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Biomedical subjects

M Coosemans

Publications and source records attributed to M Coosemans.

14 recordsLinked to original sources

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

[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

[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

[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

[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

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

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

[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

[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

[Control of malaria vectors in tropical Africa (author's transl)].

Indoor spraying with residual insecticides is at present the most effective method of malaria control. Following the failures observed during the campaigns of malaria control using D.D.T., B.H.C. and dieldrin, the W.H.O. has undertaken a wide programme for evaluating and testing new insecticides. The principal compounds tested are discussed. Only four insecticides have been held back: malathion, propoxur, fenitrothion and dichlorvos. However this compounds are very expensive and less remanent than D.D.T.

Africa