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PubMed1989

A preliminary study of mercury contamination in the surface soil and river sediment of the Roscio District, Bolivar State, Venezuela.

The present study constitutes a comparison of mercury in surface soil and river sediments of a contaminated and an uncontaminated area of Venezuela. In the contaminated area, gold prospectors have been using mercury to separate gold from auriferous sand and rock powders for many years. The baseline level of mercury in the river sediments of the uncontaminated area (Manzanares River, Sucre State) was 0.06 micrograms g-1, while in the contaminated area in the Roscio District of Bolivar State the concentration varied from 0.12 to 129 micrograms g-1. In the river sediments the average level of mercury was 0.71 micrograms g-1 and in the surface soil of the working areas 37 micrograms g-1, which shows a significant increase in the mercury level in the contaminated areas. This high level of mercury in the soil and sediments constitutes a serious risk to public health in the contaminated area, where the local people use the water for drinking and other domestic purposes; moreover, they also consume fish from these rivers.

Geography↗
PubMed1994

Metal content of drinking water supplied to the city of Maracaibo, Venezuela.

Total dissolved aluminum, calcium, iron, potassium, magnesium and sodium were evaluated in the drinking water supplied to the city of Maracaibo, Venezuela, to ascertain the water quality for human consumption. Mean concentrations (+/- S.D.) of 533 +/- 313 micrograms/l Al, 32 +/- 4 mg/l Ca, 167 +/- 104 micrograms/l Fe, 2 +/- 1 mg/l K, 5 +/- 2 +/- 1 mg/l K, 5 +/- 1 mg/l Mg and 16 +/- 4 mg/l Na were obtained during a 4-month sampling period that included dry (January-February 1991) and wet (March-April 1991) seasons. Significant seasonal variations (P < 0.002) for aluminium, potassium and magnesium were as follows: 641 +/- 275 and 445 +/- 340 micrograms/l aluminium, 3 +/- 0.5 and 2 +/- 0.5 mg/l potassium and 4 +/- 0.2 and 6 +/- 2 mg/l magnesium for the wet and dry seasons, respectively. The concentration of aluminum was consistently higher than the levels accepted by most international water quality criteria (approximate acceptable value < 300 micrograms/l aluminum), probably because of the inadequate flocculation treatment given to the raw water at the water plant. The rest of the metals under consideration complied with international guidelines of quality criteria for drinking water. The presence of an elevated concentration of humic material (22 +/- 2 mg/l of total organic carbon) in the drinking water should be a matter of public concern.

Aluminum↗
PubMed1991

Immunogenetics of human American cutaneous leishmaniasis. Study of HLA haplotypes in 24 families from Venezuela.

Twenty-four families with one or multiple cases of localized cutaneous leishmaniasis (LCL) from an endemic region with the highest incidence of LCL in Venezuela were typed from HLA-ABC, DR, DQ antigens and complement factors. The parental HLA haplotypes segregated at random among healthy and affected siblings but in backcross families significantly higher frequencies of HLA-A28 (p = 0.0018), -Bw22 (p = 0.0122), or -DQw8 (p = 0.0364) were present in affected compared to healthy siblings. HLA-B15 showed a higher frequency (p = 0.0062) among the latter group. Haplotypes Bw22CF31 (p = 0.0076) and Bw22DRw11DQw7 (p = 0.0163) were also significantly more frequent in affected compared to healthy siblings and A2Cw- (p = 0.0445) among the latter. No HLA genetic linkage with a putative LCL susceptibility gene(s) could be demonstrated in this study. A case/control comparison of 26 unrelated LCL patients (one proband from each family) and healthy individuals of the same ethnic origin confirmed the association of HLA-Bw22 (pc = 0.048) and -DQw3 (pc = 0.036) with LCL. The relative risk reached 12.5 for Bw22 and 4.25 for DQw3 with ethiologic factors of 0.17 and 0.64, respectively. HLA-DQw3 apparently makes the major contribution as a genetic risk factor for LCL at the population level.

Female↗
PubMed1993

Substance use among resident doctors in Venezuela.

This study was aimed to develop a self-administered questionnaire to detect substance use disorders based on the Spanish version of the Diagnostic Interview Schedule (DIS) and to evaluate the frequency of substance abuse and/or dependence among resident physicians of a large university hospital in Venezuela. The questionnaire showed a high concordance with the clinical diagnoses. Frequency of substance abuse and dependence was evaluated among 191 resident doctors. The frequencies of lifetime diagnoses were: tobacco dependence: 20.9%; alcohol abuse: 11%; alcohol dependence: 0.5%; drug abuse: 1% and drug dependence: 1%; non-pathological use of drugs: 20.4%.

