Chagas disease in the Brazilian Amazon: IV. a new cross-sectional study

A new conglomerate family sample of 194 dwellings with 996 resident persons were studied in the town of Barcelos, State of Amazonas, in order to re-evaluate the risk of Chagas disease. During the survey the persons were interviewed and in this occasion we showed to them a collection of Panstrongylus, Rhodnius and Triatoma, asking if they recognized and eventually have been bitten by this kind of bugs. At this time we collected 500 ul of blood in microtainer® tubes from 886 interviewed persons who gave permission after informed consent. A screening test for T. cruzi antibodies based on agglutination of colored polymer particles, sensitized with three different synthetic peptides of T. cruzi (ID-PaGIA Chagas Test)®, showed 13.2% of sera positivity, but only 6.8% were confirmed by indirect immunofluorescence, and ELISA with purified T. cruzi antigens. Two hundred and six interviewed persons (20.7%) recognized the triatomines, as "piaçavas' lice" and 62 (30%) confirmed that have been bitten by the bugs, 25.8% of them had a positive serology for T. cruzi infection. Electrocardiographic alterations were shown in 9.3% of the seropositives and in 11.9% of the seronegative cases. This was considered not statistically significant.

Heterologous antigen extract in ELISA for the detection of human IgE anti-Strongyloides stercoralis

Strongyloides ratti larval extract was used for the standardization of ELISA to detect genus-specific IgE in human strongyloidiasis. Forty serum samples from monoinfected patients shedding S. stercoralis larvae (Group I), 40 from patients with other intestinal parasites (Group II), and 40 from copronegative healthy subjects (Group III) were analyzed. Genus-specific IgE levels (ELISA Index: EI) were significantly higher in the group I (EI = 1.43) than groups II (EI = 0.70) and III (EI = 0.71), showing positivity rates of 55%, 2.5% and 0%, respectively. Similarly, sera from copropositive patients had significantly higher levels of total IgE (866 IU/mL) as compared to those from group II (302 IU/mL) and III (143 IU/mL). A significant positive correlation was found between levels of Strongyloides specific-IgE and total IgE in sera from patients with strongyloidiasis. In conclusion, S. ratti heterologous extract showed to be a useful tool for detecting genus-specific IgE by ELISA, contributing for a better characterization of the immune response profile in human strongyloidiasis.

Evidence of active herpesvirus 6 (variant-A) infection in patients with lymphadenopathy in Belém, Pará, Brazil

A total of 323 patients with lymphadenopathy were selected in Belém, Brazil, between January 1996 and December 2001, and screened for the presence of human herpesvirus-6 (HHV-6) IgM- and- IgG antibodies by enzyme-linked immunosorbent assay (ELISA). When seroprevalence is analyzed by gender, similar rates are found for female (60.6%) and male (55.7%) individuals. Seventy-seven (23.8%) patients were HHV-6-IgM-and- IgG-positive (IgM+ subgroup), with positivity rates of 29.7% and 17.7% (p = 0.0007) for female- and male individuals, respectively. Sera from a subgroup (n = 120) of these subjects, with high HHV-6 antibody levels (either IgM+ or IgG+ reactivities), were subsequently processed for the presence of HHV-6 DNA by polymerase chain reaction (PCR)/nested PCR. Active infections (IgM+ and/or IgG+ high levels specific antibodies plus detection of viral DNA) were diagnosed in 20/77 (20.0%) and 8/43 (18.6%); subgroup of the 120 individuals suspected of having HHV-6 suggestive recent infection. All (n = 28) cases of active infection were found to be associated with HHV-6 variant-A (HHV-6A), as detectable by PCR/nested PCR, using variant-specific primer that amplify regions of 195 base pairs (bp) (HHV-6A) and 423 bp (HHV-6B). Rates of HHV-6 DNA detection between female and male patients were similar (p > 0.05) in the IgM+ and IgG+ groups: 20.4% versus 35.7% and 25.0% versus 13.0%, respectively. HHV-6 DNA was detected across < 5 through 41-50-year age-groups for patients whose serum samples were IgM+, with rates ranging from 7.7% (female subjects aged < 5 years) to 80.0% (male, 11-20 years). Among patients whose serological status was IgG+, HHV-6 DNA was detected in < 5, 6-10, 21-30 and > 50 age-groups at rates that ranged from 15.4% (male, < 5 years of age) to 100.0% (female aged 11-20 years). Swelling cervical lymph nodes were the most common sign, accounting for 9 (32.0%) cases in each gender group. Among patients (n = 28) with active infection by HHV-6A variant, duration of symptoms lasted 1-5 days in 35.7% of subjects, whereas in 64.3% of them the disease lasted 6-20 days. Our data suggest that it is worth seeking for HHV-6 infection whenever a patient (infant or adult) presents with lymphadenopathy as a prominent symptom in the course of an acute febrile illness.

