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J Roux

Publications and source records attributed to J Roux.

212 records · Page 12Linked to original sources

[Mass chemoprophylaxis of malaria, its objectives, its limits, its difficulties].

In intertropical Africa, insecticide spreadings cannot succeed by themselves in controlling malarial endemia. They cannot provide any eradication, even if they are combined with chemoprophylaxis. On the other hand, mass chemoprophylaxis should provide a control of lethality and morbidity due to malaria. The authors define the mass prophylaxis concept, lay its basic principles and specifically the criteria used to select the available anti-malarial drugs. Then, they stress on the major set-backs such as P. falciparum resistance to amino-4-quinoleine, and drop of immunity in individuals receiving no chemoprophylaxis. Finally, they review the necessary conditions for the achievement of a mass chemoprophylaxis at a wide country level, namely: a determined policy with long term budget allowances, setting up of a specific organization and personnel training, community education at all levels, preliminary epidemiological surveys and strategical schemes suited to the various epidemiological patterns.

Adolescent↗

[Epidemic of yellow fever in the southeastern region of Upper Volta (October-December, 1983). Epidemiological study. Preliminary results].

An epidemic of yellow fever raged during the last three months of 1983 in South East of Upper Volta. It spread on about ten thousand square kilometers, in a bushy savanna area, affecting only populations living in contact with forest galleries, belonging especially to the peul ethnical group. The transmission of the virus was effected by sylvatic vectors, essentially Aedes furcifer. Serological tests showed that about 50 % of the population living in contact with forest galleries was affected, that is to say 15.000 to 17.500 people. The average death rate on the whole area was 4 % (800 to 1.700 deaths); the lethality rate was estimated between 6 and 10 % of affected people. On the whole, 54 strains of yellow fever virus were isolated from human blood samples, and 26 strains from batches of mosquitoes. We called this epidemic "intermediate sylvatic epidemic". The epidemic quickly decreased in the sylvatic area, owing to climatic conditions. A mass campaign of vaccinations prevented it from spreading to near urban centres. On this particular case, the thermostability on field of the vaccine 17D provided by the Institute Pasteur of Dakar was proved to be effective.

Adolescent↗

[Systematic chemotherapy of febrile attacks: an alternate strategy for the control of malaria in rural areas].

While the socio-economic development has generally improved malaria eradication in towns, this endemic disease remains of deep concern in the field of Public Health in the major part of the Intertropical African country side, despite the use of direct means of control (such as control of both anopheles and parasites, health education ...), of which the efficacy is, however, recognised. This fact is due to the present unfeasibility of the proposed strategies, which is the consequence of some economical, technical, logistic, and human difficulties. The authors suggest the use of a substitute strategy: the routine chemotherapy of feverish attacks by means of chloroquine, as long as either socio-economic development reaches a sufficient level to enforce an effective control of malaria in rural areas, or other reliable means of control are made available (vaccination e.g.). This strategy is able to provide an effective control of malaria death rate curve; it avoids some of the problems related to mass chemoprophylaxis, with a special mention to immunity. Its salient feature consists in its present large-scale operational feasibility within the framework of the Primary Health System.

Africa↗

Response of the lymphoid organs of the mouse to the peptidoglycan of a gram-positive bacterium (Streptococcus pyogenes).

The response of the lymphoid organs of the mouse to the injection of a Gram-positive (Streptococcus pyogenes) bacterial peptidoglycan (PGL) has been investigated by several complementary techniques. Special cares were brought to: a) the extraction mode and the characterization of the bacterial fraction, b) the sanitary and microbiological status of the mice, and c) the lack of biologically active contaminants, even at a trace level. In these conditions, the local reaction at the site of inoculation was very moderate, transient and not very distinctive. No toxic reactions were observed, even with doses of several milligrams per mouse. Changes in lymphoid organs, as determined by changes in weight, incorporation of radioactive precursors and detailed histological study revealed that PGL did not induce the typical responses of ordinary antigens. Changes in the weight of organs were not significant and there was no dose-response relationship. In the lymph node, the response was confined to the paracortical area; the lymphocyte activation stood at an early stage and became characterized only after booster injection. There was no activation of antibody-producing cells. An important recruitment of active macrophages was observed; this could participate to the adjuvant activity of PGL, whose at least a part of the biological activity is therefore independent of the inflammatory and/or toxic response.

