Dengue Fever and Aedes aegypti in indigenous Brazilians: seroprevalence, risk factors, knowledge and practices.

OBJECTIVE: Dengue remains an important public health problem in Brazil. We estimated the associated factors of dengue seroprevalence among native Indians of the Tremembé ethnic and their knowledge about the aspects related to the presence of mosquitoes of the genus Aedes. METHODS: An analytical cross-sectional study and a prospective environmental study to monitor the trapping of mosquito eggs monthly were performed. The serological portion of the study involved indigenous people living in the village of Tapera in northeastern Brazil. Ovitraps were monitored for 12 months. RESULTS: Two hundred and ninety of 350 indigenous people (82.9%) participated in the study, with an average age of 30.2 years. The seroprevalence was 22.1% and positivity increased with age, with rates of 4.2% in children under 15 years of age, 26.8% in 15 to 59-year-olds and 42.3% in those older than 59 (CI: 2.25-15.96; P < 0.001). A higher incidence of moving to the city and the presence of underlying diseases were associated with the occurrence of dengue (P < 0.001). Four serotypes were detected, with the highest prevalence of DENV-1 (77.8%), followed by DENV-2 (70.4%), DENV-3 (14.8%) and DENV-4 (11.1%). Eggs were collected in all months of the year and in the traps located in the vicinities of the domiciles (57%). CONCLUSIONS: We present the first seroepidemiological survey of dengue conducted among indigenous populations in Brazil. This lack of studies is likely due to the great bureaucratic challenge of working with indigenous populations, which may lead to greater negligence in the health of these populations.

Is there an overestimation of dengue compared with that of other acute febrile syndromes in childhood?

A group of children with clinical suspicion of dengue were assessed to determine if there was an overestimation of dengue compared with that of leptospirosis and leishmaniasis. This descriptive and analytical cross-sectional study, based on the active search of participants with acute febrile illness, was conducted at two pediatric hospitals. The collection of clinical and epidemiological data was performed using questionnaires, and laboratory tests specific for dengue were performed using immunochromatographic, serological, and molecular methods. Dengue-negative samples were assessed for Leptospira and Leishmania spp. using molecular tests. Data were assessed using analysis of variance (ANOVA), the chi-square test, and Fisher's exact test. In total, 86 participants were evaluated, of whom 39 (45%) were positive for dengue fever, 4 (5%) for leptospirosis, and 1 (1%) for leishmaniasis. Forty-two participants (49%) presented dengue-like symptoms. The predominant age range for the virus was 3-10 years. Most clinical manifestations were nonspecific, with frequent concomitant gastrointestinal and respiratory symptoms. Furthermore, we found that the acute febrile syndrome in childhood persists as a challenge for health professionals, especially in the early days of the disease, due to a plurality of diagnostic hypotheses, associated with the difficulty of establishing well-defined symptoms in children, especially in infants. Dengue fever continues to be a frequent pathology with acute febrile infections in childhood; however, there is an overestimation of the disease, especially in endemic regions, when one considers only the clinical epidemiological diagnosis.

Screening for coronavirus disease 2019 in pregnant women admitted for delivery: an observational study.

OBJECTIVE: The aim of this study was to examine the impact of symptom-based screening on the prevalence and outcomes of neonatal coronavirus disease 2019 in pregnant women admitted for delivery. METHODS: A retrospective observational study was conducted from June to August 2020 at Gonzaga Mota of Messejana Hospital, Fortaleza, CE, Brazil. All pregnant women were screened for coronavirus disease 2019 based on symptoms. Reverse transcription-polymerase chain reaction or immunology assays for severe acute respiratory syndrome coronavirus 2 were performed when a patient reported a symptom. All newborns of symptomatic patients were submitted for Reverse transcription-polymerase chain reaction. Newborns were divided into groups according to the Reverse transcription-polymerase chain reaction results to identify the relationship between maternal symptoms and neonatal coronavirus disease 2019. RESULTS: A total of 55 (55/1,026, 5.4%) and 50 (50/1,026, 4.8%) pregnant women reported symptoms and had a positive confirmatory test, respectively. The most common symptom of coronavirus disease 2019 among the pregnant women with positive confirmatory test was cough (n=23, 46%). Seven newborns (7/50, 14%) of symptomatic mothers had positive Reverse transcription-polymerase chain reaction. Upon birth, no newborn had serious complications. CONCLUSION: Universal screening of pregnant women admitted for delivery can reduce the perinatal transmission of coronavirus disease 2019. Symptom-based screening can be an alternative for regions with a low prevalence of the disease where a better allocation of financial resources is necessary.

