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Biomedical subjects

G Bellis

Publications and source records attributed to G Bellis.

At least 19 recordsLinked to original sources
PubMed2003

Collection of wind-borne haematophagous insects in the Torres Strait, Australia.

Circumstantial evidence has implicated wind-borne mosquitoes (Diptera: Culicidae) in the introduction of Japanese encephalitis (JE) virus into Australia from the New Guinea mainland. A study was initiated on Saibai Island in the northern Torres Strait, during January and February 2000, to identify the potential source of insects collected in aerial (kytoon) and surface-level traps. Wind speed and direction were recorded to determine wind profiles during insect sampling. Northerly winds capable of carrying insects from New Guinea to Saibai Island were only present on three out of 18 nights sampled. Only three male mosquitoes, comprising two Verrallina funerea (Theobald) and one Ochlerotatus vigilax (Skuse), were collected in aerial samples, and were most likely of local origin. Culicoides midges were also collected in aerial nets and included gravid/parous C. bundyensis Lee and Reye, and one parous C. histrio Johannsen. Highest densities of arthropods (up to 1562/million m3) were on 30 January 2000 when NW winds, sustained for six hours, probably introduced midges from the New Guinea mainland. Adult mosquitoes (including three female Ve. funerea and a single female Ficalbia) and Culicoides (including two gravid C. bundyensis and one parous C. cordiger Macfie) were also collected in 2 m high mast nets during northerly surface winds. Although the results do not provide evidence that wind-blown mosquitoes introduced JE from New Guinea into Australia, they do not preclude that strong N winds associated with low pressure systems SW of the Torres Strait could have done so. However, results suggest that Culicoides were more likely than mosquitoes to reach high altitude and travel long distances during the light N winds experienced during the study.

Animals↗
PubMed2001

Disease knowledge in a high-risk population for cystic fibrosis.

Cystic fibrosis (CF) has high incidence (1/936 live births) and carrier rate (1/15 inhabitants) in Saguenay-Lac-Saint-Jean (SLSJ). One objective of a major enquiry among several subsets of individuals from this high-risk population for CF was to evaluate the knowledge of the disease and its genetic transmission. The overall score of correct answers pertaining to the clinical signs of CF among medical doctors (general practitioners and specialists) was 42.2 and 65.6%, respectively; it was 84.2% for questions regarding the genetic transmission of CF. The knowledge of the clinical signs was reasonable among CF patients and their parents (about 65% of correct answers), but it was much higher for the genetics (over 88% among parents). Aunts and uncles of CF children were poorly informed of the clinical signs (33.9% of correct answers) but well informed of the genetic transmission (73.8%). Specific subsets of the SLSJ population showed important gaps in the knowledge of the clinical signs of CF but, overall, they were well informed of its genetic transmission.

Adolescent↗
PubMed1998

Endemic goitre: a research protocol elaboration for eradication.

The iodine deficiency (ID), which affects 1 person out of 6, is relatively neglected by the responsible of Public Health Service, particularly in developing countries. Consequences of ID are far from being negligible: mental retardation, hypofertility, hyperplasia, carcinoma, early ageing and, in very exposed areas, endemic cretinism. Nevertheless, eradication is easy and cheap but it requires rigorous protocols and control of results. The elaboration of these protocols is complex because it must be adapted to environment, population and financial possibilities of concerned countries. Based on our experience in this field, we propose a combined protocol, between the Public Health too liberal approach and that of too expensive research, which can be adapted to several situations.

Data Collection↗
PubMed1998

Endemic cretinism in a traditional society in Mali: from the collectivity to the individual.

The prevalence of endemic cretinism was measured in a village belonging to the Bwa ethnic group in Mali liable to iodine deficiency and suffering from endemic goitre. In this village according to mental and motor handicaps found in cretinism, we used two psychometric tests: the Raven's Progressive Matrice (PM 47) and a "peg test". Using the fiduciary inference method on the two tests associated with a clinical and qualitative approach, we obtained a prevalence of myxedematous cretinism close to 1.2%.

Adolescent↗
PubMed1998

The prevalence of goitre and cretinism in a population of the west Ivory Coast.

Iodine deficiency is a major public health problem in developing countries. The main areas where goitre is prevalent have been identified, but the different degrees of severity and the populations affected have not. Most countries are now attempting to obtain reliable and more extensive data. A pilot study was carried out in the Ivory Coast in order to improve epidemiological knowledge of iodine deficiency and collect the information required to set up an elimination programme. The aim of this study was to assess the prevalence of goitre and cretinism and to measure the main biochemical indicators of thyroid function (T3, T4 and TSH). The study involved 1433 people identified from a census. The prevalence of goitre was 50.3%. There was a significant difference between the examined ethnic groups: 52.7% of the Yacouba and 28.6% of the non-Yacouba had goitre. The most affected age group was 15-45 year. The predominance of women demonstrated the susceptibility of women at child-bearing age to develop the condition. The prevalence of cretinism was approximately 1.5%. Through the assessment carried out using a grid of clinical indicators, it was possible to identify 10 cases of laboratory proven myxedematous cretinism due to hypothyroidism. The concentration of iodine in foodstuffs was below the limit of detection (< 7.5 micrograms/kg) and iodine could not be detected in the water (< 1 microgram.l) The biological profile of the population was affected to a very limited extent, with a mean value (+/- standard deviation) for TSH of 1.93 (+/- 1.56) mIU/l (0.1-4.0) and a free T4 value of 10 (+/- 3.46) pmol/l (8.2-20). These initial results confirm the high prevalence of endemic goitre and the low iodine content of the soil, water and food in the investigated region. The study will be complemented by a nutritional investigation to improve the understanding of iodine balance, after which an appropriate action plan will be proposed.

