Omaira Parra - Academia.edu (original) (raw)
Papers by Omaira Parra
Acta virologica, 2016
Rotavirus infection is the most frequent cause of infantile gastroenteritis worldwide and a signi... more Rotavirus infection is the most frequent cause of infantile gastroenteritis worldwide and a signifi cant cause of death in infants and young children, following severe diarrhea and dehydration. Rotavirus vaccines are considered the most eff ective way to prevent rotavirus infections. In the process of developing rotavirus vaccines, it is crucial to establish a reliable and standardized method to determine vaccine titer. In this study, we developed an indirect immunofl uorescence assay (IFA) to determine the infectious titer of Lanzhou lamb rotavirus (LLR) vaccine grown in MA104 cells. Th e activating concentration of trypsin was 1 μg/ml for healthy monolayers of MA104 cells at 100% confl uence. Aft er incubation for 18 hr, a rabbit anti-SA11 polyclonal antibody, diluted at 1:800 in PBS, was added to all wells, followed by an Alexa-488-conjugated secondary antibody diluted at 1:500 in PBS. Cells were examined with a fl uorescence microscope. Our results show that IFA was more reproducible, more sensitive, simpler, and more rapid than the log 50% cell culture infectious dose-ELISA (lgCCID 50-ELISA) in measuring the rotavirus vaccines. IFA provided a reliable basis for the qualitative and quantitative analysis of rotavirus, and the certifi cation of rotavirus vaccine production.
Veterinary Pathology, Mar 1, 2003
Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Mar... more Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Maracaibo, Venezuela, using buffy coat smears stained with Dip Quick. Three dogs were inoculated with an A. platys strain. When parasitemia reached 60–97%, blood samples obtained from the inoculated dogs and from two naturally infected dogs were centrifuged to obtain platelet-rich plasma, which was mixed with 0.1% glutaraldehyde at 37 C for 10 minutes. Platelet pellets were fixed in 3% glutaraldehyde for 72 hours and processed for conventional transmission electron microscopy. Platelets contained pleomorphic organisms with a distinct double membrane that was not observed when the bodies were in a determinate developmental stage. There were 1–15 individual bodies included in a host cell vacuole. The organisms had an electron-lucent inner area, whereas the internal surface of their inner plasma membranes exhibited an electron-dense rough substance. In naturally infected dogs, organisms with different ultrastructural features were found inside the same platelet. Some organisms contained central dense material surrounded by a pale zone, which was in turn surrounded by a moderately dense peripheral area. Other organisms contained an eccentrically electron-dense material. The intravacuolar space appeared fully electron-lucent. Each organism usually exhibited inner fine strands. Empty structures displaying junctions with the vacuolar membrane were observed. Our results indicate that distinct ultrastructural characteristics are associated with different stages of A. platys development and may differ among A. platys strains.
Revista Científica de la Facultad de Ciencias Veterinarias de la Universidad del Zulia, Oct 20, 2008
Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastroint... more Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis catus) que asistieron al
Revista científica, 2006
La otitis externa es una enfermedad de etiología multifactorial que comúnmente afecta a los canin... more La otitis externa es una enfermedad de etiología multifactorial que comúnmente afecta a los caninos. Representa una patología compleja que se asocia a infecciones causadas por bacterias y levaduras, y que muchas veces no responden a los tratamientos. El objetivo de este estudio fue aislar e identificar los microorganismos patógenos y no patógenos presentes en pacientes con otitis externa. Esta investigación fue realizada sobre 53 pacientes caninos con otitis externa que fueron atendidos en el Servicio de
Microscopy and Microanalysis, Jul 18, 2003
Revista Cientifica, Facultad de Ciencias Veterinarias, Universidad del Zulia, 2015
RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos g... more RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis ca-tus) que asistieron al Servicio de Consulta Externa de la Poli-clínica Veterinaria de la Universidad del Zulia (PVU), durante el período de enero a diciembre 2004. Para ello se recolecta-ron directamente del recto, heces de 64 gatos, procesándose mediante el método de flotación fecal con solución salina satu-rada, obteniéndose una prevalencia general de helmintos gas-trointestinales de 46,9%. Los helmintos observados fueron Ancylostoma spp. (29,7%), Trichuris spp. (10,9%), Toxocara spp. (7,8%) y Physaloptera spp. (6,3%). No se observaron di-ferencias estadísticamente significativas de los valores de pre-valencia entre sexos (42,9% en hembras y 50% en machos), ni entre grupos raciales (48,1% en gatos mestizos y 41,7% en gatos de razas puras). En referencia a los grupos etarios, la prevalencia general fue: animales menores de 1 año, 52,6%; entre 1 y 2 a...
