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G Hendrickx

Publications and source records attributed to G Hendrickx.

18 recordsLinked to original sources
PubMed2001

Spatial trypanosomosis management: from data-layers to decision making.

The use of geographical information systems (GIS) in the management of African animal trypanosomosis in sub-Saharan Africa offers potential in assisting decisions on allocation of resources, prioritization of control areas, and planning and management of field operations. Here, Guy Hendrickx and colleagues review approaches being used to develop reliable data-layers and to incorporate these data into GIS models. They argue that techniques should be further refined to produce more-detailed data layers and to include a dynamic element, a problem rarely addressed until now.

Africa South of the Sahara↗
PubMed2000

The spatial pattern of trypanosomosis prevalence predicted with the aid of satellite imagery.

Information on the spatial pattern of African animal trypanosomosis forms a prerequisite for rational disease management, but few data exist for any country in the continent. The present study describes a raster or grid-based Geographic Information System for Togo, a country representative of subhumid West Africa, with data layers on tsetse, trypanosomosis, animal production, agriculture and land use. The paper shows how trypanosomosis prevalence and packed cell volume (PCV) map displays may be predicted from correlations between representative field data and environmental and satellite data acquired from the National Oceanographic and Atmospheric Administration (NOAA) and Meteosat platforms. Discriminant analytical methods were used to assess the relationship between the amount of field data used and the accuracy of the predictions obtained. The accuracy of satellite derived predictions decreases from tsetse abundance to trypanosomosis prevalence to PCV value. The predictions improve when eco-climatic and epidemiological predictors are combined. In Togo, and probably elsewhere, the patterns of trypanosomosis prevalence and PCV are much influenced by animal husbandry and other anthropogenic factors. Additional predictor variables, incorporating these influences might therefore further improve the models.

Altitude↗
PubMed1999

The area-wide epidemiology of bovine trypanosomosis and its impact on mixed farming in subhumid West Africa; a case study in Togo.

This paper reports on an area wide study of all major variables determining the expression of trypanosomosis in cattle in the subhumid eco-zone of West Africa, taking Togo as an example. To enable systematic area-wide sampling, the country was divided in 311 grid-squares of 0.125 x 0.125 sides. Cross-sectional surveys were then conducted to generate maps or digital layers on cattle density, herd structure, ownership and breed. These data layers, except for the breed data, were subjected to a cluster analysis in order to define spatial patterns in animal husbandry systems. This analysis revealed two main systems: one is oriented towards integration with crop-agriculture and a second towards investment in cattle. These two systems could be further characterised by incorporating breed data. Zebu cattle and their crossbreeds are more favoured in the second system. The breed distribution map shows the actual situation but also serves to predict the outcome of progressive crossbreeding. An area wide trypanosomosis survey allowed the production of prevalence maps for Trypanosoma congolense, T. vivax and the associated packed cell volume (PCV) values. A simple curvi-linear relationship was established between vector density and disease prevalence. The regression between disease prevalence and PCV for taurine and zebu plus crossbreeds separately, revealed that taurine cattle maintain a comparatively high PCV level particularly in high prevalence scenarios. The relationship between the average herd PCV and cattle density suggests that herd PCV value may provide a mirror for the number of animals not kept because of the prevailing risk. The regression between agricultural intensity and cattle density subsequently in areas with decreasing herd PCV values reveals that the level of integration of cattle in crop production decreases with a decreasing PCV. Thus, despite the presence of taurine animals in Togo, the omnipresence of tsetse in particular Glossina tachinoides, remains a major obstacle to cattle raising and indirectly mixed farming development and intensification. It is argued that only with the present type of wide scale, spatial studies it becomes possible to clarify all the major variables influencing the expression of trypanosomosis. Spatial epidemiological studies at a macro level may form the basis for area wide trypanosomosis control in West Africa.

Agriculture↗
PubMed1998

Assessment of a new immunoassay for serological confirmation and discrimination of human T-cell lymphotropic virus infections.

The present study evaluated a new confirmatory assay for antibodies to human T-cell lymphotropic virus type 1 and 2 (HTLV-1 and HTLV-2) proteins performed with serum samples from various commercial sources. The new test is a line immunoassay (LIA) with a nylon membrane sensitized with the most relevant antigens of HTLVs: the envelope gp46 and gp21 as well as the gag p24 and p19 antigens, represented by either recombinant proteins or synthetic peptides. A total of 176 serum or plasma samples were tested, of which 66 were HTLV-1 positive, 72 were HTLV-2 positive, and 38 were HTLV negative; of the 38 HTLV-negative samples 23 were indeterminate by Western blotting (WB). Serially diluted samples (n = 33) from HTLV-1- and HTLV-2-infected patients were also analyzed to determine the sensitivity of the new assay. The new confirmatory assay (INNO-LIA HTLV) performed markedly better than WB assays for those samples reactive by screening. Accurate confirmation of the presence of HTLV-1 and HTLV-2 antibodies and accurate discrimination of HTLV-1 and HTLV-2 antibodies were obtained for all the HTLV-seropositive samples. Due to its enhanced specificity and sensitivity, the new assay not only improves the ability to confirm and discriminate HTLV infections but also eliminates the vast majority of WB-indeterminate and false-positive specimens.

