Brain abscess caused by Cladophialophora (Xylohypha) bantiana in a renal transplant patient.

Infectious disease is the most significant cause of morbidity and mortality in allotransplantation because of heavy immunosuppression. Brain abscesses caused by melanized fungi have been found occasionally and are an example of this complication. In this paper, we describe a case in a 61-year-old black man, who received a cadaveric kidney transplantation in December 1993, followed by triple therapy with cyclosporine, azathioprine, and prednisone. The patient developed right hemiparesis at the beginning of April 1998. A computed tomography scan showed a mass in the left parieto-temporal region of the brain. The patient underwent surgery and a brown-colored encapsulated brain abscess was resected. Histology of the tissue revealed a large number of pigmented fungal hyphae. Culture in a Sabouraud dextrose medium with cyclohexamide and chloramphenicol at 25 degrees C resulted in the growth of dark-green colonies. The fungus identified was Cladophialophora bantiana, based on characteristic microscopic features and on growth at 40 degrees C. The abscess recurred in spite of treatment with fluconazole. The patient was submitted to a second brain surgical procedure and was treated with amphotericin B in addition to fluconazole. Ten days later the patient's blood cultures became positive for Escherichia coli. After 3 days the patient died due to septic shock.

Seroconversion for Helicobacter pylori in adults from Brazil.

We studied, prospectively, seroconversion for Helicobacter pylori in adults from a developing country and investigated risk factors for the acquisition of the microorganism in this population. A group of 213 volunteers of low socioeconomic level from a district in the metropolitan area of Belo Horizonte, south-east Brazil was evaluated. Anti-H. pylori IgG antibodies were measured by ELISA using Cobas Core anti-H. pylori EIA (Roche) in serum samples collected in 1992 and in 1997. The subjects were interviewed and sociodemographic data were collected. A total of 174 (81.7%) subjects presented anti-H. pylori antibodies on the occasion of the first visit. During 56 months of follow-up, 2 of 39 seronegative adults converted to seropositive with an annual infection rate of 1.1%, and 2 of 174 seropositive subjects reverted to seronegative (0.2%/year). The prevalence of infection increased significantly with age and an inverse association was observed between prevalence of infection and educational level. In conclusion, the results of the present study demonstrate that in a developing country there is a low but continuous risk of H. pylori infection in adulthood.

Humoral immune responses in patients with acute Schistosoma mansoni infection who were followed up for two years after treatment.

Eighteen patients with acute Schistosoma mansoni infection were followed up for 2 years after treatment with praziquantel or oxamniquine. Cure rates, clinical features, abdominal ultrasonographic findings, and specific humoral responses were determined at 2-, 6-, and 24-month follow-ups. Fourteen patients (77.8%) were considered parasitologically cured. Levels of IgA antibody to soluble egg antigen (SEA) and IgM antibody to keyhole limpet hemocyanin (KLH) became negative or decreased to the cutoff level for chronic infection 2 months after treatment, while levels of IgG antibody to KLH declined between 12 and 24 months after treatment. Levels of IgM and IgG antibodies to saline worm adult protein as well as IgM and IgG antibodies to SEA remained positive during the follow-up period. Discrete lymph node enlargement and hepatomegaly were still present in six of the eight cured children 2 years after treatment, while complete regression was observed in adults. In our group of patients, in addition to presenting with more intense clinical manifestations, children were cured less often and had slower abatement of symptomatology after treatment than adults.

Validation of a chart to estimate true Schistosoma mansoni prevalences from simple egg counts.

Schistosoma mansoni egg counts by faecal examination vary considerably and are not very sensitive, so prevalences are underestimated. The distribution of egg counts can adequately be described by a stochastic model which distinguishes variation in counts between persons and variation in repeated counts within a person. Based on this model a pocket chart has been developed which predicts the proportion of individuals harbouring at least 1 S. mansoni worm pair-the 'true prevalence'-from a simple single survey prevalence and geometric mean egg count (using common duplicate 25 mg Kato-Katz smears). The current paper describes the validation of this chart by comparing predicted true prevalences with prevalences observed after 5-7 repeated Kato-Katz faecal examinations (Burundi), by examination of a large quantity of stool using the Visser filter (Brazil) or a selective sedimentation-filtration method (Surinam). Because 5-7 repeated examinations do not suffice to measure all infections, predictions have been made of the cumulative proportion positives over 5-7 surveys-the 'approximate true prevalence'-as well. After dividing the data into age groups, 12 different subsets were considered for validation. In all 12 cases, predicted true prevalences (or approximate true prevalences for the Burundi data) agree well with those observed. The overall agreement depends only slightly on the assumed relationship between worm numbers and mean egg counts, with a good fit for a productivity between 0.8 and 4.4 eggs per gramme faeces (EPG) per worm pair (WP). This interval includes the most plausible value from the literature, i.e. 1.0 EPG/WP, which has been applied in the initial pocket chart. These findings support the validity of the chart to predict true prevalences for a wide range of productivity assumptions, and reinforces the applicability of its underlying stochastic model to describe egg count variation. However, as predictions appear to vary importantly when using only part of the data, it is also concluded that the pocket chart never compensates for limited validity of initial single survey prevalences and geometric means in consequence of small sample sizes.

