Lúcia Maria Almeida Braz

Trypanosoma cruzi parasitemia in chronic Chagas disease : Comparison between human immunodeficiency virus (HIV)-positive and HIV-negative patients

This study evaluated Trypanosoma cruzi parasitemia in persons with chronic Chagas disease, compared the parasitemia in human immunodeficiency virus (HIV)-positive and -negative subjects, and, for HIV-positive subjects, analyzed the association between parasitemia and occurrence of acquired immunodeficiency syndrome-defining illnesses, CD4 cell counts, HIV loads, and antiretroviral therapy. In total, 110 adults with chronic Chagas disease (29 HIV positive, 81 HIV negative) were studied. T. cruzi parasitemia was evaluated by xenodiagnosis, blood culture, and direct microscopic examination of blood. T. cruzi parasitemia was detected significantly more frequently in HIV-positive than in HIV-negative subjects (odds ratio, 12.3; 95% confidence interval, 3.7-41.2). HIV-positive patients also had higher levels of parasitemia. No statistically significant association was seen between parasitemia and the variables of interest among the HIV-positive subjects.

Reactivation of Trypanosoma cruzi infection in immunosuppressed patients: contributions for the laboratorial diagnosis standardization

Sao Paulo, October 2, 2007Dear Sir,Diagnosis of parasitemia associated with reactivation of Chagasdisease remains a challenge in clinical practice. Since 1990, criteria toestablish the differential diagnosis of chronic Chagas disease sporadicparasitemia, and reactivation have been proposed in heart transplantrecipients including magnitude of parasitemia, severity of clinicalmanifestations, evidence of miocarditis, and the finding of

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 Heines method and modified Kinyouns 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. Heines was better for quantitation of the cysts and was faster. Kinyouns 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)

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.

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.

The detection of Trypanosoma cruzi in Triatoma infestans: comparison of a PCR-based assay with microscopical examination.

The laboratory diagnosis of human American trypanosomiasis (Chagas disease) is currently usually based on serology or the detection of a Trypanosoma cruzi parasitaemia (Maldonado et al., 2004). Unfortunately, most of the serological methods perform poorly when used to detect the re-activation of infections, and are therefore not recommended for determining post-treatment cure (PortelaLindoso and Shikanai-Yasuda, 2003). Parasitaemia can be detected by the direct microscopical examination of samples of blood or buffy coats, haemoculture or xenodiagnosis. Although xenodiagnosis remains the ‘gold standard’, this technique requires expertise and is both cumbersome and time-consuming, often requiring 30–60 days to yield a final result. Despite these drawbacks, xenodiagnosis is indicated in the acute phase of disease or during possible reactivation, whenever the other techniques give negative results (Luquetti and Rassi, 2000). Romaña and Briones (1954) found that infections could sometimes be detected in triatomine bugs fed on acute cases of Chagas disease as early as 6 days post-feed. In the last decade, the use of PCR to detect the DNA of Try. cruzi in faecal samples collected from bugs used in xenodiagnosis has not only increased the sensitivity of the diagnosis but also shortened the time needed to obtain a useful result (Russomando et al., 1996; ShikanaiYasuda et al., 1996). The aim of the present study was to explore and compare the potential usefulness of PCR and direct microscopical examination for detecting Try. cruzi infection in bugs used for xenodiagnosis. Most (220) of the 275 bugs used — thirdand fourth-instar, laboratoryreared Triatoma infestans — were fed on BALB/c mice that had been experimentally infected with the Y strain of Try. cruzi, while the mice were in the acute phase of disease and had low parasitaemias (of approximately 10 parasites/ml blood). The aim of using mammalian hosts with low parasitaemias was to mimic the situation found, during re-activation of Chagas disease, in immunosuppressed heart-transplant patients. The other 55 bugs were fed on uninfected mice, as negative controls. Digestive-tract samples (faeces or abdominal contents) were collected from 25 bugs (20 that had fed on infected mice and five of the negative controls) 1, 2, 3, 4, 5, 10, 15, 20, 25, 30 and 60 days post-feed, with different bugs being used at each timepoint. Each sample was split into two aliquots. A subsample (2–10 ml) of one aliquot was mixed with one to five volumes of 0.9% NaCl solution and then checked by microscopy (at 6400, as a wet smear), while the same volume of the other aliquot was checked by PCR (see below). The primers used in the PCR — F2 (59TGC ACT CGG CTG ATC GTT TTC GAG-39) and B3 (59-AGG GTT GTT TGG TGT CCA GTG TGTG-39), both produced by Integrated DNA Technologies (Belo Horizonte, Brazil) — were designed to produce a 144-bp amplicon from the TCZ repetitive sequence of Try. cruzi (Moser et al., 1989). Genomic DNA was extracted, from a mixture of a digestive-tract aliquot Annals of Tropical Medicine & Parasitology, Vol. 101, No. 5, 461–465 (2007)

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-maiarial 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.

Usefulness of kDNA PCR in the diagnosis of visceral leishmaniasis reactivation in co-infected patients.

SUMMARY It is important to develop new methods for diagnosing relapses in the co-infection of visceral leishmaniasis (VL) and HIV to enable earlier detection using less invasive methods. We report a case of a co-infected patient who had relapses after VL treatment, where the qualitative kDNA PCR showed a good performance. The kDNA PCR seems to be a useful tool for diagnosing VL and may be a good marker for predicting VL relapses after treatment of co-infected patients with clinical symptoms of the disease.

Avaliação da eficácia da azitromicina e pirimetamina em camundongos infectados por cepa cistogênica de Toxoplasma gondii

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.

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 200mg/kg and 12.5mg/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 efficacy of azithromycin and pyrimethamine in experimental infection of mice with Toxoplasma gondii was tested. Daily dosages of 200mg/kg and 12.5mg/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. Key-words: Infection by Toxoplasma gondii. Mice. Treatment. Azythromicin. Pyrimethamine. Lucia Maria Almeida Braz, Andreia Otaviani Di Pietro, Vicente Amato Neto e Francisco Oscar de Siqueira Franca Evaluation of the efficacy of azithromycin and pyrimethamine, alone or in combination, for the treatment of experimental infection of mice with Toxoplasma gondii O Toxoplasma gondii adquiriu paralelamente cada vez maior importância como patogeno oportunista, acometendo dessa maneira, numero crescente de imunodeprimidos, exemplificados por pac ientes que recebem orgaos por transplantes ou sao tratados atraves de quimioterapias diversas. Alem disso, a partir da decada de 80, passou com frequencia a determinar em in fectados pe lo v i rus da imunodeficiencia (HIV) graves disturbios cerebrais2 5 7 8. A terapeutica classica mais efetiva quanto a toxoplasmose consiste no uso da associacao da sulfadiazina e pirimetamina. No entanto, esses farmacos nao raramente causam disturbios colaterais expressivos, sobretudo de naturezas alergica ou hematologica, sendo tambem improprios para emprego durante a gravidez. Ainda mais, o sulfamidico, provoca reacoes adversas em mais de 40% dos pacientes com aids, tornando conveniente avaliar a eficacia de novos remedios2 5. E m b o r a j a e x i s t a m a l g u n s o u t r o s medicamentos com reconhecida atividade ant i toxop lasma como a c l indamic ina, o sulfametazol-trimetroprim e a espiramicina