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PubMedDate not supplied

Evidence for high seroprevalence of Taenia solium cysticercosis in individuals from three rural communities in Venezuela.

A serological study was undertaken in 1998 to evaluate levels of Taenia solium cysticercosis in 3 rural Venezuelan communities. Infection with viable metacestodes was diagnosed with a trapping enzyme-linked immunosorbent assay (ELISA) that detects a secreted product of viable parasites. Anti-metacestode antibodies were assayed by ELISA using T. solium vesicular fluid as antigen. A total of 1254 sera was collected from 3 communities (Canoabo, Sanare, and Rio Tocuyo) where previous studies had suggested the presence of T. solium. Our results demonstrate an unusually high seroprevalence of cysticercosis, indicating an attendant risk of transmitting the disease to other areas. The seroprevalence of infection with viable cysts, as indicated by detection of circulating parasite antigen, was 9.1% in Canoabo, 6.1% in Sanare, and 5.7% in Rio Tocuyo. The corresponding frequency of antibodies to T. solium cyst antigens was 36.5% in Canoabo, 36.5% in Sanare, and 4% in Rio Tocuyo. As these communities are probably representative of many others in Venezuela, T. solium cysticercosis may be a significant public health problem and more work is certainly indicated. An important finding was that local knowledge of the disease and its transmission do not necessarily guarantee diminished disease prevalence, indicating a lack of appropriate vigilance towards disease control.

Adolescent↗
PubMedDate not supplied

Cutaneous leishmaniasis vector control perspectives using lambdacyhalothrin residual house spraying in El Ingenio, Miranda State, Venezuela.

An indoor vector control trial was carried out between December 1996 and February 1997, with the aim of reducing the population densities of Lutzomyia ovallesi, the proven vector of cutaneous leishmaniasis (CL) in El Ingenio, Miranda State, Venezuela. Houses were matched according to their structure ("bahareque" [mud and straw], concrete, and wood) and randomly assigned to a control group (n = 19) or a treated group (n = 20) that was sprayed with 25 mg/m(2) of lambdacyhalothrin. This dose was selected on the basis of a laboratory susceptibility test of Lu. ovallesi to pyrethroids. Sandfly abundance was measured using CDC light traps 7-79 d post-intervention, by which time the sandfly population in control houses had declined to very low levels, at what was the end of the transmission season. Catches of total females, fed females, and males were significantly lower in sprayed than in control houses immediately after treatment. Catches of total females and males in sprayed houses recovered, reaching the level of control houses after 7 and 11 weeks, respectively. Bioassays following WHO protocols using contact cones on a sandfly laboratory colony showed a short residual effect of the insecticide explaining these results. In contrast, there was no tendency for catches of fed females in the sprayed houses to recover during the course of the trial. Previous studies of adult population dynamics showed a short season of high abundance. Combined with these results, we believe that 2 indoor sprayings with lambdacyhalothrin, the first at the beginning of November and the second at the beginning of January, would considerably reduce the Lu. ovallesi population, and control CL transmission in this and other foci where this sandfly is considered to be the main vector.

Adult↗
PubMedDate not supplied

Onchocerciasis hyperendemic in the Unturán mountains: an extension of the endemic region in southern Venezuela.

A new region with human onchocerciasis is reported in the Unturán mountains, South Venezuela, affecting Yanomamö populations not surveyed in previous studies conducted in the Venezuelan-Brazilian border area. Its distribution probably extends towards the Upper Toototobi endemic area in Brazil. The age-standardized prevalence of Onchocerca volvulus microfilariae (mf) (67%), the prevalence of infection in those aged > or = 20 years (86%), and the community microfilarial load (CMFL) (24 mf/mg), are consistent with hyperendemic transmission. Both prevalence and mean intensity increased monotonically with age without reaching a plateau, the highest values being recorded in the > or = 45 years age class (respectively, 95% and 42 [geometric mean of Williams] or 172 [arithmetic mean] mf/mg). The degree of parasite overdispersion (measured by the variance/mean ratio) also increased with host age. The CMFL value, the presence of sclerosing keratitis, hanging groin, and severe skin lesions, indicated that the infection poses an important public health problem in the region.

