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PubMed2001

Possible association between gastric cancer and bracken fern in Venezuela: an epidemiologic study.

To explore a possible connection between specific environmental factors that might explain the high rates of stomach cancer in people living in the highlands of western Venezuela, an epidemiologic study was conducted in 2 regions of contrasting topography. The regions embrace 3 Andean states, Mérida, Táchira and Trujillo, and the vicinal lowland surrounding the Maracaibo lake basin of Zulia State. Statistical sanitary records from 1986 to 1996 comprising 5.5 million people in the study area indicated that age-sex-adjusted gastric cancer death rate per 100,000 people (DR) was up to 3.64 times higher in highland than lowland areas, although total cancer-related DRs were comparable in both regions. DRs of other less frequent cancers from the upper alimentary tract [esophagous (1.18/0.99) and mouth-throat (1.39/2.64)] showed comparable values in both regions as well as colorectal, breast, and uterus-cervix cancers, suggesting that the stomach cancer DRs were related to geographically determined factors. Comparison of some nutrition issues, incidence of Helicobacter pylori infection in selected areas, the discovery of the bracken carcinogen ptaquiloside in milk from bracken-fed cows, the prevalence of this plant in mountain cattle households and pasturelands and the rates of bracken-evoked bovine enzootic hematuria led us to conclude that consumption of ptaquiloside-contaminated milk may contribute to human gastric cancer in the Andean states of Venezuela.

Animals↗
PubMedDate not supplied

Use of short tandem repeats loci to study the genetic structure of several populations from Zulia State, Venezuela.

Genetic relationships between populations can be studied by comparing genotypic and allelic similarities. This investigation aims to demonstrate that selected autosomal microsatellite markers could be used to study the genetic structures of different populations living in northwest Venezuela, in Zulia State. Seven autosomal systems (CSF1PO, TPOX, TH01, vWA, D7S820, D13S317, and D5S818) were tested by PCR in a multiplex format on 688 different chromosomes from unrelated individuals living in Maracaibo, "Isla de Toas," and "San José de Heras," and from two Amerindian populations from the "Sierra de Perijá," Barí' and Yukpa. Allele frequencies, Hardy-Weinberg equilibria, genetic distances, phylogenetic trees, and ethnic admixtures were estimated. The study shows the existence of a clear genetic difference among these populations in accordance with their historic evolution. The populations of Maracaibo and "Isla de Toas" showed a triracial origin, with a large European contribution, followed by an Amerindian component and a small African component. The indigenous groups, Barí' and Yukpa, showed exclusively an Amerindian component, and "San José de Heras" showed only an African component. These results indicate that microsatellite markers are useful for molecular anthropology in a regional and worldwide context and provide important genetic information about contemporary populations of Venezuela.

Alleles↗
PubMed2001

A case-control study of gastric cancer in Venezuela.

A case-control study to evaluate risk factors for gastric cancer was carried out among 292 cases of gastric cancer and 485 controls in a high-risk area of Venezuela. Subjects were interviewed using a structured questionnaire, which elicited information on residential history, socio-economic status, family history of gastric diseases, smoking, drinking and dietary habits. Habitual diet was estimated from a meal-structured food frequency questionnaire on 75 food items. There was a strong inverse association with social class, as measured by education and by indicators of poverty. The results of the dietary analysis suggest that a diet high in starch and low in meat, fish and fresh vegetables increases risk of gastric cancer. A protective effect was observed for frequent consumption of allium vegetables. Inverse associations were found with height, which may reflect nutritional status in childhood, and with refrigerator use in the first two decades of life. Alcohol and tobacco consumption was investigated among males only, since the prevalence of alcohol and tobacco use was very low in females. Alcohol drinkers were at higher risk than non-drinkers and there was a small excess risk for current smokers compared with never smokers. There was some evidence of familial aggregation of gastric cancer. These findings will have important implications in planning preventive strategies for gastric cancer in Venezuela.

Adult↗
PubMed1994

Prevalence of antibodies against hepatitis E virus among urban and rural populations in Venezuela.

Antibodies against hepatitis E virus (HEV) were detected in sera by a synthetic peptide-based enzyme immunoassay (EIA) from different populations in Venezuela. Antibodies against HEV were found in 1.6% (3/184) of urban pregnant woman (Caracas), in 3.9% (8/204) of rural populations (San Camilo, Edo Apure), and in 5.4% (12/223) of rural Amerindians (Padamo, Edo Amazonas). Positivity was confirmed by a neutralization EIA based on the use of competing soluble free peptides. The prevalence of antibodies in the Amerindian group was significantly higher than in urban pregnant women. No relation was found between age and HEV prevalence in rural populations. Three of 21 positive sera were also weakly positive by Western blot for IgM antibodies. This result, together with the low optical density values observed by EIA, suggested that the presence of antibodies in these sera reflects past infections. Based on these results, Venezuela does not seem to be highly endemic for hepatitis E. This is the first report of serological evidence of infection by HEV in South America.

