[show abstract][hide abstract] ABSTRACT: This study aimed to determine the age-specific aetiologic agents of diarrhoea in children aged less than five years. The study also assessed the efficacy of the empiric treatment of childhood diarrhoea using Integrated Management of Childhood Illness (IMCI) guidelines.
This study included 280 children aged less than 5 years, admitted with diarrhoea to any of the four major hospitals in Dar es Salaam. Bacterial pathogens were identified using conventional methods. Enzyme Linked Immunosorbent Assay (ELISA) and agglutination assay were used to detect viruses and intestinal protozoa, respectively. Antimicrobial susceptibility was determined using Kirby-Bauer disk diffusion method.
At least one of the searched pathogens was detected in 67.1% of the cases, and mixed infections were detected in 20.7% of cases. Overall, bacteria and viruses contributed equally accounting for 33.2% and 32.2% of all the cases, respectively, while parasites were detected in 19.2% patients. Diarrhoeagenic Escherichia coli (DEC) was the most common enteric pathogen, isolated in 22.9% of patients, followed by Cryptosporidium parvum (18.9%), rotavirus (18.1%) and norovirus (13.7%). The main cause of diarrhoea in children aged 0 to 6 months were bacteria, predominantly DEC, while viruses predominated in the 7-12 months age group. Vibrio cholerae was isolated mostly in children above two years. Shigella spp, V. cholerae and DEC showed moderate to high rates of resistance to erythromycin, ampicillin, chloramphenicol and tetracycline (56.2-100%). V. cholerae showed full susceptibility to co-trimoxazole (100%), while DEC and Shigella showed high rate of resistance to co-trimoxazole; 90.6% and 93.3% respectively. None of the bacterial pathogens isolated showed resistance to ciprofloxacin which is not recommended for use in children. Cefotaxime resistance was found only in 4.7% of the DEC.
During the dry season, acute watery diarrhoea is the most common type of diarrhoea in children under five years in Dar es Salaam and is predominantly due to DEC, C. parvum, rotaviruses and noroviruses. Constant antibiotic surveillance is warranted as bacteria were highly resistant to various antimicrobial agents including co-trimoxazole and erythromycin which are currently recommended for empiric treatment of diarrhoea.
[show abstract][hide abstract] ABSTRACT: There has been an increasing number of diagnosed cases of Chlamydia trachomatis in many countries, in particular among young people. The present study was based on a growing request to examine urine as a supplementary or primary specimen in screening for Chlamydia trachomatis in women, with the Becton Dickinson ProbeTec (BDPT) Strand Displacement Assay (SDA). Urine samples may be particularly important in screening young people who are asymptomatic.
A total of 603 women aged 15 and older were enrolled from the Sexually Transmitted Infection (STI) clinic at Haukeland University Hospital, Norway, in 2007. Only 31 women were older than 35 years. Cervical swabs and urine samples were tested with BDPT for all participants. In cases of discrepant test results from a given patient, both samples were retested by Cobas TaqManCT and a Polymerase Chain Reaction (PCR)-method (in-house). Prevalence of C. trachomatis, sensitivity, and specificity were estimated by latent class analysis using all test results available. Bootstrap BC confidence intervals (10,000 computations) were estimated for sensitivity and specificity, and their differences in cervix vs. urine tests.
A total of 1809 specimens were collected from 603 patients. 80 women (13.4%) were positive for C. trachomatis. Among these, BDPT identified 72 and 73 as positive in cervix and urine samples, respectively. Of the 523 C. trachomatis negative women, BDPT identified 519 as negative based on cervical swabs, and 514 based on urine samples. Sensitivity for cervical swabs and urine samples with the BDPT were 89.0% (95% CI 78.8, 98.6) and 90.2% (95% CI 78.1, 95.5), respectively. The corresponding values for specificity were 99.2% (95% CI 98.3, 100) and 98.3% (95% CI 96.4, 100).
This study indicates that urine specimens are adequate for screening high-risk groups for C. trachomatis by the SDA method (BDPT). Such an approach may facilitate early detection and treatment of the target groups for screening, and be cost-effective for patients and the health services.
BMC Women s Health 03/2010; 10:9. · 1.51 Impact Factor
[show abstract][hide abstract] ABSTRACT: A substantial number of individuals are excluded from blood donation due to indeterminate results in screening tests for hepatitis C virus antibody (anti-HCV). Disclosure of the characteristics of the indeterminate serologic pattern could optimize the testing and the management and care of blood donors.
Ninety-two former blood donors deferred from blood donation due to consistent reactivity in anti-HCV enzyme immunoassay and indeterminate HCV recombinant immunoblot assay (RIBA) results were retested for anti-HCV to examine the extent of disappearance of reactivity. In addition, they were screened for selected viral, immunologic, and inflammatory variables to detect possible causes of the test reactivity pattern.
