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C Botto

Publications and source records attributed to C Botto.

At least 19 recordsLinked to original sources
PubMed2006

Should we consider gestational diabetes a vascular risk factor?

Few and contrasting data have reported vascular endothelial dysfunction and increased serum levels of endothelial dysfunction and inflammatory markers in women with previous gestational diabetes mellitus (pGDM). We aimed at evaluating 6.5 years after delivery: intimal medial thickness (IMT), and C-reactive protein (CRP), interleukin-6 (IL-6), E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) levels in 82 non-pregnant pGDM and 113 control women without pGDM. A subgroup of 21 women, taken from the pGDM group, showing current normal BMI, and no metabolic abnormalities, was separately analysed. All the subjects were free of medication and non-smokers. Women with pGDM, independently by their current BMI and presence of metabolic abnormalities, showed significantly higher E-selectin, ICAM-1 and IMT values than controls. IMT proved to be significantly associated with pGDM in a regression model, after adjustments for BMI, waist circumference, blood pressure, and glucose values (beta=0.046; 95% CI 0.028-0.064). In all pGDM women, E-selectin, ICAM-1, IL-6 and hs-CRP values were significantly associated with IMT in the same model. Post-GDM women, despite being currently free from metabolic abnormalities, showed higher values of markers of endothelial dysfunction and IMT than controls, consistent with an increased future cardiovascular risk.

Adult↗
PubMed2005

Geographical patterns of onchocerciasis in southern Venezuela: relationships between environment and infection prevalence.

Onchocerciasis is a chronic filarial infection transmitted by Simulium flies that has a focal geographical distribution in Latin America. The southern Venezuelan focus has a gradient of endemicity that includes the largest number of hyperendemic communities in the continent, many of them in remote forest and mountainous areas, where it is an important public health problem among the Yanomami indigenous population. The recent introduction of Geographical Information Systems (GIS) tools and a landscape epidemiology approach for study of vector borne diseases is helping to understand relationships between environment and transmission dynamics of onchocerciasis. Striking differences in the transmission dynamics of onchocerciasis between different river courses were detected. A significant relationship between onchocerciasis and temperature was also demonstrated. The geologic substrate, kind of landscape and vegetation seemed also to influence the transmission of onchocerciasis. In the Venezuelan Amazon, different kinds of landscapes associated with distinctive vector species, show different intensities of transmission of onchocerciasis. In this sense, landscape analysis aided by GIS, may prove to be a useful tool for better identification of the spatial distribution of onchocerciasis risk in the Orinoco basin.

Altitude↗
PubMed2001

Human onchocerciasis in the Amazonian area of southern Venezuela: spatial and temporal variations in biting and parity rates of black fly (Diptera: Simuliidae) vectors.

We investigated some entomological factors underlying altitudinal prevalence variation in the Venezuelan Amazonia human onchocerciasis focus. Spatial and temporal variation in relative abundance, daily biting rate, proportion of parous flies, and monthly parous biting rate were studied for the three main simuliid vectors (based on their vectorial competence: Simulium oyapockense s.l. Floch & Abonnenc approximately = S. incrustatum Lutz << S. guianense s.l. Wise). Yanomami villages were selected among sentinel communities of the ivermectin control program, representing hypo- to hyperendemicity conditions of infection. Spatial variation was explored via increasing village altitude on two river systems (A: Ocamo-Putaco and B: Orinoco-Orinoquito). Temporal variation was studied between 1995 and 1999 by sampling the biting population during dry and rainy mouths. Environmental variables included monthly rainfall and maximum river height. Simuliid species composition itself varied along the altitudinal and prevalence gradient. S. oyapockense s.l. prevailed below 150 m. Above this altitude and up to 240 m, S. incrustatum and S. guianense s.l. became more frequently and evenly collected along A but not along B, where S. incrustatum remained absent. The daily biting rate of S. oyapockense s.l. was higher during the dry season along A, whereas the converse took place along B. Daily biting rate of S. incrustatum was lowest during early rains. By contrast, the daily biting rate of S. guianense s.l. was highest during this period. There was a significant negative cross-correlation between proportion of parous of S. oyapockense s.l. and river height (2 and 3 mo lagged), whereas this variable (1 and 2 mo lagged) was positively correlated with the proportion of parous flies for S. incrustatum. Monthly parous biting rate values suggest that the months contributing most to onchocerciasis transmission in the area are likely to be the dry season and the transition periods between seasons.