Adolescent↗
PubMed1994

Epidemiology of hepatitis C virus in western Venezuela: lack of specific antibody in Indian communities.

Hepatitis C virus (HCV) is transmitted mainly by the parenteral route after percutaneous exposure to virus-infected products or body fluids. Thus, HCV shares with hepatitis B and D (HBV, HDV) viruses this common transmission route. The prevalence of antibody against HCV (anti-HCV) was studied in 1155 serum samples from individuals at risk of infection by bloodborne or sexually transmitted agents, as well as from others lacking such risk factors, from the city of Maracaibo, Venezuela. Anti-HCV and serological markers of infection by HBV and HDV were also studied in further 550 samples taken from Bari Indians living in different communities in the Perijá mountains, State of Zulia, Venezuela. The results obtained showed that recipients of blood or blood products are at increased risk of HCV infection in Maracaibo, whereas sexual transmission plays only a minor role if any. Both HBV and HDV infections were highly prevalent among Bari Indians (64.4% positive for anti-HBc; 11.1% of HBsAg carriers; 15.3% positive for anti-HDV among HBsAg carriers). No anti-HCV positive samples were, however, detected among them, thus suggesting either that HCV has not still reached this population or that HBV and HDV are transmitted by routes unshared by HCV. Anti-HCV was also absent among samples from mentally retarded patients from Maracaibo, thus confirming similar findings from other countries and supporting the existence of specific transmission mechanisms for HBV and HDV which are not working for HCV.

Antibody Specificity↗
PubMed2002

Heavy metals in green mussel (Perna viridis) and oysters (Crassostrea sp.) from Trinidad and Venezuela.

Heavy metal concentrations were monitored in edible soft tissues of shellfish from Trinidad and Venezuela. Oysters (Crassostrea sp.) and the green mussel (Perna viridis), which is a recently transplanted species to the Caribbean from the Far East, were collected at six locations in Venezuela and five in Trinidad, the latter along the coast line of the Gulf of Paria. Simple and low-cost methods of analysis were optimized and validated using standard reference materials. Cadmium, copper, lead, nickel, and zinc were analyzed by flame atomic absorption spectrometry. Mercury was determined by cold-vapor atomic absorption spectrometry. The present study has confirmed that oysters have a much greater capacity for accumulation of copper and zinc than does green mussel. In addition, concentrations of copper and zinc in oysters (Crassostrea sp.) at many of the sites in the Gulf of Paria exceeded local and international standards, whereas green mussel P. viridis contained generally acceptable levels for human consumption.

Animals↗
PubMed2007

Casas Muertas and Oficina No. 1: internal migrations and malaria trends in Venezuela 1905-1945.

To compare internal migration and temperature as factors behind the decreasing trend in malaria deaths observed in Venezuela from 1905 to 1945, linear autoregressive models are fitted to a historical dataset. The model that only incorporates internal migration is the one with the best fit. The decreasing trend in malaria deaths in Venezuela, from 1905 to 1945, is not explained by a trend in mean annual temperature, but it is associated with an increase in the proportion of population in the Capital District, during a time period when the area was the principal attractor of migrations within the country.

History, 20th Century↗
PubMed2002

Renal diseases in children in Venezuela, South America.

The present study reports epidemiological data on renal disorders in children in Venezuela. Information was obtained from 14 centers for the period January through December 1998. A total of 3,624 patients were evaluated as either a first outpatient consultation or as a first hospital admission. Nearly 70% of the patients could be grouped in one of the following categories: (1) urinary tract infections (32%), with detection of abnormalities of the urinary tract in 25%, (2) metabolic disorders (28%), mainly idiopathic hypercalciuria and hyperuricosuria, (3) glomerulonephritis (9.5%). The other 30% corresponded to urolithiasis 7%; renal tubular acidosis 5.6%; nephrotic syndrome 4.5%; primary hematuria 4.2%; acute renal failure 2.8% (43% were secondary to acute dehydration, 15% to birth asphyxia, 14% to septicemia, and 23% to multiple factors); chronic renal failure 1.6% (secondary to glomerulopathies, predominantly focal glomerulosclerosis, structural abnormalities of the urinary tract, hereditary disorders, and renal hypoplasia/dysplasia); miscellaneous diseases 4.8%. Hence, the spectrum of renal disorders in Venezuela is wide, sharing similarities with countries of both the developed and developing world. These data will hopefully contribute to the development of national healthcare policies appropriate to the epidemiology of the country.