The serological differentiation of acute and chronic schistosomiasis japonica using IgA antibody to egg antigen

Two groups of Schistosoma japonicum infected patients (acute and chronic) and non-infected individuals were studied using IgA antibody to egg antigen (SEA) and IgG and IgM antibodies to keyhole limpet haemocyanin (KLH). The means and standard deviation of the optical density in ELISA of acute, chronic and negative groups for IgA anti-SEA were 583ñ124.7, 98.2ñ78.8 and 82.2ñ39.3, respctively. There was a statistically significance between acute patients and chronic patients (P<0.01). The means and standard deviation of IgG and IgM antibodies to KLH were 501.5ñ150.6, 113.0ñ79.1, 28.8ñ56.3 and 413.6ñ148.5, 70.2ñ14.8, 65.3ñ45.3, repectively. The detection results of IgA to SEA compared with the IgG and IgM to KLH did not demonstrate a significant difference (P>0.01). The sensitivities of IgA to SEA and IgG and IgM antibodies to KLH for the detection of acute infection were 95.24 per cent, 90.48 per cent and 85.71 per cent respectively. Therefore, this study showed that the detection of IgA to SEA is also a useful new method for the serological differentiation of acute and chronic schistosomiasis japonica in humans.

The serological differentiation of acute and chronic schistosomiasis japonica using IgA antibody to egg antigen.

Two groups of Schistosoma japonicum infected patients (acute and chronic) and non-infected individuals were studied using IgA antibody to egg antigen (SEA) and IgG and IgM antibodies to keyhole limpet haemocyanin (KLH). The means and standard deviation of the optical density in ELISA of acute, chronic and negative groups for IgA anti-SEA were 583 +/- 124.7, 98.2 +/- 78.8 and 82.2 +/- 39.3, respectively. There was a statistically significance between acute patients and chronic patients (P < 0.01). The means and standard deviation of IgG and IgM antibodies to KLH were 501.5 +/- 150.6, 113.0 +/- 79.1, 28.8 +/- 56.3 and 413.6 +/- 148.5, 70.2 +/- 14.8, 65.3 +/- 45.3, respectively. The detection results of IgA to SEA compared with the IgG and IgM to KLH did not demonstrate a significant difference (P < 0.01). The sensitivities of IgA to SEA and IgG and IgM antibodies to KLH for the detection of acute infection were 95.24%, 90.48% and 85.71%, respectively. Therefore, this study showed that the detection of IgA to SEA is also a useful new method for the serological differentiation of acute and chronic schistosomiasis japonica in humans.

Humoral immune responses in acute schistosomiasis mansoni: relation to morbidity.

An analysis of 25 individuals simultaneously exposed to cercariae of Schistosoma mansoni showed that morbidity (measured by the clinical/sonographic index) was more severe in patients with high-level egg output, irrespective of age or intensity of water contact. High levels of IgM and IgG antibodies to keyhole limpet hemocyanin and of IgA antibody to soluble egg antigen were documented predominantly during the acute phase of illness. Increased levels of these antibodies and of IgM antibody to soluble egg antigen correlated positively with morbidity after adjustment for age and intensity of water contact.

Abdominal ultrasonography in acute clinical schistosomiasis mansoni.

Abdominal ultrasonography was performed on eight children and four adults with acute schistosomiasis mansoni, 12 chronically infected patients, and 12 noninfected individuals from the endemic area, who were paired by age and sex with the acute group. In all acute patients, lymphadenomegaly as well as liver and spleen enlargement were detected. Lymph nodes surrounding the portal vein and the hepatic artery in the hepatic hilus were visualized. In the children, the right lobe of the liver was statistically significantly larger in the acute group than in the noninfected group. The portal and splenic vein diameters were significantly larger in children with acute schistosomiasis than in the chronically infected and negative control groups. The left hepatic lobe and a longitudinal scan of the spleen in acute adult patients were statistically significantly larger than in the chronically infected and negative control groups. Ultrasonography is shown to be a useful tool for the differential diagnosis of acute schistosomiasis mansoni.

The serological differentiation of acute and chronic Schistosoma japonicum infection by ELISA using keyhole limpet haemocyanin as antigen.