Animals↗
PubMed2000

Parasitological indicators of onchocerciasis relevant to ivermectin control programmes in the Amazonian focus of Southern Venezuela.

In the previous paper it was concluded that those aged > or = 15 years of both sexes could comprise the indicator group for rapid epidemiological assessment (REA) of onchocerciasis in the Amazonian focus. This paper explores relationships between community microfilarial (mf) prevalence, intensity, and nodule prevalence in 20 Yanomami communities, that would allow identification of REA methods in the region. The mean nodule ratio (prevalence of nodules/prevalence of mf) was 0.54 when onchocercomata in the indicator group were considered. The Spearman correlation coefficient between mf and nodule prevalence was 0.686 (P = 0.001). Palpation of nodules had 92 % specificity and 32 % sensitivity when compared to skin-snipping for the diagnosis of onchocerciasis. The predictive value positive increased from 75 % to 81 % when the indicator group was used. A microfilarial prevalence > 75 % in this group would be indicative of hyperendemic status in the village, between 30 and 75 % of mesoendemicity, and < 30 % of hypoendemicity. For the assessment of infection intensity, biopsies may be taken from the iliac crest for all endemicity levels. Five of the hyperendemic villages surveyed in this work had a community microfilarial load (CMFL) greater than 10 mf/skin snip; the remaining 5 had a CMFL between 5 and 9. These levels of infection merit high priority ivermectin treatment. In Latin America, communities at both moderate and severe risk are included in mass chemotherapy programmes (i.e. when mf prevalence is over 20 %). Roughly, a nodule prevalence in the indicator group > 10 % would suggest a community mf prevalence > 20 % with a sensitivity of 85 % and a specificity of 71 %. A multiple linear regression model of the arc-sine transformed mf prevalence in the village (all ages) on nodule prevalence in those aged > or = 15 years and altitude of the village explained 72 % of the variance. The model combining nodule and altitudinal information had a sensitivity of 92 % and a specificity of 71 % in comparison to an estimated mf prevalence of 21 % or more. It is suggested that the usefulness of the REA methods proposed be assessed in other areas of the Amazonian onchocerciasis focus.

Adolescent↗
PubMed2000

Amazonian onchocerciasis: parasitological profiles by host-age, sex, and endemicity in southern Venezuela.

This paper describes, for the human onchocerciasis focus of southern Venezuela, the age profiles of Onchocerca volvulus microfilarial (mf) and nodule prevalence, mf intensity, and mf aggregation for the whole examined population (836 Yanomami people) living in 20 villages, and for these communities classified according to endemicity levels (hypoendemic: < or = 20 %; mesoendemic: 21-59 %; hyperendemic: < or = 60 % infected). Mf prevalence and intensity increased with age, particularly in the hyperendemic areas, and there were no marked differences between the sexes. The prevalence of nodules followed the same age pattern. Fifty percent mf prevalence was reached in the 15-19 year age-class when the population was taken as a whole; nearly in the 10 to 14-year-olds for the hyperendemic level, in those aged 20-29 years in mesoendemic areas, and not reached at all in hypoendemic villages. The degree of mf aggregation was measured by the k value of the negative binomial distribution and by the variance to mean ratio (VMR). The relationship between the standard deviation (S.D.) of mf counts and the mean mf density was also explored. These 3 indices (k, VMR, and S.D.) showed a tendency to increase with both mean mf load and host age. Since infection intensity and host age were themselves positively related, it was not possible to draw definite conclusions about age-specific changes of parasite aggregation. There was not a significant decrease of mf intensity after an earlier peak neither was there a shift towards younger ages of the maximum no. of mf/mg reached as the endemicity level increased. These results are discussed in relation to detection of density dependence in the human host, selection of an indicator age-group for rapid epidemiological assessment (REA) methods, and strategies of ivermectin distribution in the Amazonian focus. It is recommended that, for the Amazonian onchocerciasis focus, the indicator group for REA consists of all those aged 15 years and over.