Pustulose Generalizada Exantemática Aguda Associada ao Diltiazem

Acute generalized exanthematous pustulosis (AGEP) usually presents with the acute appearance of oedematous and erythematous lesions, on which multiple sterile pustules appear, associated with fever. Almost 90% of cases are associated with drugs, with antibiotics (penicillins and macrolides) being the most frequent causative agents. We describe a 36-year-old female patient, which started diltiazem 120mg/day for hypertension. After 6 days of therapy, multiple erythematous and oedematous lesions appeared, with associated multiple small non-follicular pustules. Oral corticosteroids were started, with progressive and complete improvement. Patch-tests were performed, which revealed positivity for diltiazem. Although a rare entity, AGEP must be considered in cases of acute eruptions with disseminated pustules and fever. The use of patch tests in this disease may be useful as positive reactions are frequent.

Rotavirus serotypes and electropherotypes identified among hospitalised children in São Luís, Maranhão, Brazil

During June 1997-June 1999 rotavirus infection was screened in infants aged up to 2 years and hospitalised with acute diarrhoea in São Luís, Northeastern Brazil. Altogether, 128 stool samples were collected from diarrhoeic patients and additional 122 faecal specimens from age- and- temporal matched inpatients without diarrhoea were obtained; rotavirus positivity rates for these groups were 32.0% (41/128) and 9.8% (12/122), respectively (p < 0.001). Both electropherotyping and serotyping could be performed in 42 (79.2%) of the 53 rotavirus-positive stool samples. Long and short electropherotypes were detected at similar rates - 38.1% and 40.5% of specimens, respectively. Overall, a G serotype could be assigned for 35 (83.3%) of specimens, the majority of them (66.7%) bearing G1-serotype specificity. Taking both electropherotypes and serotypes together, G1 rotavirus strains displaying long and short RNA patterns accounted for 30.9% and 19.0% of tested specimens, respectively; all G2 strains had short electropherotype. Rotavirus gastroenteritis was detected year-round and, in 1998, the incidence rates tended to be higher during the second semester than in the first semester: 45.2% and 26.1% (p = 0.13), respectively. Rotavirus infections peaked at the second semester of life with frequencies of 30.1% and 13.5% for diarrhoeic children and controls, respectively. While the six rotavirus strains bearing G2-type specificity were circulating throughout the whole study period, G1 serotypes (n = 27) emerged as from June 1998 onwards, 20 (74.1%) of which clustering in 1998. These data underscore the importance of rotaviruses in the aetiology of severe infantile gastroenteritis in Northeastern Brazil and sustain the concept that a future vaccine should confer protection against more than one serotype.