RT-LAMP Multicenter Study for SARS-CoV-2 Genome Molecular Detection in Brazilian Swab and Saliva Samples.

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a rapid method that can replace RT-qPCR. A simple molecular assay for SARS-CoV-2 RNA detection in gold-standard diagnosis through swabs and alternative specimens such as saliva could be helpful in promoting genomic surveillance. A multicenter study was conducted to evaluate the RT-LAMP assay method as an alternative for the molecular detection of SARS-CoV-2 lineages in swab and saliva samples. A total of 350 swabs from individuals with (n = 276) or without (n = 74) COVID-19 tested by RT-qPCR were collected. Paired saliva was also collected from 90 individuals who had SARS-CoV-2 RNA that was detectable (n = 30) or undetectable (n = 60) via RT-qPCR. For the RT-LAMP methodology, six primers were used for ORF1 gene amplification. As for SARS-CoV-2 genotyping, 39 swabs had the whole genome sequenced by MinION. The sensitivity of RT-LAMP to the swab was 90.2%. For the swab samples with Ct ≤ 30, the sensitivity improved by 96%. Considering saliva with Ct ≤ 30 in RT-qPCR testing, the RT-LAMP sensitivity was 100%. The RT-LAMP specificity was 100% for both the swab and saliva samples. This RT-LAMP assay was capable of detecting all the SARS-CoV-2 lineages circulating in the Brazilian swab samples. The RT-LAMP method has significant potential for use in clinical routines since it was capable of detecting SARS-CoV-2 RNA in swab and saliva samples.

HIV-1 tropism and CD4 T lymphocyte recovery in a prospective cohort of patients initiating HAART in Ribeirão Preto, Brazil.

While human immunodeficiency virus (HIV)-1 chemokine co-receptors 5 tropism and the GWGR motif in the envelope third variable region (V3 loop) have been associated with a slower disease progression, their influence on antiretroviral response remains unclear. The impact of baseline V3 characteristics on treatment response was evaluated in a randomised, double blind, prospective cohort study with patients initiating highly active antiretroviral therapy with lopinavir or efavirenz plus azithothymidine/3TC (1:1) over 48 weeks. Similar virological and immunological responses were observed for both treatment regimens. The 43 individuals had a mean baseline CD4 T cell count of 119 cells/mm(3) [standard deviation (SD) = 99] and a mean viral load of 5.09 log(10) copies/mL (SD = 0.49). The GWGR motif was not associated with a CD4 T cell response, but predicted R5 tropism by the geno2pheno([clinical20%]) algorithm correlated with higher CD4 T cell levels at all monitoring points (p < 0.05). Moreover, higher false-positive rates (FPR) values from this analysis revealed a strong correlation with CD4 T cell recovery (p < 0.0001). Transmitted drug resistance mutations, documented in 3/41 (7.3%) cases, were unrelated to the assigned antiretroviral regimen and had no impact on patient outcomes. In conclusion, naÏve HIV-1 R5 infected patients exhibited higher CD4 T cell counts at baseline; this difference was sustained throughout therapy. The geno2pheno([clinical]) option FPR positively correlated with CD4 T cell gain and may be useful in predicting CD4 T cell recovery.

