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Biomedical subjects

M Coosemans

Publications and source records attributed to M Coosemans.

At least 55 records · Page 3Linked to original sources
PubMed1994

Population dynamics of anophelines in a malathion treated village in the intermediate zone of Sri Lanka.

As part of research programme on malaria transmission in Sri Lanka, a study was made of man-biting anophelines at Nikawehera, a village on the border of the intermediate and dry rainfall zones. Weekly mosquito collections by night human bait (NHB) were performed inside and outside four fixed stations from October 1992 till March 1993. Houses in the village were treated with malathion by the Anti-Malaria Campaign in October and at the end of January 1993. An. culicifacies and An. tesselatus were the most abundant species. An. culicifacies was probably the only species responsible for malaria transmission. An. culicifacies densities varied between stations and reflected differences in availability of breeding places. An. culicifacies aggressivity is closely related to the rainfall pattern, increasing after the first monsoon rains in November and reaching a peak in late December--early January. Vectorial capacity, however, decreased during the first weeks of the rainy season. The maximum vectorial capacity was found in January. The night biting cycle of An. culicifacies showed a peak between 20.00 and 23.00 h. Since the introduction of electricity in the village, people go to bed later. This might reduce the impact of impregnated bednets on malaria transmission. The results show that malathion spraying as performed now is not very effective. The timing of the spray rounds should be improved. In order to limit malaria transmission, we suggest to advance the malathion spraying campaign of January with one month.

Animals↗
PubMed1992

Transmission factors in malaria epidemiology and control in Africa.

Genetic and environmental components of factors contributing in malaria transmission are reviewed. Particular attention is given to density dependent regulation of vector populations in relation to the survival rate of anophelines. The expectation of vector control activities are different according to the epidemiological characteristics of malaria, mainly its stability. In areas with perennial and high transmission (stable malaria) vector control could reduce malaria related morbidity and mortality, without any effect on the endemicity. However this need further investigations. In areas where the transmission period is very short (unstable malaria), vector control will have an important impact on the disease and on the endemicity. Control projects using indoor spraying with insecticide and impregnated bed nets are discussed.

Africa↗
PubMed1991

[Campaign against malaria vectors in the framework of a rural development project in Burundi].

In the context of a large project for the socio-economic improvement of the Imbo area, measures were taken for the integration at all levels of malaria control: health centres for improvement of curative care; hygiene and sanitation centres, communes and agricultural projects for vector control; craftsmen, cooperatives and social centres for the manufacture and selling of impregnated bed-nets. The adopted strategy for malaria control results from preliminary epidemiological studies. The recommended measures are the improvement of medical care and vector control. The latter is based on indoor spraying of malathion, once a year. Malathion is only active during the period (2 months) of highest transmission, which occurs at the end of the rainy season. Occasionally other insecticides are used. Impregnated bed-nets with deltamethrin and village draining are complementary methods. In villages of the rice-growing area with good participation of the community, vector control activities have a considerable impact on malaria prevalence. About 70% before the intervention, the prevalence does not exceed 10% in 1990. High parasitaemia (greater than 2000 troph./microliters), and hence morbidity, decreased considerably (35% in 1983 to less than 5% in 1990). In villages with poor community participation, the decrease of prevalence is less spectacular (from 70% to 25%). Drains are not kept in repair and constitute new breeding places of vectors in the populated areas. The use of mosquito bed-nets is not common, a better information campaign should overcome this unpopularity. In peri-urban villages, inhabitants are complaining about indoor spraying, but the results are satisfactory. This programme demonstrates that reducing malaria prevalence and morbidity with conventional measures is feasible in particular biotopes. Health education activities in the Imbo Centre must be pursued and adapted according to the professional activities of the community.

Animals↗
PubMed1991

[Which structures in anti-vector control?].

The lack of efficient tools is often incriminated to explain the absence of anti-vectorial activities in control programmes of vector borne diseases. However, we must recognize that the available tools are under utilized due to the lack of appropriate structures. Existing structures are reviewed. So far, results achieved by the Primary Health Care System (PHCS) are scarce. In fact, even simple methods need specific know-how for execution and specialised knowledge for planning and supervision, which differ from those needed for medical care committed to the PHCS. To develop the use of simple methods, adequate structures have to be elaborated, maintaining a peripheral character but in direct connection with a central level, which provides expertise, supervision of the activities and evaluation of the results. The association of research and operational programmes is essential to face problems linked with epidemiological, environmental, socio-economical modifications or changes in sensitivity to insecticides and for the integration of new techniques. It is also this tandem "research-control operations" which will provide the best environment for training.

Animals↗
PubMed1991

[Going into the 21st century: should one dream or act?].

