A survey of congenital Chagas’ disease, carried out at three Health Institutions in São Paulo City, Brazil

The congenital transmission of Chagas’ disease was evaluated in 57 pregnant women with Chagas’ disease and their 58 offspring. The patients were selected from three Health Institutions in São Paulo City. The maternal clinical forms of Chagas’ disease were: indeterminate (47.4%), cardiac (43.8%) and digestive (8.8%); 55 were born in endemic areas and two in São Paulo City. The transmission of Chagas’ disease at fetal level was confirmed in three (5.17%) of the 58 cases studied and one probably case of congenital Chagas’ disease. Two infected infants were born to chagasic women with HIV infection and were diagnosed by parasitolological assays (microhematocrit, quantitative buffy coat-QBC or artificial xenodiagnosis). In both cases the placenta revealed T. cruzi and HIV p24 antigens detected by immunohistochemistry. In one case, a 14-week old abortus, the diagnosis of congenital T. cruzi infection was confirmed by immunohistochemistry. The other probable infection, a 30-week old stillborn, the parasites were found in the placenta and umbilical cord. The Western blot method using trypomastigote excreted/secreted antigens of T. cruzi (TESA) was positive for IgG antibodies in 54/55 newborns and for IgM in 1/55 newborns. One of the two newborns with circulating parasites had no detectable IgG or IgM antibodies. The assessment of IgG antibodies in the sera of pregnant women and their newborns was performed by ELISA using two different T. cruzi antigens: an alkaline extract of epimastigotes (EAE) and trypomastigote excreted/secreted antigens (TESA). The analysis showed a linear correlation between maternal and newborn IgG antibody titers at birth.

Inoculation of Lacazia loboi into the subcutaneous tissue of the hamster cheek pouch

The subcutaneous tissue of the hamster cheek pouch, a site of immunologic privilege, has been used to investigate the potential infectivity of different types of parasites. It has been demonstrated that the implantation of fragments of lesions induced by the fungus Lacazia loboi, the etiologic agent of Jorge Lobo's disease, into the subcutaneous tissue of the hamster cheek pouch resulted in parasite multiplication and dissemination to satellite lymph nodes16. Here we describe the evolution of lesions induced by the inoculation of the isolated fungus into this immunologically privileged site. The morphology of the inflammatory response and fungal viability and proliferation were evaluated. Inoculation of the fungus into the cheek pouch induced histiocytic granulomas with rare lymphocytes. Although fungal cells were detected for a period of up to 180 days in these lesions, the fungi lost viability after the first day of inoculation. In contrast, when the parasite was inoculated into the footpad, non-organized histiocytic lesions were observed. Langhan's giant cells, lymphocytes and fungal particles were observed in these lesions. Fungal viability was observed up to 60 days after inoculation and non-viable parasites were present in the persistent lesions up to 180 days post-inoculation. These data indicate that the subcutaneous tissue of the hamster cheek pouch is not a suitable site for the proliferation of Lacazia loboi when the fungus isolated from human tissues is tested.

Persistent infections in chronic Chagas' disease patients treated with anti-Trypanosoma cruzi nitroderivatives

We used a molecular method and demonstrated that treatment of the chronic human Trypanosoma cruzi infections with nitroderivatives did not lead to parasitological cure. Seventeen treated and 17 untreated chronic Chagas' disease patients, with at least two out of three positive serologic assays for the infection, and 17 control subjects formed the study groups. PCR assays with nested sets of T. cruzi DNA primers monitored the efficacy of treatment. The amplification products were hybridized to their complementary internal sequences. Untreated and treated Chagas' disease patients yielded PCR amplification products with T. cruzi nuclear DNA primers. Competitive PCR was conducted to determine the quantity of parasites in the blood and revealed < 1 to 75 T. cruzi/ml in untreated (means 25.83 ± 26.32) and < 1 to 36 T. cruzi/ml in treated (means 6.45 ± 9.28) Chagas' disease patients. The difference between the means was not statistically significant. These findings reveal a need for precise definition of the role of treatment of chronic Chagas' disease patients with nitrofuran and nitroimidazole compounds.

Heart rate responses to a muscarinic agonist in rats with experimentally induced acute and subacute chagasic myocarditis

