No abstract

In October 1986, 7 to 22 days after a meeting at a farm in Paraíba state, 26 individuals presented with a febrile illness associated with bilateral eyelid and lower limb edema, mild hepatosplenomegaly, lymphadenopathy and, occasionally a skin rash. A 11-year-old boy exhibited atrial premature complexes and a 74-year-old patient developed acute heart failure. In two patients hospitalized in São Paulo city, acute Chagas' disease was diagnosed by the demonstration of circulating Trypanosoma cruzi. At autopsy in a fatal case, acute Chagas' cardiomyopathy was demonstrated. Xenodiagnosis were positive in 9 out of 14 tested patients. A specific IgG immune response was found in all patients and specific IgM antibodies were identified in 20 out of 22 tested patients. A epidemiological survey showed the existence of Triatoma brasiliensis in the outbuildings of this farm, but none in the house where most of the guests stayed. A high rate of infection with Trypanosoma cruzi was found in opossums. These observations together with those related to the food consumed by the patients, lead the authors to suggest that the human infections resulted from oral contamination probably originating from naturally infected marsupials in the area or crushed infected bugs.

Eumycetoma and chromoblastomycosis are chronic, disfiguring fungal infections of the subcutaneous tissue that rarely resolve spontaneously. Most patients do not achieve sustained long-term benefits from available treatments; therefore, new therapeutic options are needed. We evaluated the efficacy of posaconazole, a new extended-spectrum triazole antifungal agent, in 12 patients with eumycetoma or chromoblastomycosis refractory to existing antifungal therapies. Posaconazole 800 mg/d was given in divided doses for a maximum of 34 months. Complete or partial clinical response was considered a success; stable disease or failure was considered a nonsuccess. All 12 patients had proven infections refractory to standard therapy. Clinical success was reported for five of six patients with eumycetoma and five of six patients with chromoblastomycosis. Two patients were reported to have stable disease. As part of a treatment-use extension protocol, two patients with eumycetoma who initially had successful outcome were successfully retreated with posaconazole after a treatment hiatus of > 10 months. Posaconazole was well tolerated during long-term administration (up to 1015 d). Posaconazole therapy resulted in successful outcome in most patients with eumycetoma or chromoblastomycosis refractory to standard therapies, suggesting that posaconazole may be an important treatment option for these diseases.

One of the major drawbacks limiting the use of synthetic peptide vaccines in genetically distinct populations is the fact that different epitopes are recognized by T cells from individuals displaying distinct major histocompatibility complex molecules. Immunization of mice with peptide (181-195) from the immunodominant 43 kDa glycoprotein of Paracoccidioides brasiliensis (gp43), the causative agent of Paracoccidioidomycosis (PCM), conferred protection against infectious challenge by the fungus. To identify immunodominant and potentially protective human T-cell epitopes in gp43, we used the TEPITOPE algorithm to select peptide sequences that would most likely bind multiple HLA-DR molecules and tested their recognition by T cells from sensitized individuals. The 5 most promiscuous peptides were selected from the gp43 sequence and the actual promiscuity of HLA binding was assessed by direct binding assays to 9 prevalent HLA-DR molecules. Synthetic peptides were tested in proliferation assays with peripheral blood mononuclear cells (PBMC) from PCM patients after chemotherapy and healthy controls. PBMC from 14 of 19 patients recognized at least one of the promiscuous peptides, whereas none of the healthy controls recognized the gp43 promiscuous peptides. Peptide gp43(180-194) was recognized by 53% of patients, whereas the other promiscuous gp43 peptides were recognized by 32% to 47% of patients. The frequency of peptide binding and peptide recognition correlated with the promiscuity of HLA-DR binding, as determined by TEPITOPE analysis. In silico prediction of promiscuous epitopes led to the identification of naturally immunodominant epitopes recognized by PBMC from a significant proportion of a genetically heterogeneous patient population exposed to P. brasiliensis. The combination of several such epitopes may increase the frequency of positive responses and allow the immunization of genetically distinct populations.

Forty-two patients with active paracoccidioidomycosis were randomized to receive itraconazole (50-100 mg d(-1)), ketoconazole (200-400 mg d(-1)) or sulfadiazine (100-150 mg kg d(-1) up to 6 g d(-1)) for 4-6 months, followed by slow release sulfa until negativity of serological tests. All 14 patients in itraconazole and sulfadiazine groups and 13 in the ketoconazole group showed an adequate clinical response to the chemotherapy. One patient in the latter group showed treatment failure according to clinical and mycological criteria. The test of the hypothesis that the drugs reduced antibody levels up to ten months of treatment showed a p value equal to 0.0001 for itraconazole, 0.017 for ketoconazole and 0.0012 for sulfadiazine; this reduction was similar for the three groups. In this first randomized study for the treatment of paracoccidioidomycosis we could not show superiority of any one regimen over the others in the clinical and serological responses of patients with the moderately severe form of the disease.

A series of 18 patients with chronic Chagas' disease and human immunodeficiency virus infection were followed up for 2 to 66 months (median, 15.5 months). Artificial xenodiagnosis was positive for 81.3% and natural xenodiagnosis was positive for 81.8% of patients for whom they were performed; 81.8% of 11 patients had medium- or high-level parasitemia. Reactivation of Chagas' disease--direct microscopic examination of blood revealing parasites and, clinically, patients presenting with cardiac disease--occurred in three patients (16.7%). Specific antitrypanosomal treatment with benznidazole was effective in reducing the level of parasitemia and improving the clinical condition in three of the four patients treated.

American tegumentary leishmaniasis (ATL), an endemic anthropozoonosis in various countries in the world, is caused by parasites of the genus Leishmania. Despite reports on ATL reactivation as a result of immunosuppression, to the best of our knowledge, this paper describes the first case of ATL reactivation in its localized form (cutaneous leishmaniasis) associated with the administration of systemic corticosteroids. The possible action of corticosteroids on the host immune response to the parasite in patients with localized cutaneous leishmaniasis is discussed. This report demonstrates the possibility of ATL reactivation in patients using corticosteroids, an observation that should be considered in individuals treated with this medication.

To evaluate the possible role of parasitemia on Chagas' disease reactivation in Chagas' disease/human immunodeficiency virus (HIV) coinfection cases and the impact of HIV coinfection on Trypanosoma cruzi genetic diversity, 71 patients with Chagas' disease (34 HIVϩ and 37 HIV-) were surveyed. Moreover, 92 T. cruzi stocks from 47 chronic chagasic patients (29 HIVϩ and 18 HIV-) were isolated and analyzed by multilocus enzyme electrophoresis and a random amplified polymorphic DNA procedure. High parasitemia appeared to play a major role in cases of Chagas' disease reactivation. In HIVϩ patients, the genetic diversity and population structure (clonality) of T. cruzi was similar to that previously observed in HIV-patients, which indicates that immunodepression does not modify drastically genotype repartition of the parasite. There was no apparent association between given T. cruzi genotypes and specific clinical forms of Chagas' disease/HIV associations. Chagas' disease, the American trypanosomiasis, is widespread from the southern United States (where the indigenous cases are rare) to northern Argentina. It is characterized by two successive phases, an acute one, with high parasitemia, and a chronic one, with low parasitemia. Although efficient measures of transmission control have been implemented in some countries (by eliminating the insect vector), Chagas' disease still is a priority health problem in Latin America. Chagas' disease/human immunodeficiency virus (HIV) associations appear to be a growing threat in large Latin American cities, and can be extremely pathogenic, with severe cases involving the central nervous system (CNS) with either tumoral lesions or meningoencephalitis. 1-5