Toxoplasma encephalitis in AIDS patients in São Paulo during 1988 and 1991. A comparative retrospective analysis

We conducted a retrospective analysis of Toxoplasma encephalitis patients from Instituto de Infectologia Emílio Ribas, the main AIDS hospital of São Paulo, Brazil, during two different stages of the HIV epidemics, in 1988 (38 patients) and 1991 (33 patients). There were AIDS-related demographic differences, but the clinical presentation and diagnostic efficiency were similar, usually based on tomography and clinical response to therapy, with a clear distinction from other CNS infections, based on clinical and laboratory findings. Specific serologic studies were performed less often in 1991, with a high frequency of therapy change. The direct acute death rate from Toxoplasma encephalitis was high during both periods, i.e. 8/38 in 1988 and 10/33 in 1991. The direct acute death rate for the patients from the two periods as a whole was 25.4% (18/71), related to the time of HIV infection, absence of fever and presence of meningeal irritation at presentation, blood leukocytes higher than 10,000/mm³ and blood lymphocytes lower than 350/mm³. Toxoplasma encephalitis is a preventable disease when adequate prophylactic therapy is used and is relatively easy to treat in diagnosed HIV patients. Unfortunately, this severe and deadly disorder is the HIV diagnostic disease in several patients, and our data support the need for careful management of these patients, especially in those countries with a high toxoplasmosis prevalence where AIDS is concurrent with economic and public health problems.

Evaluation of intrathecal synthesis of specific IgG antibodies against Toxoplasma gondii in the diagnosis assessment of presumptive toxoplasma encephalitis in aids patients

The diagnosis of neurotoxoplasmosis in patients with acquired immunodeficiency syndrome is mainly based on tomographic or magnetic resonance findings and on the response to specific treatment. We studied 55 patients with AIDS and neurotoxoplasmosis according to these diagnostic criteria (group 1), 37 patients with AIDS and neurological involvement of other etiology (group 2), and 16 anti-HIV-negative individuals with neurological manifestations (group 3). Serum and cerebrospinal fluid were examined for the presence of anti-T. gondii IgG, by indirect immunofluorescence. In 72 of them, the total amounts of these antibodies were determined in order to assess local production of anti-T. gondii antibodies in the central nervous system and to correlate their titers with infection activity in patients with AIDS and neurotoxoplasmosis. IgG titers > 1/64 in cerebrospinal fluid reached 100% specificity for the diagnosis of neurotoxoplasmosis in AIDS. Evidence of local synthesis of these antibodies was detected in 42.8% of patients of group 1, in 29.1% of patients of group 2 and in no patient of group 3. The test showed 70.8% specificity and therefore was not useful in our study for the differential diagnosis of neurotoxoplasmosis in patients with AIDS.

Discontinuation of maintenance therapy against toxoplasma encephalitis in AIDS patients with sustained response to anti-retroviral therapy

Discontinuation of maintenance therapy against toxoplasma encephalitis (TE) for individuals infected with human immunodeficiency virus (HIV) who are receiving successful anti-retroviral therapy is considered safe. Nevertheless, there are few published studies concerning this issue. Within the setting of the Swiss HIV Cohort Study, this report describes a prospective study of discontinuation of maintenance therapy against TE in patients with a sustained increase of CD4 counts to > 200 cells/microL and 14% of total lymphocytes, and no active lesions on cerebral magnetic resonance imaging (MRI). In addition to clinical evaluation, cerebral MRI was performed at baseline, and 1 and 6 months following discontinuation. Twenty-six AIDS patients with a history of TE agreed to participate, but three patients (11%) could not be enrolled because they still showed enhancing cerebral lesions without a clinical correlate. One patient refused MRI after 6 months while clinically asymptomatic. Among the remaining 22 patients who discontinued maintenance therapy, one relapsed after 3 months. During a total follow-up of 58 patient-years, there was no TE relapse among the patients who had remained clinically and radiologically free of relapse during the study. Thus, discontinuation of maintenance therapy against TE was generally safe, but may fail in a minority of patients. Patients who remain clinically and radiologically free of relapse at 6 months after discontinuation are unlikely to experience a relapse of TE.

Oligodendroglioma in a patient with AIDS: case report and review of the literature

In the last years, new techniques of neuroimages and histopathological methods have been added to the management of cerebral mass lesions in patients with AIDS. Stereotactic biopsy is necessary when after 14 days of empirical treatment for Toxoplasma gondii encephalitis there is no clinical or neuroradiologic improvement. We report a woman with AIDS who developed a single focal brain lesion on the right frontal lobe. She presented a long history of headache and seizures. After two weeks of empirical treatment for toxoplasma encephalitis without response, a magnetic resonance image with spectroscopy was performed and showed a tumoral pattern with a choline peak, diminished of N-acetyl-aspartate and presence of lactate. A stereotactic biopsy was performed. Histopathological diagnosis was a diffuse oligodendroglioma type A. A microsurgical resection of the tumor was carried out and antiretroviral treatment was started. To date she is in good clinical condition, with undetectable plasma viral load and CD4 T cell count > 200 cell/uL.