Animals↗

[Human chlamydia infections (authors' transl)].

Human Chlamydia infections have diverse clinical presentations and various biological methods are used for their diagnosis. Despite progress in laboratory techniques, theses methods are relatively slow: inoculation of chick embryos requires 4 to 12 days, cell culture from 2 to 3 days and indirect immunofluorescence a whole morning. Counter immunoelectrophoresis seems to have a future, as it is rapid (45 minutes), easy to perform, highly sensitive and applicable to routine examinations.

Adult↗

[Attempts of ultrastructural and biochemical characterisation of cell wall deficient "Brucella" (L forms) (author's transl)].

In previous studies the in vivo conversion of Brucella suis to L-form state was put in evidence. The L forms isolated from mouse spleen had original structural aspects in common: the absence of the cell wall layer and the extracellular multilayer "membranous" structures. The biological characterization of these L forms and the preliminary identification of specific chemical markers of the bacterial envelope is reported in the present study, performed with the stable L forms well-growing in the liquid media. The electron microscopy confirmed the absence of cell wall and the presence of numerous dense multilayer membranous structures in the L forms cultivated for a long time on appropriate media. This aspect was changed in the L forms adapted to growth on the ordinary medium for brucella: numerous small dense bodies limited by unit membrane were observed. The chemical analysis of stable L forms showed the absence of diaminopimelic acid, confirming the lack of peptidoglycan. The result of chemical determination in L forms of the Na-2-keto-3-deoxyoctonate was negative. However, biological assays suggested that outer membrane components such as LPS and receptors for the bacteriophage Weybridge remained in the L forms, albeit in reduced amount as compared to parental brucella.

Brucella↗

Isolation of L-forms from the spleens of Brucella suis-infected, penicillin-treated mice.

Previous attempts to obtain in vitro wall-deficient stable L-forms of various strains of Brucella have failed because the obtained spheroplasts revert quickly to bacterial form. Here, we report the isolation of L-forms from mice infected with a B. suis strain type 1 and treated with penicillin. In defined experimental conditions, L-type microcolonies associated with tissue debris were observed in primary spleen cultures, even on antibiotic free media. After several transfers on penicillin-containing medium. typical, tissue-free L colonies were obtained. At first, when cultivated on antibiotic-free medium, these colonies reverted to the bacterial form (identified as B suis, biotype 1). Later, after approximately fifteen transfers on penicillin-supplemented medium, they no longer reverted even after several subcultures on antibiotic-free medium. The L-forms' ultrastructural features included many giant empty bodies, considerable variation in size, shape and density of the wall-deficient cells, and many multilayered membranes. The stabilized L-forms were propagated in vitro and inoculated into mice, and then recovered from their spleens as tissue associated L-microcolonies. An occasional in vivo revertant was identified as B. suis, biotype 1. These data provide one possible explanation for earlier failures to detect the presence of atypical bacteria in clinical or experimental Brucella infections.

Animals↗

[Distribution of schistosomiasis in French speaking countries of West Africa (author's transl)].

After reporting an abstract of the surveys prior to 1969, the authors recall their methodology and give the data collected during the surveys carried out since 1969 by the O.C.C.G.E. in 23 districts of 7 west african countries. -Urinary schistosomiasis is widespread but the highest endemic levels are observed in the Sahel area. - S. mansoni schistosomiasis, on the contrary, has a more restricted area of diffusion. It is frequent in sudanese and guinean savanna and does not affect the Sahel and the southern coast.

Adolescent↗

[Study of the distribution of schistosomiasis mollusks intermediate hosts in west africa. First results (author's transl)].

