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Introduction: Toxoplasmosis is usually a benign infection, except in the event of ocular, central nervous system (CNS), or congenital disease and particularly when the patient is immunocompromised. Treatment consists of drugs that frequently cause adverse effects; thus, newer, more effective drugs are needed. In this study, the possible activity of artesunate, a drug successfully being used for the treatment of malaria, on Toxoplasma gondii growth in cell culture is evaluated and compared with the action of drugs that are already being used against this parasite., Methods: LLC-MK2 cells were cultivated in RPMI medium, kept in disposable plastic bottles, and incubated at 36ºC with 5% CO2. Tachyzoites of the RH strain were used. The following drugs were tested: artesunate, cotrimoxazole, pentamidine, pyrimethamine, quinine, and trimethoprim. The effects of these drugs on tachyzoites and LLC-MK2 cells were analyzed using nonlinear regression analysis with Prism 3.0 software., Results: Artesunate showed a mean tachyzoite inhibitory concentration (IC50) of 0.075µM and an LLC MK2 toxicity of 2.003µM. Pyrimethamine was effective at an IC50 of 0.482µM and a toxicity of 11.178µM. Trimethoprim alone was effective against the in vitro parasite. Cotrimoxazole also was effective against the parasite but at higher concentrations than those observed for artesunate and pyrimethamine. Pentamidine and quinine had no inhibitory effect over tachyzoites., Conclusions: Artesunate is proven in vitro to be a useful alternative for the treatment of toxoplasmosis, implying a subsequent in vivo effect and suggesting the mechanism of this drug against the parasite.

Introduction: Following advances in the control of vector and blood transfusion transmission of Chagas disease, alternative mechanisms of transmission have become more relevant. This article discusses the importance of each one of these alternative mechanisms and the measures to prevent them., Methods: A review was conducted of the scientific literature concerning alternative transmission mechanisms of Trypanosoma cruzi occurring in Brazil and the measures to prevent them. PubMed and BVS databases were consulted., Results: Twenty-five publications describing alternative mechanisms of transmission of Chagas disease were identified., Conclusions: Oral transmission, through ingestion of contaminated food items has been the most frequent mode of transmission in Brazil in recent years. Other alternative mechanisms of transmission occur less frequently. It is important to understand these occurrences, especially now that vector transmission of the parasite is under control. Preventive measures have been presented, according to each of the situations considered, in line with current knowledge.

Vectorial, transfusion and congenital are considered the main transmission mechanisms in human Chagas disease. Alternative mechanisms are accidental, oral and by organ transplantation. Other hypothetic mechanisms could be by other vectors, sexual, criminal and by means of marsupial anal secretions. The present accorded strategies for prevention are: CONGENITAL: early case detection and immediate treatment. If possible, start during the pre natal period, throughout mothers serology, performing parasitological tests in the new born from positive women. For positive cases, immediate treatment; for those negative babies, conventional serology at the 8th month, treating specifically those with positive results. ACCIDENTAL TRANSMISSION: Rigorous training and utilization of protection equipments. IF accident occurs, immediate disinfection, conventional serology and beginning of specific treatment by ten days. Revision of the serology after 30 days: if positive, extend the treatment until the total dose (60 days or more). ORGAN TRANSPLANTATION: previous serology for donor and receptor. When the former is infected and the last negative, cancel the surgery or install the specific treatment by ten days before the surgery for the donor, followed by the receptor during ten days after the transplantation. ORAL TRANSMISSION: Specific measures are not available, food hygiene is recommended, including the cooking of meats delivered from possible reservoirs. Nowadays, the detection and immediate treatment of the case is recommended, followed by active research of new cases around the detected one.

Strongyloidiasis affects 30 million people in 70 countries. This enteral parasitosis is usually diagnosed using parasitological tests based on hydrotropism or thermotropism of larvae eliminated in feces, but these tests have been shown to have low sensitivity. In this study, antigenic extracts were tested by means of ELISA, immunoblotting and IFI, using filariform larvae of Strongyloides venezuelensis, a parasite of rodents that shows cross-reactions with Strongyloides stercoralis epitopes. Sensitivity of 89, 85 and 57% for the ELISA reaction and 100, 100 and 96% for immunoblotting with the SAL, ZWIP and ZW antigens, and specificity of 90, 60 and 81% for ELISA and 96, 92 and 91% for immunoblotting with the same antigens, were found in these assays.