organism in human platelets from patients with symptoms of ehrlichiosis
Invest Clin, Mar 1, 1996
La Ehrlichiosis humana es una enfermedad zoonotica, causada por una rickettsia leucocitaria descr... more La Ehrlichiosis humana es una enfermedad zoonotica, causada por una rickettsia leucocitaria descrita por primera vez en los Estados Unidos de Norteamerica en 1986.Mas de 300 casos han sido reportados en ese pais.,asi como un caso en Portugal, dos en Francia y uno en un turista procedente de Mali (Africa). En Venezuela, un pais tropical, donde la ehrlichiosis es endemica en caninos y equinos, se reporta el primer caso de ehrlichiosis humana en una nina de 17 meses de edad, quien presento inicialmente sintomatologia compatible con una virosis, progresando con exantema, complicaciones pulmonares, hepaticas, esplenicas, renales, nerviosas y hematologtcas incluyendo pancitopenia y coagulacion intravascular diseminada (CID). Diferentes diagnosticos fueron planteados antes de concluir que se trataba de una ehrilichiosis. Ante tal evidencia se indico tratamiento con tetraciclina y se obtuvo rapida recuperacion. El diagnostico inicial fue realizado usando frotis de capa blanca tenido con Diff Quick Stain. La presencia de anticuerpos especificos contra Ehrlichia chaffeensis, fue demostrada utilizando la tecnica de Inmunofluorescencia indirecta (IFI) en el laboratorio del CDC de Atlanta (titulo 1: 126). Se describe tambien la presencia de una ehrlichia plaquetaria, semejante a la E. platys de perro, en la sangre de la nina. Estos hallazgos en humanos no habian sido descritos con anterioridad. No se pudo demostrar que la enfermedad fue transmitida por picaduras de garrapatas.
Revista Cientifica, 2006
Otitis externa is a multi-factorial etiology disease commonly affecting canines. It represents a ... more Otitis externa is a multi-factorial etiology disease commonly affecting canines. It represents a complex pathology associated to infections caused by bacteria and yeasts, many times not responding to treatments. The goal of this study was to isolate and identify the pathogenic and non-pathogenic microorganisms existent in otitis externa patients. This research was performed on 53 canine patients which were attended at the Outpatient Consult Service of the University Veterinary Policlinic at Zulia State University (UVP), and which showed clinical signs such as: auditory canal erythema, increased secretion, pain, continuous head shaking and pruritus, purulent secretions and pruritus being the most frequent. Samples were recollected from auditory canal horizontal portion exudates. Different bacteria groups were isolated in culture media, the most frequent were Pseudomona aeruginosa (22.22%), Proteus mirabilis (13.89%), Staphylococcus aureus (12.50%), Staphylococcus epidermidis (8.33%), Escherichia coli (5.56%) and Staphylococcus coagulase-negative (5.56%). In the control group, Bacillus spp. (16.67%), Staphylococcus epidermidis (16.67%) and Staphylococcus coagulase-negative (16.67%) were the most frequently isolated. Cytological examination showed Malassezia pachydermatis to be present in 69.8% of the cases studied. The most affected breeds were Poodles (30.19%), Mongrels (26.42%), Cocker Spaniels (16.98%) and German Shepherd Dogs (9.49%); likewise, a higher incidence of otitis was evidenced in dogs between 2 and 5 months of age (43.40%).