Antibodies (immunoglobulin (Ig) G and IgM) that recognize keyhole limpet haemocyanin (KLH), which shares a well defined carbohydrate epitope with the surface of larval schistosomes, were determined by enzyme-linked immunosorbent assay in patients with acute or chronic schistosomiasis japonica. Marked differences in IgG and IgM responses were evident between acute and chronically infected patients at a serum dilution of up to 1:2000. The acute sera had mean (+/- standard deviation) optical density values at 405 nm for IgG and IgM of 0.64 +/- 0.18 and 0.30 +/- 0.19 respectively; the chronic sera had mean readings for IgG and IgM of 0.14 +/- 0.08 and 0.04 +/- 0.03 respectively. Setting the lowest positive limit at 2 standard deviations above the mean value for chronic sera, 41 (98%) of the 42 patients previously diagnosed as having acute schistosomiasis were correctly identified by anti-KLH IgG and 35 (83%) of the 42 patients were correctly identified by anti-KLH IgM detection. Of 17 patients studied longitudinally, IgG optical density values dropped 45% and those of 5 patients fell below the established cut-off level 6 months after treatment. This study supports the use of KLH for rapidly and easily identifying individuals with acute Schistosoma japonicum infection.

Quantitative diagnosis of Schistosoma infections by measurement of circulating antigens in serum and urine.

Recent research on the detection of the schistosome circulating antigens, circulating anodic antigen (CAA) and circulating cathodic antigen (CCA), has greatly expanded the scope of applications. In the present paper aspects of assay development, in particular of highly sensitive assays and of field-applicable assays, are discussed. The progress in the use of CAA- and CCA-detection for diagnosis, follow-up of chemotherapy and sero-epidemiological studies is evaluated.

Cell-mediated immunity to schistosomes. Evaluation of mechanisms operating against lung-stage parasites which might be exploited in a vaccine.

This report describes parallel studies examining T cell and cytokine responses to Schistosoma mansoni in mice and man. The prevalence of IFNg production amongst murine (C57BL/6) T cell lines and clones, plus good DTH reactivity by IFNg-secreting clones, highlights the predominance of the Th1 response in the pulmonary immunity characteristics of the murine irradiated vaccine model. In human studies, effects of anti-cytokine antibodies on the proliferation of PBMC from human patients to various soluble schistosome antigen preparations have been examined. Data suggest that both Th1 (against early antigens) and Th2 (against late antigens) responses are present. A role for IL-10 is highlighted in chronic intestinal, but not acute or chronic hepatosplenic patients, as a downregulator of responses which are associated with morbidity and are against late stage antigens.

Dot-dye-immunoassay and dot-ELISA for the serological differentiation of acute and chronic schistosomiasis mansoni using keyhole limpet haemocyanin as antigen.

Two immunoassays, dot enzyme-linked immunosorbent assay (dot-ELISA) and dot-dye immunoassay (dot-DIA), using soluble egg antigen and keyhole limpet haemocyanin as antigens, were evaluated for the serological differentiation of 25 acute and 37 chronic patients infected with Schistosoma mansoni and 20 non-infected individuals, in comparison with ELISA. Efficiency was 92.7%, 90.0% for ELISA, dot-ELISA and dot-DIA, respectively. Dipstick dot-ELISA and dot-DIA are described and shown to be reliable cheap and simple methods for the serological differentiation of acute and chronic schistosomiasis.

Evaluation of proteinuria in an area of Brazil endemic for schistosomiasis using a single urine sample.

A two-step protocol was designed to evaluate the frequency of proteinuria related to Schistosoma mansoni infection in an endemic area, as measured by the protein/creatinine ratio (P/C R). A pre-test on 32 in-patients with renal disease and 20 healthy individuals showed a high correlation (r = 0.948) between the classical measurement of protein excretion per square metre of body surface during 24 h and the P/C R. The P/C R was then used to evaluate the frequency of proteinuria in 189 individuals in an endemic area in the northeast of Minas Gerais state, Brazil, with a schistosomiasis prevalence of 49.3% and 3.4% with the hepatosplenic form. The low prevalence of proteinuria (1.06%) in the studied population can be attributed to the accuracy of the method used and to the low prevalence of the hepato-splenic form of schistosomiasis. The P/C R is a reliable and appropriate method for the measurement of proteinuria in field studies.

Stool examination and rectal biopsy in the diagnosis and evaluation of therapy of schistosomiasis mansoni.