Acute Disease↗
PubMed2005

Intestinal canine pythiosis in Venezuela confirmed by serological and sequencing analysis.

An 11-months-old mixed Terrier male originally from Venezuela, was referred to a Veterinary Hospital with signs of depression, anorexia, vomiting and diarrhea. The illness had begun 1 month earlier. Despite antibiotic chemotherapy and vitamins, the disease progressed. Radiological exams showed involvement of the small intestine. Histopathological studies of tissue samples taken during surgical intervention revealed eosinophilic areas in the center of which, abundant eosinophils, histiocytes and giant cells were observed. Silver stained cross-sections of the small intestine showed slender sparsely septate hyphae within the necrotic areas. Attempts to isolate the etiologic agent in pure culture were fruitless. The dog died without a definitive diagnosis. Fixed tissue samples of the small intestine were later investigated using specific fluorescent antibodies for pythiosis and molecular tools. These exams indicated that the hyphae in the infected tissues belong to the straminipilan pathogen Pythium insidiosum. This is the first confirmed case of dog pythiosis in Venezuela.

Animals↗
PubMed2005

Tinea nigra: report of twelve cases in Venezuela.

Tinea nigra is a superficial mycotic infection produced by Hortaea werneckii, formerly known as Phaeoannelomyces werneckii, formerly known as Exophiala werneckii, and Stenella araguata, the latter autochthonous in Venezuela, it was first described and named as Cladosporium castellanii in 1973. The present report describes 12 cases in the period of 1972-2002, diagnosed at the Medical Mycology Section at the Tropical Institute of the Universidad Central de Venezuela, in Caracas. This mycosis is more prevalent among young people, with fair skin, from 3 to 28 years of age, who visited beaches and in whom the lesions are more evident. Out of these 12 patients, 8 (66.66%) had Phaeoannelomyces werneckii as the causal agent and 2 (16.67%) Stenella araguata was isolated. Two patients had more than one macule, and curiously in these cases, each lesion was caused by a different species of the aforementioned fungus.

Adolescent↗
PubMed2005

Risk of Trypanosoma cruzi I (Kinetoplastida: Trypanosomatidae) transmission by Panstrongylus geniculatus (Hemiptera: Reduviidae) in Caracas (Metropolitan District) and neighboring States, Venezuela.

The collection of Panstrongylus geniculatus bugs by inhabitants of dwellings in Caracas city (Metropolitan District) and in the neighboring Miranda and Vargas Sates, Venezuela, allowed for the gathering of data on the potential role of this sylvatic triatomine bug as a vector of Chagas disease in this area. The natural infection by Trypanosoma cruzi was recorded by examining fresh and stained faeces of the bugs. Additionally, a random amplification of polymorphic DNA technique for parasite identification and group typing was employed. A dot-ELISA test was used to identify the gut content of the triatomine bugs with the aim of assessing and quantifying the vector-human contact. Sixty-seven specimens (76.1%) were positive to T. cruzi (identified as T. cruzi I) and 60.2% (53/88) gave a positive reaction to the human antiserum. The human blood-positive samples included mixed blood meals with domestic animals (dog, pig and cow) (9.4%) and with mouse (3.8%). The overall Human Blood Index, measured as the percentage of bugs whose gut contents reacted with human antiserum on the total numbers of bugs that reacted with all the antisera tested, was 98.1%. Almost 41% of the bugs that had fed on humans were also positive for T. cruzi. These data show that the feeding of P. geniculatus on humans does not seem to be accidental and that its rate of infection by T. cruzi is high in this area which is not regarded as endemic for Chagas disease by the National Control Programme. This situation is particularly striking because it occurs in and around Caracas, the capital city, where 20% of the whole population of Venezuela live, human migrations from endemic areas are continuous, people in the crowded shantytown as well as people living in high-quality country houses are equally at risk and the epidemiological cycle Didelphis marsupialis/Rattus rattus-P. geniculatus-human does appear to occur successfully.

Animals↗
PubMed2006

New advances in molecular epizootiology of canine hematic protozoa from Venezuela, Thailand and Spain.