During 18 surveys carried out in 29 regions of 6 West african countries (Benin, Ivory Coast, Upper Volta, Mali, Niger and Togo), one species of Biomphalaria (Biomphalaria pfeifferi) and six species of Bulinus (Bulinus truncatus rohlfsi, B. globosus, B. jousseaumei, B. umbilicatus, B. senegalensis and B. forskalii) were collected. First indications of the distribution of these species demonstrated: the presence of 3 principal species (B. pfeifferi, B. globosus and B. truncatus rohlfsi); the absence of B. pfeifferi, above latitude 14 degrees north; the presence of a zone of B. truncatus rohlfsi in the north, a zone of B. globosus in the south and an intermediate zone where these two species are sympatrie; the possible presence of two strains of Schistosoma haematobium, each being transmitted by only one of the two preceding intermediate hosts. The authors point out that the parasitic diseases and their intermediate hosts are extending, as a result of the various hydraulic works and insist that the authorities should be duly made aware of the health problems generated by any development project.

Africa, Western↗

[Schistosomiasis epidemiology (author's transl)].

Schistosomiasis are, with three hundred million of infested people, the second world endemy, after malaria. For each of the four species, the distribution areas, the life cycle and the main epidemiological features are recalled in the first chapter. In the five following chapters, the authors consider the human or animal reservoirs of virus, the importance of these diseases towards public health, the gasteropod molluscs acting as intermediate hosts, and the problems of immunity in man. The concepts of "schistosomian infection" and "schistosomian disease" are exposed as well as the differences affecting the various strains of schistosomes and snails intermediate hosts. The authors emphasize the value of quantitative parasitological techniques and sero-immunological methods for epidemiological surveys. They underline the difficulties met in the evaluation of the effect of these diseases upon public health. The main causes inducing the duration of the endemy and those responsible for its extension are studied. The value of mathematic patterns is briefly discussed. Quantitative data compiled through epidemiological surveys should improve the use of the various means presently available for controling schistosomiasis.

Adolescent↗

[Bases for control of arthropod vectors: II--Present means (author's transl)].

A review of the present means of control of arthropod vectors in which the authors consider:--individual means aimed at the prevention of bites by utilizing clothes, repellents, mosquito nets and insecticide sprays,--collective means which are either physical, biological or chemical. Physical means are specially used for water control either in "peridomestic actions" or in large scale campaign's related to rural or industrial development scheme. Actually biological means are represented only by larvivorous fishes. The chemical control is the most important, its various requisites, and techniques are given.

Animals↗

[Rice: source of life and death on the plateaux of Madagascar].

Since the 17th century, Europeans travelling in Madagascar described the contrast between the fever-free Plateau and the fever-ridden coasts. The former were inhabited by people of Asiatic origins and the latter by African migrants. At the end of the 18th century, "Merina" kings developed land irrigation and rice cultivation, using manpower from the coasts. Since then, rice has become a monoculture covering most of the arable lands of the Highlands. The first malaria epidemic occurred in the Tananarive area in 1878, and rapidly spread throughout the Plateau. The mortality rate was high. A second epidemic in 1895 may have been a resurgence of the previous one. Subsequently, malaria became meso-epidemic despite control measures, mainly consisting of larvivorous fishes, quinine treatment and prophylaxis. In 1949, an eradication program was launched based on DDT house-spraying and chloroquine prophylaxis in children. It was very successful on the Highlands where malaria disappeared, in 1962. Spraying was cancelled and only three small foci remained under surveillance. In 1987 and 1988, a malaria outbreak devastated the plateau. Subsequently, intensive spraying operations brought the situation under control by 1993. The main malaria vector on the Madagascar Highlands is An. funestus. More than 95% of its breeding sites are in the rice fields just before the harvest and afterwards in the fallow lands. The vector peak and the corresponding peak of malaria cases occur between February and May, depending on the farming calender. The second but less important vector, An. arabiensis, breeds in the rice fields just after seeding when the surface water is sunlit. Although rice fields remain the main source of this vector, it also breeds in rainwater pods and borow-pits. Malaria vectors on the plateau are products of human activities of rice cultivation, which is the basis of the economy. The epidemiological importance of rice fields varies greatly from one country to another. In Southeast Asia, the rice fields harbor several anopheline species most of which are only vectors of P. vivax. In West Africa where malaria is holoendemic, they produce large populations of An. gambiae; however, the malaria pattern is unaltered and remains at peak levels. In the dry areas of southern Madagascar, the vector An. funestus and meso-hyperendemic malaria are restricted to areas of cultivated rice. In West and Central Africa, An. funestus is never found in rice fields even though it is common in marshes. In Madagascar, this vector breeds in irrigated rice fields. Because it is practically impossible to control anophelines in rice fields by chemical, biological and ecological methods on the Highlands of Madagascar, house-spraying remains the best method for mass malaria control. Bed-nets impregnated with pesticides may offer an alternative, but their use is resisted by the local population.

