Svein Arne Nordbø

Outbreak of Human metapneumovirus infection in Norwegian children

Introduction: Human metapneumovirus (hMPV) was recently discovered in children with acute respiratory tract infection. We have studied the occurrence of hMPV and report clinical findings of 50 hMPV-infected children who were hospitalized during an outbreak in Norway. Methods and population: During 5 months from November 15, 2002 to April 14, 2003 we collected nasopharyngeal aspirate specimens from 236 children admitted because of respiratory tract infection (RTI). Samples were analyzed for influenza virus A/B, parainfluenza viruses 1, 2 and 3 and respiratory syncytial virus by direct immunofluorescence assays and cell culture. Rhinovirus, adenovirus and hMPV were identified by polymerase chain reaction. Results: Human metapneumovirus was identified in 50 of 236 children (21%). Most (41 of 50) hMPV-infected children were hospitalized between November 15 and January 15, and during these 2 months hMPV was the most common isolate (41 of 72 isolates; 57%). Respiratory syncytial virus was identified in 36 children (15%), among whom 34 were admitted after the hMPV outbreak. The median age of hMPV-infected children was 12 months (range, 1 to 115 months), and one-half of the children had an underlying chronic disease. The most common symptoms were fever (86%), cough (90%), dyspnea (80%), wheezing (56%), rhinorrhea (44%), anorexia (48%) and vomiting (36%). Eight (16%) had an upper respiratory tract infection (rhinopharyngitis, n = 6; laryngitis, n = 2), 24 (48%) had bronchiolitis and 17 (34%) had pneumonia. Two-thirds with a lower RTI also had signs of upper RTI. Fourteen (28%) children needed supplemental oxygen, 1 was treated with continuous positive airway pressure and 2 were ventilated mechanically. Conclusion: Human metapneumovirus was the most common virus isolate during the winter season 2002 to 2003 in children hospitalized for respiratory tract infection. Upper respiratory tract infections and mild to severe bronchiolitis were most common, but a relatively high proportion of hospitalized children developed severe pneumonia.

Human bocavirus in children: Mono-detection, high viral load and viraemia are associated with respiratory tract infection

Abstract Background and objectives Human bocavirus 1 (HBoV1) has recently been detected in children with respiratory tract infections (RTI). In order to study whether HBoV1 can cause RTI, we investigated its presence in children with upper RTI (URTI), lower RTI (LRTI) and a control group of children without RTI. Study design Nasopharyngeal aspirates (NPA) and blood samples were collected from children admitted to hospital with RTI from 6 June 2007 to 28 February 2009 (n =1154), and from children admitted for elective surgery who had no RTI (n =162). Using polymerase chain reaction (PCR), the NPAs were examined for 17 infectious agents including HBoV1. Blood samples were tested with HBoV1-PCR only. Results HBoV1 was detected in NPAs from 10% of patients and 17% of controls. Adjusted for age, gender and the presence of other viruses, HBoV1 was not associated with RTI. In the HBoV1-positive NPAs, at least one other virus was detected in 75% and the virus appeared alone in 25%. Adjusted for age and gender, the detection of HBoV1 as the sole virus was associated with RTI, but not with LRTI. Viraemia was found only in children with RTI. The study showed that it was associated with RTI and LRTI. A high HBoV1-load was associated with LRTI, but not with RTI. No interactions between HBoV1 and other infectious agents were found. Conclusions Our data support the hypothesis that HBoV1 causes RTI in children, because detection of HBoV1 alone, viraemia and high viral load are associated with RTI and/or LRTI in this age group. However, HBoV1 is common in healthy children.

Human bocavirus commonly involved in multiple viral airway infections

Abstract Background Human bocavirus (HBoV) was recently discovered in children with acute respiratory tract infections. We have included a PCR for HBoV in a study on airway infections in children. Objectives To study the occurrence of HBoV in Norwegian children, and to evaluate the results of a semiquantitive PCR. Study design During a 4-month period in the winter season 2006/2007 we collected nasopharyngeal aspirations from children who were admitted to the Department of Pediatrics. All samples were examined for 17 agents with real-time PCR. Results HBoV was detected in 45 of 376 samples (12%). The occurrence of HBoV was stable during the study period. Multiple viral infections were present in 78% of the samples (42% double, 20% triple and 16% quadruple infections). RS-virus, enterovirus and human metapneumovirus were the most frequently codetected agents. In samples with a high load for HBoV, significantly fewer multiple infections were found than in the other samples. Eighty-eight percent of the 25 patients with HBoV recorded as either the only or the dominating virus, and 50% of the other patients, had lower respiratory tract infection. The difference was statistically significant. Conclusions HBoV was frequently detected in nasopharyngeal aspirates from children with airway infections in Norway. Multiple viral infections were common among the HBoV-infected patients. Semiquantitive PCR results may be useful for interpretation of clinical relevance.

chlamydia Trachomatis Infections Increase the Risk for Ectopic Pregnancy: A Population-based, Nested Case–control Study