Dried blood spot sampling as an alternative for the improvement of hepatitis B and C diagnosis in key populations.

BACKGROUND: To achieve the elimination of hepatitis B and C, there is an urgent need to develop alternative strategies to increase the access of diagnosis, particularly among key populations such as people living with human immunodeficiency virus (HIV), individuals with coagulopathies and chronic kidney disease (CKD) patients. AIM: To evaluate the use of dried blood spot (DBS) in the detection of hepatitis B virus (HBV) and hepatitis C virus (HCV) markers. METHODS: A total of 430 individuals comprised of people living with HIV, coagulopathies and CKD provided paired serum and DBS samples. HBsAg, anti-HBc and anti-HCV were tested in those samples using a commercial electrochemiluminescence. Demographic and selected behavioral variables were evaluated to assess possible association with HBV and HCV positivity. RESULTS: Using DBS, HBsAg prevalence varied from 3.9% to 22.1%, anti-HBc rates varied from 25.5% to 45.6% and anti-HCV positivity ranged from 15.9% to 41.2% in key populations. Specificities of HBV and HCV tests using DBS varied from 88.9% to 100%. The HBsAg assay demonstrated the best performance in CKD and coagulopathy individuals and the anti-HCV test had a sensitivity and specificity of 100% in people living with HIV. Accuracy of HBV and HCV detection in DBS varied from 90.2% to 100%. In the CKD group, HBsAg positivity was associated with infrequent use of condoms, and anti-HBc positivity was associated with sharing nail cutters/razors/toothbrushes. Anti-HCV reactivity was positively associated with a history of transplantation and length of time using hemodialysis in both specimens. In people living with HIV, only the male gender was associated with anti-HBc positivity in serum and DBS. CONCLUSION: DBS with electrochemiluminescence are useful tools for the diagnosis and prevalence studies of hepatitis B and C among key populations and may increase the opportunity to foster prevention and treatment.

In silico analysis of mismatches in RT-qPCR assays of 177 SARS-CoV-2 sequences from Brazil.

INTRODUCTION: Quantitative reverse transcription polymerase chain reaction (RT-qPCR) can detect the severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) in a highly specific manner. However, a decrease in the specificity of PCR assays for their targets may lead to false negative results. METHODS: Here, 177 high-coverage complete SARS-CoV-2 genome sequences from 13 Brazilian states were aligned with 15 WHO recommended PCR assays. RESULTS: Only 3 of the 15 completely aligned to all Brazilian sequences. Ten assays had mismatches in up to 3 sequences and two in many sequences. CONCLUSION: These results should be taken into consideration when using PCR-based diagnostics in Brazil.

High prevalence of parvovirus B19 infection in patients with chronic kidney disease under hemodialysis: A multicenter study.

OBJECTIVES: Parvovirus B19 (B19V) infection is commonly acute and self-limited, but in chronic kidney disease (CKD) patients under dialysis treatment, this infection could increase susceptibility to acute and chronic anemia. The aim of this study was to evaluate the frequency and risk of B19V infection among Brazilian CKD patients under dialysis. METHODS: A study was conducted among 221 CKD patients and a control group of 142 blood donors. B19V infection was evaluated in serum samples by real-time PCR, and ELISA (anti-B19V IgM and IgG). RESULTS: B19V DNA was detected in 65% (145/221) of CKD patients, which was significantly higher (p < 0.001) than in the blood donors (6.3%). Simultaneous detection of B19V IgG and viremia was shown in 40.3% of CKD patients, which was indicative of persistent B19V infection. CKD patients showed an increased risk of developing B19V infection (OR = 28.1, CI = 13.5-58.5, p = 0.001). CONCLUSIONS: Despite an absence of clinical signs of B19V infection, these data highlight the importance of B19V infection in this high-risk population, since a persistent B19V infection could become clinically significant after renal transplant. Moreover, the persistent viremia should be considered as a potential risk, mainly because of the contamination of dialysis equipment.