Agriculture↗

[Drug resistance and therapeutic strategy].

In Madagascar, Plasmodium falciparum resistance to chloroquine was clinically suspected in 1975 by Goasguen and demonstrated in 1981 by Arronson et al. Since then, many studies were conducted throughout the island, in the North, South, East and West, on the high Plateau and on the coasts. Two methods were used, including an in vivo method similar to the therapeutic standard protocol of the WHO, and an in vitro method employing the semi-microtest of Le Bras and Deloron. From 1982 to 1986, the 291 in vivo tests performed showed that 20% of the strains were of the types R1 or R2 (SR1 included). From 1987 to 1994, of the 621 in vivo tests performed, 369 (59.4%) of the cases responded to treatment. The deterioration of the situation observed in 1988 (Lepers et al.) seemed to be stabilized (Ringwald et al.). No strain of the type R3 was found. In conclusion, we report the absence of strain type R3 and also the clinical efficacy of chloroquine. The action of chloroquine was spectacular on the fevers and there was remarkable reduction of the parasitaemia. Thus, for treating outbreaks of simple malaria in Madagascar, chloroquine remains the best choice if it is administered at an efficacious dose.

Antimalarials↗

[The impact of curtains impregnated with deltamethrin on the vectors and morbidity of malaria: results in Ankazobe, on the plateaus of Madagascar].

To evaluate the efficacy of deltamethrin impregnated curtains on malaria morbidity in a low transmission area, we studied volunteer families in the village of Ankazobe in the Madagascar Highlands from February 1993 to June 1994. After randomization, we provided 46 houses having 244 inhabitants with impregnated curtains (I) and 45 others having 257 inhabitants with nonimpregnated curtains (NI) as controls. We first estimated the number of mosquito bites in the protected versus nonprotected households. Every month, we captured mosquitos on humans in 6 houses per night for 4 nights. For the I group compared to the NI group, the number of bites by the Anopheles funestus vector per human per night was reduced by 64% in 1993 and 39% in 1994. We also analyzed the malaria morbidity. Malaria morbidity was defined as patients having both temperatures greater than 37.5 degrees C and Plasmodium falciparum parasitemia greater than 1500/microliter with clinical symptoms. From February to July 1993, we observed no significant difference in morbidity: there were 103 cases of malaria among 244 inhabitants of the I group and 117 cases among 257 inhabitants of the NI group. However, during the period of highest transmission from March to May in 1993, there were significantly fewer cases in the I group (68) than in the NI group (94). From January to June 1994, the difference was clear: only 35 malaria cases were observed among the 208 inhabitants of the I group as compared to 65 cases among the 223 inhabitants of the NI group (Chi square = 9.17, p = 0.0024). Inhabitants of the I group could have been contaminated before the curtains were set up. After treatment of the cases and use of curtains during the second year, we observed a reduction in the number of mosquito bites and malaria cases. The small size of the trial made the interpretation of the data difficult. Nonetheless, the results tentatively support the use of impregnated curtains as an antimalaria tool in an integrated control program.

Animals↗