The prevalence of hematozoan infections (Hepatozoon canis and Babesia sp., particularly Babesia canis vogeli) in canids from Venezuela, Thailand and Spain was studied by amplification and sequencing of the 18S rRNA gene. H. canis infections caused simultaneously by two different isolates were confirmed by RFLP analysis in samples from all the geographic regions studied. In Venezuela, blood samples from 134 dogs were surveyed. Babesia infections were found in 2.24% of the dogs. Comparison of sequences of the 18S rRNA gene indicated that protozoan isolates were genetically identical to B. canis vogeli from Japan and Brazil. H. canis infected 44.77 per cent of the dogs. A representative sample of Venezuelan H. canis isolates (21.6% of PCR-positives) was sequenced. Many of them showed 18S rRNA gene sequences identical to H. canis Spain 2, albeit two less frequent genotypes were found in the sample studied. In Thailand, 20 dogs were analyzed. No infections caused by Babesia were diagnosed, whereas 30 per cent of the dogs were positive to hematozoan infection. Two protozoa isolates showing 99.7-100% identity to H. canis Spain 2 were found. In Spain, 250 dogs were studied. B. canis vogeli infected 0.01% of the animals. The sequence of the 18S rRNA gene in Spanish isolates of this protozoa was closely related to those previously deposited in GenBank (> 99% identity). Finally, 20 red foxes were screened for hematozoans employing semi-nested PCR and primers designed to detect Babesia/Theileria. Fifty percent of the foxes were positive to Theileria annae. In addition, it was found that the PCR assay was able as well to detect Hepatozoon infections. Thirty five percent of the foxes were infected with two different H. canis isolates showing 99.8-100% identity to Curupira 1 from Brazil.

Animals↗
PubMed2000

Simulation of rotational grazing to evaluate integrated pest management strategies for Boophilus microplus (Acari: ixodidae) in Venezuela.

Ranchers in Venezuela historically have controlled the cattle-fever tick, Boophilus microplus (Canestrini), with acaricide treatments of cattle but no technical planning. We developed a simulation model to evaluate cattle-tick population dynamics in systematic pasture rotation systems and Integrated Pest Management (IPM) approaches to managing ticks in the tropical dry-forest ecological zone of Venezuela. Model output showed five generations of cattle-ticks produced each year throughout the dry and rainy seasons that occur in this zone. Sensitivity analyses showed disproportionately large changes in on-host B. microplus populations in response to small changes in larval mortality rates, such as those resulting from differences in the innate resistance of cattle to tick parasitism. Simulation results with 1-6 pasture systems suggest that adjusting the graze:rest sequence with systematic rotation among 4-6 pastures could suppress, but not eradicate, tick populations.

Animal Husbandry↗
PubMed1998

Multicenter evaluation of the antimicrobial activity for six broad-spectrum beta-lactams in Venezuela using the Etest method. The Venezuelan Antimicrobial Resistance Study Group.

In early 1997, a 15-laboratory surveillance project was initiated in Venezuela to monitor the potency and spectrum of 6 broad-spectrum antimicrobial agents (cefepime, cefotaxime, ceftazidime, piperacillin, piperacillin/tazobactam, and imipenem) tested against approximately 100 organisms per participant center (1297 strains). Ten groups of organisms were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by concurrent quality control strain analysis. Results from all centers were tabulated and 96.3% of quality assurance tests were within ranges recommended by the National Committee for Clinical Laboratory Standards. Among the six beta-lactam class drugs tested, imipenem and cefepime were the most active against all isolates tested. Overall, the rank order of susceptibility of the six agents was imipenem (97.2%, susceptible; MIC90 2 micrograms/ml) > cefepime (92.8%; MIC90 6 micrograms/mL) > piperacillin/tazobactam (77.2-83.0%; MIC90 > 256 micrograms/mL) > cefotaxime (72.2%; MIC90 > 256 micrograms/mL) > piperacillin (56.8-65.8%; MIC90 > 256 micrograms/mL) > ceftazidime (64.66%; MIC90 128 micrograms/mL). Both cefepime and imipenem were active against ceftazidime-resistant strains of Enterobactericaeae as well as against Pseudomonas aeruginosa and oxacillin-susceptible staphylococci. Resistance phenotypes consistent with extended spectrum beta-lactamases (ESBLs) and stably derepressed Bush group 1 cephalosporinases were documented in strains of Klebsiella spp. and Enterobacters, respectively. These data should be used to guide empiric therapy with beta-lactams in Venezuela, and additionally will provide a reference statistical baseline to which future studies in this nation can be compared.

Acinetobacter↗
PubMedDate not supplied

Identification of bovine rotaviruses in Venezuela: antigenic and molecular characterization of a bovine rotavirus strain.