Investigación clínica, 1996
Human ehrlichiosis is a zoonotic disease, caused by a rickettsia that infects leukocytes. It was ... more Human ehrlichiosis is a zoonotic disease, caused by a rickettsia that infects leukocytes. It was described for the first time in the United States of America in 1986. More than 300 cases have been reported in that country. One case has been reported in Portugal, two in France and one more in a tourist coming from Mali (Africa). In Venezuela, a tropical country, where ehrlichiosis is endemic in dogs and horses, the first case of human ehrlichiosis is reported in a seventeen month old girl. She initially had symptoms compatible with a viral illness. Then she developed a rash, acute respiratory failure, hepato-splenomegaly, neurologic abnormalities, renal failure and hematologic alterations including pancytopenia and disseminated intravascular coagulation (DIC). Different diagnoses were given before it was concluded that it was a case of ehrlichiosis. She was treated with tetracycline and very soon recovered. The initial diagnosis was made using buffy coat blood smears stained with Dif...
The American Journal of Tropical Medicine and Hygiene, 2014
This article presents two case reports of Anaplasma platys detection in two women from Venezuela.... more This article presents two case reports of Anaplasma platys detection in two women from Venezuela. Both patients were exposed to Rhipicephalus sanguineus, the presumed tick vector, and experienced chronic, nonspecific clinical signs including headaches and muscle pains. Intra-platelet inclusion bodies resembling A. platys were observed in buffy coat smears and A. platys DNA was amplified and sequenced from whole blood; however, treatment with doxycycline did not alleviate their symptoms. These cases provide further support for A. platys as a zoonotic tick-borne pathogen, most likely of low pathogenicity; nonetheless, the cause of illness in humans by A. platys is yet to be confirmed.
Journal of Medical Microbiology, 1999
Since 1982, Ehrlichia platys infection has been diagnosed in canines from Venezuela by the use of... more Since 1982, Ehrlichia platys infection has been diagnosed in canines from Venezuela by the use of buffy coat smears. In 1992, ehrlichia-like bodies were observed in platelets from a severely ill girl by light microscopy. The patient was seropositive to E. chaffeensis by the indirect fluorescent antibody test (IFAT). Tetracycline was administered and the patient recovered. More than 400 cases with such intra-platelet organisms have been studied at this laboratory over the past 6 years, and all the patients had a good response to the treatment. To determine whether the organisms in human blood platelets were truly platelet ehrlichiae, IFAT and transmission electron microscopy (TEM) studies were undertaken in four patients. Light microscopic examination of blood samples revealed the dense organism inside platelets, and a great reactivity of the blood cells. Sera from the four patients were seronegative against E. chaffeensis and E. platys antigens. Three of four samples contained the intra-platelet organisms when examined by TEM. Electron microscopy showed platelets with vacuoles containing pleomorphic organisms. These organisms had a thickened membrane, an electron-translucent inner area and an electron-dense granular component in the periphery. An abundant electron-dense material was observed surrounding them. The ultrastructure of such microorganisms has not been reported previously. Based on the similarity of many of their characteristics with rickettsiae, we suggest that the microorganisms found in the present study might belong to the family Rickettsiaceae.
Veterinary Pathology, 2003
Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Mar... more Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Maracaibo, Venezuela, using buffy coat smears stained with Dip Quick. Three dogs were inoculated with an A. platys strain. When parasitemia reached 60–97%, blood samples obtained from the inoculated dogs and from two naturally infected dogs were centrifuged to obtain platelet-rich plasma, which was mixed with 0.1% glutaraldehyde at 37 C for 10 minutes. Platelet pellets were fixed in 3% glutaraldehyde for 72 hours and processed for conventional transmission electron microscopy. Platelets contained pleomorphic organisms with a distinct double membrane that was not observed when the bodies were in a determinate developmental stage. There were 1–15 individual bodies included in a host cell vacuole. The organisms had an electron-lucent inner area, whereas the internal surface of their inner plasma membranes exhibited an electron-dense rough substance. In naturally infected dogs, organisms with d...