Background: Chlamydia trachomatis (CT) as a risk factor for ectopic pregnancy (EP) has mainly been established through seroepidemiologic cross-sectional studies. Goal: The goal of this study was to obtain EP risk estimates for women diagnosed with CT using women with negative tests as the reference group. Methods: We linked prospectively collected CT laboratory data (1990–2003) to EP hospital data (discharge and outpatient registries) in a nested case–control study. Six hundred sixteen women with CT test(s) before first EP were eligible as cases. Three controls were matched to each case for year of birth, age at first test, and number of prior tests. Results: Previous CT infection was associated with elevated EP risk (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0–2.0). In stratified analysis, the association was only significant for the youngest women (born 1970–1984) who had a nearly complete CT testing history (OR, 2.1; 95% CI, 1.3–3.2). Conclusion: A history of diagnosed CT infection is associated with a 2-fold increased EP risk.

Births and ectopic pregnancies in a large cohort of women tested for Chlamydia trachomatis.

Background: Recent studies show divergent results concerning the risk of ectopic pregnancy following Chlamydia trachomatis (CT) infection. Goal: Our goal was to investigate future reproductive health outcomes (births and ectopic pregnancies) among women tested for CT. Methods: Our cohort consisted of 20,762 women born during 1970–1984 who were tested for CT during 1990–2003. We linked CT data to data on ectopic pregnancies and births during 1990–2004. Cox regression with time-dependent covariates was used to assess the association between CT history and births/ectopic pregnancies adjusted for age at first test. Analyses with ectopic pregnancy as outcome were also adjusted for parity. Results: We observed 9.6 births per 100 person-years of observation among women with negative tests only and 10.2 per 100 person-years among women with at least 1 positive test (hazard ratio adjusted for age at first test, 1.07; 95% CI, 1.01–1.12). Ectopic pregnancy incidence rates were higher for women with positive test(s) compared with women with negative test only (0.24 vs. 0.13 per 100 person-years; hazard ratio adjusted for age at first test and parity, 1.82; 95% CI, 1.27–2.60). Among women with at least 1 registered pregnancy, the adjusted hazard ratio was 2.03; 95% CI, 1.28–3.22). Conclusion: Although women diagnosed with CT were at higher risk for ectopic pregnancy than women with negative test results only, our study suggest that their fertility prospects were better than they would have been had CT screening not been implemented in this population. Opportunistic CT screening is an appropriate method for maintaining female reproductive health.

Incidence and Risk Factors for Genital chlamydia trachomatis Infection: A 4-year Prospective Cohort Study

Background: Few long-term studies reporting incidence and behavioral data for Chlamydia trachomatis (CT) infection in the general population have been published. Such studies are important to understand risk factors associated with infection and to develop screening recommendations. Methods: A fixed prospective 4-year cohort study of 898 sexually active Norwegian women, aged 16 to 23 years at study start, was conducted to assess incidence, repeat infection, and risk factors associated with genital CT infection. Participants were interviewed at study start and at 6-month intervals thereafter for behavioral characteristics. The women were tested for CT infection at 12-month intervals beginning at study start. Risk factors were assessed using Fisher exact test and conditional logistic regression. Person-time was estimated in survival analyses and incidence of CT infection was reported as events per 100 woman-years. Results: Median duration of observation was 48.0 months (range 10–74) whereas 4.4 specimens were collected per woman (range 2–5). Of the 836 women eligible for the analysis, 19 (2.2%) had a prevalent infection at baseline. The 4-year cumulative incidence of CT infection was 7.7 (95% CI: 6.7–8.7) with annual incidences ranging from 1.2 to 2.9 per 100 woman-years. The 2-year cumulative incidence of repeat CT infection was 11.2 (95% CI: 9.3–13.1) per 100 woman-years. In multivariate analyses, factors associated with incident CT infection were young age (≤24 years) and number of new partners over the last 12 months prior being tested. Conclusion: The annual incidences observed for women 24 years or younger with 1 or more new partners over the last 12 months support recommendations for annual testing for CT in this age group in Norway.

IUD users in Norway are at low risk for genital C. trachomatis infection.

From May 1993 to April 1995, 30 general practitioners located at 13 general practice settings in the city of Trondheim, central Norway, recruited 957 eligible participants in a prospective use-effectiveness study on performance of two copper IUDs. In this report we focus on screening for C. trachomatis at insertion and its possible effect on cause-related terminations during the first 90 days after insertion. All women were screened at IUD insertion for C. trachomatis. All specimens were analyzed applying a nucleic acid test (rRNA, GenProbe). Five out of 957 women (0.5%) were positive for C. trachomatis. All were treated within two weeks of diagnosis. No cases of pelvic inflammatory disease were diagnosed during the first three months of the study. Screening of C. trachomatis at IUD insertion is not recommended in Norwegian women because of the extremely low prevalence of C. trachomatis in those who choose IUD as their primary contraceptive method. Recommendations for universally screening women for sexually transmitted diseases at IUD insertion should be based upon review of local/national prevalence data.