Questing one Brazilian query: reporting 16 cases of Q fever from Minas Gerais, Brazil

Q fever has been considered non-existing in Brazil where reports of clinical cases still cannot be found. This case-series of 16 patients is a result of a systematic search for such illness by means of clinical and serologic criteria. Serologic testing was performed by the indirect microimmunofluorescence technique using phase I/II C. burnetii antigens. Influenza-like syndrome was the most frequent clinical form (eight cases - 50%), followed by pneumonia, FUO (fever of unknown origin), mono-like syndrome (two cases - 12.5% each), lymphadenitis (one case - 6.3%) and spondylodiscitis associated with osteomyelitis (one case - 6.3%). The ages varied from four to 67 years old with a median of 43.5. All but one patient had positive serologic tests for phase II IgG whether or not associated with IgM positivity compatible with acute infection. One patient had both phase I and phase II IgG antibodies compatible with chronic Q fever. Seroconvertion was detected in 10 patients. Despite the known limitations of serologic diagnosis, the cases here reported should encourage Brazilian doctors to include Q fever as an indigenous cause of febrile illness.

Survival of Trypanosoma cruzi in sugar cane used to prepare juice

Chagas disease can be transmitted to man by many different means, including contact with infected triatomine feces, blood transfusion, laboratory accidents, organ transplants, and congenital or oral routes. The latter mode has received considerable attention recently. In this assay, we evaluate the survival of Trypanosoma cruzi contaminating sugar cane used to prepare juice, as well as the viability and capacity for infection by the parasite after recovery. Thirty triatomines were contaminated with T. cruzi Y strain and 45 days later pieces of sugar cane were contaminated with the intestinal contents of the insects. The pieces were ground at different intervals after contamination (time = 0, 1, 4, 6, 12 and 24 hours) and the juice extracted and analyzed. Different methods were used to show T. cruzi in the juice: direct analysis, hematocrit tube centrifugation and QBC, and experimental inoculation in 47 female BALB/c mice (five control mice and seven mice for each interval examined (five inoculated orally and two intraperitoneally). Positive results were found using the direct analysis and QBC methods for juice prepared up to 12 hours after initial contamination. However, by the centrifugation technique, positivity was found only up to four hours after contamination of the sugar cane. Inoculated animals showed parasitemia during a 14 day observation period, demonstrating the high survival rate of T. cruzi in sugar cane.

Serodiagnosis of neurocysticercosis in patients with epileptic seizure using ELISA and immunoblot assay

Sera from 88 patients from Santa Catarina and São Paulo states of Brazil, with epileptic seizures who underwent cerebral computed tomography (CT) were analyzed for the detection of antibodies to T. solium cysticercus by ELISA and Immunoblot (IB) with the following antigens: Taenia solium cysticercus total saline (Tso), Taenia crassiceps cysticercus vesicular fluid (Tcra-vf) and T. crassiceps cysticercus glycoproteins (Tcra-gp). ELISA carried out with Tso, Tcra-vf and Tcra-gp antigens showed 95%, 90% and 80% sensitivities, respectively, and 68%, 85% and 93% specificities, respectively. In the epileptic patients group, ELISA positivity was 30%, 51% and 35% with Tso, Tcra-vf and Tcra-gp antigens respectively. Considering the IB as the confirmatory test, the positivity was 16% (14/88) in the epileptic patients total group and 22% (12/54) in the epileptic patients with positive CT and signals of cysticercosis. We found a significant statistical correlation among ELISA or IB results and the phase of the disease when any antigens were used (p < 0.05). We emphasize the need to introduce in the laboratory routine the search for neurocysticercosis (NC) in patients presenting with epileptic seizures because of the high risk of acquiring NC in our region and its potential cause of epilepsy.

Molecular screening of Plasmodium sp. asymptomatic carriers among transfusion centers from Brazilian Amazon region

The transmission of malaria in Brazil is heterogeneous throughout endemic areas and the presence of asymptomatic Plasmodium sp. carriers (APCs) in the Brazilian Amazon has already been demonstrated. Malaria screening in blood banks is based on the selection of donors in respect to possible risks associated with travel or residence, clinical evidence and/or inaccurate diagnostic methods thereby increasing the probability of transfusion-transmitted infection. We evaluated the frequency of APCs in four blood services in distinct areas of the Brazilian Amazon region. DNA was obtained from 400 human blood samples for testing using the phenol-chloroform method followed by a nested-PCR protocol with species-specific primers. The positivity rate varied from 1 to 3% of blood donors from the four areas with an average of 2.3%. All positive individuals had mixed infections for Plasmodium vivax and Plasmodium falciparum. No significant differences in the results were detected among these areas; the majority of cases originated from the transfusion centres of Porto Velho, Rondônia State and Macapá, Amapá State. Although it is still unclear whether APC individuals may act as reservoirs of the parasite, efficient screening of APCs and malaria patients in Brazilian blood services from endemic areas needs to be improved.