Seric Antibody and Anemia detection in broiler to AIA in Mara and La Canada de Urdaneta Farms of ... more Seric Antibody and Anemia detection in broiler to AIA in Mara and La Canada de Urdaneta Farms of the Zulia State. One hundred and forty vine broiler from Mara and La Canada de Urdaneta commercial farms of the Zulia State were tested for presence of avian anemia infection (A.I.A) serum antibodies and anemia as a clinical sign of disease. From these serums, 68.5% (102/149) showed a antibodies title ≥ 4 (1:16 dilution) to ELISA test which is considered positive for it. The 87.2% positive sera belong to chickens between 6 and 14 days of age. Microhematocrit technique showed that only 13.4% (20/149) of tested birds had anemia (hematocrits < 27%). From these 90% (18/20) had antibodies against A.I.A and 6 to 14 days of age. All these factors permit to think of clinical disease is present in the birds. A highly significant negative correlation (r < 0.5; P ≤ 0.05) between age and presence of antibodies against A.I.A was found in the birds under testing which shows chicken sensitivity t...
Rev. Cient.( …, 2008
RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos g... more RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis catus) que asistieron al Servicio de Consulta Externa de la Policlínica Veterinaria de la Universidad del Zulia (PVU), durante el período ...
Revista …, 2008
Unidad de Investigación en Biotecnología Animal. Facultad de Ciencias Veterinarias y Facultad Exp... more Unidad de Investigación en Biotecnología Animal. Facultad de Ciencias Veterinarias y Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo, Venezuela. Unidad de Investigación en Producción Animal (UNIPA). Facultad de Ciencias Veterinarias, Universidad del Zulia, ...
Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock... more Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock. Due to the limited information on the immune response against this parasite in ruminants, the present investigation was undertaken with the aim to evaluate and compare the immune response of sheep experimentally infected with two T. vivax isolates. The isolates were obtained from different geographic areas of Venezuela (TvLIEM176 from Trujillo State and TvMT1 from Monagas State). Three sheep were inoculated with each isolate and three others were used as controls for a total of nine animals. Every three days (d), during a period of 60 d, blood and serum samples were taken to determine anti-Trypanosoma spp. antibodies (by iELISA), parasitemia, white blood cell count and a leukocyte profile. TvMT1- inoculated animals showed higher levels of antibodies than TvLIEM176-infected animals, although parasitaemia behaved inversely. The TvLIEM176 isolate produced higher levels of parasitemia than...
Acta virologica, 2016
Rotavirus infection is the most frequent cause of infantile gastroenteritis worldwide and a signi... more Rotavirus infection is the most frequent cause of infantile gastroenteritis worldwide and a signifi cant cause of death in infants and young children, following severe diarrhea and dehydration. Rotavirus vaccines are considered the most eff ective way to prevent rotavirus infections. In the process of developing rotavirus vaccines, it is crucial to establish a reliable and standardized method to determine vaccine titer. In this study, we developed an indirect immunofl uorescence assay (IFA) to determine the infectious titer of Lanzhou lamb rotavirus (LLR) vaccine grown in MA104 cells. Th e activating concentration of trypsin was 1 μg/ml for healthy monolayers of MA104 cells at 100% confl uence. Aft er incubation for 18 hr, a rabbit anti-SA11 polyclonal antibody, diluted at 1:800 in PBS, was added to all wells, followed by an Alexa-488-conjugated secondary antibody diluted at 1:500 in PBS. Cells were examined with a fl uorescence microscope. Our results show that IFA was more reproducible, more sensitive, simpler, and more rapid than the log 50% cell culture infectious dose-ELISA (lgCCID 50-ELISA) in measuring the rotavirus vaccines. IFA provided a reliable basis for the qualitative and quantitative analysis of rotavirus, and the certifi cation of rotavirus vaccine production.
Veterinary Pathology, Mar 1, 2003
Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Mar... more Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Maracaibo, Venezuela, using buffy coat smears stained with Dip Quick. Three dogs were inoculated with an A. platys strain. When parasitemia reached 60–97%, blood samples obtained from the inoculated dogs and from two naturally infected dogs were centrifuged to obtain platelet-rich plasma, which was mixed with 0.1% glutaraldehyde at 37 C for 10 minutes. Platelet pellets were fixed in 3% glutaraldehyde for 72 hours and processed for conventional transmission electron microscopy. Platelets contained pleomorphic organisms with a distinct double membrane that was not observed when the bodies were in a determinate developmental stage. There were 1–15 individual bodies included in a host cell vacuole. The organisms had an electron-lucent inner area, whereas the internal surface of their inner plasma membranes exhibited an electron-dense rough substance. In naturally infected dogs, organisms with different ultrastructural features were found inside the same platelet. Some organisms contained central dense material surrounded by a pale zone, which was in turn surrounded by a moderately dense peripheral area. Other organisms contained an eccentrically electron-dense material. The intravacuolar space appeared fully electron-lucent. Each organism usually exhibited inner fine strands. Empty structures displaying junctions with the vacuolar membrane were observed. Our results indicate that distinct ultrastructural characteristics are associated with different stages of A. platys development and may differ among A. platys strains.