Adolescent↗
PubMed1998

Relationship between helminthic infection and IgE response in atopic and nonatopic children in a tropical environment.

BACKGROUND: Although IgE antibody is clearly involved in allergic reactions to environmental allergens, this immunoglobulin is an important component of host-protective immune responses against the helminthic parasites that are endemic in the majority of the world population. However, these infections not only stimulate the production of antiparasite IgE antibody but can nonspecifically induce polyclonal IgE synthesis that results in highly elevated total serum IgE levels. Such polyclonal stimulation can diminish specific IgE antibody responses and cause saturation of mast cell Fc epsilon receptors, thus inhibiting allergic reactivity. This may represent a mechanism of immune evasion by the parasite. OBJECTIVE: Because an atopic disposition is generally recognized to be associated with elevated IgE synthesis against environmental allergens, the aim of this study was to evaluate the influence of atopy on the antiparasite response. To this end, we examined two groups of Venezuelan children in whom the intestinal helminth Ascaris lumbricoides is endemic but that differ greatly in their level of atopy. One group was from an island population (Coche Island) that has a very strong atopic background and in which the prevalence of allergic disease is extremely high. The other was a group of nonatopic children belonging to a mainland population (Barrio Los Erasos) that is of comparable socioeconomic level and has an exposure to helminthic infection similar to that of the island group but a relatively low expression of allergic diseases. RESULTS: Although the living conditions and the prevalence of Ascaris infection of the two groups were comparable, the intensity of the parasitic infection was considerably higher in the nonatopic mainland children (geometric mean values of eggs per gram of feces: Barrio Los Erasos, 7621; Coche Island, 1435; p < 0.001). In addition, their total serum IgE levels were significantly more elevated than in the atopic island group (geometric mean: Barrio Los Erasos, 2172; Coche Island, 941 IU/ml; p < 0.001). In contrast, the specific anti-Ascaris response was much stronger in the atopic children (geometric mean: Barrio Los Erasos, 0.30; Coche Island, 0.91 PRU/ml; p < 0.001), which resulted in the ratio of specific to total IgE being nine times higher than in the nonatopic mainland subjects. These differences were maintained even when the children were matched on the basis of infection intensity, thus indicating that the atopic children have an intrinsic propensity to favor specific over polyclonal IgE responses to the parasite. CONCLUSIONS: The children with a strong atopic background demonstrated IgE responses concordant with an enhanced protective response against helminthic parasites and had significantly lower intensities of infection than their nonatopic counterparts. These observations support the concept that the atopic state has conferred a selective evolutionary advantage that could compensate for its involvement in allergic disease.

Animals↗
PubMed1997

[Tuberculous meningoencephalitis].

Tuberculosis (TBC) in children is still a public health problem in developing countries. Its most serious complication in children is meningo-encephalitis (ME TBC), which is one of the main causes of death from TBC. The objective of this review is to outline its aetiopathological, clinical and prognostic characteristics and compare these with three studies made in our University between 1984 and the present time. METBC is always a complication secondary to an unknown (but often pulmonary) focus. The morbid anatomy of the deposit of basal exudate explains all the subsequent clinical findings. The data given in the literature regarding the commonest presentation, that of subacute or chronic meningo-encephalitis, is similar to our findings. However there are some differences. These are: a tendency to presentation in older children, much lower mortality, a long-term incidence of sequelae of less than 50% which is much less than would be expected (especially in certain areas of superior nerve function). With regard to treatment, we emphasize that the standard recommendation is still to use four drugs for twelve mouths. Although steroids have not been shown to be of use with regard to either mortality or morbidity, they continue to be given.