The recently proposed CSF method for diagnosing intestinal helminthiases was compared with the other methods (direct; Faust et al.; spontaneous sedimentation in water; and Kato-Katz) that are routinely for this purpose. The CSF method performed satisfactorily, thus showing that this technique can be adopted for use in diagnoses or epidemiological analyses.

We report some observations made from routine parasitological examinations on feces. The methods of Faust et al. and of spontaneous sedimentation in water are not enough to identify Blastocystis hominis. Significant percentage presence of this protozoan was found, especially when staining with iron hematoxylin was performed. Cyclospora cayetanensis was found in 0.7% of the cases, which suggests that this parasite should also routinely be investigated by appropriate techniques.

When indirect hemagglutination, indirect immunofluorescence and enzyme-linked immunosorbent assay are used together for serologically diagnosing Chagas disease, results that are considered discordant sometimes occur because there is disagreement between what these tests indicate. The availability of the chemiluminescent ELISA method enabled tests on 200 serum samples that had previously produced discordant results from the three above-mentioned methods. CL-ELISA revealed that 193 of these samples were negative and seven were positive. The use of this new procedure provides further support for understanding this subject, but more concrete advances will depend on documentation with blood analyses from people previously demonstrated to be unquestionably infected or uninfected with Trypanosoma cruzi.

TESA blot was compared with indirect hemagglutination, indirect immunofluorescence and ELISA tests. In sera from 30 participants infected with Trypanosoma cruzi, and in 30 non infected the four techniques produced entirely equivalent results, all positive and all negative, respectively. In cases admitted to be inconclusive or in visceral leishmaniasis, frequent false positives were detected. However, TESA blot contributed with the least proportion of them.

The efficacy of prolonged administration of azithromycin and pyrimethamine was evaluated in mice experimentally infected with cystogenic strain of Toxoplasma gondii. The animals were intraperitoneally inoculated with one cyst of T. gondii and after 20 days were allocated into four groups: GI, infected without treatment; GII, infected and treated with the association of pyrimethamine (12.5 mg/kg/day) and azithromycin (100 mg/kg/day); GIII, infected and treated with the same dose of pyrimethamine; and GIV, infected and treated in the same way with azithromycin. The oral treatment lasted 120 days, after this period all the animals were sacrificed and the count of cysts in the brain was done. The association of both drugs provided the best results, by diminishing the cyst count in the brain of the animals treated in this way.

Maternal transmission of Trypanosoma cruzi from 278 children of 145 mothers, chronically infected with this protozoan, to their offspring was investigated. This study was based upon serological tests. In only two cases (2/278 = 0.70%), such mode of transmission was demonstrated to have occurred. However, as according to extant records both patients had also been breast-fed, and the contribution of this factor could not be ruled out. In any case, maternal transmission, an alternative mode of acquiring the infection with Trypanosoma cruzi, was demonstrated. The methodology used is a further contribution to the evaluation of the prevalence of this propagating mechanism of T. cruzi; in addition to those aimed at the main objective of the investigation, records were kept about pregnancy, parturition, puerperium, abortion, prematurity, perinatal deaths and breast-feeding, which might contribute to a better interpretation of the subject.

As a part of medical assistance activities, parasitological examination of fecal samples from 227 school children from a public institution of São Paulo (SP) revealed a rather high proportion of results positive for Blastocystis hominis. Other protozoan and worm species were markedly scarcer, a peculiar situation according to our judgement. It is acknowledged that blastocystosis is still largely an indefinite and controversial subject, which deserves adequate analysis to avoid drawbacks in the sphere of action of public health and general medical assistance.

Blastocystosis is the infection caused by Blastocystis hominis. It is associated with frequent and unquestionably very important controversy and lack of definition, above all due to its implications for general assistance and medical care. In that connection, there is considerable disagreement on the subject of the pathogenicity of this protozoan, which should be categorically defined. Other aspects besides the above, require clarification through results from well conducted studies aiming at attributing Blastocystis hominis a proper role within the context of public health. Another matter worthy of attention is the diagnostic value of the parasitological stool examination, with the proviso that it is adequate, as are fecal smears suspended in saline solution or permanent mounts stained with iron hematoxylin or thionine. The use of inadequate techniques tends to produce false negative results, thereby impeding investigation into the real importance of this microorganism.