Adolescent↗
PubMedDate not supplied

Malaria diagnosis by the polymerase chain reaction: a field study in south-eastern Venezuela.

A polymerase chain reaction (PCR) method that amplifies genus- and species-specific sequences present within the small subunit of ribosomal ribonucleic acid (ssRNA) genes of the human malaria parasites was used for the diagnosis of malaria in south-eastern Venezuela. One hundred blood samples were submitted to deoxyribonucleic acid extraction, PCR amplification and electrophoretic analysis of the PCR products, and the results were compared to those of routine microscopical diagnosis. The sensitivity of PCR for detection of Plasmodium vivax and P. falciparum malaria was 99% and 100%, respectively. However, 6 patients (6%) harboured parasites undetected by microscopy. The PCR assay detected a high proportion of mixed infections: 29% (17/59) of the infections microscopically diagnosed as P. vivax were shown to be mixed infections of P. vivax and P. falciparum. Forty per cent (7/17) of the individuals with a missed P. falciparum infection had received chloroquine in the previous 30 d. These results suggest that, in places where transmission of both P. vivax and P. falciparum occurs, PCR detection of malaria parasites can be a very useful complement to microscopical diagnosis in order to ascertain the true incidence of each species and for the follow-up of patients after specific treatment.

Adult↗
PubMedDate not supplied

Seasonal and nocturnal domiciliary human landing/biting behaviour of Lutzomyia (Lutzomyia) evansi and Lutzomyia (Psychodopygus) panamensis (Diptera; Psychodidae) in a periurban area of a city on the Caribbean coast of eastern Venezuela (Barcelona; Anzoátegui State).

In recent years, in addition to American cutaneous leishmaniasis (ACL), a significant number of cases of American visceral leishmaniasis (AVL) have been reported in periurban areas of Barcelona city (Anzoátegui State, Venezuela). We studied the bionomics of Lutzomyia (Lutzomyia) evansi and Lutzomyia (Psychodopygus) panamensis, possible vectors of AVL and ACL, respectively, in El Rincón, a periurban village of that city. To evaluate the seasonal domiciliary landing/biting activity of sandflies on human bait, a house was chosen in El Rincón. Landing catches were carried out between 18:00 and 06:00, once a month for a year. The results show the presence of 2 species, Lu. (Lu.) evansi (89.9%) and Lu. (Psy.) panamensis (10.1%). Lu. evansi was most abundant in the months of October and July, associated with the bimodal cycle of annual rainfall in the area. Maximum landing/biting activity of Lu. evansi was observed at 24:00 and 03:00. These findings suggest that at this time of the year and at these hours there is heightened risk of the transmission of AVL. Lu. panamensis monthly abundance also shows a direct association with rainfall and maximum landing/biting activity was observed between 02:00 and 03:00. The lower domiciliary abundance of Lu. panamensis suggests its greater importance in the extradomiciliary transmission of ACL.

Animals↗
PubMedDate not supplied

Onchocerciasis hyperendemic in the Unturán Mountains: the value of recombinant antigens in describing a new transmission area in southern Venezuela.

A recently described hyperendemic onchocerciasis area, located in the Unturán Mountains (between the Siapa and Orinoco basins) of southern Venezuela was studied using a cocktail of 3 low molecular weight onchocercal recombinant antigens (OvMBP/10, OvMBP/11, and OvMBP/29). The resulting seroepidemiological data were compared with those from a hypoendemic community (Altamira) situated in the northern coastal mountain range. Parasitological (skin biopsy) and serological (enzyme-linked immunosorbent assay, ELISA) methods for the specific diagnosis of Onchocerca volvulus in these 2 very different endemic areas were, respectively, 88% and 96% sensitive in Unturán, and 57% and 91% sensitive in Altamira. The mean microfilarial load, the mean optical density (OD), and the seropositivity rates all increased significantly with age in both communities. The serological variables (mean OD and prevalence of anti-O. volvulus antibodies) were both significantly higher in Unturán than in Altamira for children and young adults (aged < 25 years), although above this age no differences between communities were detected. Seroprevalence had already reached 50% in the under 15 year-olds examined at Unturán but was just 5% at Altamira for the same age-class. The prevalence of specific antibodies (mainly a marker of exposure to risk of infection) exceeded 85% in the remaining age-categories at the hyperendemic area. This is in agreement with the high community microfilarial load recorded in Unturán (> 20 mf/mg) and the presence of sclerosing keratitis and hanging groin, suggesting that onchocerciasis is a public health problem in this community. The ELISA test used here, based on a cocktail of 3 low molecular weight onchocercal recombinant antigens, appears, therefore, to constitute a practical tool for the description of endemicity levels in remote areas, particularly given the fact that finger-prick blood samples are routinely taken from children in the Upper Orinoco region for surveys of malaria incidence. Such studies could aid in defining the true extent of the Amazon focus (still unknown) and providing priority indicators for the selection of communities where onchocerciasis control programmes should be implemented.

