LATERAL FLOW ASSAY FOR CRYPTOCOCCAL ANTIGEN: AN IMPORTANT ADVANCE TO IMPROVE THE CONTINUUM OF HIV CARE AND REDUCE CRYPTOCOCCAL MENINGITIS-RELATED MORTALITY

SUMMARYAIDS-related cryptococcal meningitis continues to cause a substantial burden of death in low and middle income countries. The diagnostic use for detection of cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid by latex agglutination test (CrAg-latex) or enzyme-linked immunoassay (EIA) has been available for over decades. Better diagnostics in asymptomatic and symptomatic phases of cryptococcosis are key components to reduce mortality. Recently, the cryptococcal antigen lateral flow assay (CrAg LFA) was included in the armamentarium for diagnosis. Unlike the other tests, the CrAg LFA is a dipstick immunochromatographic assay, in a format similar to the home pregnancy test, and requires little or no lab infrastructure. This test meets all of the World Health Organization ASSURED criteria (Affordable, Sensitive, Specific, User friendly, Rapid/robust, Equipment-free, and Delivered). CrAg LFA in serum, plasma, whole blood, or cerebrospinal fluid is useful for the diagnosis of disease caused by Cryptococcusspecies. The CrAg LFA has better analytical sensitivity for C. gattii than CrAg-latex or EIA. Prevention of cryptococcal disease is new application of CrAg LFA via screening of blood for subclinical infection in asymptomatic HIV-infected persons with CD4 counts < 100 cells/mL who are not receiving effective antiretroviral therapy. CrAg screening of leftover plasma specimens after CD4 testing can identify persons with asymptomatic infection who urgently require pre-emptive fluconazole, who will otherwise progress to symptomatic infection and/or die.

The avirulence of the cultivated PF strain of Trypanosoma cruzi: V - the evaluation of parasitologic tests after vaccination of different animal species

After vaccination with the live PF strain of Trypanosoma cruzi, 194 blood cultures were performed in 143 mice, 9 dogs, 5 Cebus monkeys and 7 human subjects. Some of these blood cultures were simultaneously done with xenodiagnosis, subinoculation in baby mice and/or culture of viscerae. The trypanosomes isolated from the few positive cases (6,1%) were incapable of infecting baby mice were considered as cases of immunotolerance. All the other tests were negative.

Longitudinal study of the indirect immunofluorescence and complement fixation tests for diagnosis of chagas' disease in immunosuppressed patients submitted to renal transplantation

Clinical and serological follow-up of 7 patients submitted to renal transplantation and presenting positive serological reactions to Chagas 'disease before immunossupression did not show significant changes in indirect immunofluorescence and complement fixation titres for Chagas ' disease, or signs and symptoms indicating exacerbation of the disease during follow- up. In addition, 18 of 66 recipients of renal transplants considered to be non-chagasic before immunosuppression showed at least one positive result to the indirect immunofluorescence test for Chagas ' disease during the study period. The results suggest that the immunosuppression State induced in chagasic patients submitted to renal transplant did notpromoted exacerbation of the chronic infection in these patients and not interfere with the serological response of chronic chagasics, thus permitting the use of these serologic reactions for diagnostic purposes in these cases. However, the positive results ofthe indirect immunofluorescence test in non- chagasic patients indicate the needforjudicious interpretation ofthe indirect immunofluorescence test for the diagnosis of Chagas' disease in renal transplanted patients.

Diagnostic tests for amoebic liver abscess: comparison of enzyme - linked immunosorbent assay (Elisa) and counterimmunoelectrophoresis (CIE)

The liver abscess is the most frequent extraintestinal complication of intestinal amoebiasis: its diagnosis is suggested by the clinical picture but it must be confirmed by paraclinic tests. Themost stringent diagnosis requires identification of E. histolytica. But this is possible only in a few cases. Serological tests greatly improve the diagnosis of this severe complication of amoebiasis. We compared the Enzyme Linfed Immunosorbent Assay and the Counterimmunoeletrophoresis techniques. Both techniques were used to detect amoebic antibodies in 50 control patients, 30 patients with liver abscess and 30 patients with intestinal amoebiasis. All the sera from control patients gave negative results iin both techniques. When analysing the sera from patients with intestinal amoebiasis, 10% of them were positive by ELISA but non by CIE. The sera of patients with liver abscess, we found that 90% were positive by the ELISA method and 66.6% by the CIE technique. In patients with amoebic liver abscess, the results showed that the ELISA was more sensitive than the CIE, as it presented a higher sensitivity (100%) than that of the CIE technique (66%).