By using a simple and easily available device which contains a 10% buffered formaldehyde solution, fecal samples are rendered odorless and can be stored at room temperature with no biosafety hazards. Cryptosporidium oocysts contained in such fecal samples can be identified without difficulty by using the Kinyoun method. This system permits an adequate preservation of the material, which facilitates the execution of tasks related to assistance and epidemiology.

Ten patients with chronic Chagas' disease were treated with nifurtimox (8-9 mg/kg/day) associated with betamethasone (9 mg/day initially and then gradually reduced) during 60 days, with one exception. It was intended to combine the respective anti-parasitic and anti-inflammatory actions of these drugs. The expected stimulating effect of betamethasone on the infection could possibly enhance the anti-Trypanosoma cruzi action of nifurtimox. Long term persistence of negative xenodiagnosis, used to control the results, was observed in only one of the cases. Regaridng the other patients, post-treatment positivity of xenodiagnosis and serological testes attested the failure of this therapy. As this study has demonstrated, adequate and long term follow-up of treated cases is necessary to ensure correct conclusions.

Sera from people in the chronic stage of Chagas disease, whose infection had been parasitologically validated, were assayed by using the indirect immunofluorescence test to evaluated its performance at the 1:20 dilution. All tests were consistently positive at 1:20 and higher dilutions, even in the presence of concomitant infection with the human immunodeficiency virus (HIV). It is thus valid, into the light of this experiment, to take into account the remarkable sensitivity of such serological test at the above mentioned dilution.

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.

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.

In a previous study, ticlopidine decreased the parasitemia and mortality of mice infected by Trypanosoma cruzi. Therefore, this drug was administered to 12 patients with Chagas' disease, in the chronic phase. For 90 days, 150, 200 or 250 mg were utilized according to whether the recipients were children, adolescents or adults, respectively. A fully unsuccessful outcome was documented, both serologically as well as parasitologically.

Patients in the chronic phase of Chagas' disease and receiving corticoid because of concommitant diseases were treated with benznidazole, which was initiated at the same time of the use of corticoid in a group of 12 patients or 15 days afterwards in 6 patients. It has been proved in another paper that in the chronic phase of Chagas' disease corticoid use is associated with increased parasitemia, as evaluated by xenodiagnosis. In this study benznidazole use prevented this increase, and we suggest that in immunocompromised patients with chronic Chagas' disease the use of this drug could be useful.

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.

The microsporidia have been involved in several clinical manifestations in patients with AIDS, of whom diarrhoea is the commonest. The diagnosis of microsporidiasis depended on invasive procedures and the identification of the organisms is made by electron microscopy. The modified trichrome staining method allows that the diagnosis be made without such procedures by using light microscopy. In the present work, the modified trchrome method was applied in stools from 62 patients with diarrhoea, who had asymptomatic HIV infection or AIDS. Of the 62 samples analyzed, there was detection of microsporidial spores in one. This work confirms the existence of such protozoans in our patients, associated with manifestations of chronic diarrhoea in patients with AIDS who have severe immunodeficiency and ascertains that this staining method allows satisfactory identification of microsporidia from faeces, as well points out some directions to further studies.

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.

The authors report a case of a 89 years-old woman with mucocutaneous leishmaniasis and previous diabetes mellitus and high blood pressure, who had been treated with allopurinol for 10 months without healing of lesions. Afterwards, she has been treated with meglumine antimonate, "glucantime" for 4 days, with a total dose 2,380 mg of Sbv, but developed cardiac side effects and hypokalemia, hence the treatment was withdrawn. However, this patient developed total clinical regression of lesions, in spite of she has been received low dose of this drug.

Taking for granted the sensitivity of the Quantitative Buffy Coat (QBC) system, as documented in a murine experimental model, we assayed to detect Trypanosoma cruzi in the peripheral blood of 100 patients with Chagas disease in its chronic phase. By means of the method, no positivity occurred, evently as a consequence of small parasitemias, undetectable by this technique as assessed by the cases in consideration.