Adult↗
PubMed1999

Seroprevalence to bovine virus diarrhoea virus and other viruses of the bovine respiratory complex in Venezuela (Apure State).

Six hundred and fifteen serum samples obtained from cows in five districts of Apure State, Venezuela, were tested by ELISA for antibodies to bovine virus diarrhoea virus (BVDV). The same samples were also ELISA-tested for antibodies to bovine herpesvirus type 1 (BHV-1) and bovine respiratory syncytial virus (BRSV). Additionally, the haemagglutination-inhibition (HI) test was used for detecting antibodies to parainfluenza virus type 3 (PIV-3). Overall, seroprevalence to BVDV was 36+/-7% (SE); seroprevalence varied by district (19-42%). BHV-1 seroprevalence was 67+/-4%; variation by district was similar to that of BVDV. However, the first 80 serum samples tested by BHV-1 ELISA all had a strong background reaction with the control antigen. Therefore, these sera were adsorbed to a homogenate of non-infected bovine kidney cell line (MDBK) and retested by ELISA. The non-specific reactivity was significantly reduced (p<0.001 by Wilcoxon's signed-rank test). Compared to the virus-neutralisation (VN) test, the adsorbed BHV-1 ELISA showed 94% agreement and gave a kappa value of 0.84, indicating that the adsorption did not interfere with test accuracy. Seroprevalence against BRSV was 85+/-3%, and showed differences across districts. Most of the cows (94+/-2%) were seropositive to PIV-3, and there were no significant differences among districts.

Animals↗
PubMed2004

Petro-state constraints on health policy: guidelines for workable reform in Venezuela.

This article reviews the performance of the Venezuelan health care sector and suggests guidelines for workable health policy under difficult conditions. Two special circumstances constrain policy options. First, Venezuelans share a traditional value, solidarity, which includes a strong desire for equity. Reforms must comply with this norm to succeed. Second, foreign sales of state-controlled oil constitute the bulk of the government budget and the gross domestic product (GDP). Petroleum market fluctuations expose the country to extreme economic cycles. In response, policy making and stakeholders adopt a rentier attitude, focusing on preserving or enlarging entitlements to government oil monies. The side effects of this largesse include poor productivity, a weak private sector, a widespread sense of entitlement without accountability, and a crippled state which controls most of the available resources yet is unable to effectively tax, regulate, steer the economy, or pursue long-term policies. The health care sector shares these problems. As a result, Venezuela's health systems are fragmented, poorly coordinated, excessively centralized, inequitable, and ineffective. Policies to improve public health and public and private medical care must take into account these constraints.

Delivery of Health Care↗
PubMed2000

Rhesus rotavirus-based quadrivalent vaccine is efficacious despite age, socioeconomic conditions and seasonality in Venezuela.

This report describes the results of additional analyses of the trial carried out with the rhesus rotavirus-based quadrivalent vaccine in Venezuela. In the present study, we re-examined the data from this previous rotavirus vaccine trial to assess the statistical interaction between vaccine efficacy and (i) the duration of efficacy into the second year of life, (ii) socioeconomic conditions, and (iii) rotavirus seasonality. We found that among Venezuelan children, the rotavirus vaccine confers protection against severe diarrhea during the first 2 years of life independently of socioeconomic conditions and seasonality.

Age Factors↗
PubMed2002

Brucellosis in Venezuela.