Acute Disease↗
PubMed1994

Vector competence of Simulium metallicum s.l. (Diptera: Simuliidae) in two endemic areas of human onchocerciasis in northern Venezuela.

Experimental infections of Simulium metallicum s.l. with Onchocerca volvulus were carried out in two onchocerciasis foci, Altamira and Trincheras, in northern Venezuela, to determine vector competence. Wild-caught flies, fed on infected volunteers, were maintained in the laboratory for 13-15 days at 27 degrees C. Parasite development was complete but asynchronous and retarded. No differences in the vector competence of the two populations of S. metallicum s.l. were found. However, a less efficient development of the parasite occurred during the dry season at both localities. The distribution of the parasite within the vector was aggregated and also displayed seasonal variation. The seasonal susceptibility may be a consequence of a density-dependence regulation mechanism of the parasite within the vector. These results indicate a relatively low vector competence for S. metallicum s.l. in northern Venezuela.

Animals↗
PubMed1993

First description of endemic HTLV-II infection among Venezuelan Amerindians.

We describe for the first time the presence of human T lymphotropic virus type II (HTLV-II) infection in Venezuela, among the Pume Amerindians living in the southern plains of the country. Antibodies to HTLV-II antigens were assessed by enzyme immunoassays (Elisa), Western blot, radioimmuno-precipitation, and immunofluorescence; titration studies against HTLV-I- and HTLV-II-infected cell lines were very useful in the differentiation of HTLV-I and HTLV-II antibodies. The HTLV-II general prevalence was 5%; however, there is a striking difference in prevalence between the truly isolated villages (0%) when compared to those living along the riverside and thus in contact with outsiders (9%). Preliminary evidence suggests sexual contact as the main source of transmission. These findings might suggest that HTLV-II in Venezuela originated through contact with outsiders rather than ancient infection related to the origins of the Pume.

Adolescent↗
PubMed1990

Filariasis focus due to Mansonella ozzardi and Mansonella perstans in the Amazon Federal Territory of Venezuela.

The presence of filariasis was investigated through Knott's method in 40 Curripaco Indians from communities located on the Casiquiare and Guainia Rivers in the Amazon Federal Territory of Venezuela. The results gave an 82.5% prevalence for infections with Mansonella perstans and 30% for infections with M. ozzardi (mixed infections with M. perstans). In almost all the patients the parasite load was greater for M. perstans and varied between 1 and 327 microfilariae per ml. This paper presents for the first time the presence of a transmission focus of M. perstans in the Amazon Federal Territory and confirms the finding of M. ozzardi in the region.

Adolescent↗
PubMed1989

Effect of albendazole in experimental toxocariasis of mice.

Fifty-five mice were each infected with 800 embryonated eggs of Toxocara canis. Beginning on the second day of the infection, one group received a single 9 mg dose of albendazole every 24 hours for an eight-day period while a second group received 3 mg of albendazole every eight hours for the same period. On the tenth day of infection, mice in each treatment group and their corresponding controls were sacrificed, and the presence and motility of T. canis larvae in the brain were determined. With both therapeutical procedures the administration of albendazole reduced the number of larvae which reach the brain. However, for the same total dose, the administration of the drug every eight hours yielded results which were significantly superior to those produced by administering a single dose every 24 hours, reducing both the number of larvae in the brain and their motility.

Albendazole↗
PubMed1988

Morphological differences between Venezuelan and African microfilariae of Onchocerca volvulus.

Comparative morphological and biometric characteristics of microfilariae of Onchocerca gutturosa and O. volvulus from different geographical areas (Upper Orinoco, Venezuela; Togo; Liberia) were assessed. "Stepwise" discriminant analysis and Mahalanobis estimators were applied to measure distance between populations. The results indicate a strong similarity between the two strains from the Upper Orinoco (Venezuela) and the Togo strain, as well as a clear separation between these strains and that of O. gutturosa. The Liberian strain was easily distinguishable from microfilariae from Togo and Venezuela. Discriminant analysis showed the Liberian deme to be as different from the Venezuelan and Togo demes as these demes were from microfilariae of the reference species, O. gutturosa. Although it is necessary to confirm these data using formalin-fixed specimens obtained from the skin, the present findings suggest the existence of geographically-different strains of O. volvulus in America and Africa.