Advantages and pitfalls of the polymerase chain reaction in the diagnosis of esophageal ulcers in AIDS patients.

HIV-1-infected patients frequently have opportunistic esophageal infections which, when associated with severe immunodeficiency, can be attributed to unusual pathogens. The clinical presentation of several esophageal diseases is similar and the best method for a specific diagnosis of these patients has not been well defined. To evaluate the role of the polymerase chain reaction (PCR) in the etiologic definition of esophageal ulcers in HIV-1-infected patients, 96 esophageal biopsies from 79 HIV-1-infected patients were processed by PCR using specific primers for cytomegalovirus (CMV), herpes virus (HSV), human papilloma virus (HPV), HIV-1, Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium intracellulare, Treponema pallidum, and Haemophilus ducreyi. The PCR results were compared to the histopathologic results. Seventy-nine patients were studied (mean age: 34 years; 62% men; median CD4 + T cell = 103.59 cells/microl (range 1-795.2 cells/microl). The most common endoscopic findings were as follows: esophageal candidiasis (37.1%), esophageal ulcers (24.7%), esophagitis (11.2%), and lugol-negative areas (10.1%). The histopathologic findings in the esophageal ulcers (22 biopsies) were non-specific inflammation (31.8%), HSV (36.4%), Candida (13.6%), CMV (13.6%), or HPV disease (4.5%). In the esophageal ulcer biopsies, the PCR results were negative in 27.6% of cases, and positive for HIV (65.5%), CMV (31%), HPV (20.7%), HSV (10.3%), and H. ducreyi (6.9%). The histopathologic examination did not identify a pathogen or identified only Candida in 15 biopsies of esophageal ulcers. PCR was positive in ten (66.7%) and negative in five (33.3%) of these biopsies (idiopathic ulcers). PCR detected: HIV (53.3%), CMV (20%), HPV (13.3%), and H. ducreyi (6,7%). PCR detected more etiologic agents in esophageal ulcers than histopathology and was able to detect unusual pathogens. On the other hand, sometimes more than one pathogen was detected in the esophageal ulcers, making it difficult to reach an accurate diagnosis. This finding indicates the need for more studies to evaluate the benefit of this method in the routine evaluation of esophageal ulcer biopsies in HIV-1-infected patients.

Dengue: 30 years of cases in an endemic area.

The present study aimed to review literature on studies of dengue cases conducted over 30 years in the state of Ceará.Between November 2015 and January 2016, articles published in Portuguese and English in 7 databases were searched using keywords and a Boolean operator. A total of 191 articles were identified in the databases; 133 were excluded according to the exclusion criteria, and 58 were included in the study.Of the 58 articles analyzed, 6 reported data from Brazil; including the Northeast region and the state of Ceará; 41 reported data for only the city of Fortaleza; 7 reported data for the state of Ceará; 4 reported data for cities in the interior of the state; and 3 included only children. The studies adopted different approaches and focused on different aspects of the disease. Study outcomes included the identification of serological, epidemiological, clinical, and laboratory characteristics; potential larvicides and biological predators of mosquitoes; potential antiviral agents; vector density characteristics; and educational dengue prevention and control strategies. Additionally, one vaccine trial was included.Although studies on dengue in the state of Ceará are scarce, they are encompassing, including several lines of research, and the number of studies and reports on dengue in the state of Ceará continues to increase.

A DNA vaccine candidate expressing dengue-3 virus prM and E proteins elicits neutralizing antibodies and protects mice against lethal challenge.

