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J Mouchet

Publications and source records attributed to J Mouchet.

At least 19 recordsLinked to original sources
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↗
PubMed1992

[Anopheles paludis: important vector of malaria in Zaire].

An entomological study was carried out on the transmission of malaria in the Bandundu region, Zaïre, during the dry season (July and August 1991). Five Anopheles species were recorded: Anopheles paludis, A. gambiae, A. funestus, A. moucheti and A. nili. A paludis was the dominant species and represents 55.1% of the total; the average number of A. paludis bites per man/day was 4.2. The sporozoite index was 6.2%; the inoculation rate due to A. paludis was h = 0.26, 1 infective bite each 4 days. A. paludis plays an important role with A. gambiae and is considered as one of the main vectors of malaria in this region.

Animals↗
PubMed1992

[Evaluation of the efficacy of fenitrothion (Sumithion PM40) on vector density and the prevalence of malaria in Pout (Thiès, Sénégal)].

House-spraying with fenitrothion for malaria control was evaluated in three villages of the Pout rural community (Senegal) between August 1988 and October 1990. The baseline data were collected during the first year. The malaria vector was identified as Anopheles arabiensis and the highest malaria prevalence was observed in October 1988 (38%) in the child population (2-9 years old). A simple round of fenitrothion house-spraying at 1 g/m2 was carried out in the second part of July 1989. About 90% of the houses were treated. The malaria vector was reduced to negligible density and a rapid decrease of malaria prevalence was observed. In this area of short seasonal transmission, where the stability of malaria is low, one single round of spraying led to a marked reduction of malaria transmission and prevalence. The cost of the treatment was about 50 US cents per capita.

Animals↗
PubMed1992

[Diversity of malaria in the Sahelo-Saharan region. A review apropos of the status in Niger, West Africa].

The concept of epidemiologic facies of malaria underlines the diversity in the expression of the disease in areas where important ecological variations interfere largely with transmission. Niger is quite a border region between the afrotropical fauna from the south and the Palearctic fauna from the north. The last one filters through the mountains where it maybe represents a relic of ancient paleoclimates. Annual variations of the northern limit of Anopheles arabiensis, in the Sahelo-Saharan region including some oasis, are related to temporary breeding places produced by seasonal rainfall, after estivation during the dry season or after a long migration with the wind. An. gambiae s.s is present in the south and along the Niger river, with An. funestus, even till Zinder. The northern limit of An. nili is the Niger river. The permanent variations of the environment induce great differences in the level of transmission between an intermediate stable situation in the south to an unstable one in the north. Epidemic outbreaks appear some years in vulnerable populations. The implementation of a malaria program supposes to take account of the various eco-epidemiologic situations all over the country. Even if mortality and morbidity became lower, natural precaution in some groups of people must be preserved.

Adolescent↗
PubMed1991

[The impact of impregnated mosquito nets on prevalence and morbidity related to malaria in sub-Saharan africa].

Insecticide treated bed nets (permethrin, deltamethrin and lambda cyalothrin) were used for malaria control in The Gambia, Burkina Faso and Tanzania where Anopheles gambiae (and An.funestus in Burkina Faso) is the main vector. Treated mosquito nets are efficient when used on a large scale and not on an individual level. Such a large scale use, acting on longevity and infectivity of vectors, always induced a decrease of malaria transmission by more than 90%. Treated bed nets had no significant effect on the overall parasite rate, showing that malaria transmission was not stopped. But it was usually found that there was a significantly smaller number of children with parasitemia higher than a critical threshold, a sensitive parameter of malaria morbidity. Indeed, in the three situations studied, malaria morbidity (fever + high parasitemia greater than critical level in the concerned area) has generally shown a similar drop of 60%. These data demonstrate that treated bed nets are useful to reduce transmission and morbidity. Advised as a new way for reduction of nuisance, treated bed nets were always welcomed by the populations and this method may be considered as a complementary weapon in public health.

Adolescent↗
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↗
PubMed1990

[Recent achievements and perspectives in medical entomology and vector control].