Brucellosis is a public health problem in Venezuela and affects large numbers of animals. The most important biovar in the country is Brucella abortus. In cattle and buffalo it causes high rates of abortions in females and infertility in males; it is transmissible to occupationally exposed humans. In 1968, an official program was set up for the control and eradication of the disease and it is still in place. Amongst the control provisions, this program provides for the vaccination of female calves with strain 19 and the slaughtering of positive reactors following the official diagnosis (rapid agglutination in plate test). According to the official reports, the positive reactors ranged from 0.8 to 1.2% in the past few years. These values do not corroborate reports showing an average positive rate of 10.5% and even higher values in some areas of the country. The government is working to approve a new resolution that will replace the rapid agglutination in plate test with the Card Test, the use of 2-Mercaptoetanol, fixation of complement and competitive ELISA as confirmatory tests. In addition, there will be an obligatory vaccination with B. abortus strain 19 or B. abortus RB51 of all female calves between 3- and 8-month-old and a recommended revaccination at 10-15-month-old and adult cows in high prevalence areas. These measures should allow help to reduce the prevalence of the disease in cattle herds and thus minimize the risk for human populations.

Animals↗
PubMed1996

Antiinflammatory activity of some medicinal plant extracts form Venezuela.

Six medicinal plant extracts from Venezuela, used in traditional medicine, were investigated for their anti-inflammatory potential against adjuvant-carrageenan-induced inflammation (ACII). All doses expressed here are equivalents of dried starting plant materials (1.50 g dry plant/kg body wt.). The most interesting plant extracts were Synedrella nodiflora, and the hexane leaf extract of Bursera simaruba. In ACII, orally administered extracts (at doses 40 and 80 mg/kg, respectively), inhibited both the acute and chronic phases of this experimental model of inflammation, mainly the chronic phase. These extracts exhibited potent anti-inflammatory activity daily throughout the experiment, and were as effective as reference drugs, phenylbutazone (80 mg/kg) and indomethacin (3 mg/kg).

Animals↗
PubMed2003

Mite and cockroach sensitization in allergic patients from Caracas, Venezuela.

BACKGROUND: Mites and cockroaches are important allergen sources in most countries, especially in the tropics. They have been incriminated as the cause of the increased prevalence of inhalant allergen sensitization that has occurred in many areas of Latin America. OBJECTIVE: To study the prevalence of sensitization to mites and cockroaches in allergic patients from Caracas, Venezuela. METHODS: Patients who attended the allergy clinics of two medical institutions, one public and the other private, were skin tested with two mite (Dermatophagoides pteronyssinus and Blomia tropicalis) and six cockroach extracts (Periplaneta americana, Periplaneta fuliginosa, Periplaneta australasiae, Blattella germanica, Blattella orientalis, Supella longipalpis) by the skin prick method. The socioeconomic level of the patients was determined by a modification of the Graffar method. RESULTS: Of the 176 patients included in the study, sensitization to D. pteronyssinus was present in 97.2% of the patients and sensitivity to B tropicalis in 91.6%, whereas skin prick test results to at least one cockroach extract were positive in 83.1% of the atopic patients. An increased sensitization rate to cockroach allergens was observed in patients from lower socioeconomic levels and those attending the public institution. CONCLUSIONS: Because of the high sensitization rates observed in this study, we propose that mite and cockroach allergens are important inducers of symptoms in allergic patients in Caracas. People from low socioeconomic levels and those who live with inadequate hygienic conditions show higher degrees of sensitization to cockroach allergen.

Adolescent↗
PubMed2006

[Profile of antifungal susceptibility of species of Candida isolated from hemocultures in a university hospital, Maracaibo, Venezuela].

The aim of this study was to determine the in vitro susceptibility of amphotericin B, fluconazole and itraconazole, to several Candida spp recovered from blood cultures on hospitalized patients at the University Hospital of Maracaibo, Venezuela. The determination of the antifungal susceptibility was carried out according to the microdilution method in broth developed by The European Committee for Antimicrobial Susceptibility Testing (EUCAST). The profile of susceptibility of the 74 isolates showed that all the studied species were susceptible to amphotericin B, and 97.2% and 89.2% to fluconazole and itraconazole, respectively.