Assessment of chemiluminescence and PCR effectiveness in relation to conventional serological tests for the diagnosis of Chagas' disease

While testing 414 sera for the diagnosis of Chagas' disease, the conventional reactions of indirect hemagglutination, indirect immunofluorescence and the immunosorbent assay showed a sensitivity of 95.7%, 100% and 98.2% and a specificity of 98%, 98% and 96.4%, respectively, and an excellent association using Fisher's exact test. Chemiluminescence presented 100% sensitivity and 89.6% specificity, while PCR showed 100% specificity and 1.2% sensitivity. It is believed that the three conventional serological reactions are still adequate for diagnosing Chagas' disease.

International meeting: new diagnostic tests are urgently needed to treat patients with Chagas disease

Trypanosoma cruzi infection is often not detected early on or actively diagnosed, partly because most infected individuals are either asymptomatic or oligosymptomatic. Moreover, in most places, neither blood banks nor healthcare units offer diagnostic confirmation or treatment access. By the time patients present clinical manifestations of advanced chronic Chagas disease, specific treatment with current drugs usually has limited effectiveness. Better-quality serological assays are urgently needed, especially rapid diagnostic tests for diagnosis patients in both acute and chronic phases, as well as for confirming that a parasitological cure has been achieved. Some new antigen combinations look promising and it is important to assess which ones are potentially the best, together with their requirements in terms of investigation and development. In August 2007, a group of specialized researchers and healthcare professionals met to discuss the state of Chagas infection diagnosis and to build a consensus for a plan of action to develop efficient, affordable, accessible and easy-to-use diagnostic tests for Chagas disease. This technical report presents the conclusions from that meeting.

Validation of a case definition for leptospirosis diagnosis in patients with acute severe febrile disease admitted in reference hospitals at the State of Pernambuco, Brazil

INTRODUCTION: Leptospirosis is often mistaken for other acute febrile illnesses because of its nonspecific presentation. Bacteriologic, serologic, and molecular methods have several limitations for early diagnosis: technical complexity, low availability, low sensitivity in early disease, or high cost. This study aimed to validate a case definition, based on simple clinical and laboratory tests, that is intended for bedside diagnosis of leptospirosis among hospitalized patients. METHODS: Adult patients, admitted to two reference hospitals in Recife, Brazil, with a febrile illness of less than 21 days and with a clinical suspicion of leptospirosis, were included to test a case definition comprising ten clinical and laboratory criteria. Leptospirosis was confirmed or excluded by a composite reference standard (microscopic agglutination test, ELISA, and blood culture). Test properties were determined for each cutoff number of the criteria from the case definition. RESULTS: Ninety seven patients were included; 75 had confirmed leptospirosis and 22 did not. Mean number of criteria from the case definition that were fulfilled was 7.8±1.2 for confirmed leptospirosis and 5.9±1.5 for non-leptospirosis patients (p<0.0001). Best sensitivity (85.3%) and specificity (68.2%) combination was found with a cutoff of 7 or more criteria, reaching positive and negative predictive values of 90.1% and 57.7%, respectively; accuracy was 81.4%. CONCLUSIONS: The case definition, for a cutoff of at least 7 criteria, reached average sensitivity and specificity, but with a high positive predictive value. Its simplicity and low cost make it useful for rapid bedside leptospirosis diagnosis in Brazilian hospitalized patients with acute severe febrile disease.