Adult↗
PubMed1987

Characterization of rotaviruses isolated from pigs with diarrhoea in Venezuela.

The prevalence of porcine rotavirus infection was studied in 15 different herds located in the north-western region of Venezuela. The presence of rotavirus was studied by direct electron microscopy (EM) and by an enzyme-linked immunosorbent assay (ELISA). From 136 samples analyzed during the six months of the study (September 1983-February 1984), 38 (27.9%) were found to be positive for rotaviruses, with infection more common in animals that were 4-6 weeks old. Atypical rotaviruses were not detected in any of the samples examined. Most rotavirus positive specimens were subgrouped using specific monoclonal antibodies in an ELISA test. The majority of the samples (26 out of 38) were found to exhibit Subgroup I antigenicity. Only two specimens, collected from the same herd in two consecutive months, were found to belong to Subgroup II. To characterize further the circulating rotaviruses, electrophoretic analysis of the RNA genome was performed on samples selected from nine different herds. Great variability in the RNA electropherotypes was observed. No correlation was found between subgroup specificity and the migration of the two smaller segments (Genes 10 and 11), as has been described for human rotaviruses.

Animals↗
PubMed1987

Preliminary characterization of Escherichia coli isolated from pigs with diarrhoea in Venezuela.

The aetiology of neonatal porcine diarrhoea was studied in 15 different herds located in the north-western region of Venezuela. Of 56 strains of Escherichia coli analyzed, 16 (28.6%) were shown to produce heat-stable (STa) enterotoxin, as detected by infant mouse assay. Only four of these STa+ isolates also possessed the K88 pilus antigen, two were 987P+ and none possessed the K99 antigen, leaving 10 STa+ samples in which no pilus antigen was identified. Among the 40 STa negative samples were six K88+ specimens, one K99+, four 987P+, one which reacted as K88+ + K99+ and one K88+ + 987P+. Considering as pathogenic any strain showing at least one of the characters studied, pathogenic E. coli were detected with an overall frequency of 42.9%, being more prevalent during the second week of life. An electrophoretic analysis of the plasmid content of the field isolates of E. coli, revealed the presence of numerous species of extrachromosomal DNA, although no direction association could be made between a particular plasmid and any of the pathogenic characteristics identified. Results of Southern blot analysis indicate that the STa enterotoxin was preferentially encoded within an endemic plasmid of 4.9 Md. Other plasmids present in the E. coli isolates could be related to antibiotic resistance. With the exception of one strain, all E. coli isolates were resistant to more than one of the nine drugs tested; multiresistant E. coli were frequently isolated, including four strains which were resistant to seven antibiotics.

Animals↗
PubMedDate not supplied

Antimicrobial activity of lomefloxacin (NY-198, SC 47111) against bacterial strains from Venezuela.

Lomefloxacin (SC 47111, NY-198) is a recently developed difluorinated quinolone that has been reported to be active against a broad range of both gram-positive and gram-negative pathogens in a number of laboratories around the world. Our laboratory tested the in vitro activity of 451 recent bacterial isolates compared to that of cephradine and gentamicin to define the in vitro spectrum of activity of this compound versus bacterial isolates from Venezuela. Lomefloxacin showed excellent in vitro activity versus Enterobacteriaceae with all isolates inhibited at a concentration of less than or equal to 2 mcg/ml. Lomefloxacin also had significant activity versus the aerobic gram-negative rods tested; the MIC90 for Pseudomonas aeruginosa being 4 mcg/ml. The activity of lomefloxacin versus gram-positive isolates was comparable to that of the gram-negative organisms. The MIC90 for S. aureus, S. epidermidis, and Group D Streptococcus were 1, 0.5 and 4 mcg/ml, respectively. The results of this study confirm the broad spectrum in vitro activity of lomefloxacin seen in earlier studies. Lomefloxacin appears to be active versus a wide variety of both gram-negative and gram-positive isolates including those resistant to cephradine and gentamicin. The excellent in vitro activity of lomefloxacin seen in this study shows that this compound could be a useful addition to currently available antimicrobial agents.

4-Quinolones↗
PubMed1996

Corpus luteum activity, fertility, and adrenal cortex response in lactating Carora cows during rainy and dry seasons in the tropics of Venezuela.