Two serotypes of bovine group A rotaviruses were demonstrated by enzyme-linked immunoassay (ELISA) and polyacrylamide gel electrophoresis (PAGE) in 20 of 171 faecal samples collected from diarrhoeic calves in two dairy farms in Venezuela. By serotyping ELISA using G and P serotype-specific monoclonal antibodies, bovine rotaviruses (BRV) circulating on one farm were identified as serotype G6, while BRVs circulating on the other farm were identified as serotype G10. Only one BRV (033) could be successfully isolated in MA104 cells, and the nucleotide sequences of the VP7 and the VP8* trypsin-cleavage product of the VP4 were determined. Cross-neutralization tests and comparative sequence analysis showed that BRV 033 belonged to serotype G6 and genotype P1. This is the first report of BRVs identified in Venezuela.

Amino Acid Sequence↗
PubMed2000

Molecular basis of extended-spectrum beta-lactamase production in nosocomial isolates of Klebsiella pneumoniae from Mérida, Venezuela.

Twelve Klebsiella pneumoniae isolates resistant to expanded-spectrum cephalosporins and aztreonam, from patients with nosocomial septicaemia at the intensive care unit of the Andes University Hospital, Mérida, Venezuela, were studied for production of extended-spectrum beta-lactamase (ESbetaL) activity. All were also resistant to gentamicin, kanamycin, tetracycline and chloramphenicol but sensitive to cefoxitin, imipenem, amikacin and tobramycin. Production of ESbetaL activity was confirmed by restoring susceptibility to ceftazidime in the presence of clavulanic acid. All isolates carried an identical plasmid of approximately 87 kb. Resistance to beta-lactams, aminoglycosides, tetracycline and chloramphenicol was lost en bloc after plasmid curing by treatment with acridine orange and was transferable en bloc to Escherichia coli by conjugation. Transconjugants always showed the same plasmid profile as that of Klebsiella donors. Isoelectric focusing analysis of the crude extracts of transconjugants showed in all cases, the presence of two beta-lactamases of pI 5.4 and 8.2. Analysis of the plasmid carried by one of the transconjugants by means of hybridization assays, revealed the presence of both bla(TEM) and bla(SHV) determinants. Cloning and sequencing of each determinant identified them as bla(TEM-1) and bla(SHV-5), respectively, the latter being responsible for the ESbetaL activity. Results of this study indicate that ESbetaL determinants of the SHV-type carried by transferable elements, are spreading among nosocomial isolates of K. pneumoniae in Mérida, Venezuela.

Anti-Bacterial Agents↗
PubMed2002

Is Rhodnius robustus (Hemiptera: Reduviidae) responsible for Chagas disease transmission in Western Venezuela?

We present evidence for the putative role of Rhodnius robustus as extradomestic vector of Chagas disease in Western Venezuela. First, we assessed the validity of this triatomine species by genetic characterization in relation with some other species of the prolixus group. Random amplified polymorphic DNA data showed a clear separation between this species and R. prolixus and indicated a probable genetic heterogeneity within R. robustus. Faeces and gut contents were microscopically examined in 54 of 137 R. robustus collected in palm trees. According to this morphological examination, 18% were positive for Trypanosoma cruzi, 11% harboured T. rangeli and 11% showed mixed infection. Five of the seven samples examined gave a polymerase chain reaction major band of 270 bp specific of T. cruzi. The hybridization probes showed that R. robustus may transmit clones 20 and 39 (or genetically related ones) in Venezuela. Such a transmission might occur when, in absence of domestic R. prolixus and attracted by artificial light, R. robustus enters houses and feeds on humans, or when people are bitten outdoors. The lack of bugs inside houses could mean that the insects leave houses after feeding, or die without reproducing there.

Adult↗
PubMed2002

End-stage renal disease and its treatment in Venezuela.

In Venezuela there are 3234 new cases (132 per million population [pmp]) requiring renal replacement therapy each year, and only 40% of these are admitted to the different modalities of dialysis. In the year 2000, there were 195 patients pmp in chronic hemodialysis (4700 patients). Diabetes, glomerular diseases, and hypertension account for more than 60% of the patients in chronic dialysis. Gross mortality in hemodialysis is around 20%, and cardiovascular causes are the primary cause of death (39.5%). Hospital admission in the dialysis patients amounts to 4.6 days/patient/year. Rehabilitation is inadequate. Only 45% of the dialysis patients report normal home or work activities. Transplantation in Venezuela has a general graft survival rate of 83% at 1 year (90% for living related grafts) and 50% (64% for living related grafts) at 10 years. Future tendencies include emphasis in preventive strategies, including early detection and treatment of diabetes and hypertension, as well as efforts to increase the rate of renal transplantation.

Adult↗