[Evaluation of an indirect hemagglutination test for the serodiagnosis of amebiasis]. / Evaluation d'un test d'hémagglutination indirecte amibiase (HAI) pour le serodiagnostic de l'amibiase.

167 sera have been tested to appreciate the value of an indirect hemagglutination test (Amibiase HAI FUMOUZE) comparatively to an agglutination test of sensibilized particles of latex (Bichro latex Amibe Fumouze BLA) Amibiase HAI test comes out as sensitive and specific for the detection of antibodies in patients suffering from visceral amoebiasis. But some antibodies are also detected in patients with an antecedent of amoebiasis, as it is usually the case with some other techniques. A high positivity of the indirect hemagglutination test, and the concordance between the test HAI and the BLA one are in favour of a visceral amoebiasis. While lower rates or discrepancy between the two tests may evoke an hidden infestation in patients coming out or originated from endemic zones.

Enquete paludometrique dans trois villages de la vallee de la Kadei; Cameroun

L'enquete paludometrique menee en janvier 1991 dans trois villages riverains de la riviere Kadei a l'Est du Cameroun revele un paludisme hyperendemique. L'indice plasmodique des enfants de 2 a 9 ans est de 63;5 pour cent. La formule parasitaire montre la preponderance de plasmodium falciparum et la presence de plasmodium malariae et de plasmodium ovale. La reaction d'immunofluorescence met en evidence un indice serologique eleve et une acquisition precoce des anticorps antipalustres; reflets d'une transmission intense. La pression medicamenteuse est restee tres faible dans la population traditionnelle et la construction d'un barrage ne devrait pas modifier la morbidite palustre en raison d'une transmission deja tres intense dans la region

Etude epidemiologique des helminthiases intestinales (necatorose; ascaridiose; tricocephalose) dans la vallee de la Kadei (Cameroun)

Les examens coprologiques avec numerotation des oeufs dans les selles; pratiques dans les villages de Boden; Zimbi et colomines situes dans la vallee de la Kadei ou un barrage va etre construit; permettent d'evaluer les prevalences et les charges parasitaires de trois nematodoses intestinales; la necatorose; l'ascaridiose et la tricocephalose; tres repandues dans la region. Ces affections; et en particulier la necatorose; sont plus frequentes chez les femmes que chez les hommes et leurs prevalences sont plus elevees a Boden et a Zimbi en plaine que sur la colline de Colomines. Il est possible que la mise en eau de la retenue; en faisant remonter le niveau de la nappe phreatique; favorise la transmission par le sol de ces affections; notamment a Boden qui sera situe juste au bord du lac

[Inhibition of Plasmodium berghei in rats infested with Strongyloides ratti or Trichinella spiralis; role of high blood corticosterone in reaction to the development of helminths]. / Inhibition de Plasmodium berghei chez des rats infestes par Strongyloides ratti ou par Trichinella spiralis; rôle de l'hypercorticostéronémie réactionnelle à l'évolution des helminthes.

The plasma corticosterone induced in the rat by the development of Strongyloides ratti or Trichinella spiralis reaches a sufficient level of intensity to determine reticulocytopenia. The latter is linked chronologically to the inhibition of parasitemia in Plasmodium berghei, which occurs when this protozoa develops at the same time as the Nematodes, and seems to be the causal factor. This hypothesis may be verified by replacing the helminths with the corticotropic action of A.C.T.H. which causes a decrease in the number of reticulocytes.

[Course of blood corticosterone in trichinosis in rats; its relation with immunosuppression]. / Evolution de la corticostéronémie au cours de la trichinose du rat; ses relations avec l'immunodépression.

Beyond a certain level of parasite density, trichinellosis of the rat is accompanied by high plasma corticosterone, the intensity of which depends on that of the parasitism. It develops in two phases: a primary phase, starting early on (40 hours after infestation), is characterized by a more or less high degree of plasma corticosterone, varying according to parasite intensity. It stops around the fifteenth day. The second phase develops from approximately the third week onwards, and can last five or six months; it occurs even when the primary phase is not pronounced. The discussion points to parallel between this reaction and the characteristic immunodepression of trichinellosis, with respect to kinetic and physio-pathological parameters. A fundamental role in immunodepression may therefore be attributed to plasma corticosterone.

[Relations between parasitism of the rat by Strongyloides ratti, female sex hormones and blood corticosterone]. / Relations entre le parasitisme du rat par Strongyloides ratti, les hormones sexuelles femelles et la corticostéronémie.

Situated under strict conditions in order to try to limit experimental aggravation and to respect the accomplishment of an endocrine balance, the experiments carried out study the influence on parasitism by Strongyloides ratti of ovariectomie and the treatments, of female rats castrated or not, by oestradiol, hexoestrol, diethylstilboestrol, progesterone, mestranol, chlormadinone association. Similarly, adrenal cortex reactions (corticosterone) to the treatment and parasitism are recorded. The analysis of the results lead to the thought that the glucocorticosteroid function of adrenal cortex could be one of the relays between gonades and the development of parasitism (intensity, removal of parasites).