The effect of the rainy (RS) and the dry season (DS) on fertility, corpus luteum activity, and adrenal cortex response relationships were evaluated after first service (49 +/- 6 d postpartum) in Carora cows, a dairy cattle of Venezuela raised in tropical conditions. Cows (n = 84 in RS and n = 98 in DS) were kept semistabled, had two or three calvings, body condition score 3.5 on a 5-point scale and similar milk yield (2450 +/- 560 kg of milk during the previous lactation). Cows were grouped retrospectively according to pregnancy status. A split-plot model with repeated measures over Days 5, 7, 10, 14, and 15 after insemination was used to analyze the effects of season, pregnancy status, and their interaction involving the day on: 1) serum concentration of progesterone in four treatments: RS pregnant (n = 26), RS nonpregnant (n = 24), DS pregnant (n = 24), and DS nonpregnant (n = 20) cows; 2) serum concentration of cortisol at Days 0, 10, 14, 15, and 16 postservice in the previous treatments (n = 9, 7, 6, and 8, respectively); and 3) concentrations of cortisol after 0.1 mg of adrenocorticotropin in these last four groups of cows at Day 14 postinsemination. Breeding during the DS decreased (P < 0.05) conception rate to first service and increased (P < 0.01) days in service. In addition, the DS decreased (P < 0.05) the percentages of cows with normal interestrous interval (20-22 d), expression of estrus, and (P < 0.01) luteal phase progesterone; but DS increased (P < 0.05) percentages of short and long estrous cycles, anovulatory estrus, and repeat breeding rate. Mean serum concentration of progesterone was lower (P < 0.05) at Days 10, 14, and 15 in DS nonpregnant than in DS pregnant cows, and lower during luteal phase (P < 0.05) in DS nonpregnant than RS nonpregnant cows. Serum cortisol concentration was greater (P < 0.05) at Days 10, 14, and 16 in DS nonpregnant than DS pregnant cows. A significant (P < 0.05) negative correlation (r = -0.78) between serum concentrations of progesterone and cortisol was found within DS nonpregnant cows. Concentrations of cortisol after adrenocorticotropin were greater (P < 0.05) in DS nonpregnant cows than in other groups. These results indicate that elevated concentrations of cortisol associated with the DS may decrease progesterone secreted by the corpus luteum and therefore mediate the negative effect of the DS on fertility.

Adrenal Cortex↗
PubMed2005

Genetic variation of 15 STR autosomal loci in the Maracaibo population from Venezuela.

Allele frequencies for 15 short tandem repeats (STRs) autosomal loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA, included in the AmpFLSTR Identifiler, Applied Biosystems) were studied in the city of Maracaibo, Venezuela and were compared with other published Latin-American populations for the same loci. Population and forensic parameters were estimated.

DNA Fingerprinting↗
PubMed2004

The analysis of near full-length genome sequences of human immunodeficiency virus type 1 BF intersubtype recombinant viruses from Chile, Venezuela and Spain reveals their relationship to diverse lineages of recombinant viruses related to CRF12_BF.

Human immunodeficiency virus type 1 (HIV-1) BF intersubtype recombinant viruses are common in Argentina and Uruguay, where CRF12_BF and related recombinants are frequently found, and, in a lower proportion, in Brazil. Full-length genome sequences have been characterized in several of these recombinant viruses. Here, we analyze six newly derived near full-length genome sequences of BF recombinant viruses, three from Chile, one from Venezuela and two from Spain. Five of them had known epidemiological links to Argentina. Genomes were amplified by PCR from plasma RNA or from peripheral blood mononuclear cells' DNA. Mosaic structures and phylogenetic relationships were analyzed by bootscanning, neighbour-joining phylogenetic trees and by examination of subtype signature nucleotides. One virus from Spain had a mosaic structure fully coincident with CRF12_BF. The others had unique mosaic structures, except the viruses from two Chilean sisters infected vertically from the same mother, who showed identical recombination patterns. Each of the unique recombinants had one to six breakpoints coincident with CRF12_BF and three also had two or three breakpoints coincident with a previously characterized unique recombinant from Argentina (A025) related to CRF12_BF. A phylogenetic tree of concatenated subtype F segments supported the relationship of five recombinants with CRF12_BF. In trees of partial subtype F and B segments, four recombinants clustered with A025. The examination of CRF12_BF signature amino acids and nucleotides supported the common ancestry of all the analyzed viruses. Based on these results, a model of generation of HIV-1 BF recombinants of Argentinean ancestry by successive rounds of recombination along diverse lineages deriving from a common BF recombinant ancestor related to CRF12_BF is proposed.