High technologies of molecular biology and genetics, supported by computer use brought considerable advances in taxonomy, physiology, host/parasite relationships, ecology and epidemiology. New insecticides, IGR and bacteria are now available. Both simple methods (e.g. tsetse trapping, impregnated bednets) and large programs using heavy material (e.g. O. C. P. in West Africa, mosquito control in Northern hemisphere) have been successful. Guineaworm control lies in an intermediate position. Malaria control has difficulties and needs new tools and a better use of those already existing. A few progresses are noticed in biological and genetical control. Appropriate structures, well trained and motivated personnel, adequate funding and political willingness are the keys for the implementation of any control programme.

Animals↗
PubMed1990

[Current strategies for the prevention of malaria].

Two billion of persons live in regions where endemic malaria prevails or has reappeared. An estimated on hundred million infected individuals per year have been reported around the world. In front of this alarming situation, the diversity and even the incoherence of the currently proposed prophylactic regimens confuses the therapists and renders difficult the adoption of an efficacious strategy. The extension and gravity of drug resistance of P. falciparum and the withdrawal of anti-vectorial campaign constitute two reasons for the present recrudescence of malaria. The preventive strategies in 1990 are based on: rehabilitation of anti-vectorial campaign particularly against nocturnal mosquito bites, applicable to all, everywhere and at all times, by the means of individual and collective measures and mostly by impregnated nets; chemoprophylaxis for which two situations should be distinguished: the non immune traveler leaving for a short period (inferior or equal to 3 months) to an endemic area: individuals living permanently or for long periods in tropical regions. Prevention for short stays In low risk transmission zone (North Africa, Mexico, large cities of South East Asia) whatever the duration, suppression of chemoprophylaxis is acceptable. In high risk transmission zone, three strategies exist according to the intensity and frequency of drug resistance: zone 1 (P. vivax or drug sensitive P. falciparum): chloroquine at a dose of 100 mg/day for adults (1.5 mg/kg/day for children) 6 days out of 7, from the day of departure trough the whole stay and for one month after the return, is still efficacious; zone 2 (moderate frequency of drug resistance): protection is again ensured by chloroquine only, as in zone 1, or better than that by the association of chloroquine 300 mg once a week and proguanil 200 mg/day (3 mg/kg/day for children). The side effects of mefloquine and the risk of generation drug resistance argue against its general use in this zone particularly in West Africa. In one year, we have already observed three chemoprophylactic failures with mefloquine in individuals returning from this region; zone 3 (high frequency of drug resistance and multiresistance): mefloquine, if well tolerated is justified in weekly intake. In case of contraindications or intolerance to mefloquine, which are becoming more frequent, no substitution for that chemoprophylactic regimen is presently available. In view of these facts, indications, contraindications and posologies of mefloquine should be reviewed to better profit from the remarkable characteristics of this antimalarial. Mefloquine should only be prescribed (excluding curative treatment) for chemoprophylaxis of short stays in zone 3. Some contraindications of this drug should be maintained (pregnant women) or made relative (treatment with B-blockers and in the absence of pediatric studies, children weighing less than 15 kg).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

[Agriculture-health interface in the field of epidemiology of vector-borne diseases and the control of vectors].

This paper is a review of the interactions between agriculture and vector borne diseases. Rain forest clearing makes possible the development of heliophilous species of anophelines and snails leading to an increase of malaria and schistosomiasis in Africa. But in Asia, clearing is a control method against Anopheles balabacensis, an important malaria vector. Clearing of forest galleries is followed by the disappearance of shore-dwelling tsetse flies. Woodcutters and pioneer farmers are contaminated with arbovirus and leishmaniasis when entering in natural sylvatic foci of these diseases. Management of drinking water reduces guinea worm as well as cholera and other diarrhoeal diseases. More over when piped water becomes available people are no more obliged to store drinking water in containers where vectors use to breed. Reservoirs of dams offer large possibilities for the development of mosquitoes including anophelines vectors of malaria and filariasis and of snails hosts of schistosomiasis. The medical importance of these man-made breeding sites depends of the local epidemiological features of the diseases. Dam spillways provide breeding for blackflies and man-made foci of onchocerciasis have been described in West Africa. Irrigation channels mainly when non cleared of vegetation are good breeding places for anophelines and snails. Irrigated surfaces like rice fields are highly productive in anophelines and other dangerous species of Culicinae. Insecticides used in agriculture, mainly to control cotton and rice pests, have been at the origin of insecticide resistance of several anopheline species. On an other hand, sometimes rice pests control lead to the control of rice field mosquitoes until they become resistant, e.g. for Culex tritaeniorhynchus the vector of Japanese encephalitis in South Korea. Many international organizations have emphasized the role of intersectorial collaboration to control man-made vector borne diseases foci. Good planning of the infrastructures (e.g. twin spillways) and adequate maintenance are essential. Vector control in rice field is a puzzling question. Wet irrigation was a hope but it cannot be done everywhere. Biological control methods have not been proven to be very efficient. Even Bacillus thuringiensis H14 and B. sphaericus have severe limitation. New tools for intersectorial activities should be a goal for scientists imagination.