We administered arecoline to rats, with experimentally induced chagasic myocarditis, in order to study the sinus node sensitivity to a muscarinic agonist. Sixteen month old rats were inoculated with 200,000 T. cruzi parasites ("Y" strain). Between days 18 and 21 (acute stage), 8 infected rats and 8 age-matched controls received intravenous arecoline as a bolus injection at the following doses: 5.0, 10.0, 20.0, 40.0, and 80.0 mug/kg. Heart rate was recorded before, during and after each dose of arecoline. The remaining 8 infected animals and 8 controls were subjected to the same experimental procedure during the subacute stage, i.e., days 60 to 70 after inoculation. The baseline heart rate, of the animals studied during the acute stage (349 ± 68 bpm, mean ± SD), was higher than that of the controls (250 ± 50 bpm, p < 0.005). The heart rate changes were expressed as percentage changes over baseline values. A dose-response curve was constructed for each group of animals. Log scales were used to plot the systematically doubled doses of arecoline and the induced-heart rate changes. The slope of the regression line for the acutely infected animals (r = - 0.99, b =1.78) was not different from that for the control animals (r = - 0.97, b = 1.61). The infected animals studied during the subacute stage (r = - 0.99, b = 1.81) were also not different from the age-matched controls (r = - 0.99, b = 1.26, NS). Consequently, our results show no pharmacological evidence of postjunctional hypersensitivity to the muscarinic agonist arecoline. Therefore, these results indirectly suggest that the postganglionic parasympathetic innervation, of the sinus node of rats with autopsy proved chagasic myocarditis, is not irreversibly damaged by Trypanosoma cruzi.

Occurrence of Cryptosporidium oocysts and Giardia cysts in raw water from the Atibaia river, Campinas, Brazil

Cryptosporidium parvum and Giardia duodenalis are waterborne parasites that have caused several outbreaks of gastrointestinal disease associated with drinking water. Due to the lack of studies about the occurrence of these protozoa in water in the Southeast of Brazil, an investigation was conducted to verify the presence of cysts and oocysts in superficial raw water of the Atibaia River. The water samples were submitted to membrane filtration (3.0 mum) and elution was processed by (1) scraping and rinsing of membrane (RM method) and (2) acetone-dissolution (ADM method). Microbiologic and chemical parameters were analyzed. Aliquots of the pellets were examined by immunofluorescence (Merifluor, Meridian Diagnostics, Cincinnati, Ohio). All water samples were positive for Cryptosporidium and Giardia, in spite of the high turbidity. Higher recovery rates occurred in samples treated by the RM method than by the ADM technique. The goal for future work is the assessment of viability of cysts and oocysts to determine the public health significance of this finding.

Leishmaniasis in the genital area

Two patients from the gold mines of Bolivar State, Venezuela, presenting cutaneous leishmaniasis in the genital region, an unusual location, are described. The first patient showed an ulcerated lesion of the glans penis. Leishmanin skin test was positive. A biopsy specimen revealed a granulomatous infiltrate containing Leishmania parasites. In the second patient, Leishmanin skin test was positive, HIV and VDRL were negative. Leishmania parasites were present in a biopsy of an ulcerated lesion in the scrotum, with an indurated base, infiltrative borders with an yellowish exudate. Patients were treated with meglumine antimoniate and the lesions healed.

Anti-trypanosomal activity of pentacyclic triterpenes isolated from Austroplenckia populnea (Celastraceae)

Four pentacyclic triterpenes isolated from Austroplenckia populnea and four compounds of known anti T. cruzi or anti-malarial activity were tested. Of those triterpenes tested 20alpha-hydroxy-tingenone showed high activity, epikatonic acid was less active, while populnilic and populninic acids were inactive against the trypanosome of the subgenus Schizotrypanum tested. Benzonidazole, nifurtimox, ketoconazole and primaquine presented a remarkable dose-dependent inhibitory effect reaching practically to a total growth inhibition of the parasite at the end of incubation time. The trypanosome tested appear to be a suitable model for preliminary screen for anti T. (S.) cruzi compounds.

Visceral leishmaniasis caused by Leishmania (Viannia) braziliensis in a patient infected with human immunodeficiency virus

The current article reports the case of a 19-month-old-girl, from the state of Minas Gerais, Brazil, with visceral leishmaniasis, by Leishmania (Viannia) braziliensis, and Human Immunodeficiency Virus (HIV) co-infection. The child's mother and father, aged 22 and 27 years old, respectively, were both HIV positive. The child was admitted to the General Pediatric Center, in Belo Horizonte, presenting high fever, fatigue, weight loss and enlargement of liver and spleen. Indirect immunofluorescent test revealed a titer of 1:320 for Leishmania. Such result was confirmed by the presence of amastigotes in bone marrow aspirate samples and culture of promastigote forms. Parasites were identified as being Leishmania (Viannia) braziliensis through PCR, using a L. braziliensis complex primer and a generic primer, followed by hibridization. Specific leishmaniasis therapy (GlucantimeÒ antimonial) was intravenously administered.

Assessment of PCR in the detection of Leishmania spp in experimentally infected individual phlebotomine sandflies (Diptera: Psychodidae: Phlebotominae)

DNA amplification by the polymerase chain reaction (PCR) was applied in the investigation of the presence of Leishmania (Kinetoplastida: Trypanosomatidae) parasites in single phlebotomine sandflies. Three phlebotomine/parasite pairs were used: Lutzomyia longipalpis/Leishmania chagasi, Lutzomyia migonei/Leishmania amazonensis and Lutzomyia migonei/Leishmania braziliensis, all of them incriminated in the transmission of visceral or cutaneous leishmaniasis. DNA extraction was performed with whole insects, with no need of previous digestive tract dissection or pooling specimens. The presence of either mouse blood in the digestive tract of the sandflies or the digestive tract itself did not interfere in the PCR. Infection by as few as 10 Leishmania sp. per individual were sufficient for DNA amplification with genus-specific primers. Using primers for L. braziliensis and L. mexicana complexes, respectively, it was possible to discriminate between L. braziliensis and L. amazonensis in experimentally infected vectors (L. migonei).

