Suitability of a rapid DNA isolation and amplification for detection of Trypanosoma cruzi in Triatoma infestans dry fecal spots collected on filter paper.

A rapid DNA extraction was used for T. cruzi detection in triatomines dry fecal spots collected on filter paper and analyzed by PCR. Fifty T. infestans were fed on experimentally infected Balb/C mice with high T. cruzi parasitemia and divided into five groups of ten triatomines, and 100 triatomines were infected with lower parasitemia and divided into five groups of 20 triatomines. One dry fecal spot was analyzed per group on days 1, 2, 3, 4 and 5 post feeding. Amplification targeted T. cruzi TCZ sequence and resulted positive from day 4 after bugs feeding in the two models (high and lower parasitemial. The rapid DNA isolation and PCR proposed are suitable for detection of T. cruzi DNA in filter paper and should be considered in field research.

Human cyclosporiasis diagnosis: report of a case in São Paulo, SP, Brazil.

Diagnosis of the human cyclosporiasis is reported in São Paulo, SP, Brasil. Cyclospora cayetanensis has been identified in the feces of a patient by a modified Kinyoun staining method, with later sporulation in a solution of 2.5% potassium dichromate. The probability that this parasite is the eventual cause of gastrointestinal disturbances in the country was stimulated by this finding, which was arrived at by a simple technique. It had been kept in mind that the disease was expressing itself mainly among immunocompromised patients, whose number is increasing; especially in those with acquired immunodeficiency syndrome (AIDS), which is caused by the human immunodeficiency virus (HIV).

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 parasitological 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.

[New process for screening of drugs in experimental infection with Trypanosoma cruzi]. / Novo processo para triagem de medicamentos na infecção experimental pelo Trypanosoma cruzi.

We propose a screening process for detection of therapeutic activity of drugs against experimental infection with Trypanosoma cruzi. It is based on the use of infected triatominae that are fed on mice which have received the study drug. Blood meals are made at different time schedule in order to adapt with serum drug levels. The digestive tube of the hemiptera will, thus, work as a suitable structure for examination. In a initial observation, benzonidazole was used, and was shown to be only partially active at least in the conditions of this new procedure.

Trypanosoma cruzi parasitemia observed in immunocompromised patients: the importance of the artificial xenodiagnosis.

Trypanosoma cruzi parasitemia observed in immunocompromised patients (transplant or positive HIV) occurred more frequently by the artificial xenodiagnosis method (10/38) compared with hemoculture (2/38), given the same quantity of blood. Other ways of diagnosis, like mice inoculation (5/38), QBC and buffy coat (2/38), were evaluated also. This result showed the importance of the artificial xenodiagnosis. The other techniques increased only one more patient positive.

[Attempts to culturing triatominae in the laboratory using "in vitro" feeding]. / Tentativas de criação de triatomíneos em laboratório por meio de alimentação "in vitro".

In order to simplify breeding of triatominae in the laboratory, for performing xenodiagnosis and other biologic studies, we tried to feed the insects "in vitro" with citrated or defibrinated blood from commercially abated chicken. Two types of efficacy observations were carried out with Triatoma infestans: a) analysis of the chaining of successive nymphal stages, viability of satisfactory matching, fertile oviposition and adequate reproduction; b) assessment of viability and infectivity of Trypanosoma cruzi in the insects. As a conclusion, it became evident that, despite operational easiness, the objectives were not achieved, since the classical procedure used as the control, was always superior.

[Viability of Trypanosoma cruzi in sugar cane juice]. / Observações sobre a viabilidade do Trypanosoma cruzi no caldo da cana.

In Catolé do Rocha, State of Paraíba, Brasil several people were concomitantly contaminated by Chagas' disease and had the acute form of the infection. Because of this event, the hypothesis that Trypanosoma cruzi might have been transmitted by the digestive route, through the ingestion of accidentally contaminated sugar cane juice, was made. In the present study, we verified that the parasite has remained viable for four hours in the liquid, at room temperature. We have also demonstrated that, after one hour, it was capable of promoting infection in one mouse, by gastric tube administration. These observations enhance the interest on this alternative mechanism of disease transmission.

[The treatment of rats experimentally infected with Strongyloides venezuelensis by orally administered ivermectin]. / Tratamento de ratos, experimentalmente infectados pelo Strongyloides venezuelensis, através da ivermectina administrada por via oral.

Strongyloides venezuelensis experimental infection in rats was treated by two different oral preparations of ivermectin, 0.2 mg/kg. One was a human formula used by WHO in the treatment of onchocerciasis; the other was a veterinary preparation. Adult worms and larvae were evaluated. The human formulation cleared both forms in 59.3% (adult worms) and 73.0% (larvae), whereas the veterinary one cleared 98.0% and 84.2%, respectively. The antilarval action is very useful when treating systemic strongyloidiasis.