Agriculture↗
PubMed1990

[Historical epidemiology of malaria in the archipelago of the Mascarenes (Indian Ocean)].

The Mascarenes Islands (Mauritius, Rodrigues and Reunion) have been for the last few centuries a place of rest and convalescence for sailors, soldiers and inhabitants of the other regions of the Indian Ocean affected by "intermittent fevers". In the middle of the nineteenth century a severe and deadly malaria epidemic occurred first in Mauritius and then in Reunion Island. It took a century to bring the disease under control, but this has in no way diminished the risk of its re-introduction. Comparative study of the way the disease appeared and got established in these two islands and not in the adjoining ones (Rodrigues, Chagos, Seychelles) leads us to formulate the hypothesis that massive deforestation for sugar cane cultivation created a favourable environment for the implantation of the malaria vector, the african origin of which is beyond doubt. The evolution of the environment, subjected to natural catastrophe (cyclones) and to human activities (often as a consequence of economic development) has exerted pressure on the vector which in a way gives an answer of the development of the disease over time. This study highlights the importance of epidemiological analysis of the history of major communicable diseases not only in the cognitive context but also in predicting probable public health problem arising from environmental modifications.

Animals↗
PubMed1989

[Impact of the spraying of deltamethrin in a focus of leishmaniasis in Bolivia].

After one month of entomological observations to record pretreatment data, a sub Andean village of Yungas, Bolivia (alt. 1500 m) was sprayed at the beginning of the rainy season (January 1987). Houses were treated inside and outside with deltamethrin at 0.025 g/sq.m.; kennels, hen-houses and stacks of adobe were also sprayed in the same way. As a result of the treatment, Lutzomyia longipalpis, the local vector of visceral leishmaniasis, disappeared from houses and animal shelters for 9 and 10 months respectively. The impact of the treatment on the populations of Lu. nuneztovari and anglesi, the presumed vector of tegumentary leishmaniasis, was not obvious. As compared with pretreatment data, the rate of engorged females in houses decreased by two, and their density was also reduced. But these data are difficult to interpret due to the natural seasonal variation in density in this species. Moreover, the information from the control village did not correspond as expected. Lu. n. anglesi is a highly exophilic species in this area, a behaviour which could explain the limited impact of the treatment on this sandfly.

Aerosols↗
PubMed1989

[Epidemiology of cutaneous leishmaniasis in Bolivia. 1. Description of study zone and prevalence of the disease].

An epidemiological survey of tegumentary leishmaniasis (Leishmania (Viannia) braziliensis) was carried out in three regions of Bolivia in the Andean foothill and Amazonian forest. It was based on the record of lesions and scars on all the inhabitants of selected representative villages. In the Yungas, an area cultivated from the XVIIth century, males and females are equally infested, mostly before they were 10 years old (65%); 48% of scars were on the head. In Alto Beni and Pando, areas covered with primary rain forest, males are significantly more affected than females. The majority of scars were on the legs. The males of the three areas were equally affected. These results suggest that: --in the Yungas, contamination takes place among children in villages during the night; --in the Alto Beni and in the Pando, the infection rate is linked to the professional activities of adults, and men are more at risk than women. Only 7% of the lesions are evolving in grave forms of mucocutaneous ulcers. These forms represent the main load of the disease from the public health point of view. It has been found heavier in the Yungas (1.32%) and in the Alto Beni (1.14%) than in the Pando (0.21%). It should be noted that the first infection can give raise to several lesions. But reinfections are rare, which supports the view that the first infection is protective against the following ones.