Contributions of culture and antimicrobial susceptibility tests to the retreatment of patients with pulmonary tuberculosis

Introduction This study evaluated the efficacy of retreatment of pulmonary tuberculosis (TB) with regard to treatment outcomes and antimicrobial susceptibility testing (ST) profiles. Methods This retrospective cohort study analyzed 144 patients treated at a referral hospital in Brazil. All of them had undergone prior treatment, were smear-positive for TB and received a standardized retreatment regimen. Fisher's 2-tailed exact test and the χ2 test were used; RRs and 95% CIs were calculated using univariate and multivariate binary logistic regression. Results The patients were cured in 84 (58.3%) cases. Failure was associated with relapsed treatment and abandonment (n=34). Culture tests were obtained for 103 (71.5%) cases; 70 (48.6%) had positive results. ST results were available for 67 (46.5%) cases; the prevalence of acquired resistance was 53.7%. There were no significant differences between those who achieved or not therapeutic success (p=0.988), despite being sensitive or resistant to 1 or more drugs. Rifampicin resistance was independently associated with therapeutic failure (OR: 4.4, 95% CI:1.12-17.37, p=0.034). For those cases in which cultures were unavailable, a 2nd model without this information was built. In this, return after abandonment was significantly associated with retreatment failure (OR: 3.59, 95% CI:1.17-11.06, p=0.026). Conclusions In this cohort, the general resistance profile appeared to have no influence on treatment outcome, except in cases of rifampicin resistance. The form of reentry was another independent predictor of failure. The use of bacterial culture identification and ST in TB management must be re-evaluated. The recommendations for different susceptibility profiles must also be improved.

Serological cross-reactivity of Trypanosoma cruzi, Ehrlichia canis, Toxoplasma gondii, Neospora caninum and Babesia canis to Leishmania infantum chagasi tests in dogs

Introduction: The aim of this study was to evaluate the serological cross-reactivity between Leishmania sp. and other canine pathogens. Methods: Positive serum samples for Ehrlichia canis, Babesia canis, Toxoplasma gondii, Neospora caninum and Trypanosoma cruzi were tested using three serological methods enzyme linked immunosorbent assay (ELISA), indirect immunofluorescent antibody test (IFAT) and Kalazar Detect™, for canine visceral leishmaniasis. Results: Of the 57 dog samples tested, 24 (42.1%) tested positive using one of the three serological methods: 10/57 (17.5%) for ELISA, 11/57 (19.3%) for IFAT and 3/57 (5.3%) for Kalazar Detect™. Conclusions: Our results demonstrated that the presence of other infectious agents may lead to cross-reactivity on leishmaniasis serological tests.

Hybrid capture II and PapilloCheck® tests for detection of anal high-risk human papillomavirus

Introduction This study evaluated the level of concordance between hybrid capture II (HCII) and PapilloCheck® for the detection of high-risk human papillomavirus (HPV) in anal samples. Methods Anal cell samples collected from 42 human immunodeficiency virus (HIV)+ patients were analyzed. Results Considering only the 13 high-risk HPV types that are detectable by both tests, HCII was positive for 52.3% of the samples, and PapilloCheck® was positive for 52.3%. The level of concordance was 80.9% (Kappa = 0.61). Conclusions Good concordance was observed between the tests for the detection of high-risk HPV.

Evaluation of diagnostic tests for Wuchereria bancrofti infection in Brazilian schoolchildren

Introduction Since the launch of the Global Programme to Eliminate Lymphatic Filariasis, more than 70% of the endemic countries have implemented mass drug administration (MDA) to interrupt disease transmission. The monitoring of filarial infection in sentinel populations, particularly schoolchildren, is recommended to assess the impact of MDA. A key issue is choosing the appropriate tools for these initial assessments (to define the best intervention) and for monitoring transmission. Methods This study compared the pre-MDA performance of five diagnostic methods, namely, thick film test, Knott's technique, filtration, Og4C3-ELISA, and the AD12-ICT card test, in schoolchildren from Brazil. Venous and capillary blood samples were collected between 11 pm and 1 am. The microfilarial loads were analyzed with a negative binomial regression, and the prevalence and associated 95% confidence intervals were estimated for all methods. The accuracies of the AD12-ICT card and Og4C3-ELISA tests were assessed against the combination of parasitological test results. Results A total of 805 schoolchildren were examined. The overall and stratified prevalence by age group and gender detected by Og4C3-ELISA and AD12-ICT were markedly higher than the prevalence estimated by the parasitological methods. The sensitivity of the AD12-ICT card and Og4C3-ELISA tests was approximately 100%, and the positive likelihood ratios were above 6. The specificity of the Og4C3-ELISA was higher than that of the AD12-ICT at different prevalence levels. Conclusions The ICT card test should be the recommended tool for monitoring school-age populations living in areas with ongoing or completed MDA.