Toxoplasma gondii: The severity of toxoplasmic encephalitis in C57BL/6 mice is associated with increased ALCAM and VCAM-1 expression in the central nervous system and higher blood-brain barrier permeability

In order to investigate the differential ALCAM, ICAM-1 and VCAM-1 adhesion molecules mRNA expression and the blood-brain barrier (BBB) permeability in C57BL/6 and BALB/c mice in Toxoplasma gondii infection, animals were infected with ME-49 strain. It was observed higher ALCAM on day 9 and VCAM-1 expression on days 9 and 14 of infection in the central nervous system (CNS) of C57BL/6 compared to BALB/c mice. The expression of ICAM-1 was high and similar in the CNS of both lineages of infected mice. In addition, C57BL/6 presented higher BBB permeability and higher IFN-gamma and iNOS expression in the CNS compared to BALB/c mice. The CNS of C578L/6 mice presented elevated tissue pathology and parasitism. In conclusion, our data suggest that the higher adhesion molecules expression and higher BBB permeability contributed to the major inflammatory cell infiltration into the CNS of C57BL/6 mice that was not efficient to control the parasite. (C) 2010 Elsevier Inc. All rights reserved.

Toxoplasma gondii isolates: Multi locus RFLP-PCR genotyping from human patients in Sao Paulo State, Brazil identified distinct genotypes

This study investigated the genetic characteristics of Toxoplasma gondii samples collected from 62 patients with toxoplasmosis in Sao Paulo State, Brazil. DNA samples were isolated from blood, cerebrospinal fluid and amniotic fluids of 25 patients with cerebral toxoplasmosis and AIDS, two patients with acute toxoplasmosis, 12 patients with ocular toxoplasmosis, six newborns with congenital toxoplasmosis and 17 pregnant women with acute infection. Diagnosis of toxoplasmosis was based in clinical, radiological and laboratory features. Genotyping was performed using multilocus PCR-RFLP genetic markers including SAG1, SAG2, 5`- and 3`-SAG2, alt.SAG2, SAG3, BTUB, GRA6, C22-8, c29-2, L358, PK1 and Apico. Among the 62 clinical samples, 20 (32%) were successfully genotyped at eight or more genetic loci and were grouped to three distinct genotypes. Eighteen samples belonged to ToxoDB Genotype #65 and the other two samples were identified as ToxoDB Genotypes #6 and #71, respectively (http://toxodb.org/toxo/). Patients presenting Genotypes #6 and #71 had severe and atypical cerebral toxoplasmosis, characterized by diffuse encephalitis without extensive brain lesions. These results indicate that T. gondii Genotype #65 may have a high frequency in causing human toxoplasmosis in Sao Paulo State, Brazil. This unusual finding highlights the need to investigate the possible association of parasite genotypes with human toxoplasmosis. (C) 2011 Elsevier Inc. All rights reserved.

Usefulness of the detection of Toxoplasma gondii antigens in AIDS patients

Toxoplasmic encephalitis (TE) is a mayor cause of central nervous system infection in patients with acquired immunodeficiency syndrome (AIDS). Toxoplasma antibodies were detected in 56 of 79 patients with AIDS (71%), in the present study. Fourteen out of 57 seropositive patients developed TF (25%) and had Toxoplasma gondii antigen detected in their urine. For this, most of them received an effective therapy, with the subsequent disappearance of the symptoms and discontinuity of excretion of the T. gondii antigens. Our results suggest that the monitoring of T. gondii antigen in the urine of AIDS patients may be useful to decide on the proper time for therapy, as well as to avoid the beginning of neurologic signs in these patients.

Detection of Toxoplasma gondii soluble antigen, SAG-1(p30), antibody and immune complex in the cerebrospinal fluid of HIV positive or negative individuals

Active infection by T. gondii was evaluated by immunoassay for soluble SAG-1 (p30), the major surface antigen from T. gondii, specific antibodies and immune complexes in human cerebrospinal fluid (CSF) samples. A total of 263 samples of CSF were collected from hospitalized patients presenting neurological disorders and analyzed for antibodies to HIV. Patients were divided into two groups: HIV positive (n = 96) or HIV negative (n =167). The results of the assays showed that 45% of all samples were positive for soluble SAG-1. Toxoplasma Ag/Ab immune complexes were detected in 19% of the CSF samples and 62% were positive for T. gondii- specific IgG. A combination of these assays in the presence of clinical findings consistent with active Toxoplasma infection may predict the presence of toxoplasmic encephalitis. Moreover, detection of soluble SAG-1 in the CSF of these individuals appears consistent with active infection.