In an effort to develop a suitable DNA vaccine candidate for dengue, using dengue-3 virus (DENV-3) as a prototype, the genes coding for premembrane (prM) and envelope proteins (E) were inserted into an expression plasmid. After selecting recombinant clones containing prM/E genes, protein expression in the cell monolayer was detected by indirect immunofluorescence and immunoprecipitation assays. After selecting three vaccine candidates (pVAC1DEN3, pVAC2DEN3 and pVAC3DEN3), they were analyzed in vivo to determine their ability to induce a DENV-3-specific immune response. After three immunizations, the spleens of the immunized animals were isolated, and the cells were cultivated to measure cytokine levels by ELISA and used for lymphoproliferation assays. All of the animals inoculated with the recombinant clones induced neutralizing antibodies against DENV-3 and produced a T cell proliferation response after specific stimuli. Immunized and control mice were challenged with a lethal dose of DENV-3 and observed in order to assess their survival capability. The groups that presented the best survival rate after the challenge were the animals vaccinated with the pVAC3DEN3 clones, with an 80% survival rate. Thus, these data show that we have manufactured a vaccine candidate for DENV-3 that is able to induce a specific immune response and protects mice against a lethal challenge.

Is early HIV infection diagnosis at a reference center a reality in the state of Ceara?

INTRODUCTION: Early diagnosis of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) can decrease transmission and significantly affect morbidity and mortality; however, Brazil still confronts the reality of late HIV diagnosis. METHODS: Medical records of 284 HIV-positive patients were reviewed in this cross-sectional study. RESULTS: Of all patients, 28% were diagnosed in the context of health assessments, whereas 27% were symptomatic at diagnosis. Early HIV infection (Group 1) was diagnosed in 60.2% of participants. They were younger than those with late diagnosis (Group 2) (p = 0.002). CONCLUSIONS: These findings highlight the need for strategies to increase HIV testing in asymptomatic individuals and older patients.

Kyrle's disease associated with HIV infection, diabetes, and chronic kidney disease.

Kyrle's disease (KD) is a rare skin pathology characterized by transepidermal elimination of abnormal keratin. The aim of this article is to report a rare case of KD associated with diabetes mellitus, chronic kidney disease, and HIV. A 51-year-old male patient complained of diarrhea for 8 months. He was submitted to HIV testing, which showed a positive result. He started antiretroviral therapy with zidovudine, lamivudine, and lopinavir. The diagnostic investigation was negative for opportunistic diseases. After 2 months, skin lesions started appearing, characterized by hyperchromic, pruritic macules and papules distributed in the trunk, back, and upper limbs. He also developed erythematous, scaly lesions in the facial region. A biopsy of the skin was performed, of which histopathological report consisted of perforating disorder, favoring a diagnosis of KD. Treatment with keratolytic soap (Actine) was started, with skin lesion improvement. In this reported case, it is possible that, in addition to diabetes and renal failure, HIV infection played an important role in the genesis of the lesions.

Performance of point of care assays for hepatitis B and C viruses in chronic kidney disease patients.

AIMS: Point of care testing (POCT) has been used for hepatitis B and C diagnosis in general population, but little is known about the influence of clinical conditions in the accuracy of these assays. This study aims to evaluate the performance of POCTs for detection of hepatitis B virus surface antigen (HBsAg) and antibodies to Hepatitis C Virus (anti-HCV) in Chronic Kidney Disease (CKD) patients. METHODS: A total of 286 subjects were included in this study. HBsAg and anti-HCV were detected using commercial EIAs and four POCTs: HBsAg (WAMA Imuno-Rápido HBsAg and VIKIA HBsAg) and anti-HCV (DOLES HCV teste rápido and WAMA Imuno-Rápido anti-HCV) in serum and whole blood. RESULTS: Using EIA, HBsAg and anti-HCV prevalence was 4.5% and 16.1% in CKD patients. HBsAg and anti-HCV POCTs had sensitivities from 92.3% to 100% and 84.8% to 89.1% while specificities were 99.3% to 100% and 99.2% to 99.6%, respectively. POCT using serum samples performed well compared with whole blood samples and true positive samples of POCTs had high optical density to cut-off (OD/CO) values compared with EIA. CONCLUSIONS: This study demonstrates good performance of HBsAg and anti-HCV POCTs in CKD patients, especially in serum samples indicating low interference of this disease in the performance of these assays. POCTs could be an important tool for HBV and HCV screening in high-risk populations.