Adolescent↗
PubMed1989

[Epidemiology of cutaneous leishmaniasis in Bolivia. 2. Transmission patterns].

In Bolivia the transmission of tegumentary leishmaniasis due to Leishmania (V.) braziliensis depends both on environmental factors and human activities. In the Yungas, transmission takes place in the houses during the night. The vector is Lutzomyia nuneztovari anglesi Le Pont & Desjeux, which enters the houses after 10 p.m. and leaves them before 6 a.m. This transmission pattern explains why men and women are equally infected, generally before 10 years old. Some more adults are infected very likely in coffee plantations or in the relict forest where the same vector species abounds and bites in daytime. In the Alto Beni, pioneers, mainly males, are infected when clearing the forest. Three Psychodopygus species have been shown to be the vectors. The risk is drastically decreasing when people establish in plantations or nearby villages because sandfly vectors do not get easily out of the forest cover. In the Pando, forest people are infected when harvesting Brazil-nuts or bleeding the rubber-trees, the two main activities in the area. It is very likely that Ps. c. carrerai is one of the vectors. Pando and Alto Beni primary rain-forests are natural primary foci of Le. braziliensis. So far the mammalian reservoirs are unknown but the circulation of the parasite has been proven by the fast contamination of receptive people entering the forest. The Yungas primary forest may be also considered as a relict focus. The cultivated area of the Yungas is an anthropic secondary focus. The vector Lu. n. anglesi became adapted to coffee plantations from which it enters the houses and transmits the parasite to man.

Adolescent↗
PubMed1989

[Malaria in Guiana. I. General status of the endemic].

Before 1949 malaria was highly prevalent in the whole territory of French Guiana. When malaria control based on house-spraying and drug prophylaxis was implemented in 1950 the disease sharply dropped below 20 cases per year. Since 1976 despite vector control malaria is rising again. In 1987, 3,269 cases have been notified giving an incidence of 37.6 per thousand for the whole country population; only four deaths were recorded. All the age groups were concerned but the transmission was restricted to some foci along the Oyapock river (prevalence rate 25%), along the Maroni river (prevalence 2.3%) and in a few places of the coastal area. The main cities remain malaria free. In vivo resistance to chloroquine was observed in 22% of the cases which could be cleared by amodiaquine or quinine.

Adolescent↗
PubMed1989

[Malaria in Guiana. II. The characteristics of different foci and antimalarial control].

In French Guiana, the distribution of malaria in foci inhabited by quite different ethnic groups calls for specific studies. Along the Oyapock on the Brasilian border and along the Litani on the Surinam border, incidence among American Indians and Creoles ranges from 300 and 900 per thousand; Plasmodium falciparum accounts for 65% and P. vivax for 35%. Along the middle and lower Maroni on the Surinam border, the Boni and Ndjukas Negroes move freely through the frontier and since the civil strife Surinamese used to attend health centres of Guiana. Therefore it is difficult to find the sources of contamination and the incidence among French citizens; P. falciparum is the only parasite recorded in this focus. In 1987 a small outbreak mainly due to P. vivax, occurred in a Lao refugees village in the hinterland. The coastal foci harbour large communities of Haitian and Brazilian migrants. The vector is Anopheles darlingi and up to now there is no evidence that other species could be involved. The rise of malaria despite of control measures involves several factors: the house spraying is no more accepted by a large percentage of house holders and the alternative larviciding has only a limited efficacy; the houses of American Indians have no walls to be sprayed; there is a continuous introduction of parasites by migrants. It has been said that vectors have change their behaviour toward exophily but such a statement has not yet been supported by evidence. All these factors should be taken in account to improve malaria control.

Animals↗
PubMed1989

Integrated malaria control achieves results in Mayotte.

A malaria control campaign in the island territory of Mayotte has achieved remarkable success owing to the integration of activities with the general health service and to the high degree of decentralization practised.

Animals↗