Revista Científica de la Facultad de Ciencias Veterinarias de la Universidad del Zulia, Oct 20, 2008
Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastroint... more Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis catus) que asistieron al
Revista científica, 2006
La otitis externa es una enfermedad de etiología multifactorial que comúnmente afecta a los canin... more La otitis externa es una enfermedad de etiología multifactorial que comúnmente afecta a los caninos. Representa una patología compleja que se asocia a infecciones causadas por bacterias y levaduras, y que muchas veces no responden a los tratamientos. El objetivo de este estudio fue aislar e identificar los microorganismos patógenos y no patógenos presentes en pacientes con otitis externa. Esta investigación fue realizada sobre 53 pacientes caninos con otitis externa que fueron atendidos en el Servicio de
Microscopy and Microanalysis, Jul 18, 2003
Revista Cientifica, Facultad de Ciencias Veterinarias, Universidad del Zulia, 2015
RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos g... more RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis ca-tus) que asistieron al Servicio de Consulta Externa de la Poli-clínica Veterinaria de la Universidad del Zulia (PVU), durante el período de enero a diciembre 2004. Para ello se recolecta-ron directamente del recto, heces de 64 gatos, procesándose mediante el método de flotación fecal con solución salina satu-rada, obteniéndose una prevalencia general de helmintos gas-trointestinales de 46,9%. Los helmintos observados fueron Ancylostoma spp. (29,7%), Trichuris spp. (10,9%), Toxocara spp. (7,8%) y Physaloptera spp. (6,3%). No se observaron di-ferencias estadísticamente significativas de los valores de pre-valencia entre sexos (42,9% en hembras y 50% en machos), ni entre grupos raciales (48,1% en gatos mestizos y 41,7% en gatos de razas puras). En referencia a los grupos etarios, la prevalencia general fue: animales menores de 1 año, 52,6%; entre 1 y 2 a...
organism in human platelets from patients with symptoms of ehrlichiosis
Invest Clin, Mar 1, 1996
La Ehrlichiosis humana es una enfermedad zoonotica, causada por una rickettsia leucocitaria descr... more La Ehrlichiosis humana es una enfermedad zoonotica, causada por una rickettsia leucocitaria descrita por primera vez en los Estados Unidos de Norteamerica en 1986.Mas de 300 casos han sido reportados en ese pais.,asi como un caso en Portugal, dos en Francia y uno en un turista procedente de Mali (Africa). En Venezuela, un pais tropical, donde la ehrlichiosis es endemica en caninos y equinos, se reporta el primer caso de ehrlichiosis humana en una nina de 17 meses de edad, quien presento inicialmente sintomatologia compatible con una virosis, progresando con exantema, complicaciones pulmonares, hepaticas, esplenicas, renales, nerviosas y hematologtcas incluyendo pancitopenia y coagulacion intravascular diseminada (CID). Diferentes diagnosticos fueron planteados antes de concluir que se trataba de una ehrilichiosis. Ante tal evidencia se indico tratamiento con tetraciclina y se obtuvo rapida recuperacion. El diagnostico inicial fue realizado usando frotis de capa blanca tenido con Diff Quick Stain. La presencia de anticuerpos especificos contra Ehrlichia chaffeensis, fue demostrada utilizando la tecnica de Inmunofluorescencia indirecta (IFI) en el laboratorio del CDC de Atlanta (titulo 1: 126). Se describe tambien la presencia de una ehrlichia plaquetaria, semejante a la E. platys de perro, en la sangre de la nina. Estos hallazgos en humanos no habian sido descritos con anterioridad. No se pudo demostrar que la enfermedad fue transmitida por picaduras de garrapatas.