Screening for coronavirus disease 2019 in pregnant women admitted for delivery: an observational study

SUMMARY OBJECTIVE: The aim of this study was to examine the impact of symptom-based screening on the prevalence and outcomes of neonatal coronavirus disease 2019 in pregnant women admitted for delivery. METHODS: A retrospective observational study was conducted from June to August 2020 at Gonzaga Mota of Messejana Hospital, Fortaleza, CE, Brazil. All pregnant women were screened for coronavirus disease 2019 based on symptoms. Reverse transcription-polymerase chain reaction or immunology assays for severe acute respiratory syndrome coronavirus 2 were performed when a patient reported a symptom. All newborns of symptomatic patients were submitted for Reverse transcription-polymerase chain reaction. Newborns were divided into groups according to the Reverse transcription-polymerase chain reaction results to identify the relationship between maternal symptoms and neonatal coronavirus disease 2019. RESULTS: A total of 55 (55/1,026, 5.4%) and 50 (50/1,026, 4.8%) pregnant women reported symptoms and had a positive confirmatory test, respectively. The most common symptom of coronavirus disease 2019 among the pregnant women with positive confirmatory test was cough (n=23, 46%). Seven newborns (7/50, 14%) of symptomatic mothers had positive Reverse transcription-polymerase chain reaction. Upon birth, no newborn had serious complications. CONCLUSION: Universal screening of pregnant women admitted for delivery can reduce the perinatal transmission of coronavirus disease 2019. Symptom-based screening can be an alternative for regions with a low prevalence of the disease where a better allocation of financial resources is necessary.

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.

Bixinoids Derived from Bixa orellana as a Potential Zika Virus Inhibitor Using Molecular Simulations. Antiviral Effect on the Zika Virus of Bixinoids

Abstract Zika fever is a viral infection of great relevance in public health, especially in tropic regions, in which there is a predominance of mosquitoes of the genus Aedes, vectors of the disease. Microcephaly in neonatal children and Guillain-Barré syndrome in adults can be caused by the action of the Zika virus (ZIKV). Non-structural proteins, such as NS2B, NS3 and NS5, are important pharmacological targets, due to their action in the life cycle. The absence of anti-Zika drugs raises new research, including prospecting for natural products. This work investigated the in silico antiviral activity of bixin and six other derived molecules against the Zika viral proteins NS2B-NS3 and NS5. The optimized structure was subjected to molecular docking to characterize the interaction between bixinoids and ZIKV non-structural proteins, where significant interactions were observed with amino acid residues in the catalytic site in each enzyme. These results suggest that bixin and ethyl bixin has the potential to interfere with the enzymatic activity of NS2B, NS3 and NS5, thus being an indication of being a promising anti-Zika agent.

Performance of rapid diagnostic tests for detection of Hepatitis B and C markers in HIV infected patients.

There is little information describing the influence of HIV infection upon the performance of rapid diagnostic tests (RDTs) for hepatitis B and C virus diagnosis. This study aims to evaluate the performance of RDTs for HBsAg and anti-HCV detection among HIV-infected individuals. A total of 362 HIV infected individuals were recruited from clinics between January 2013 to November 2014 in the southeast and northeast of Brazil. HBsAg and anti-HCV were detected using commercial EIAs and four RDTs: HBV (Vikia HBsAg® and Wama Imuno-Rapido HBV®) and HCV (Bioeasy Teste Rápido HCV® and Wama Imuno-Rapido HCV®). Reactive HBsAg and anti-HCV serum samples were tested for HBV DNA and HCV RNA. Sensitivity, specificity and kappa statistic were determined. Using EIA, HBsAg and anti-HCV were detected in 14 (3.9%) and 37 (10.2%) serum samples respectively. Using serum only, HBsAg RDTs demonstrated sensitivities and specificities above 92.0% and Kappa values above 89.0%. Anti-HCV RDTs demonstrated sensitivity and specificities above 82.0% and Kappa higher than 89.0%. Using whole blood samples, Vikia HBsAg® and Wama Imuno-Rapido HCV® showed sensitivity and specificity above 99.0% with Kappa of 66.4% and 100%, respectively. HIV viral load was higher among discordant results for anti-HCV RDT. RDTs demonstrated good performance in HIV infected individuals showing the usefulness of assays in this population.