Detection of parvovirus B19 infection in formalin-fixed and paraffin-embedded placenta and fetal tissues

Parvovirus B19 infection was first discovered in 1975 and it is implicated in fetal death from hydrops fetalis the world over. Diagnosis is usually made through histological identification of the intranuclear inclusion in placenta and fetal organs. However, these cells may be scarce or uncharacteristic, making definitive diagnosis difficult. We analyzed histologically placentas and fetal organs from 34 cases of non-immune hydrops fetalis, stained with Hematoxylin and Eosin (HE) and submitted to immunohistochemistry and polymerase chain reaction (PCR). Of 34 tissue samples, two (5.9%) presented typical intranuclear inclusion in circulating normoblasts seen in Hematoxylin and Eosin stained sections, confirmed by immunohistochemistry and PCR. However, PCR of fetal organs was negative in one case in which the placenta PCR was positive. We concluded that parvovirus B19 infection frequency is similar to the literature and that immunohistochemistry was the best detection method. It is highly specific and sensitive, preserves the morphology and reveals a larger number of positive cells than does HE with the advantage of showing cytoplasmic and nuclear positivity, making it more reliable. Although PCR is more specific and sensitive in fresh or ideally fixed material it is not so in formalin-fixed paraffin-embedded tissues, frequently the only one available in such cases.

Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro area, Brazil

A parasitological, clinical, serological and molecular cross-sectional study carried out in a highly endemic malaria area of Rio Negro in the Amazon State, Brazil, revealed a high prevalence of asymptomatic Plasmodium vivax infection. A total of 109 persons from 25 families were studied in five villages. Ninety-nine inhabitants (90.8%) had at least one previous episode of malaria. Serology showed 85.7% and 46.9% of positivity when P. falciparum antigens and P. vivax MSP-1, respectively, were used. Twenty blood samples were PCR positive for P. vivax (20.4%) and no P. falciparum infection was evidenced by this technique. No individual presenting positive PCR reaction had clinical malaria during the survey neither in the six months before nor after, confirming that they were cases of asymptomatic infection. Only one 12 year old girl presented a positive thick blood smear for P. vivax. This is the first description of asymptomatic Plasmodium infection in this area studied.

Seroepidemiological aspects of human Strongyloides stercoralis infections in Chile

To determine the frequency of Strongyloides stercoralis antibodies by means of the enzyme linked immunosorbent assay (ELISA) in Chile, in 2001-2003, 675 blood samples of patients of two psychiatric hospitals and 172 of healthy individuals (doctors, nurses and paramedicals) of these institutions, and 1,200 serum samples of blood donors of Northern region (Arica and Antofagasta), Central region (Valparaiso and Santiago) and Southern region (La Union) were collected. ELISA showed positivity of 12.1% in psychiatric hospitalized patients, none (0%) in the health personnel and 0.25% in blood donors (p < 0.05). Only in blood donors of Arica (1%) and La Union (0.5%) the ELISA test was positive suggesting that strongyloidiasis is focalized in determinate zones of the country. In Chile, human infections by S. stercoralis are endemic with very low frequency in apparently healthy individuals and high prevalence in risk groups such as the mentally ill hospitalized patients.