[Experimental infection in mice by Plasmodium berghei: an evidence of antiparasitic action of azithromycin]. / Evidência da ação antiparasitária da azitromicina na infecção experimental de camundongos pelo Plasmodium berghei.

Infections of Plasmodium berghei in mice was stopped by azithromycin which was administered orally in dosages of 100mg/kg, for 28 days. This antibiotic was given since the same day that the animals were infected. The outcome suggests the necessity of more investigations on this antiparasitic activity.

[Evaluation of antiparasitic activity of allopurinol, against Trypanosoma cruzi, in experimental system using infected triatomines]. / Avaliação da atividade antiparasitária do alopurinol, referente ao Trypanosoma cruzi, em sistema experimental que utiliza triatomíneos infectados.

The antiparasitic activity of allopurinol, against Trypanosoma cruzi, was evaluated by a procedure using infected triatomines. This methodology indicated that the drug was unable to eliminate the protozoa in the digestive tract of the insects. Therefore, further knowledge to improve our understanding of allopurinol in the context of the etiologic treatment of infection by T. cruzi was not acquired. Despite this finding the drug continues to be used, even though its performance appears to be full of divergences and contradictions.

[The evaluation of the effect of formol and sodium hypochlorite on the demonstration of Cryptosporidium oocysts in feces by Heine's method]. / Avaliação da influência do formol e do hipoclorito de sódio na pesquisa de oocistos de Cryptosporidium nas fezes, através do método de heine.

Cryptosporidium oocysts were searched by Heine's method in stools of nine calves with cryptosporidiosis after stool treatment with two disinfectants, 10% paraformaldehyde solution and 14.5% sodium hypochlorite solution. After 30 minutes exposition to sodium hypochlorite solution oocysts became non refractile and acquired a reddish tinge, making their identification difficult. No morphological alterations occurred in oocysts after paraformaldehyde treatment. We recommend paraformaldehyde at 10% concentration as means of human immunodeficiency virus (HIV) inactivation for routine use in stool examinations and therefore making safer those type of procedures for laboratory personnel, when using Heine's method.

[The evaluation of the efficacy of azithromycin and pyrimethamine used alone or in combination in the treatment of an experimental infection in mice by Toxoplasma gondii]. / Avaliação da eficácia da azitromicina e da pirimetamina, usadas isolada ou associadamente, no tratamento de infecção experimental de camundongos pelo Toxoplasma gondii.

The efficacy of azithromycin and pyrimethamine in experimental infection of mice with Toxoplasma gondii was tested. Daily dosages of 200 mg/kg and 12.5 mg/kg, respectively, were given orally over a period of ten days. The medications were administered in combination or separately. The combined use of the drugs yielded better results, and a similar investigation using a cystogenic strain of the parasite will be conducted in a future study.

[Oocysts of Cryptosporidium sp in feces: comparison of the modified Kinyoun and Heine methods]. / Pesquisa de oocistos de Cryptosporidium sp em fezes: comparação entre os métodos de Kinyoun modificado e de Heine.

The diagnosis of intestinal infection by Cryptosporidium sp is crucial today; with the progression of the AIDS epidemic, many cases of cryptosporidiosis have appeared in this setting and in other immunodeficiency diseases. We compared the advantages and disadvantages of Heine's method and modified Kinyoun's method in the following parameters: morphology of the parasite, quantitation of cysts, stability of the staining characteristics timewise on the slides and time spend at staining. All positive fecal smears were obtained from patients with AIDS. The sensitivity of these two techniques was the same. The choice should be made by the best aspects of each method. Heine's was better for quantitation of the cysts and was faster. Kinyoun's was better for conserving the stained smear.

[Detection of Cyclospora sp oocysts in the feces of stray dogs in Greater São Paulo (São Paulo State, Brazil)]. / Pesquisa de oocistos de Cyclospora sp em fezes de cães da Grande São Paulo, Estado de São Paulo, Brasil.

Fecal samples from 140 adult stray dogs of Greater São Paulo (São Paulo State, Brazil) were examined for Cyclospora sp oocysts. No cases of infection by this coccidium were detected.

[The use of sodium azide as a fecal preservative for studying the eggs of Schistosoma mansoni and of other helminths by the Kato-Katz method: a study in an endemic area]. / Emprego da azida sódica, como conservador de fezes, para a pesquisa de ovos de Schistosoma mansoni e de outros helmintos, pelo método de Kato-Katz: estudo em área endêmica.

In two aliquots of 208 samples of stool, tests have been made by the Kato-Katz method, one being made after the use of 0.2mg of sodic azide for 200mg, and the other without the aforesaid conservant. The resulted percentages with or without the conservant were, respectively, for Ancylostomideos: 12.5 and 25.9; for Ascaris lumbricoides: 71.6 and 72.5; for Schistosoma mansoni: 7.6 and 17.7, and for Trichuris trichiura: 86 and 85. The count of the eggs with and without the conservant was, respectively, 264 and 539 for Ancylostomideos, 13186 and 33751 for A. lumbricoides, 55.5 and 63.5 for S. mansoni, and 1345 and 2068 for T. trichiura. The authors did not confirm the advantage of using sodic azide for study in endemic areas. They suggest that the exsiccation of the stool and the low intensity of infections can explain the unfavourable results of the present clinical trial.