Identification of mycobacterium species in contaminated cultures by polymerase chain reaction.

STUDY OBJECTIVES: The detection of Mycobacterium sp on a culture remains the "gold standard" technique for the diagnosis of mycobacterial infections. A small percentage of these cultures, however, may be contaminated by other nonfastidious microorganisms, making accurate diagnosis difficult. We evaluated the use of a polymerase chain reaction (PCR) protocol that was specific for the genus Mycobacterium, and specifically for Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare, for the identification of Mycobacterium sp growing on contaminated cultures. DESIGN: This prospective study was designed to identify Mycobacterium sp growing on mycobacterial cultures contaminated with other microorganisms. Samples and patients: Twenty-six samples, taken from 23 patients with probable mycobacterial disease, that resulted in Mycobacterium growth but were contaminated during their processing were evaluated in this study. Clinical data and the clinical status of each patient were used to ascertain the final diagnosis. RESULTS: All samples studied here exhibited Mycobacterium growth on solid media but were contaminated by nonfastidious bacteria, compromising the biochemical identification of the Mycobacterium sp. PCR correctly identified the genus Mycobacterium in all samples. M tuberculosis was identified in 14 samples, and M avium in 10 samples. No amplification of M intracellulare was obtained, and in two samples there was amplification only for the genus Mycobacterium. In the cultures of those patients in whom a mycobacterial infection was evident, PCR identified M avium and M tuberculosis in samples from 6 and 12 patients, respectively. However, PCR identified M avium (two patients) and M tuberculosis (two patients) in the cultures of four patients for whom a mycobacterial disease could not be confirmed by our case definition. Finally, in two samples from one patient only the genus Mycobacterium was amplified by PCR. CONCLUSION: PCR, with its advantages of greater speed and effectiveness than conventional detection methods, was successfully used to identify the Mycobacterium sp growing on contaminated cultures.

Serological evidence of leptospirosis in patients with a clinical suspicion of dengue in the State of Ceará, Brazil.

INTRODUCTION: Dengue and leptospirosis are two febrile illnesses of great clinical and epidemiological importance in Brazil. Their significant degree of symptomatic similarity makes clinical diagnosis difficult. OBJECTIVE: To diagnose leptospirosis differentially in patients with clinically suspected dengue. MATERIALS AND METHODS: In this study, 86 patients with clinically suspected dengue underwent virological and serological diagnostic evaluations for dengue (reverse transcriptase polymerase chain reaction, NS1 immunochromatographic test, and NS1 enzyme-linked immunosorbent assay, ELISA), as well as tests to detect immunoglobulin M (IgM; IgM/IgG Rapid Test and IgM ELISA). The same patients were subsequently evaluated for leptospirosis using Rapid Test IgG/IgM (Bioeasy®) and Leptospira IgM ELISA (PanBio®). RESULTS: Of the 86 patients, 48 (55.8%) had positive results for dengue in at least one of the tests and five (7.35%) showed positive reactions for leptospirosis. CONCLUSION: During dengue epidemics, this disease may be misdiagnosed as other infections, including leptospirosis, when diagnosis is based on nonspecific clinical and laboratory criteria alone.