Argentina↗
PubMed2005

Detection of dengue viruses in field-caught Aedes aegypti (Diptera: Culicidae) in Maracay, Aragua state, Venezuela by type-specific polymerase chain reaction.

Virological surveillance of dengue viruses in Aedes aegypti populations constitutes a powerful tool for early prediction of dengue outbreaks. We have standardized a protocol for viral RNA extraction from individual and pools of mosquitoes that permits a sensitive detection of dengue virus without RNA degradation or PCR inhibition when we apply a semi-nested RT-PCR. The limit of detection for each dengue serotype was 0.1 PFU. In a prospective field study conducted from November 2000 to December 2001, adult female A. aegypti mosquitoes from several municipalities with high dengue transmission in Maracay, Aragua State, Venezuela were collected and screened for dengue viruses using RT-PCR. We analyzed a total of 296 A. aegypti pools (1,632 mosquitoes); of these, 154 pools (469 mosquitoes) were collected from houses with persons with clinical diagnosis of dengue (dengue houses), and 142 pools (1,163 mosquitoes) from adjacent residences (neighbour houses). From the dengue houses, eight mosquito pools (5.2%) were positive for DENV-1 (0.7%), DENV-3 (3.2%) and DENV-4 (1.3%) viruses. From the neighbour houses, 18 mosquito pools (12.7%) were positive for DENV-3 (12%) and DENV-4 (0.7%) viruses. From these 26 RT-PCR positive mosquito pools (containing 1-25 mosquitoes each), 22 pools (84.6%) were positive for DENV-3. The most prevalent serotype in the 2001 dengue outbreak was also DENV-3. The minimum infection rate in both A. aegypti collections, from dengue houses and neighbour houses was 17 and 15 per 1,000, respectively. The relevance of these results for dengue surveillance is discussed.

Aedes↗
PubMed2006

Two new Fusicoccum species from Acacia and Eucalyptus in Venezuela, based on morphology and DNA sequence data.

Botryosphaeria spp. are common endophytes of woody plants, and they also include some serious pathogens of Eucalyptus and Acacia species. Numerous anamorphs have been associated with Botryosphaeria, of which the species Fusicoccum are amongst the most common. Here, we characterize two new Fusicoccum species, isolated from Eucalyptus and Acacia trees in Venezuela, based on morphological features in culture and comparisons of DNA sequence data. The two taxa named Fusicoccum andinum and F. stromaticum spp. nov, reside in two well-supported clades (BS values = 100%) based on a combined data set of the ITS of the rDNA operon and translation elongation factor 1-alpha (EF1- alpha) gene sequences. The conidia of F. andinum are unusually large amongst Botryosphaeria anamorphs, and peripherally resemble those of B. mamane and B. melanops. F. stromaticum is characterized by large conidiomata in cultures, growth at 35 degrees C and slightly thickened conidial walls, which is different to most other Fusicoccum spp. No teleomorphs were observed for these fungi, but DNA sequence data show that they are anamorphs of Botryosphaeria.

Acacia↗
PubMed2006

Serological evidence of Neospora caninum in dual-purpose cattle herds in Venezuela.

Bovine neosporosis is a parasitic disease produced by Neospora caninum that induces abortion in cows, and consequently has a negative impact on the herd's reproductive efficiency. The main objective of this research was to determine the serological evidence of N. caninum in cattle herds from Venezuela using an indirect antibody capture ELISA test. Four hundred and fifty-nine (459) serum samples from crossbred adult cows were collected to be tested for Neospora antibodies. The sampled cows came from 15 large farms located in eight important cattle states that have predominant dual-purpose production systems (cattle from these farms are used for both milk and meat production). Fifty-two cows (11.3%) were seropositive to N. Caninum. Thirteen (86.7%) of 15 studied herds had cows seropositive to N. caninum. The average within-herd seroprevalence was 11.5% (range 3.8-36.7%). Cows that aborted in some of these farms had 2.71 (P: 0.009) greater odds to be seropositive when compared to cows that did not abort. Each one of the eight states represented in our study had seropositive animals. These results are the first evidence of exposure to N. caninum in Venezuelan cattle herds, indicating the possible circulation of this pathogen in the country. Further epidemiological studies should be granted to determine the spread of the disease in the Venezuelan cattle industry and its associated risk factors.