Cytomegalovirus in colorectal cancer and idiopathic ulcerative colitis

Cytomegalovirus (CMV) is a genus in the family Herpesviridae that has been associated with gastrointestinal syndromes. In this work we looked for a possible association of CMV infection with colorectal cancer and ulcerative colitis (UC). Blood and enteric tissue samples of 14 patients with colorectal cancer and of 21 with UC were subjected to a nested-PCR that amplifies part of the gB gene of CMV and also to immunohistochemistry using a specific monoclonal antibody to IE 76kDa protein of CMV. CMV was detected by nested-PCR in the blood and/or the enteric tissue of nine (64.3%) colorectal cancer and 16 (76.2%) ulcerative colitis patients. In the immunohistochemistry it was observed that 12 (12/21, 57.1%) positive enteric tissue samples of patients with UC and none from patients with colorectal cancer (0/14) were positive to CMV. The positivity of CMV infections in the UC patient group (12/21, 57.1%) showed by both techniques, was significantly higher (p = 0.015) than that observed for colorectal cancer patients (2/14, 14.3%). These results suggest an association of ulcerative colitis with CMV infection of the enteric tissue.

Clinical and serological evidence of Toxocara infection in school children from Morrope District, Lambayeque, Peru

The aim of this study was to estimate the frequency of human toxocariosis in a child population from Morrope district, Lambayeque, Peru. From October to December 2005, 182 school children (96 male and 86 female) were studied. Blood samples were collected for Toxocara ELISA-IgG test and hematological examination. Additionally, stool samples were collected for coproparasitological examination to check cross reactions. We found frequency of positives in 32.4% (59/182) with a significant higher proportion of positivity in male children (p < 0.00001). 71.2% of the children with positive serology (52 male and seven female), were between five and 10 years old, 77.96% had respiratory symptoms, 61.02% had ocular manifestations, 38.98% had hepatic symptoms, 38.98% had mild or moderate eosinophilia, signs statistically associated with seropositivity. 83.5% of studied population had some intestinal parasite, such as: Blastocystis hominis (53.3%), Giardia lamblia (31.3%), Entamoeba coli (29.1%), Entamoeba histolytica/E. dispar (1.1%), Hymenolepis nana (5.49%), and Ascaris lumbricoides (3.3%), but they had not any association with serology results. The ownership of dogs or/and cats were significantly associated with seropositivity to anti-Toxocara antibodies although the presence of such pets within the house was not. In conclusion, clinical and serological evidence of Toxocara infection exists in the studied population.

Specificity and Sensitivity of Screening for Anti-HLA Antibodies in Kidney Allograft Dysfunction

BACKGROUND: Prospective testing for posttransplant circulating anti-HLA antibodies seems to be a critical noninvasive tool, but confirmatory data are lacking. MATERIALS AND METHODS: Over the last 3 years, peritubular capillary (PTC) C4d deposition was prospectively sought by an immunofluorescence technique applied to frozen tissue in biopsies obtained for allograft dysfunction. Screening for circulating anti-HLA class I/II alloantibodies (AlloAb) by the flow cytometric test was performed simultaneously. RESULTS: We evaluated 132 sets of biopsies and simultaneous serum samples. PTC C4d deposition was demonstrated in 15.9% (21/132) of biopsies. Circulating anti-HLA I/II AlloAb were detected in 25% (33/132) of serum samples. Employing receiver-operator characteristic (ROC) curves for all C4d-positive biopsies, screening for AlloAb showed a global specificity of 82% and sensitivity of 61.9%. When this analysis was restricted to biopsies obtained in the first month posttransplantation, the sensitivity increased to 81.8%, but the specificity decreased to 76.9%. After the first month posttransplantation, we observed sensitivity of 40.0% and a specificity of 86.4%. In the first month posttransplantation, all patients with a diagnosis of acute antibody-mediated rejection displayed circulating anti-HLA class I/II, but not always at the same time as the C4d-positive biopsy. CONCLUSIONS: In the first month posttransplantation, prospective monitoring of anti-HLA antibodies may be useful. The high sensitivity allows the identification of patients at risk, affording an earlier diagnosis of antibody-mediated rejection. After the first month, the test can be used to evaluate allograft dysfunction episodes, since positivity is highly suggestive of an antibody-mediated process.