Date: 
03/01/1996
Investigation Line: 

Abstract

The occurrence of leishmaniasis patients carrying a double infection with Trypanosoma cruzi has been suspected but not proved. In this study, we analyzed sera of leishmaniasis patients from a region endemic for both parasites by using immunoblotting with epimastigotes and a purified antigen specific for T. cruzi (Ag 163B6). Seven of 12 patients showed a pattern of bands characteristic of chagasic patients reacting with antigens with molecular weights of 131, 125, 116, 111, 51-45, and 43 kD, and positive reactivity with Ag 163B6. Xenodiagnosis for T. cruzi was carried out in all patients; this technique has a positivity rate of 50% in chronic chagasic patients. The presence of T. cruzi trypomastigotes was shown in the blood of three, thus confirming the existence of a double infection in humans. Since the two parasites possess cross-reacting antigens, it may be assumed that previous infection with one of the parasites may affect the course of subsequent infection with the other. Nevertheless, T. cruzi infection did not prevent the appearance of typical leishmaniasis lesions. Therefore, antigenic cross-reactivity is unable to induce a sterilizing immune response against Leishmania.

Date: 
01/01/1996
Investigation Line: 

Abstract

In many regions of South America there are overlapping endemic areas for American Trypanosomiasis (Chagas' disease) and Leishmaniasis. T. cruzi and Leishmania spp, the causative agents of these parasitoses belong to the Trypanosomatidae family and share various antigens that cause cross-reactivity in serological diagnosis when complex antigenic mixtures are used. We studied patients who sought medical attention because of cutaneous or mucocutaneous lesions typical of leishmaniasis infection. These patients were from the province of Salta where Trypanosomiasis and Leishmaniasis are endemic diseases. Sixty-two patients gave a positive Montenegro skin test and, of these, 53 (85, 48%) showed the presence of amastigotes in Giemsa stained smears of dermal scrapings. Seven patients were not included because they were negative for both assays. We analyzed the leishmaniasic sera against homologous antigens to study the immune response and against complex heterologous antigens from T. cruzi to evaluate cross-reactivity phenomena. We also tested these sera against specific antigens for diagnosis of Chagas' disease in order to search for mixed infections. When complex antigens from leishmania were used, the sera showed an unusually strong antibody response 100% positive by IFA, 88.7% by ELISA and 80.6% by immunoblotting. Furthermore, significant cross-reactivity was found when conventional antigens for the serodiagnosis of Chagas' disease were used: 74.19% by IHA, 91.93% by IFA, and 76.80% by ELISA. We have previously purified by immunoaffinity, using a monoclonal antibody, an antigen termed Ag163B6 which is not present in L. mexicana. This antigen has shown the ability to specifically differentiate sera of chronic chagasic patients from those of leishmaniasic patients in ELISA. Furthermore, recent studies from our laboratory by immunoblotting, have demonstrated that chronic chagasic patients exhibit a specific reactivity pattern against T. cruzi epimastigotes that can be distinguished from those presented by leishmaniasic patients in spite of cross-reactive antigens. According to the results obtained in these assays, we classified the patients in two groups: 1) Patients with evidence of T. cruzi infection, those who tested positive in at least one assay: 2) Patients with no evidence of T. cruzi infection who were negative for both assays. More than 50% (32/62) of the patients showed strong evidence of mixed infection with T. cruzi. On the other hand, high cross-reactivity between these two parasitoses was shown in the second group without any evidence of T. cruzi infection since 18 out of 30 were positive in at least two conventional serological reactions. This implies that they would be misdiagnosed as chagasics if conventional reactions were used. These results emphasize the importance of the use of defined antigens and appropriate techniques for the differential diagnosis of these parasitoses, which is more important in areas endemic for both of them.

Author: 
Date: 
01/01/1995
Investigation Line: 

Abstract

A fatal case of strongyloidiasis in a boy aged 8 months, referred to our hospital, with severe malnutrition, dehydration, brownish fluid through the naso-gastric tube and relapsing chronic diarrhea with bloody mucus. Through all symptoms and observation of rabditoid larvae, eggs and even adult females, parasitologic diagnosis was achieved. In spite of medical intensive care the patient died after 18 days of hospitalization. Disease's pathophysiology is discussed as well as a review about the trustfulness of the parasite biological cycle as is traditionally described in the literature. Ability is questioned of rabditoid larvae to follow the alternative way as free living adults or parasitic living in adults.

Date: 
01/01/1994
Investigation Line: 

Abstract

In an open trial, longer courses of pentavalent antimonials (Sbv) at sub-optimal doses (10 mg/kg body weight), in association with recombinant human interferon-gamma (IFN-gamma) (100 micrograms/m2 of body surface area) were administered, by daily intramuscular injections, to 13 patients with diagnoses of cutaneous or mucocutaneous leishmaniasis unresponsive to Sbv. Four patients presented with large skin ulcers, and 9 had mucosal involvement as the main manifestation, the latter affecting the nose (3 cases), nose and septum (2 cases), nose and oral cavity (1 case), and nose, pharynx and larynx (3 cases). Except for one case with severe involvement of the upper respiratory tract, the lesions were fully resolved by the end of therapy (mean duration 40 +/- 12 [SD] d, range 30-60 d) in the 11 patients who completed therapy. The main side effects were headache and fever (7 cases), together with leucopenia and eosinophilia (4 cases). It is concluded that combined administration of low doses of Sbv plus IFN-gamma may provide a novel therapeutic approach for the treatment of antimony-resistant cutaneous or mucocutaneous leishmaniasis. The possible mechanisms by which IFN-gamma contributes to resolution of the disease are discussed.

Date: 
07/01/1993
Investigation Line: 

Abstract

An enteroparasitological, clinical and epidemiological study was carried out in 36 infants who attended the Hospital San Vicente de Paul from Orán for medical assistance. The age of the children varied between 0 and 4 years with an average of 28 months. The main clinical causes for consultation were bronchitis (52.8%), inappetence (52.8%) and paleness (27.8%). The general characteristics of the stool samples were: formed 44.4% and diarrheic 55.6%. The frequency of intestinal helminthic and protozoan elements was the following: S. stercoralis 30(83.3%) N. americanus 5(13.9%), A. lumbricoides 7(19.4%), T. trichiura 3(8.3%), H. nana 5(13.9%), G. intestinalis 10(27.8%), I. belli 1 (2.8%) and E. coli 4 (11.1%). The nutritional condition found in the infants, according to the relation high/weight was: eutrophic 17(42.2%), lightly undernourished 9(20.0%), moderately undernourished 9(25.0%) and severely undernourished 1(2.8%). The mean values of hematocrit and hemoglobin found were under those established as minima by the W.H.O. The white blood cells and eosinophils countings were over the normal mean values.

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