Abortion, Veterinary↗
PubMed2004

Maporal virus, a hantavirus associated with the fulvous pygmy rice rat (Oligoryzomys fulvescens) in western Venezuela.

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 genetic diversity of the hantaviruses associated with oryzomine rodents in South America. An infectious hantavirus was isolated from two fulvous pygmy rice rats captured in western Venezuela. Analyses of complete nucleocapsid protein and glycoprotein precursor sequences indicated that the isolates are strains of a novel hantavirus (proposed name "Maporal") which is phylogenetically most closely related to the viruses known to cause hantavirus pulmonary syndrome in southern South America.

Animals↗
PubMed2003

Pyrethroid-impregnated curtains for Chagas' disease control in Venezuela.

The use of insecticide treated materials for the control of Chagas' disease transmission is potentially a cost-effective and sustainable option where vectors are sylvatic. A study was undertaken in two rural Chagas' disease endemic communities (96 households) of Trujillo State, Venezuela. After a baseline study (including a short questionnaire survey, assessment of housing conditions, vector behaviour and preferences in vector protection), 37 households were chosen at random for protection by impregnated or non-impregnated curtains. During the 30-day entomological study vector collection of triatomine bugs were conducted in the early morning. The protective efficacy of curtains was determined by the number of vectors found dead or alive in control and experimental houses. It was found that house infestation of Chagas' disease vectors was high (60% of houses) in spite of good-quality houses due to a re-housing programme. The vectors were sylvatic (mainly Rhodnius robustus) and entered the houses at night. More than half the population (52%) preferred curtains to bednets for Chagas' disease protection. Users of pyrethroid-impregnated curtains were well protected as no living triatomines were found in bedrooms of houses with impregnated curtains compared to houses with non-impregnated curtains where an average of 4/7 vectors were found alive in bedrooms. In houses with impregnated curtains 21/30 triatomines died within 72 h; the triatomines which survived were found exclusively in rooms where no impregnated curtains had been placed. In houses with non-impregnated curtains 20% (6/30) of vectors died, probably due to rough handling. It is concluded that pyrethroid-impregnated curtains represent an important option for the reduction or even elimination of man-vector contact and thus of Chagas' disease transmission in areas where species of small triatomine bugs such as Rhodnius prolixus and R. robustus are the main vectors.

Adult↗
PubMedDate not supplied

Canine visceral leishmaniasis on Margarita Island (Nueva Esparta, Venezuela).

The frequency of American visceral leishmaniasis affecting humans on Margarita Island, Venezuela, has increased in recent years, and infected dogs appear to constitute the principal source of infection. ELISA tests with Leishmania donovani promastigotes and rK39 antigen from L. chagasi in serum from 541 dogs were positive in 33.1% and 21.6% of the samples, respectively. A second blood sample taken from 50 animals after 8-10 months revealed an increase from 24% to 40% of ELISA positivity to both antigens, suggesting high susceptibility and transmission in the canine population. Among 42 serologically positive dogs, 33% of which showed clinical signs of disease, 79% were positive in polymerase chain reactions using primers specific for the L. donovani complex. Control measures including epidemiological hypersurveillance, the humane sacrifice of infected dogs, and rapid diagnosis and treatment of human cases have been initiated.

Animals↗
PubMed2002

Molecular epidemiology of cutaneous leishmaniasis in Venezuela.

This paper discusses the utility of a set of primers (3J1, 3J2) designed from a repetitive nuclear deoxyribonucleic acid sequence for the diagnosis of Leishmania braziliensis infection in samples obtained from humans, insect vectors and mammalian reservoir hosts from different endemic areas in Venezuela. A high incidence of Leishmania (Viannia) braziliensis infection was found in the endemic areas studied. The sensitivity and specificity of the primers used were adequate for the identification of the natural vectors and reservoir hosts of L. (V.) braziliensis. The polymerase chain reaction was more sensitive than culture and stained smear examination in the diagnosis of cutaneous leishmaniasis, detecting 80% of cases compared to 42% and 72%, respectively.

Animals↗
PubMedDate not supplied

Sandfly fauna of endemic leishmaniasis foci in Anzoátegui State, Venezuela.

A census of the sandfly fauna was undertaken in 1993-98 in 5 endemic leishmaniasis foci situated at different altitudes in Anzoátegui State, Venezuela. From the 17 species of Lutzomyia identified, we believe that Lu. ovallesi, Lu. panamensis and Lu. gomezi are the probable vectors of cutaneous leishmaniasis, while Lu. evansi might transmit visceral leishmaniasis.

Animals↗