Integrative literature review of the reported uses of serological tests in leprosy management

Abstract: An integrative literature review was conducted to synthesize available publications regarding the potential use of serological tests in leprosy programs. We searched the databases Literatura Latino-Americana e do Caribe em Ciências da Saúde, Índice Bibliográfico Espanhol em Ciências da Saúde, Acervo da Biblioteca da Organização Pan-Americana da Saúde, Medical Literature Analysis and Retrieval System Online, Hanseníase, National Library of Medicine, Scopus, Ovid, Cinahl, and Web of Science for articles investigating the use of serological tests for antibodies against phenolic glycolipid-I (PGL-I), ML0405, ML2331, leprosy IDRI diagnostic-1 (LID-1), and natural disaccharide octyl-leprosy IDRI diagnostic-1 (NDO-LID). From an initial pool of 3.514 articles, 40 full-length articles fulfilled our inclusion criteria. Based on these papers, we concluded that these antibodies can be used to assist in diagnosing leprosy, detecting neuritis, monitoring therapeutic efficacy, and monitoring household contacts or at-risk populations in leprosy-endemic areas. Thus, available data suggest that serological tests could contribute substantially to leprosy management.

Liver synthesis function in chronic asymptomatic or oligosymptomatic alcoholics: correlation with other liver tests

Liver function and its correlation with bilirubin and hepatic enzymes were evaluated in 30 male chronic asymptomatic or oligosymptomatic alcoholics admitted into the psychiatric hospital for detoxification and treatment of alcoholism. Hypoalbuminemia, lowered prothrombin activity, hypotransferrinemia and hypofibrinogenemia were detected in 32 %, 32 %, 28 %, and 24 % of patients, respectively. Transferrin was elevated in 8 %. Greater prevalence of hyperbilirubinemia was found in patients with lowered prothrombin activity, hypofibrinogenemia, or hypotransferrinemia. No correlation was found between serum bilirubin or aminotransferase levels and normal or elevated albumin levels, time or activity of prothrombin, and fibrinogen levels. Serum alkaline phosphatase was elevated in normoalbuminemics and gamma-glutamyltransferase in patients with lowered prothrombin activity. Hypoalbuminemia was associated with hypofibrinogenemia, hypotransferrinemia with elevated aspartate aminotransferase or gamma-glutamyltransferase, and hypertransferrinemia with elevation of alanine aminotransferase. These data indicated the occurrence of hepatic dysfunction due to liver damage caused directly by alcohol or by alcoholism-associated nutritional deficiencies.

Analysis of exploratory eye movements in patients with schizophrenia during visual scanning of projective tests' figures

OBJECTIVE: Compare pattern of exploratory eye movements during visual scanning of the Rorschach and TAT test cards in people with schizophrenia and controls. METHOD: 10 participants with schizophrenia and 10 controls matched by age, schooling and intellectual level participated in the study. Severity of symptoms was evaluated with the Positive and Negative Syndrome Scale. Test cards were divided into three groups: TAT cards with scenes content, TAT cards with interaction content (TAT-faces), and Rorschach cards with abstract images. Eye movements were analyzed for: total number, duration and location of fixation; and length of saccadic movements. RESULTS: Different pattern of eye movement was found, with schizophrenia participants showing lower number of fixations but longer fixation duration in Rorschach cards and TAT-faces. The biggest difference was observed in Rorschach, followed by TAT-faces and TAT-scene cards. CONCLUSIONS: Results suggest alteration in visual exploration mechanisms possibly related to integration of abstract visual information.