H Blystad

A Unique Hepatitis A Virus Strain Caused an Epidemic in Norway Associated with Intravenous Drug Abuse

A major epidemic of hepatitis A virus (HAV), associated with intravenous drug abuser (IVDA) communities, was studied by molecular epidemiology using a 348 bp region of the VP1/2PA junction of the HAV genome. A total of 621 cases were notified during the 2-year epidemic, 492 of whom were IVDA. Serum samples, taken from 79 patients during the acute phase of infection, were selected for analysis of HAV RNA by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing. A unique epidemic strain was detected among 49 cases thought to be associated with the epidemic, and among 10/30 patients with no apparent association to the epidemic. The other 20 HAV variants differed from the epidemic strain, and in several cases could be connected to the patients destination of travel. These strains were mostly associated with smaller outbreaks that were soon eradicated. Our data indicate different dissemination routes of HAV, suggesting that needle sharing practises contribute to a wide spread of the virus in the IVDA communities. By early detection of an outbreak, by epidemic survey and sequence analysis, preventive measures can be applied, and thereby limit the epidemic at an early stage.

Low Frequency of Complications in Imported Falciparum Malaria: A Review of 222 Cases in South-eastern Norway

We performed a retrospective study of 222 cases of falciparum malaria diagnosed in Oslo and Akerhus counties, Norway, from January 1988 to December 1997. Except for 12 cases, all had acquired the disease in sub-Saharan Africa. Sixty-four (28.8%) cases occurred in assumed non-immune individuals; of these, 41 (64.1%) were compliant to recommended antimalarial chemoprophylaxis. The mean time lag from first symptom to diagnosis (total diagnosis delay) was 4.6 d (median 3 d, range 0-30 d) and the mean time from presentation to diagnosis (doctors delay) was 1.3 d (median 0 d, range 0-25 d). There were no fatal cases, and only 8 (3.6%) had a complicated course. The following factors were significantly associated with development of complicated disease: higher age, non-immunity combined with chemoprophylaxis non-compliance, prolonged doctors delay and prolonged total diagnosis delay (p < or = 0.05). Our data suggest that complicated disease in imported falciparum malaria may largely be prevented by high chemoprophylaxis compliance rates in non-immune travellers and a high index of suspicion in physicians evaluating febrile travellers.

Prevention of viral hepatitis in the Nordic countries and Germany

The Viral Hepatitis Prevention Board (VHPB) convened a meeting of international experts from the public and private sectors in the Nordic countries and Germany, in order to review the epidemiological situation, the surveillance systems for infectious diseases, the immunization programmes and policy, and the monitoring of adverse events after hepatitis vaccination in those countries, to evaluate prevention and control measures, and to identify the issues that arose and the lessons learnt. Considerable progress has been made in the past decades in the prevention and control of viral hepatitis in the respective countries. Vaccination programmes have been set up, blood products’ safety has significantly been improved, and outbreak investigations remain the basis for the implementation of control measures. However, additional work remains to be done. Awareness of viral hepatitis among the public and professionals should further be raised, and more political support is needed regarding the value of prevention efforts and vaccination programmes.

Epidemiology of acute and chronic hepatitis B virus infection in Norway, 1992-2009

BackgroundNorway is classified as a low prevalence country for hepatitis B virus infection. Vaccination is only recommended for risk groups (intravenous drug users (IDUs), Men who have Sex with Men (MSM), immigrants and contacts of known carriers). We describe the epidemiology of reported cases of hepatitis B in Norway, during the years 1992-2009 in order to assess the validity of current risk groups and recommend preventive measures.MethodsWe used case based data from the national surveillance system on acute and chronic hepatitis B. The Norwegian Statistics Bureau provided population and migration data and the Norwegian Institute for Alcohol and Drug Research the estimated number of active IDUs between 2002-2007. Incidence rates (IR) and incidence rate ratios (IRR) for acute hepatitis B and notification rates (NR) and notification rate ratios (NRR) for chronic hepatitis B with 95% confidence intervals were calculated.ResultsThe annual IR of acute hepatitis B ranged from 0.7/100,000 (1992) to 10.6/100,000 (1999). Transmission occurred mainly among IDUs (64%) or through sexual contact (24%). The risk of acquiring acute hepatitis B was highest in people aged 20-29 (IRR = 6.6 [3.3-13.3]), and in males (IRR = 2.4 [1.7-3.3]). We observed two peaks of newly reported chronic hepatitis B cases in 2003 and 2009 (NR = 17.6/100,000 and 17.4/100,000, respectively). Chronic hepatitis B was more likely to be diagnosed among immigrants than among Norwegians (NRR = 93 [71.9-120.6]), and among those 20-29 compared to those 50-59 (NRR = 5.2 [3.5-7.9]).ConclusionsIDUs remain the largest risk group for acute hepatitis B. The observed peaks of chronic hepatitis B are related to increased immigration from high endemic countries and screening and vaccination of these groups is important to prevent further spread of infection. Universal screening of pregnant women should be introduced. A universal vaccination strategy should be considered, given the high cost of reaching the target populations. We recommend evaluating the surveillance system for hepatitis B as well as the effectiveness of screening and vaccinating immigrant populations.