Evaluation of a rapid dipstick test, Malar-CheckTM, for the diagnosis of Plasmodium falciparum malaria in Brazil

The present study was carried out to evaluate the Malar-CheckTM Pf test, an immunochromatographic assay that detects Plasmodium falciparum Histidine Rich Protein II, does not require equipment, and is easy and rapid to perform. In dilution assays performed to test sensitivity against known parasite density, Malar-CheckTMwere compared with thick blood smear (TBS), the gold standard for diagnosis. Palo Alto isolate or P. falciparum blood from patients with different parasitemias was used. The average cut-off points for each technique in three independent experiments were 12 and 71 parasites/mm³ (TBS and Malar-CheckTM, respectively). In the field assays, samples were collected from patients with fever who visited endemic regions. Compared to TBS, Malar-CheckTMyielded true-positive results in 38 patients, false-positive results in 3, true-negative results in 23, and false-negative result in 1. Malar-CheckTMperformed with samples from falciparum-infected patients after treatment showed persistence of antigen up to 30 days. Malar-CheckTM should aid the diagnosis of P. falciparum in remote areas and improve routine diagnosis even when microscopy is available. Previous P. falciparum infection, which can determine a false-positive test in cured individuals, should be considered. The prompt results obtained with the Malar-CheckTM for early diagnosis could avoid disease evolution to severe cases.

Clinical and laboratory findings of Plasmodium vivax malaria in Colombia, 2001

A descriptive study was carried out in 104 patients with Plasmodium vivax malaria, from the region of Turbo (Antioquia, Colombia). Clinical features and levels of hemoglobin, glycemia, serum bilirubin, alanine-aminotransferase (ALT), aspartate-aminotransferase (AST), creatinine and complete blood cell profile were established. 65% of the studied individuals were men and their mean age was 23. Of all individuals 59% had lived in the region for > 1 year and 91% were resident in the rural area. 42% were farmers and 35% had a history of malaria. The mean parasitaemia was 5865 parasites/mm³. The evolution of the disease was short (average of 4.0 days). Fever, headache and chills were observed simultaneously in 91% of the cases while the most frequent signs were palmar pallor (46%), jaundice (15%), hepatomegaly (17%), and spleen enlargement (12%). Anemia was found in 39% of the women and in 51% of the men, 8% of individuals had thrombocytopaenia and 41% had hypoglycemia.

P System antigenic determiners expression in Ascaris lumbricoides

The P System antigens have been detected in numerous parasites, bacterias and viruses, nevertheless the clinical significance is still unknown. The aim was to study the presence of P1 antigenic determiners in A. lumbricoides extracts by means of the use of 6 different monoclonal antibodies of well-known concentrations and Ig class. We worked with 14 A. lumbricoides extracts. Inhibition Agglutination Test was made in a bromelin enzymatic medium and 4 ºC temperature. Titre, Score and Sensitivity Parameter were determined for each monoclonal antibody against red cells suspension used as revealing system. Ten extracts inhibited the agglutination of all anti P1 monoclonal antibodies. The 4 remaining extracts only inhibited the agglutination of some of them. It is demonstrated that the extracts have P1 activity. This activity is independent of titre, Score, Sensitivity Parameter, concentration and Ig class and it depends on the epitope at which the monoclonal antibody is directed.

ABO System: molecular mimicry of Ascaris lumbricoides

A. lumbricoides has been associated to the ABO System by various authors. The objective was to detect ABO System epitopes in A. lumbricoides of groups O, A, B and AB patients. 28 adult parasites were obtained from children to be used as assay material. The patients ABO blood groups were determined. Extracts of A. lumbricoides [AE] were prepared by surgical remotion of the cuticle and refrigerated mechanical rupture. Agglutination Inhibition (AI) and Hemoagglutination Kinetics (HK) tests were used with the [AE]. Of the 28 [AE], eight belonged to O group patients, 15 to A group, three to B group and the remaining two to AB children. The AI Test showed A epitopes in two [AE] of group A patients and B epitopes in two [AE] of group B patients. The HK Test showed B antigenic determiners in two [AE] of group B patients and in two [AE] of group AB patients as well as A antigenic determiners in one [AE] of A group patient. Of the 28 [AE] studied in both tests B epitopes were detected in all [AE] from B and AB patients and A epitopes in three of the 15 [AE] of group A patients. The experiments carried out suggest that A. lumbricoides might absorb A and B antigens from the host, and/or modify the cuticular carbohydrates expression as a kind of antigenic mimicry.