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.

Quinine was the first antimalarial drug to be employed and also the first resistance was noticed to. After 1960 quinine urged to be reintroduced in routine therapy alone or in combination. Aiming at evaluating the effectiveness of different schedules we studied 484 patients seen at the Malaria Laboratory. We used quinine alone in 126 patients, quinine plus sulfadoxine and pyrimethamine in 119 patients and quinine plus tetracycline in 239 patients. The results shown that 81% of all patients were treated with success and only 0.6% were R2. and there is no R3. We emphasize a high resistance rate to quinine either alone (23.1%) or associated to sulfadoxine and pyrimethamine (37.8%). A higher resistance rate seen with the combination might be linked to the smaller dose of quinine used in that instance. It is worth noting the high cure rate with the quinine-tetracycline association.

Classical serological screening assays for Chagas' disease are time consuming and subjective. The objective of the present work is to evaluate the enzyme immuno-assay (ELISA) methodology and to propose an algorithm for blood banks to be applied to Chagas' disease. Seven thousand, nine hundred and ninety nine blood donor samples were screened by both reverse passive hemagglutination (RPHA) and indirect immunofluorescence assay (IFA). Samples reactive on RPHA and/or IFA were submitted to supplementary RPHA, IFA and complement fixation (CFA) tests. This strategy allowed us to create a panel of 60 samples to evaluate the ELISA methodology from 3 different manufacturers. The sensitivity of the screening by IFA and the 3 different ELISA's was 100%. The specificity was better on ELISA methodology. For Chagas disease, ELISA seems to be the best test for blood donor screening, because it showed high sensitivity and specificity, it is not subjective and can be automated. Therefore, it was possible to propose an algorithm to screen samples and confirm donor results at the blood bank.

Quality of life was evaluated in 11 patients with Chagas' disease 26 to 126 months after submission to heart transplantation. There was an objective improvement in their quality of life, after the transplant.

Patients with chronic Chagas' disease and simultaneous medical problems treated with corticosteroid were studied in order to evaluate steroid influence on chronic Trypanosoma cruzi infection. Parasitological assessment, radiological and electrocardiographic studies as well as non specific tests were performed in patients and in a control group that included chronic infected patients not treated with steroid. Xenodiagnosis showed a clear increase in T. cruzi parasitemia, related to the corticosteroid dosage, without clinical manifestations during the study follow-up period.

We report a patient with chronic asymptomatic Chagas' disease that presented Trypanosoma cruzi reactivation after kidney transplantation and immune depression. The only clinical manifestation of the disease was ulcerative skin lesions, which is unusual in Chagas' disease.

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.

The authors report a case of adenovirus-induced enlargement of the parotid gland involving a patient infected with human immunodeficiency virus (HIV). Physical examination revealed good general condition, no fever and bilateral enlargement of the parotid region, which was of increased consistency and slightly tender to palpation. Histological examination of the parotid gland demonstrated a slight periductal lymphomononuclear inflammatory infiltrate with the presence of focal points of necrosis. Tests to determine the presence of fungi and alcohol-acid resistant bacilli were negative. Immunohistochemistry for cytomegalovirus, herpes simplex, HIV p24 antigen and adenovirus showed positivity only for adenovirus in the epithelial nuclei of numerous gland ducts. This is the third case of this type reported in the literature, indicating the importance of including adenovirus in the differential diagnosis of this condition.

Ten patients with mucosal lesions caused by American tegumental leishmaniasis were treated with pentamidine isethionate at the dose 4 mg/kg on alternate days by the intravenous route. The mean posology was 2,140 mg. Healing of the lesions occurred in 9 (90%) of the patients who completed treatment. There was no recurrence during a follow-up time of 1 to 24 months (mean, 7,7 months). One patient discontinued treatment before healing of the lesion because be developed diabetes mellitus. In 3 (30%) patients, blood exams showed increased urea and creatinine levels and leucopenia, which were corrected by increasing the interval between administrations of the drug. Pentamidine isethionate is efficient in bringing about cicatrization of the lesions but needs further evaluation in terms of its value in preventing recurrence.

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.