Animals↗
PubMed1988

Hyperreactive malarial splenomegaly in Venezuela.

A cross-sectional seroepidemiological survey seeking hyperreactive malarial splenomegaly was carried out in isolated Yanomami hamlets in Amazonas Territory in Venezuela. All 110 inhabitants greater than 1 year of age were evaluated clinically and 98 were studied immunologically. The spleen index for individuals greater than 10 years of age was 44%. Only 3 patients had Plasmodium spp. on thick blood smears. All had serological evidence of infection with Plasmodium falciparum and P. vivax. Twenty-three patients were considered to show hyperreactive malarial splenomegaly. Clinical manifestations of the syndrome did not differ from those described in other parts of the world.

Adolescent↗
PubMed1985

Experimental and natural infection of Simulium sanchezi by Mansonella ozzardi in the Middle Orinoco region of Venezuela.

Experimental and natural infections of Simulium sanchezi by Mansonella ozzardi were studied in the area of Síquita, Territorio Federal Amazonas, Venezuela. The microfilariae developed synchronously in the blackflies, reaching stage L3 in seven to eight days at temperatures between 23 degrees and 27 degrees C. Larvae in different stages of development, including infective forms, were found in 0.6% of 662 unfed wild-caught females. These results confirm that simuliids are the main vectors of M. ozzardi in the American continent.

Animals↗
PubMed1985

A field study of paragonimiasis in Venezuela.

In a natural focus of paragonimiasis in the northeastern region of Venezuela, 130 people were clinically, parasitologically and immunologically evaluated. A specific intradermal test was positive in 13%. Besides an index case, three other active cases of paragonimiasis were identified. Adult Paragonimus worms and metacercariae were recovered from Didelphis marsupialis and Eudaniela garmani, respectively. Previous reports of Paragonimus infection in Venezuela are discussed.

Adolescent↗
PubMed1985

[Ellis-van Creveld syndrome. Contribution of echography to prenatal diagnosis. Apropos of a case].

The Ellis Van Creveld syndrome gives rise to a dwarf showing chondroectodermal dysplasia. We report a case where the diagnosis was made antenatally by ultrasound. It showed that the length of the femur was shorter than the mean for the gestational age and it also showed six fingers. A review of the literature demonstrates that it is possible to make the diagnosis of skeletal dysplasia prenatally using ultrasound.

Adult↗
PubMed1984

Onchocerciasis in Venezuela: prevalence of microfilaraemia in Amerindians and morphological characteristics of the microfilariae from the Upper Orinoco Focus.

Data are presented on microfilaraemia in 191 Yanomami Amerindians from two areas of Venezuela's Upper Orinoco Basin, where an endemic focus of onchocerciasis has been recently detected. Onchocerca microfilariae were found in the blood of 12.6% of the persons examined. In the village with the higher number of examined individuals (N = 162), the prevalence of microfilaraemia in the age groups covaried with the prevalence of microfilariae in the skin and with the parasite load (mf/mg of skin). A positive correlation was found between age and these three variables. The prevalence of Onchocerca microfilaraemia in the Upper Orinoco focus is high, and may be related to the ability of the strain to invade the blood stream. Morphobiometric characteristics of the Onchocerca microfilariae isolated from human blood are similar to those of O. volvulus fixed in formalin from skin and from the uterus of female O. volvulus worms. All have a very short cephalic space. Comparisons with the entity from the Upper Caura river designated as Microfilaria bolivarensis were also made. It was concluded that there are no valid biometric differences in thick blood smears between microfilaria bolivarensis and microfilaria of O. volvulus from the Upper Orinoco deme. A more striking difference may be in the concentration of microfilariae observed in the blood, which in one case of mf. bolivarensis was more than forty times the highest number recorded for microfilaria O. volvulus in Parima.

Adolescent↗