Prevalence and molecular characterisation of human adenovirus in diarrhoeic children in Tanzania; a case control study

BackgroundHuman adenovirus (HAdV) causes acute diarrhoea sporadically, as well as in outbreaks. Understanding the prevalence and types of HAdV in diarrhoea is important for control and preventive measures, especially in the African region where there is a high burden of diarrhoeal disease. The present study assessed the prevalence, molecular characteristics, seasonality and associated clinical features of HAdV infection Tanzanian children below two years of age with and without diarrhoea between 2010–2011.MethodsStool specimens, demographic and clinical information were collected in 690 cases and 545 controls. All stool samples were screened for HAdV-antigen using ELISA. Positive samples subsequently underwent real-time PCR and sequencing for molecular typing.ResultsHAdV was detected in 37 children, corresponding to a prevalence of 3.5% (24/690) in diarrhoeic and 2.4% (13/545) in non-diarrhoeic children (P > 0.05). Among HAdV-infected children, the median age was significantly lower in diarrhoeic than in non-diarrhoeic children (10 vs. 14 months, P˂0.001). More than half of HAdV infected (54.2%) were dehydrated as compared to diarrhoeic children without HAdV (45.8%, P = 0.01). The proportion of the enteric HAdV type 40/41 in diarrhoeic and non-diarrhoeic children was (50.0%, 12/24) and (46.2%, 6/13) respectively. Other HAdV types detected were; 1, 2, 7, 18, 19 and 31. The prevalence of adenovirus was not significantly different between rainy and dry seasons. HAdV was not detected in the 33 known HIV positive children. There was no significant association between HAdV infection and gender, nutritional status of the child and parent educational level.ConclusionThe present study provides further evidence of the contribution of adenovirus in causing gastroenteritis in young children, with symptomatic infection being significantly more prevalent in children below one year. We found similar prevalence of adenovirus in non-diarrhoeic children and in diarrhoeic children. This first report on molecular epidemiology of human adenovirus in Tanzania observed diversity of HAdV types that circulate the study setting. The study findings suggest that HAdV is not an important cause of diarrhoea in young HIV-positive children.

Chlamydia trachomatis testing patterns and prevalence of genital chlamydial infection among young men and women in central Norway 1990-2003: a population-based registry study.

Objective: The study objective was to investigate Chlamydia trachomatis (CT) testing patterns, prevalence, and incidence among men and women in Sør-Trøndelag county, central Norway, 1990–2003. Goal: The goal of this study was to obtain data for recommendations regarding CT screening. Study Design: Laboratory data on CT tests for persons 15 to 24 years old were retrieved and analyzed. Results: Four percent of men and 44% of women had been CT tested at least once by the age of 20. By the age of 25, 44% of men and 84% of women had been tested. Prevalence at first test was at its peak in 2000–2002 (men: 15–19 years 18%, 20–24 years 23%; women: 15–19 years 11%, 20–24 years 9%). Incidence estimates were higher for persons with a positive first test than for persons with a negative first test. Conclusions: More men and more female teenagers need to be tested. Repeat testing is particularly important among people who have been diagnosed with CT.

Coronavirus causes lower respiratory tract infections less frequently than RSV in hospitalized Norwegian children.

Background: We have described occurrence and clinical manifestations of human coronaviruses (HCoV) in hospitalized Norwegian children with respiratory tract infection (RTI) and compared them with a group of respiratory syncytial virus (RSV)-infected children. Methods and Population: We used in-house TaqMan multiplex real-time polymerase chain reaction to test nasopharyngeal samples from 536 RTI episodes in 452 children who were admitted during the 2006–2007 winter. Twenty-one viruses, including HCoV-OC43, HCoV-NL63, HCoV-229E, HCoV-HKU1, and RSV were tested. The amount of viral nucleic acid was recorded semiquantitatively based on the cycle threshold value. Results: A total of 665 positive polymerase chain reaction tests were recorded in 536 nasopharyngeal specimens. Coronavirus was found in 68 (12.7%): HCoV-OC43, n = 44 (8.2%), and HCoV-NL63, n = 24 (4.5%). Only RSV and rhinovirus were detected more frequently. Neither HCoV-229E nor HCoV-HKU1 was detected. Among children with HCoV-OC43, 73.0% tested positive for at least one other virus, compared with 41.2% with HCoV-NL63 and 40.3% with RSV (P = 0.03 and P < 0.01, respectively). Children with HCoV-OC43 and HCoV-NL63 were older than children with RSV (median age, 19 vs. 10 months, P = 0.01). Lower respiratory tract infection (LRTI) was half as common in children with HCoV-OC43 (48.6%) and HCoV-NL63 (47.1%) as in children with RSV (82.3%) (both P < 0.01). After adjusting for age, chronic disease, LRTI, and co-detection of other viruses in a multiple logistic regression analysis, HCoV was associated with a shorter fever period and shorter hospitalization time than RSV. Conclusions: HCoV-OC43 and HCoV-NL63 are common among hospitalized Norwegian children with RTI. Children with HCoV-OC43 and HCoV-NL63 have LRTI less frequently and may need a shorter hospital stay than children with RSV.