A historical review of vector control is made. Despite the available tools, vector borne diseases are still a priority in Public Health. Magic tools, like DDT, were often misused. Adapted strategies and structures for vector control are now required. Progress will mainly result from research and evaluation done in the framework of vector control programmes. Discovery of new tools will find in these operational programmes a point of fall for their application.

Africa↗
PubMed1991

[Development of a campaign strategy against malaria in a rice-growing region of Burundi].

Epidemiological studies undertaken in an area of low altitude in Burundi, revealed microgeographic variations of malaria endemicity, naturally unstable in the area. However transmission is relatively high near rice fields. The transmission increases at the end of the rainy season, period of natural decrease of the vector population combined with an increase of their longevity. Indoor spraying with short acting insecticides during that period of the year, reduced considerably the transmission and high parasitaemia in children, without changing the susceptibility of the vector to the insecticide.

Adolescent↗
PubMed1989

Malaria control by antivectorial measures in a zone of chloroquine-resistant malaria: a successful programme in a rice growing area of the Rusizi valley.

Within a large project for the socio-economic development of the rice growing area of the Rusizi valley in Burundi, a malarial control programme has been set up. This programme has several components: improvement of curative services, promotion of use of impregnated mosquito nets, and use of environmental engineering and indoor spraying with residual insecticides to control infection.

Animals↗
PubMed1989

Species of the Anopheles gambiae complex and chromosomal polymorphism in a rice-growing area of the Rusizi Valley (Republic of Burundi).

Chromosome studies on samples of the Anopheles gambiae complex were carried out in a village of the rice-growing area of the Rusizi Valley (Burundi). A large predominance of An. arabiensis was observed throughout the year. Anopheles gambiae was also present but represented about 4% only of the indoor resting An. gambiae s.l. The finding of human blood-fed specimens in animal shelters suggests partial exophily. Abdominal appearance observations indicated a gonotrophic dissociation during the dry season. Both An. arabiensis and An. gambiae showed a low degree of inversion polymorphism, in agreement with the general picture shown in East Africa. The most frequent karyotypes are typical of wet savannas.

Animals↗
PubMedDate not supplied

[Analysis of the genetic factors controlling malarial infection in man].

Genetic factors have clearly been shown to play a role in controlling malarial infection in animal models. There is now also increasing evidence for the genetic control of malaria in man. We carried out a segregation analysis based on blood parasite load phenotype for a population of the town of Bobo-Dioulasso (Burkina-Faso). This analysis demonstrated a strong genetic effect. Our results were not consistent with the segregation of a major gene and thus suggest that parasite load is under the control of minor genes. The genetic effect was stronger in children than in adults. We carried out a regression analysis in children and found that there was an association between the phenotype for blood parasite load and the q31-33 region of chromosome 5. We identified a gene in this region, Pfil1 (Plasmodium falciparum infection levels 1), which accounted for almost 50% of the variance in blood parasite load and which played a fundamental role in the control of infection. The 5q31-33 region contains several genes encoding cytokines that regulate T lymphocytes. The identification of genes controlling malarial infection opens up new possibilities for preventive and treatment strategies. It should be possible in the near future to identify individuals at risk of malaria, who would derive the greatest benefit from preventive and therapeutic measures. Finally, a deeper understanding of these genes controlling protective immune responses could be of value for the development of vaccines.

Adolescent↗
PubMedDate not supplied

[Current strategies in the campaign against Plasmodium falciparum malaria in an area resistant to 4-aminoquinolines].

Confronted with the extension of chemoresistance of P. falciparum and the gradual renunciation of the fight against the vectors, it is important nowadays to manage better the means of fighting in the zones where chloroquine resistance exists. If preventive treatment of chills by 4-aminoquinolines is still able to realize prevention of mortality, treatment of all confirmed chills by P. falciparum has to combine sulfadoxine-pyrimethamine with quinine or amodiaquine.

Aminoquinolines↗
PubMedDate not supplied

[Response of Plasmodium falciparum to quinine in a hospital environment in a chloroquine-resistant region. Bujumbura, Republic of Burundi].

Plasmodium falciparum's response to quinine (7.5 g of base in 5 days) was studied in vivo in 58 adult patients hospitalized in 1985--47% presented a pernicious malaria fever three deaths were registered during treatment, two of them attributed to late hospitalization, and the third patient was struck down by a sudden acute hepatitis. Three days after treatment started 89 of the patients did not present any asexual forms. At day 7, all patients responded favourably to the treatment. Parasitemia lowered very quickly whatever the route of administration had been. Quinine had no effect on production of gametocytes during the first four days. Clinical improvement is rapidly observed and the side effects of quinine disappeared when stopping the treatment. Despite the presence in the region of an important resistance of Plasmodium falciparum to chloroquine (80% specimens), one can conclude to a satisfying susceptibility of this parasite to quinine, provided posology and divided doses are respected.

Adolescent↗