[Parasitism and corticosteronemy in rats during repeated infestations with Strongyloides ratti]. / Evolution du parasitisme et de la corticostéronémie lors d'infestations répétées des rats par Strongyloides ratti.

The greater the number of larvae, the lower the possibilities of superinfestation when rats are repeated exposed to contact with Strongyloides ratti larvae, once a week or every two days for periods of up to twenty-four days: super-infestations occurs only on the 2nd day (10,000 larvae), the 4th day (5,000 larvae) and the 9th day (1,000 larvae). However, superinfestation continues throughout the entire duration of the experiment (46 days) when contamination is very low (10 larvae). Although there is now superinfestations, each new contact with larvae produces a hypercorticosteronemia reaction. Thus, the immunity acquired, although it is rapidly capable of preventing the larvae from reaching adulthood, does not prevent the larvae from beginning their migration and triggering the reaction. Progressively and slowly, this cortico-adrenal reaction decreases. It no longer takes place after 3 weeks of weekly infection by 10,000 larvae of after 2 weeks of bi-daily infection by 10,000 or 5,000 larvae. The reactional hypercorticosteronemia which follows an infestation does not intensify after repeated infections, whatever their frequency or intensity.

[Cortico-adrenal reaction in rats to attempts of reinfestation by Strongyloides ratti (author's transl)]. / La réaction corticosurrénale lors d'une tentative de réinfestation des rats par Strongyloides ratti.

After spontaneous recovery from infestation by Strongyloides ratti, reinfestation by a new generation of adult parasites is not possible if the primary infestation was by 5,000 or 10,000 larvae administered in one or more contacts and if the secondary infestation takes place 3 weeks after. Reinfestation becomes possible again 51 days after recovery from a primary infestation by 15,000 larvae. However although the larvae do not reach the adult stage, they do begin their migration and cause hypersecretion of gluco-cortico-steroids. There is thus a contrast between the ease with which the organism rapidly and lastingly prevents the transformation of larvae into adults and the difficulty in neutralising the larvae and preventing them from triggering a stress.

[Role of hypocorticosteronemy in the self cure mechanism in rats with Strongyloides ratti parasites (author's transl)]. / Rôle de l'hypocorticostéronémie dans le mécanisme de la "self-cure" des rats, parasités par Strongyloides ratti

Repeated injections of corticosterone acetate, physiological hormone of the Rat, in rats carrying Strongyloides ratti, oppose the deparasiting which normally takes place spontaneously. The secretion induced by this hormone by impregnating the organism through the corticotropic factor administered in the form of tetracosactide-zinc, achieves the same result. During all these treatments, an important hypercorticosteronemy is established. Stopping the injections is quickly followed by the worms-being rejected and the corticosteronemy returning to normal. The relations between the corticosteronemy and the parasitism are analysed and lead to the conclusion that the parasite induces an aspecific hypocorticosteronemiant reaction which, through its aspecific and specific repercussions, participates in the self-cure phenomenon.

[The effect of lactation on the parasitism of rats by Strongyloides ratti (author's transl)]. / Action de la lactation sur le parasitisme des rats par Strongyloides ratti

In lactating females of many animal species infested by Nematoda, the self-cure is, if not suppressed, at least very distinctly delayed. It does not appear that an immunological deficiency is the cause of this. We show that this phenomenon also exists in lactating female rats with Strongyloides ratti parasites. In fact, for Strongyloides ratti, the maintenance of the worms is not the only notable modification determined by lactation; much more important is the decrease in the intensity of the parasitism. This aspect is not mentioned by writers who have only studied the different parasitic states in their final phase. Parallel to these alterations in the parasitism, the evolution of the corticosteronemy differs, from two points of view, from that described in infested virgin rats: --Suppression of the hypercorticosteronemy which normally appears 48 hours after infestation; --Attenuation of the hypocorticosteronemy which usually sets in from the tenth day of infestation. This opposition of lactation to the variations in the corticosteronemy induced by the worms is explained by the effect of lactation on the secretion of gluco-cortico-steroids, described under the term of "buffer effect of lactation". The decrease in the intensity of the parasitism may be explained by the fact that lactation, by preventing the hypercorticosteronemy normally caused by larval migration, permits the intervention of aspecific defences. As for the prolongation of the parasitism, it would seem to result on one hand, from a reduced solicitation of the means of defence owing to a smaller number of worms and, on another hand, from the slowing down of the hypocorticosteronemy through the buffer effect of lactation with all the consequences flowing from this at the level of the specific and aspecific defence reactions.