Adolescent↗
PubMed1998

Epidemiology and prophylaxis of endemic goitre in the Bwa village of Sirao (Mali).

A study was conducted in Mali, in some villages exposed to iodine deficiency disorders (IDD). To treat and, above all, prevent endemic goitre, Lipiodol UF was dispensed in two ways: by intra-muscular injection (475 mg I) or by oral administration (48 mg I to 240 mg I). In two cases, hormone levels regained normal values and thyroid hypertrophies regressed significantly. Nevertheless, the impact of the treatment on the size of the goitres seems to be in favour of injections; which is probably due to the fact that in the village which received Lipiodol UF per os, many goitres were nodular.

Administration, Oral↗
PubMed1998

Registers and follow-up methods of populations in a public health survey: the example of the village Glanlé in Ivory Coast.

Demography has a fundamental place in a public health survey, and it is essential to provide the population follow-up. A population exhaustive census is the first compulsory phase. It turns out that this phase is necessary if we want to know with precision the size of the population studied and its main demographic characteristics (sex, age ...). The census allows us to provide a real population follow-up, in order to measure the evolution of the different disorders and to estimate the effects of a prophylaxis on each individual in a precise time. This follow-up requires a computerized population register which contains all the information concerning every individual. This data file is updated with new data collected by next surveys. The realization of the nominal population pyramid, is a complementary tool to the population follow-up. Each individual, characterized by sex and age, is allocated a position in the pyramid by his identification number. The figurative contrasts show several cases noticed according to the studied events. The reconstruction of the genealogy represents another form of the population follow-up, by reconstructing biological kinship relationships between the inhabitants.

Adolescent↗
PubMed1997

Information provided by pairs of distantly affected relatives to search for genes involved in rare autosomal dominant diseases.

When dominant mutations of different genes may lead to the same disease, it is often difficult to detect in a particular patient which gene is involved. A strategy is to make genealogical extensions to find affected relatives that should have inherited the same mutation. In particular, for diseases with late age of onset or short survival time, only poor information may be obtained from close relatives of probands and it can be particularly efficient to make genealogical extensions to detect pairs of distantly related affected individuals. Such a pair of affecteds may provide information concerning the region of the genome where the mutated gene should map. Two situations may be encountered depending on whether or not prior information on the location of mutated genes involved in the disease are available. If we already know, from previous linkage studies, that a gene located in a given region R of the genome may be involved in the disease, the problem is then to confirm that it is indeed a mutation of this gene that is involved in the affected pair. Once the implication of a gene in region R has been confirmed the affected pair of relatives may give information to restrict the length of this region R. In this paper we discuss these two points by deriving analytically first the lod score expected and second the expected reduction of the length of the region where the mutation is suspected to map as a function of the number of meioses between the two affected individuals and of the polymorphism of the markers available in the region.

Chromosome Aberrations↗
PubMed1996

Treatment by iodized oil (Lipiodol UF) of a population in Mali suffering from endemic goiter.

In order to reduce the prevalence of goiter in a village of Mali liable to iodine deficiency, an iodized product (Lipiodol Ultra Fluide) was orally administered to their inhabitants. Taking into account a series of demographic variables and goiter types, a protocol was conducted using Lipiodol at three different dosage levels. Six months after the treatment, the hormone levels regained normal values, whereas only the smallest dose reduces the volume of goiters significantly.

Female↗
PubMed1994

Hemoglobinopathies in the Dogon Country: presence of beta S, beta C, and delta A' genes.

The population of the Dogon, located in Mali, is divided in an endogamic Noble class and two endogamic servant castes (Tanners and Blacksmiths). We find that the polymorphic frequencies of beta c, beta S, and, unexpectedly, a mutation of the delta-chain (delta A'), are geographically (valley vs. plateau) as well as social status dependent.

Base Sequence↗
PubMed1994

Phylogenetic characterisation of bluetongue viruses from naturally-infected insects, cattle and sheep in Australia.

The polymerase chain reaction was used to detect the presence of bluetongue virus (BTV) in a number of clinical and insect samples collected in the Northern Territory of Australia. Sequence analyses of the amplified BTV genes differentiated endemic Australian and exotic viruses. Two potential exotic BTV were detected as a result of PCR analyses of blood from sentinel animals and of the insect vector, Culicoides wadai. The detection of BTV in C wadai was the first direct demonstration of the presence of BTV in this potential vector. This new technology can significantly reduce the time taken for a diagnosis from a clinical sample and increase the amount of useful information obtained on a BTV isolate by using rapid sequencing techniques. Sequence data were used to differentiate between BTV20 isolated in 1975 and two isolates of the same serotype, isolated in 1992, and indicated that the latter were probably a recent incursion into Australia from Indonesia due to their greater VP3 sequence homology to the BTV9 (Java) than to Australian BTV isolates.

Animals↗
PubMed1994

Haemoglobinopathies C and S in the Dogons.

The distribution of haemoglobins C and S was studied in a population of caste and non caste Dogons living in villages located on the plateau and scree regions in the Sangha department of Mali. Results showed a 15.77% prevalence of haemoglobinopathy AC. Haemoglobin C was found in both plateau and scree villages and equally among caste and non caste Dogons, while the homozygous form CC was absent in non Dogons. The prevalence of haemoglobinopathy AS was extremely low with a calculated frequency of 3.05%, allele S being restricted to areas where one is likely to encounter populations other than the Dogon people. Homozygotes SS were not detected and the phenotype SC was only rarely identified. An overall analysis of these data not only suggests that allele S is of recent introduction in the Dogons but also raises the question as to whether their origin is not the voltaic rather than the Manding plateau. Studies of marriage patterns and haplotypes currently in progress should enable resolution of this controversy.

Anemia, Sickle Cell↗