After a median observation time of 75 months, 66 of 92 individuals had persistent indeterminate HCV RIBA results. Reactivity against the nonstructural NS5 antigen was the most frequent finding. A significant association was detected both between indeterminate reactivity in HCV RIBA and against the NS5 antigen independently and detectable antibody against adenovirus. Novel indeterminate reactivity showed increased prevalence during autumn and winter months.
Indeterminate HCV RIBA reactivity in blood donors persists over years. Increased prevalence during autumn and winter and association to detection of adenovirus antibody indicate that viral infection and cross-reactivity are etiologic factors in indeterminate HCV RIBA reactivity. Further prospective studies are needed to confirm the results.
[show abstract][hide abstract] ABSTRACT: Hepatitis C virus (HCV) has a high propensity to establish chronic infection with end-stage liver disease. The high turnover of virus particles and high transcription error rates due to lack of proof-reading function of the viral polymerase imply that HCV exists as quasispecies, thus enabling the virus to evade the host immune response. Clearance of the virus is characterized by a multispecific, vigorous and persistent T-cell response, whereas T-cell responses are weak, narrow and transient in patients who develop chronic infection. At present, standard treatment is a combination of pegylated interferon-alpha and ribavirin, with a sustained viral response rate of 40-80%, depending on genotype. The mechanisms for the observed synergistic effects of the two drugs are still not known in detail, but in addition to direct antiviral mechanisms, the immunomodulatory effects of both drugs seem to be important, with a shift from Th2- to Th1-cytokine profiles in successfully treated patients. This article describes virus-host relations in the natural course of HCV infection and during treatment.
[show abstract][hide abstract] ABSTRACT: In Epstein-Barr virus (EBV) infection, IgG- and IgM-antibodies to viral capsid antigen (VCA) and IgG-antibodies to Epstein-Barr nuclear antigen 1 (EBNA-1) can occur simultaneously both in late primary infection and during subclinical viral reactivation in immunocompetent persons, and the differential diagnosis is of importance.
To study the prevalence of primary infection and serological reactivation in patients with suspected primary EBV infection and with all three parameters present.
Fifty serum samples from 43 consecutive patients referred for suspected infectious mononucleosis and positive for VCA IgG-, VCA IgM- and EBNA-1-antibodies by EIA, were tested for IgG-antibody avidity with an EBV IgG immunoblot. Sera were also tested for heterophile antibodies (HA). To verify the presence of IgM-antibodies an EBV IgM immunoblot was performed when high-avidity IgG-antibodies were found.
Of 43 patients with suspected primary EBV infection and VCA IgG-, VCA IgM- and EBNA-1-antibodies present, only 18 patients (42%) had a late primary infection. Twenty-one patients (49%) had high-avidity IgG-antibodies, indicating an IgM response due to reactivation, thus suggesting other causes for their symptoms. In 10 of these 21 patients the presence of IgM-antibodies was confirmed by immunoblot, indicating reactivation as a cause of IgM-antibodies in at least 23% of the 43 patients studied. Of 18 patients with primary infection, HA were detected in 16 (94%) of 17 patients tested. Only one (5%) of the patients with high-avidity antibodies had HA. Absence of HA in patients with this serological pattern is therefore a good indicator of reactivation, and conversely, the presence of HA is a good indicator of primary infection. In HA negative patients, avidity testing could be used for differential diagnosis.
Journal of Clinical Virology 05/2007; 38(4):292-7. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: Different groups of viruses have been shown to be responsible for acute diarrhea among children during their first few years of life. Epidemiological knowledge of viral agents is critical for the development of effective preventive measures, including vaccines.
In this study we determined the prevalence of the four major enteropathogenic viruses - rotavirus, norovirus, adenovirus and astrovirus - was determined in 270 stool samples collected from children aged 0 - 60 months who were admitted with diarrhea in four hospitals in Dar es Salaam, Tanzania, using commercially available ELISA kits. In addition, the molecular epidemiology of group A rotavirus was investigated using reverse transcriptase multiplex polymerase chain reaction (RT-PCR).
At least one viral agent was detected in 87/270 (32.2%) of the children. The prevalence of rotavirus, norovirus, adenovirus and astrovirus was 18.1%, 13.7%, 2.6% and 0.4%, respectively. In most cases (62.1%) of viruses were detected in children aged 7-12 months. The G and P types (VP7 and VP4 genotypes respectively) were further investigated in 49 rotavirus ELISA positive samples. G9 was the predominant G type (81.6%), followed by G1 (10.2%) and G3 (0.2%). P was the predominant P type (83.7%), followed by P (0.4%) and P (0.2%). The following G and P types were not detected in this study population; G2, G4, G8 G10, P, P and P. The dominating G/P combination was G9P, accounting for 39 (90.7%) of the 43 fully characterized strains. Three (6.1%) of the 49 rotavirus strains could not be typed.
Nearly one third of children with diarrhea admitted to hospitals in Dar es Salaam had one of the four viral agents. The predominance of rotavirus serotype G9 may have implication for rotavirus vaccination in Tanzania.