Revista Cientifica, 2006
Otitis externa is a multi-factorial etiology disease commonly affecting canines. It represents a ... more Otitis externa is a multi-factorial etiology disease commonly affecting canines. It represents a complex pathology associated to infections caused by bacteria and yeasts, many times not responding to treatments. The goal of this study was to isolate and identify the pathogenic and non-pathogenic microorganisms existent in otitis externa patients. This research was performed on 53 canine patients which were attended at the Outpatient Consult Service of the University Veterinary Policlinic at Zulia State University (UVP), and which showed clinical signs such as: auditory canal erythema, increased secretion, pain, continuous head shaking and pruritus, purulent secretions and pruritus being the most frequent. Samples were recollected from auditory canal horizontal portion exudates. Different bacteria groups were isolated in culture media, the most frequent were Pseudomona aeruginosa (22.22%), Proteus mirabilis (13.89%), Staphylococcus aureus (12.50%), Staphylococcus epidermidis (8.33%), Escherichia coli (5.56%) and Staphylococcus coagulase-negative (5.56%). In the control group, Bacillus spp. (16.67%), Staphylococcus epidermidis (16.67%) and Staphylococcus coagulase-negative (16.67%) were the most frequently isolated. Cytological examination showed Malassezia pachydermatis to be present in 69.8% of the cases studied. The most affected breeds were Poodles (30.19%), Mongrels (26.42%), Cocker Spaniels (16.98%) and German Shepherd Dogs (9.49%); likewise, a higher incidence of otitis was evidenced in dogs between 2 and 5 months of age (43.40%).
Investigación clínica, 1996
Human ehrlichiosis is a zoonotic disease, caused by a rickettsia that infects leukocytes. It was ... more Human ehrlichiosis is a zoonotic disease, caused by a rickettsia that infects leukocytes. It was described for the first time in the United States of America in 1986. More than 300 cases have been reported in that country. One case has been reported in Portugal, two in France and one more in a tourist coming from Mali (Africa). In Venezuela, a tropical country, where ehrlichiosis is endemic in dogs and horses, the first case of human ehrlichiosis is reported in a seventeen month old girl. She initially had symptoms compatible with a viral illness. Then she developed a rash, acute respiratory failure, hepato-splenomegaly, neurologic abnormalities, renal failure and hematologic alterations including pancytopenia and disseminated intravascular coagulation (DIC). Different diagnoses were given before it was concluded that it was a case of ehrlichiosis. She was treated with tetracycline and very soon recovered. The initial diagnosis was made using buffy coat blood smears stained with Dif...
The American Journal of Tropical Medicine and Hygiene, 2014
This article presents two case reports of Anaplasma platys detection in two women from Venezuela.... more This article presents two case reports of Anaplasma platys detection in two women from Venezuela. Both patients were exposed to Rhipicephalus sanguineus, the presumed tick vector, and experienced chronic, nonspecific clinical signs including headaches and muscle pains. Intra-platelet inclusion bodies resembling A. platys were observed in buffy coat smears and A. platys DNA was amplified and sequenced from whole blood; however, treatment with doxycycline did not alleviate their symptoms. These cases provide further support for A. platys as a zoonotic tick-borne pathogen, most likely of low pathogenicity; nonetheless, the cause of illness in humans by A. platys is yet to be confirmed.
Journal of Medical Microbiology, 1999
Since 1982, Ehrlichia platys infection has been diagnosed in canines from Venezuela by the use of... more Since 1982, Ehrlichia platys infection has been diagnosed in canines from Venezuela by the use of buffy coat smears. In 1992, ehrlichia-like bodies were observed in platelets from a severely ill girl by light microscopy. The patient was seropositive to E. chaffeensis by the indirect fluorescent antibody test (IFAT). Tetracycline was administered and the patient recovered. More than 400 cases with such intra-platelet organisms have been studied at this laboratory over the past 6 years, and all the patients had a good response to the treatment. To determine whether the organisms in human blood platelets were truly platelet ehrlichiae, IFAT and transmission electron microscopy (TEM) studies were undertaken in four patients. Light microscopic examination of blood samples revealed the dense organism inside platelets, and a great reactivity of the blood cells. Sera from the four patients were seronegative against E. chaffeensis and E. platys antigens. Three of four samples contained the intra-platelet organisms when examined by TEM. Electron microscopy showed platelets with vacuoles containing pleomorphic organisms. These organisms had a thickened membrane, an electron-translucent inner area and an electron-dense granular component in the periphery. An abundant electron-dense material was observed surrounding them. The ultrastructure of such microorganisms has not been reported previously. Based on the similarity of many of their characteristics with rickettsiae, we suggest that the microorganisms found in the present study might belong to the family Rickettsiaceae.