From each of a group of 217 adult males selected through enzyme-immunoassay or skin-test (Group A), six stool samples were examined by both the Lutz/Hoffman, Pons & Janer (Lutz/HPJ) and Kato/Katz methods. In addition, one oogram of the rectal mucosa was performed. By these methods, schistosomiasis was detected in 44.7%, 47.5% and 40.1% of the individuals respectively. To evaluate the methods in the assessment of cure, the last 40 patients from group A, treated with a single oral dose of oxamniquine at 15 mg/kg were followed up for six months (Group B). The criteria for parasitological cure included three stool examinations by Kato/Katz and Lutz/HPJ methods, one, three and six months post-treatment and a rectal biopsy between the fourth and sixth months post-treatment. The examinations were negative in 87.5%, 90% and 95% of the patients, respectively. The efficacy of oxamniquine was 82.5% when the three methods were considered together and there was no statistically significant difference between the sensitivity of the individual methods.

DOT-dye-immunoassay for the diagnosis of schistosomiasis mansoni.

A new serological assay dot-dye-immunoassay (dot-DIA) was evaluated for the diagnosis of schistosomiasis mansoni. This method consist of four steps: (a) biding of antigens to a nitrocellulose membrane (NC); (b) blocking of free sites of the NC; (c) incubation in specific primary antibody; (d) detection of primary antibody reactivity by color development using second antibody coupled to textile dyes. Sera from 82 individuals, 61 with Schistosoma mansoni eggs in the stool and 21 stool negative were tested by ELISA, dot-ELISA, and dot-DIA. A high level of agreement between the methods tested was observed for all sera tested: ELISA x dot-ELISA: 95.1%, ELISA x dot-DIA: 92.7% and dot-ELISA x dot-DIA: 97.6%. In this study, dot-DIA proved to be a feasible, sensitive, rapid and practical test for the diagnosis of schistosomiasis.

Parasitological diagnosis of schistosomiasis mansoni: fecal examination and rectal biopsy.

Even with all progress in the search of sensitive and specific methods for the immunological diagnosis of schistosomiasis, the microscopic detection of eggs of the parasite in the stool still remains the most widely used tool for the actual diagnosis of active infection. Among the coproscopic methods, Kato's technic modified by Katz et al (Kato/Katz) has the advantages of higher sensitivity, the possibility of egg quantification, its low operational cost and its feasibility in areas with minimal infra-structure. The oogram of the rectal mucosa is valuable in initial clinical trials of schistosomicides, when it is needed to observe egg morphology in tissue. It could be an alternative method for individual diagnosis, being more sensitive than a single stool exam in low intensity infection. However, the increased sensitivity of a higher number of fecal exams makes that invasive procedure unnecessary. In the assessment of cure of schistosomiasis, Kato/Katz method (three fecal samples in one, three and six months after treatment) and the rectal biopsy four months after treatment, are equally reliable.

Analysis of anti-keyhole limpet haemocyanin antibody in Brazilians supports its use for the diagnosis of acute schistosomiasis mansoni.

Antibody (immunoglobulin (Ig) G) to the haemocyanin of the keyhole limpet (KLH) (Megathura crenulata), which shares a well defined carbohydrate epitope with the surface of schistosomula of Schistosoma mansoni, was determined by enzyme-linked immunosorbent assay (ELISA) in the sera of Brazilians with acute schistosomiasis. Of 53 such individuals tested, 51 had a level of KLH reactivity in excess of the mean +2 standard deviations of that exhibited by chronically infected individuals. This difference in reactivity allowed the acute cases to be readily identified by visual inspection of ELISA plates. The levels of IgG in patients with hepatointestinal and hepatosplenic schistosomiasis, as well as in non-infected, seropositive residents of endemic areas and infected children from endemic areas, were not statistically different from those of intestinal patients. Significant levels of anti-KLH IgG were not detected in patients with leishmaniasis, Chagas disease, ancylostomiasis or ascariasis. The results support the use of KLH as a means of rapidly and easily identifying individuals with acute schistosomiasis.

Levels of the schistosome circulating anodic and cathodic antigens in serum of schistosomiasis patients from Brazil.

Serum levels of 2 schistosome circulating antigens, the circulating anodic antigen (CAA) and the circulating cathodic antigen (CAA), were determined in persons infected with Schistosoma mansoni in Brazil. Sensitive monoclonal antibody-based enzyme-linked immunosorbent assays were used to measure levels of the 2 antigens. The study group consisted of 38 individuals with intestinal schistosomiasis, and 20 persons with the hepatosplenic form of the disease. Age and intensity of infection were comparable for the 2 groups. CAA was detected in 65.5% of all patients' sera and CCA was found in the serum of 82.8% of all patients. CAA levels correlated well with the egg output, as determined by duplicate Kato-Katz smears; CCA was significantly positively correlated with egg output in patients with intestinal schistosomiasis only. Whereas no significant difference was found between CAA titre in patients with intestinal schistosomiasis and those with the hepatosplenic form, a significantly higher CCA titre was found in patients with hepatosplenomegaly compared to patients with intestinal schistosomiasis.