[Eventual effect of artemisinine on the experimental infection of mice by Toxoplasma gondii]. / Estudo sobre a eventual ação da artemisinina na infecção experimental de camundongos pelo Toxoplasma gondii.

Because of taxonomic similarities to previous data found in the literature, and with the aim of improving treatment of toxoplasmosis, we considered it of interest to assay artemisinin, an effective anti-malarial agent, for the treatment of experimental infection in mice by Toxoplasma gondii. Different amounts of the anti-parasitic agent were administered, including after previous contact in vitro with toxoplasma and stimulated macrophage production. With the methodology used artemisinin was not effective. Suggestions for further studies are made.

[The treatment of cryptosporidiosis in AIDS patients using paromomycin]. / Tratamento da criptosporidíase em pacientes com AIDS, por meio da paromomicina.

The authors treated with paromomycin 25 patients, with AIDS and cryptosporidiosis. The drug was given orally in a doses of 500 mg qid, for a period of 14 days. Tolerance was good, with just two cases of mild side-effects. Clinical improvement was obtained in 19 (76%) patients. Parasitological cure, however, occurred only in a low percentage (25%). In some cases where initial success was observed, recrudescence occurred after some weeks or few months, but with retreatment again clinical improvement was obtained. Even if it does not lead to frequent parasite eradication, the good clinical results and tolerance permit us to consider paromomycin one of the few drugs effective for the treatment of cryptosporidial diarrhea in AIDS patients. Studies with maintainance therapy are indicated.

[Utility of gamma rays in prophylaxis of transmissible malaria by blood transfusion]. / Estudo sobre a eventual utilidade de raios gama na profilaxia da malária transmissível por transfusão de sangue.

This study was carried out to evaluate the fortuitons advantage of using gamma irradiation in the prophylaxis of transmissible malaria by blood transfusion, with mice as the experimental model. In the first step, when the infected blood with Plasmodium berghei was submitted to 2,500 rad and 5,000 rad, with or without metronidazol, there was no success, because the animals presented parasitaemia and died after inoculation of irradiated blood. However, there was partial success in the second step, when the infected blood received 10,000 and 15,000 rad, and was inoculated in mice, which showed infection, and presented a survival rate of 20% and 40%, respectively, with later negativation of blood infected by P. berghei.

[Determination of HIV protein 24 in feces of Triatoma infestans fed with blood from AIDS patients]. / Pesquisa da proteína 24 do vírus da imunodeficiência humana (HIV) nas fezes de triatomíneos alimentados em pacientes com AIDS.

OBJECTIVE: To verify any possibility of the elimination of p24 in feces of Triatoma infestans, p24 being an antigen and one of the markers of HIV infection. The purpose of the study was the evaluation of any risk of contamination by laboratory staff who work with activities related to this particular insect, and also investigate any mechanism that might thus lead to the dissemination of HIV. METHOD: Triatoma infestans were fed with p24-marked blood from 23 AIDS patients. Twenty-four and 48 hours later, their feces were examined in order to verify the presence of the antigen. The search for p24 was performed by means of the immunoenzymatic technique. RESULT AND CONCLUSION: No protein 24 was detected in any of the samples. In accordance with the applied methodology, the purpose of showing that the elimination of p24 does not occur, was obtained. Were this question approached in other ways different results might reveal new information in terms of risks of HIV dissemination.

Human cryptosporidiosis: detection of specific antibodies in the serum by an indirect immunofluorescence.

Cryptosporidium sp., a coccidian parasite usually found in the faeces of cattle, has been recently implicated as an agent of human intestinal disease, mainly in immunocompromised patients. In the study realized, by an indirect immunofluorescence technique, specific immunoglobulins (IgG and IgM) have been demonstrated in human serum against Cryptosporidium oocysts. Purified oocysts were used as antigens in the indirect immunofluorescence assay. After analyzing this test in sera from selected groups of patients, the frequency of both specific IgG and IgM of immunocompetent children who were excreting oocysts in their faeces was 62% and in children with negative excretion of oocytes was 20% and 40%, respectively. In adults infected with the human immunodeficiency virus (HIV) and who were excreting Cryptosporidium in their stools, the frequency was 57% for IgG but only 2% for IgM. Twenty three percent of immunocompromised adults with not determined excretion of oocysts in their stools had anti-Cryptosporidium IgG in their sera. Children infected with human immunodeficiency virus had no IgM and only 14% had IgG detectable in their sera. The indirect immunofluorescence assay, when used with other parasitological techniques appears to be useful for retrospective population studies and for diagnosis of acute infection. The humoral immune response of HIV positive patients to this protozoan agent needs clarification.