Blotting, Western↗
PubMed1998

The macrocephaly-cutis marmorata telangiectatica congenita syndrome. Long-term follow-up data in 4 children and adolescents.

We present the clinical history and findings in 4 children and adolescents with the association of macrocephaly and cutis marmorata telangiectatica congenita (Macrocephaly-CMTC syndrome). This syndrome has recently been delineated within the general group of patients with manifestations of cutis marmorata telangiectatica-Klippel-Trenaunay-Weber syndrome as a clinically recognisable entity.

Adolescent↗
PubMed1996

Malformative syndrome with trigonocephaly, shallow orbits, ptosis, growth and mental retardation. De novo autosomal reciprocal t(9;13)(Q32;Q22) in a male patient.

We report a de novo autosomal reciprocal translocation t(9;13)(q32;q22) in a mildly to moderately mentally retarded boy. Clinically he presented the typical signs and symptoms of a recently delineated malformative syndrome characterized by trigonocephaly, shallow orbits, ptosis, mental and growth retardation.

Abnormalities, Multiple↗
PubMed1994

Tsetse flies and their control.

The authors use a quantitative modelling framework to describe and explore the features of the biology of tsetse flies (Glossina spp.) which are important in determining the rate of transmission of the African trypanosomiases between hosts. Examples are presented of the contribution of previous research on tsetse to quantified epidemiological and epizootiological understanding, and areas of current ignorance are identified for future study. Spatial and temporal variations in risk are important (but rarely-studied) determinants of the impact of trypanosomiasis on humans, domestic animals and agricultural activities. Recent grid-based sampling surveys to Togo provide valuable data sets on tsetse, cattle and trypanosomiasis throughout the country. A combination of ground-based meterological and remotely-sensed satellite data, within linear discriminant analytical models, enables description of the observed distributions of the five species of tsetse occurring in Togo, with accuracies of between 72% (Glossina palpalis and G. tachinoides) and 98% (G. fusca). Abundance classes of the two most widespread species, G. palpalis and G. tachinoides, are described with accuracies of between 47% and 83%. This is especially remarkable given the relatively small differences between the average values of the predictor variables in areas of differing fly abundance. Similar analyses could be used to predict the occurrence and abundance of flies in other areas, which have not been surveyed to date, in order to plan tsetse control campaigns or explore development options. Finally, some recent tsetse control campaigns are briefly reviewed. The shift of emphasis from fly eradication to fly control is associated with a devolution of responsibility for control activities from central government to local areas, communities or even individuals. The future role of central governments will remain crucial, however, in determining the areas in which different control options are practised, in facilitating control by local communities and in protecting controlled areas from re-invasion by flies from other areas.

Animals↗
PubMed1992

[Sclerectasia in a pig farm in Sotouboua, Togo].

Cases of sclerectasia were described in a pig farm, Sotouboua, Togo. The causative agent may be a pestivirus, on top of a predisposition revealed by consanguinity. Livestock owners should be kept aware.

Animals↗
PubMedDate not supplied

Hypochondrogenesis; an additional case.

In a case of hypochondrogenesis, abnormal fat deposits were found in the chondrocytes, by anatomopathological and by ultrastructural examination. In the cultured fibroblast we were unable to demonstrate abnormal lipid loading. Our case could be isolated from other types of lethal congenital chondrodysplasias--especially the lethal type of spondyloepiphyseal dysplasia congenita--by microscopic and ultrastructural investigations.

Achondroplasia↗
PubMedDate not supplied

Endoscopic balloon dilation of colonic and ileo-colonic Crohn's strictures: long-term results.

The long-term effects of endoscopic dilation of colonic or ileo-colonic Crohn's disease strictures were analyzed. In 18 patients with a Crohn's disease-related low gastrointestinal stricture, the stenosis was dilated using through-the-scope (TTS) balloon catheters. A dilation to a diameter of 18 mm was always attempted. Treatment was successfully carried out in 16 patients, and was followed by immediate symptomatic relief in 14 patients. Long-term success was observed in nine patients. There were no complications. Balloon catheter dilation of a colonic stricture or stricture of an ileo-colonic anastomosis was found to be safe and effective. This treatment modality can be an alternative to surgery in a selected group of patients.

Adult↗
PubMedDate not supplied

Can remotely sensed meteorological data significantly contribute to reduce costs of tsetse surveys?

A 0.125 degree raster or grid-based Geographic Information System with data on tsetse, trypanosomiasis animal production, agriculturerkina> and land use has recently been developed in Togo. This paper addresses the problem of generating tsetse distribution and abundance maps from remotely sensed data, using a restricted amount of field data. A discriminant analysis model is tested using contemporary tsetse data and remotely sensed, low resolution data acquired from the National Oceanographic and Atmospheric Administration and Meteosat platforms. A split sample technique is adopted where a randomly selected part of the field measured data (training set) serves to predict the other part (predicted set). The obtained results are then compared with field measured data per corresponding grid-square. Depending on the size of the training set the percentage of concording predictions varies from 80 to 95 for distribution figures and from 63 to 74 for abundance. These results confirm the potential of satellite data application and multivariate analysis for the prediction, not only of the tsetse distribution, but more importantly of their abundance. This opens up new avenues because satellite predictions and field data may be combined to strengthen or substitute one another and thus reduce costs of field surveys.

Africa, Western↗