Preliminary report of HIV and Toxoplasma gondii occurrence in pregnant women from Mozambique

Toxoplasmosis, a protozoan disease, causes severe disease in fetuses during pregnancy and deadly encephalitis in HIV patients. There are several studies on its seroprevalence around the world, but studies focusing on African countries are limited in number and mostly anecdotal. We studied two groups of samples from Mozambique by ELISA, using serum samples from 150 pregnant women and six Cerebrospinal fluid (CSF) samples from AIDS patients with encephalitis. HIV status was confirmed, and CD4 blood counts were obtained from HIV-positive pregnant women. IgG seroprevalence of the group as a whole was 18.7% (28/150), with a higher prevalence in HIV-positive individuals compared to those who were HIV-negative (31.3%, [18/58] vs. 10.9%, [10/92]) patients. These data may be biased due to cumulative effects of exposition affecting disease prevalence. If corrected, this data may indicate an interaction of HIV and T. gondii. Prevalence of both diseases increases with age, but this is more clearly seen for toxoplasmosis (p < 0.005) than HIV infection, possibly explained by higher transmission of HIV after childhood. In HIV patients suffering from encephalitis, CSF serology showed that 33% of specific IgG CSF had a high avidity, which was in accordance with the data from the group of pregnant women. Lower prevalence rates of both infections in older groups could be explained by more deaths in the infected groups, resulting in an artificially lower prevalence. Using CD4 counts as a marker of time of HIV infection, and correcting for age, patients with contact with T. gondii had fewer CD4 cells, suggesting prolonged HIV disease or other causes. Toxoplasma IgG prevalence is higher in HIV+ groups, which could be ascribed to HIV- and T. gondii-associated risk factors, such as exposure to higher and more diverse social contacts. The low incidence of Toxoplasma IgG in younger age groups shows that transmission could be related to better access to cyst-containing meat in adulthood, as environmental transmission due to oocysts is usually blamed for higher incidence in children. Taken together, these data support the urgent need of research in toxoplasmosis in Africa, especially in the presence of HIV epidemics.

Antiretroviral activity of protease inhibitors against Toxoplasma gondii

The introduction of highly active antiretroviral therapy (HAART) has caused a marked reduction in the occurrence and severity of parasitic infections, including the toxoplasmic encephalitis (TE). These changes have been attributed to the restoration of cell-mediated immunity. This study was developed to examine the activity of six antiretroviral protease inhibitors (API) on Toxoplasma gondii tachyzoites. The six API showed anti-Toxoplasma activity, with IC50 value between 1.4 and 6.6 µg/mL. Further studies at the molecular level should be performed to clarify if the use of API could be beneficial or not for AIDS patients with TE.

Outbreak of caprine abortion by Toxoplasma gondii in Midwest Brazil

An outbreak of abortion by Toxoplasma gondii in goats on a farm in the Brazilian Midwest is reported. Gross lesions were not observed in seven aborted fetuses submitted to the Veterinary Pathology Laboratory, Federal University of Mato Grosso, for necropsy investigation. The main histologic lesions were mononuclear cell pneumonia and necrotizing encephalitis in varying degrees of intensity. PCR for Brucella abortus and Neospora caninum and aerobic cultures were negative in all cases. Antibody titles against T. gondii varying from 1:1024 to 1:32.768 were detected in serum samples from four aborted goats. Nested-PCR assay for T. gondii were positive in brain samples of all cases submitted. These findings indicate that T. gondii infection should be considered in the diagnosis of abortion in goats in Midwest Brazil.

Expression of extracellular matrix components and their receptors in the central nervous system during experimental Toxoplasma gondii and Trypanosoma cruzi infection