Amphotericin B↗
PubMed2002

[Epidemiologic studies of cerebellopontine angle tumors surgically treated in Maracaibo, Venezuela, in 1985-1999].

OBJECTIVE: To analyze the epidemiological, clinical and neuropathological data of cases of cerebellopontine angle (CPA) tumors. MATERIAL AND METHODS: The clinical records, neuroimaging and neuropathological studies of 50 patients with diagnosis of CPA tumor operated in different hospitals of Maracaibo, Venezuela, during the lapse January 1st, 1985-December 31, 1999 were reviewed. The variables age, gender, side of the lesion and neuropathological diagnosis were analyzed. RESULTS: A 2:1 female to male ratio was observed. Median age was 48 +/- 12.7 years. Acoustic neuromas (AN) represented 48% of the cases, whereas nonacoustic neuroma tumors (NANT) made up for the rest (52%). Meningiomas were the second more commonly diagnosed lesions, they constituted 32% of the cases. Meningiomas and AN were more frequent in women, their ratios being 7:1 and 1.6:1, respectively. In 60% of the cases the signs and symptoms became eloquent in patients of the fourth and fifth decades of life. CONCLUSIONS: The difference between our results and the ones previously reported in the medical literature are due in part to the predominance of female patients in our series. Endocrinologic, genetic and biochemical factors could also be responsible; nevertheless, this does not constitute the objective of the present study.

Adult↗
PubMed2003

Genotypically distinct Leishmania colombiensis isolates from Venezuela cause both cutaneous and visceral leishmaniasis in humans.

Cutaneous leishmaniasis in Venezuela has been associated with different Leishmania species and the visceral form is frequently related to L. chagasi. However, in this study we have characterized as L. colombiensis by molecular techniques some isolates of Leishmania from patients presenting either cutaneous or visceral leishmaniasis. Three different molecular markers (two DNA and one protein) were used to investigate the diversity among the L. colombiensis isolates. The analysis revealed the isolates to be similar although distinct from the reference strain of L. colombiensis. Slight variation among the isolates could not be correlated with any epidemiological features of the samples however the visceral isolates were observed to cluster on a phenetic tree derived from one DNA marker. The results confirm previous findings that L. colombiensis can cause both the cutaneous and visceral forms of the disease and that there exists at least two distinct etiological agents of American visceral leishmaniasis (AVL). The report also shows the necessity of careful differentiation of leishmanial isolates in any clinical or epidemiological study of human leishmaniasis.

Animals↗
PubMed1993

Genetic distance estimated through surname frequencies of 37 counties from the state of Lara, Venezuela.

Genetic distances between all possible pairs of counties (n = 37) in the state of Lara, Venezuela were calculated using surname frequencies and the Euclidean distance as estimator. In general, Euclidean distances were smaller between counties closer together, and the product moment correlation between geographic and Euclidean distances was 0.49 (p < 0.02). The results suggest that, in Lara, geographic distance has been an important determinant of genetic structure, although topography and roadways also have had an important influence upon this structure.

Developing Countries↗
PubMed2005

Genetic homogeneity within Leishmania (L.) infantum isolated from human and dogs: the relationship with the sandfly fauna distribution in endemic areas of Nueva Esparta State, Venezuela.

Leishmania infantum has been described as a highly polymorphic group of parasites, responsible for visceral leishmaniasis and cutaneous leishmaniasis. In this paper we report the life-cycle of L. (L.) infantum in an endemic area of visceral leishmaniasis in Venezuela, by using molecular diagnosis and characterization of parasites isolated from dogs, humans with visceral leishmaniasis and sand flies. The molecular characterization was carried out by use of kDNA restriction analysis, dot-blot hybridization with species-specific probes and RFLP of the PCR products. The results demonstrated that L. (L.) infantum is the parasite responsible for VL in the island. The parasites were revealed to be genetically homogeneous with no intra-specific differences between isolates from different individuals. The highest homology of the isolates was with L. (L.) infantum from the Old World rather than with L. (L.) chagasi from the New World. Additionally, we report the geographical distribution of Lutzomyia longipalpis, and the relationship with the transmission of L. (L.) infantum in the studied area.

Animals↗