Trends in HIV infection surveillance data among men who have sex with men in Norway, 1995-2011

BackgroundRecent reports on the growing HIV epidemic among men who have sex with men (MSM) in the EU/EEA area were accompanied by an increase of reported HIV among MSM in Oslo, Norway in 2003. Our study with data from 1995 to 2011 has described the recent trends of HIV among MSM in Norway and their socio-demographic and epidemiological characteristics.MethodsThe data were collected from the Norwegian Surveillance System for Communicable Diseases. Cases were described by age, place of infection, clinical presentation of HIV infection, STI co-infection and source partner. We used simple linear regression to estimate trends over time.ResultsDuring the study period, 991 MSM, aged from 16 to 80 years, were newly diagnosed with HIV. No significant trends over time in overall median age (36 years) were observed. Most of the MSM (505, 51%) were infected in Oslo. In the years 1995-2002, 30 to 45 MSM were diagnosed with HIV each year, while in the years 2003-2011 this increased to between 56 and 97 cases. The proportion of MSM, presenting with either AIDS or HIV illness, decreased over time, while asymptomatic and acute HIV illness increased (p for trend=0.034 or less). STI co-infection was reported in 133 (13%) cases. An overall increase of syphilis co-infected cases was observed (p for trend <0.001). A casual partner was a source of infection in 590 cases (60%).ConclusionsThough the increases described could be attributed to earlier testing and diagnosis, no change in the median age of cases was observed. This indicates that it is likely that there has been an increase in HIV infections among MSM in Norway since 2003. The simultaneous increase in STI co-infections indicates risky sexual behaviour and a potential to spread both HIV and other sexually transmitted infections.

What are the most important infectious diseases among those ≥65 years: a comprehensive analysis on notifiable diseases, Norway, 1993–2011

BackgroundAs the population ages, the burden on the healthcare system might increase and require changed public health priorities. As infections are often more severe at older age, we rank notifiable infectious diseases (ID) and describe trends of ID among the general population aged ≥65xa0years in Norway in order to inform public health priorities for the aging population.MethodsWe included all eligible cases of the 58 IDs notified between 1993 and 2011 (nu2009=u2009223,758; 12% ≥65xa0years) and determined annual notification rates as the number of notified cases divided by the number of inhabitants of the corresponding year. We ranked diseases using their average annual notification rate for 2007–2011. Trends in notification rates from 1993 onwards were determined with a non-parametric test for trend. Using notification rate ratios (NRR), we compared results in those aged ≥65xa0years to those aged 20–64xa0years.ResultsInvasive pneumococcal disease was the most common ID among the population ≥65xa0years (notification rate 58/100,000), followed by pertussis (54/100,000) and campylobacteriosis (30/100,000). Most ID notification rates did not change over time, though the notification rate of symptomatic MRSA infections increased from 1/100,000 in 1995 (first year of notification) to 14/100,000 in 2011.Overall, fewer cases were notified among the population ≥65xa0years compared to 20–64xa0year olds (NRRu2009=u20090.73). The NRR of each of the invasive bacterial diseases and antibiotic-resistant infections were above 1.5 (i.e. more common in ≥65), while the NRR of each food- and waterborne disease, blood-borne disease/STI and (non-invasive) vaccine preventable disease was below 1.ConclusionsBased on our results, we emphasise the importance of focusing public health efforts for those ≥65xa0years on preventing invasive bacterial infections. This can be achieved by increasing pneumococcal and influenza vaccine uptake, and risk communication including encouraging those aged ≥65xa0years and their caretakers to seek healthcare at signs of systemic infection. Furthermore, good compliance to infection control measures, screening of the at-risk population, and careful use of antibiotics may prevent further increase in antibiotic-resistant infections.

Epidemiology of invasive group A streptococcal infections in Norway 2010–2014: A retrospective cohort study

Streptococcus pyogenes or group A streptococcus (GAS) causes mild to severe infections in humans. GAS genotype emm1 is the leading cause of invasive disease worldwide. In the Nordic countries emm28 has been the dominant type since the 1980s. Recently, a resurgence of genotype emm1 was reported from Sweden. Here we present the epidemiology of invasive GAS (iGAS) infections and their association with emm-types in Norway from 2010–2014. We retrospectively collected surveillance data on antimicrobial susceptibility, multilocus sequence type and emm-type, and linked them with demographic and clinical manifestation data to calculate age and sex distributions, major emm- and sequence types and prevalence ratios (PR) on associations between emm-types and clinical manifestations. We analysed 756 iGAS cases and corresponding isolates, with overall incidence of 3.0 per 100000, median age of 59xa0years (range, 0–102), and male 56xa0%. Most frequent clinical manifestation was sepsis (49xa0%) followed by necrotizing fasciitis (9xa0%). Fifty-two different emm-types and 67 sequence types were identified, distributed into five evolutionary clusters. The most prevalent genotype was emm1 (ST28) in all years (range, 20–33xa0%) followed by 15xa0% emm28 in 2014. All isolates were susceptible to penicillin, 15xa0% resistant to tetracycline and <4xa0% resistant to erythromycin. A PR of 4.5 (95xa0% CI, 2.3–8.9) was calculated for emm2 and necrotizing fasciitis. All emm22 isolates were resistant to tetracycline PR 7.5 (95xa0% CI, 5.8–9.9). This study documented the dominance of emm1, emergence of emm89 and probable import of tetracycline resistant emm112.2 into Norway (2010–2014). Genotype fluctuations between years suggested a mutual exclusive dominance of evolutionary clades.

Imported toxigenic cutaneous diphtheria in a young male returning from Mozambique to Norway, March 2014

Six outbreaks of infectious syphilis in the United Kingdom, ongoing since 2012, have been investigated among men who have sex with men (MSM) and heterosexual men and women aged under 25 years. Interventions included case finding and raising awareness among healthcare professionals and the public. Targeting at-risk populations was complicated as many sexual encounters involved anonymous partners. Outbreaks among MSM were influenced by the use of geospatial real-time networking applications that allow users to locate other MSM within close proximity.