Veterinary Pathology, 2003
Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Mar... more Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Maracaibo, Venezuela, using buffy coat smears stained with Dip Quick. Three dogs were inoculated with an A. platys strain. When parasitemia reached 60–97%, blood samples obtained from the inoculated dogs and from two naturally infected dogs were centrifuged to obtain platelet-rich plasma, which was mixed with 0.1% glutaraldehyde at 37 C for 10 minutes. Platelet pellets were fixed in 3% glutaraldehyde for 72 hours and processed for conventional transmission electron microscopy. Platelets contained pleomorphic organisms with a distinct double membrane that was not observed when the bodies were in a determinate developmental stage. There were 1–15 individual bodies included in a host cell vacuole. The organisms had an electron-lucent inner area, whereas the internal surface of their inner plasma membranes exhibited an electron-dense rough substance. In naturally infected dogs, organisms with d...
Seric Antibody and Anemia detection in broiler to AIA in Mara and La Canada de Urdaneta Farms of ... more Seric Antibody and Anemia detection in broiler to AIA in Mara and La Canada de Urdaneta Farms of the Zulia State. One hundred and forty vine broiler from Mara and La Canada de Urdaneta commercial farms of the Zulia State were tested for presence of avian anemia infection (A.I.A) serum antibodies and anemia as a clinical sign of disease. From these serums, 68.5% (102/149) showed a antibodies title ≥ 4 (1:16 dilution) to ELISA test which is considered positive for it. The 87.2% positive sera belong to chickens between 6 and 14 days of age. Microhematocrit technique showed that only 13.4% (20/149) of tested birds had anemia (hematocrits < 27%). From these 90% (18/20) had antibodies against A.I.A and 6 to 14 days of age. All these factors permit to think of clinical disease is present in the birds. A highly significant negative correlation (r < 0.5; P ≤ 0.05) between age and presence of antibodies against A.I.A was found in the birds under testing which shows chicken sensitivity t...
Rev. Cient.( …, 2008
RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos g... more RESUMEN Se realizó esta investigación con el objetivo de determinar la prevalencia de helmintos gastrointestinales en gatos (Felis catus) que asistieron al Servicio de Consulta Externa de la Policlínica Veterinaria de la Universidad del Zulia (PVU), durante el período ...
Revista …, 2008
Unidad de Investigación en Biotecnología Animal. Facultad de Ciencias Veterinarias y Facultad Exp... more Unidad de Investigación en Biotecnología Animal. Facultad de Ciencias Veterinarias y Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo, Venezuela. Unidad de Investigación en Producción Animal (UNIPA). Facultad de Ciencias Veterinarias, Universidad del Zulia, ...
Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock... more Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock. Due to the limited information on the immune response against this parasite in ruminants, the present investigation was undertaken with the aim to evaluate and compare the immune response of sheep experimentally infected with two T. vivax isolates. The isolates were obtained from different geographic areas of Venezuela (TvLIEM176 from Trujillo State and TvMT1 from Monagas State). Three sheep were inoculated with each isolate and three others were used as controls for a total of nine animals. Every three days (d), during a period of 60 d, blood and serum samples were taken to determine anti-Trypanosoma spp. antibodies (by iELISA), parasitemia, white blood cell count and a leukocyte profile. TvMT1- inoculated animals showed higher levels of antibodies than TvLIEM176-infected animals, although parasitaemia behaved inversely. The TvLIEM176 isolate produced higher levels of parasitemia than...