BMC Public Health 02/2007; 7:359. · 2.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: Detection of nucleic acids from infectious agents now has a fundamental role in diagnostic microbiology laboratories. Nucleic acid amplification methods have promoted this development.
In this study we give a review of the field based on searches in Medline and our own experience.
Nucleic acid sequencing, hybridisation and electrophoresis complement the gene technology available for microbiological diagnosis. Recently, equipment for automated extraction of nucleic acids and real-time quantitative PCR has contributed to faster, more reliable and robust nucleic acid detection. An increasing number of microbiological agents and virulence genes can now be diagnosed in a variety of patient samples and supplemented with additional nucleic acid-based methods for genotyping and quantitative monitoring of drug resistance and therapeutic response.
Tidsskrift for den Norske laegeforening 12/2005; 125(22):3110-4.
[show abstract][hide abstract] ABSTRACT: Following an accidental observation of reduced sensitivity for detection of antibodies to hepatitis C virus (HCV) with a novel commercially available automated chemiluminescent microparticle immunoassay (CMIA, ARCHITECT Anti-HCV) compared to a well-established microparticle enzyme immunoassay (MEIA, AxSYM HCV Version 3.0), we wanted to explore whether this could be explained by a variation in marginal sensitivity, to be expected between highly sensitive assays of different formats, or represented a reduced sensitivity of the CMIA to certain antibody profiles.
To evaluate the ability of the CMIA to detect low concentrations of anti-HCV antibodies as defined by various patterns in the recombinant immunoblot assay (RIBA) and already detected in the MEIA system.
All patient sera tested for anti-HCV reactivity during a period of 3 years (27,978) were evaluated. A total of 90 sera had a sample/cut-off ratio (S/CO) between 1.0 and 1.5 in the MEIA test and were available for further testing. Of these, 19 had a probable/possible presence of anti-HCV antibodies based on presence of at least two bands of > or = 1+ strength in the RIBA, or because the patient was known to be anti-HCV positive. These 19 sera were tested with the CMIA. In addition, 16 sera with strong reactivity to various antigen combinations in the RIBA were serially diluted until testing negative in both microparticle test systems.
Seven of the 19 sera (37%) were negative (S/CO < 1.0) in the CMIA. At least 3 (16%) of these 19 sera were very likely to be true anti-HCV positive sera (from infants with known anti-HCV positive mothers). HCV-RNA was not detected in any of the sera tested. Testing of sera after serial dilution indicates that the CMIA has a lower sensitivity to c22- and c33c-antibodies than the MEIA, possibly also to c100-3-antibodies.
Our findings indicate that ARCHITECT Anti-HCV is less sensitive than AxSYM HCV Version 3.0 in detecting antibodies to c22 and c33c in patients who have cleared their HCV-infection and have naturally declining levels of antibodies.
[show abstract][hide abstract] ABSTRACT: Assays for serological diagnosis of HSV-2 infection in clinical settings have been generally available only recently. We wanted to investigate and compare the diagnostic utility of three different ELISAs for detection of anti-HSV-2 IgG antibodies, using intact glycoprotein G or an oligopeptide from a portion of the protein as antigens. HSV-1 negative/HSV-2 negative sera (n = 32), HSV-1 positive/HSV-2 negative sera (n = 30) and sera from HSV-2 culture positive individuals (n = 36), collected at least 6 months after culture verified HSV-2 genital infection were examined. Cut-off values were determined according to the manufacturer's instructions, and also by establishing new cut-off values at the level of highest diagnostic efficiency. Sensitivities and specificities were compared for each assay. In addition, test accuracies were compared using receiver-operating characteristics (ROC) methodology. Establishment of new cut-off values increased the performance characteristics for all three tests. At similarly set cut-off values, the peptide 55 assay showed the highest diagnostic sensitivity (100%) and specificity (98%). All three assays displayed high efficiency and also high agreement between the tests (kappa > 0.85 for all comparisons). The performance of all three assays were satisfactory although the highest efficiency and accuracy was obtained with the peptide 55 assay.
Journal of Virological Methods 01/2003; 107(1):21-7. · 1.90 Impact Factor
[show abstract][hide abstract] ABSTRACT: To document the proportion of each herpes simplex virus (HSV) type in genital HSV infection and changes over time during a 10 year period.
Retrospective comparative study in sexually transmitted disease (STD) patients with genital HSV infection at the outpatient clinic for STD, Haukeland Hospital, Bergen, Norway.
HSV-2 was the major cause during the 80's, whereas HSV-1 constitutes a greater part of the cases during the 90's, especially in female patients and in the younger age groups with primary or initial disease, where HSV-1 is the causative viral type in up to 70-90% of the cases.
The documented change from HSV-2 towards HSV-1 in cases of genital HSV infection may have implications as to prognosis, future usefulness of vaccines, present and future usefulness of new type-specific serological tests.