Alterations in extracellular matrix (ECM) expression in the central nervous system (CNS) usually associated with inflammatory lesions have been described in several pathological situations including neuroblastoma and demyelinating diseases. The participation of fibronectin (FN) and its receptor, the VLA-4 molecule, in the migration of inflammatory cells into the CNS has been proposed. In Trypanosoma cruzi infection encephalitis occurs during the acute phase, whereas in Toxoplasma infection encephalitis is a chronic persisting process. In immunocompromised individuals such as AIDS patients, T. cruzi or T. gondii infection can lead to severe CNS damage. At the moment, there are no data available regarding the molecules involved in the entrance of inflammatory cells into the CNS during parasitic encephalitis. Herein, we characterized the expression of the ECM components FN and laminin (LN) and their receptors in the CNS of T. gondii- and T. cruzi-infected mice. An increased expression of FN and LN was detected in the meninges, leptomeninges, choroid plexus and basal lamina of blood vessels. A fine FN network was observed involving T. gondii-free and T. gondii-containing inflammatory infiltrates. Moreover, perivascular spaces presenting a FN-containing filamentous network filled with a4+ and a5+ cells were observed. Although an increased expression of LN was detected in the basal lamina of blood vessels, the CNS inflammatory cells were a6-negative. Taken together, our results suggest that FN and its receptors VLA-4 and VLA-5 might be involved in the entrance, migration and retention of inflammatory cells into the CNS during parasitic infections.

Falhas reprodutivas associadas com a presença de do vírus da artrite-encefalite caprina, toxoplasma gondii e neospora caninum em caprinos no estado de São Paulo, Brasil

This study aimed at assessing the occurrence of antibodies against the caprine arthritis-encephalitis virus (CAEV), Toxoplasma gondii and Neospora caninum, as well as the associations between the presence of antibodies and the occurrence of reproductive failures in goats. Serum samples were collected from 923 goats of both sexes, over 3 months of age, from 17 dairy farms located in different municipalities of São Paulo State, Brazil. Infections by T. gondii, N. caninum and CAEV were evaluated by indirect methods of diagnosis based on indirect fluorescence antibody test (IFAT), Neospora agglutination test (NAT), and agar gel immunodiffusion (AGID), respectively. A survey was conducted on the farms to obtain information about reproduction dates (abortions, stillbirths and births of weak and premature kids) and zoosanitary management. Antibodies against CAEV, T. gondii and N. caninum was found in 37.81%, 23.62% and 17.23% respectively. There was no significant association between the presence of anti-CAEV antibodies and CAEV/T. gondii or CAEV/N. caninum co-infection, suggesting that CAEV does not predispose goats to infection by these agents. However, when CAEV/T. gondii (p<0.01) or CAEV/N. caninum (p<0.001) co-infection was present, the occurrence of reproductive failures was significantly higher what could indicate that CAEV-induced immunosuppression may predispose goats to develop the clinical symptoms of toxoplasmosis and neosporosis increasing the risks of the reproductive failures.

Detecção imunoistoquímica de linfócitos T (CD3+) e B (CD79+) no encéfalo de cães com leishmaniose visceral e presença de anticorpos séricos anti-Toxoplasma gondii e anti-Neospora caninum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo soroepidemiológico de Brucella abortus, Toxoplasma gondii e vírus da artrite encefalite caprina em rebanhos caprinos nas unidades produtoras dos estados do Pará e Maranhão

Pesquisou-se a frequência da ocorrência de anticorpos anti-Brucella abortus, Toxoplasma gondii e vírus da artrite encefalite caprina (CAEV) em caprinos de 14 unidades produtoras localizadas dos Estados do Pará e Maranhão. No Estado do Pará foram analisados animais dos municípios de Benevides, Castanhal, Santa Izabel do Pará e Moju e no Estado do Maranhão, o município de Chapadinha. Os testes sorológicos realizados para o diagnóstico da brucelose foi o teste do Antígeno Acidificado Tamponado (AAT), como teste de triagem, e o 2- Mercaptoetanol (2-Me), como teste confirmatório. Para as análises de toxoplasmose foi utilizado a Reação de Imunofluorescência Indireta (RIFI) e para CAEV Imunodifusão de Gel de Agarose (IDGA). O resultado das análises de brucelose mostrou-se negativo para 100,0% das amostras analisadas. Para toxoplasmose e CAEV a frequência obtida foi 23,5% (97/412) e 21,6% (85/393), respectivamente. Foi observada diferença estatística na relação entre a ocorrência de anticorpos anti-Toxoplasma gondii e a faixa etária dos caprinos, mostrando que animais com idade superior a 24 meses tiveram mais risco de estarem infectados quando comparados com animais mais novos OR= 2,15 (IC 95% 1,19 – 3,88). Já os fatores de risco encontrados para CAEV foram: falta de conhecimento da doença OR=6,45 (IC 95% 2,88-14,47); a não utilização de material descartável, OR=10,85 (IC 95% 4,85-24,28); sistema de criação extensivo OR=10,85 (IC 95% 4,85-24,28); sistema de criação semi-extensivo OR=3,71(IC 95% 1,64-8,39) e manejo OR=11,4 (IC 95% 5,51-23,60). Conclui-se que as unidades produtoras de caprinos dos Estados do Pará e Maranhão apresentam positividade em seus rebanhos para toxoplasmose e CAEV.