems in the United States and Argentina, relative densities were not lower in crop fields than in adjacent borders nor were there differences in the structure of the rodent assemblages. Captures of Heteromys anomalus, Oecomys speciosus, and Oecomys trinitatus document range extensions for these species on the western llanos.