High added value of a population-based participatory surveillance system for community acute gastrointestinal, respiratory and influenza-like illnesses in Sweden, 2013-2014 using the web.

In 2013-2014, the Public Health Agency of Sweden developed a web-based participatory surveillance system, Hӓlsorapport, based on a random sample of individuals reporting symptoms weekly online, to estimate the community incidence of self-reported acute gastrointestinal (AGI), acute respiratory (ARI) and influenza-like (ILI) illnesses and their severity. We evaluated Hӓlsorapport's acceptability, completeness, representativeness and its data correlation with other surveillance data. We calculated response proportions and Spearman correlation coefficients (r) between (i) incidence of illnesses in Hӓlsorapport and (ii) proportions of specific search terms to medical-advice website and reasons for calling a medical advice hotline. Of 34 748 invitees, 3245 (9·3%) joined the cohort. Participants answered 81% (139 013) of the weekly questionnaires and 90% (16 351) of follow-up questionnaires. AGI incidence correlated with searches on winter-vomiting disease [r = 0·81, 95% confidence interval (CI) 0·69-0·89], and ARI incidence correlated with searches on cough (r = 0·77, 95% CI 0·62-0·86). ILI incidence correlated with the web query-based estimated incidence of ILI patients consulting physicians (r = 0·63, 95% CI 0·42-0·77). The high response to different questionnaires and the correlation with other syndromic surveillance systems suggest that Hӓlsorapport offers a reasonable representation of AGI, ARI and ILI patterns in the community and can complement traditional and syndromic surveillance systems to estimate their burden in the community.

Quantifying the incidence and cost of acute gastrointestinal illness in Sweden, 2013-2014.

In Sweden, acute gastrointestinal illness (AGI) incidence, severity, impact on productivity, related healthcare usage and associated costs are not ascertained. We measured these in 2013-2014 using a population-based cohort reporting weekly. We defined AGI as ⩾3 episodes of loose stools or vomiting/24 h; or loose stools or vomiting with ⩾2 other gastrointestinal symptoms. After each AGI episode, we collected information about perceived severity, healthcare use and absenteeism. We calculated incidence rates, AGI absenteeism and costs comprising direct healthcare costs and productivity loss due to work/school absenteeism. A total of 3241 participants reported 1696 AGI episodes [incidence 360/1000 person-years, 95% confidence interval (CI) 326-395; highest in the <5 years age group]. In the <5 years age group, 31% of episodes were perceived as mild, 61% as moderate and 8% as severe; 9·4% led to primary-care consultations, and 1·4% to hospital admissions. In the ⩾5 years age group, 18% of episodes were perceived as mild, 64% as moderate and 18% as severe; 6·4% led to primary-care consultations, and 1·9% to hospital admissions. AGI caused 8 891 000 days of absenteeism (95% CI 6 009 000-12 780 000). AGI cost €1 005 885 000 (95% CI 754 309 000-1 257 195 000) nationally for the year. In Sweden, a minority of cases perceive AGI as a mild illness. AGI is a burden on the healthcare system and causes productivity loss, with high costs. Countries may consider these estimates when prioritizing health interventions.

Syndromic surveillance of influenza activity in Sweden: an evaluation of three tools.

An evaluation was conducted to determine which syndromic surveillance tools complement traditional surveillance by serving as earlier indicators of influenza activity in Sweden. Web queries, medical hotline statistics, and school absenteeism data were evaluated against two traditional surveillance tools. Cross-correlation calculations utilized aggregated weekly data for all-age, nationwide activity for four influenza seasons, from 2009/2010 to 2012/2013. The surveillance tool indicative of earlier influenza activity, by way of statistical and visual evidence, was identified. The web query algorithm and medical hotline statistics performed equally well as each other and to the traditional surveillance tools. School absenteeism data were not reliable resources for influenza surveillance. Overall, the syndromic surveillance tools did not perform with enough consistency in season lead nor in earlier timing of the peak week to be considered as early indicators. They do, however, capture incident cases before they have formally entered the primary healthcare system.

Multiple human-to-human transmission from a severe case of psittacosis, Sweden, January-February 2013.

Proven transmission of Chlamydia psittaci between humans has been described on only one occasion previously. We describe an outbreak which occurred in Sweden in early 2013, where the epidemiological and serological investigation suggests that one patient, severely ill with psittacosis after exposure to wild bird droppings, transmitted the disease to ten others: Two family members, one hospital roommate and seven hospital caregivers. Three cases also provided respiratory samples that could be analysed by PCR. All the obtained C. psittaci sequences were indistinguishable and clustered within genotype A. The finding has implications for the management of severely ill patients with atypical pneumonia, because these patients may be more contagious than was previously thought. In order to prevent nosocomial person-to-person transmission of C. psittaci, stricter hygiene measures may need to be applied.

Unusual increase of psittacosis in southern Sweden linked to wild bird exposure, January to April 2013.

Free-living wild birds worldwide act as reservoir for Chlamydia psittaci, but the risk of transmission to humans through contact with wild birds has not been widely documented. From 12 January to April 9 2013, a total of 25 cases of psittacosis were detected in southern Sweden, about a threefold increase compared with the mean of the previous 10 years. A matched case-control study investigating both domestic and wild bird exposure showed that cases were more likely than controls to have cleaned wild bird feeders or been exposed to wild bird droppings in other ways (OR: 10.1; 95% CI: 2.1-47.9). We recommend precautionary measures such as wetting bird feeders before cleaning them, to reduce the risk of transmission of C. psittaci when in contact with bird droppings. Furthermore, C. psittaci should be considered for inclusion in laboratory diagnostic routines when analysing samples from patients with atypical pneumonia, since our findings suggest that psittacosis is underdiagnosed.

Two geographically separated food-borne outbreaks in Sweden linked by an unusual Cryptosporidium parvum subtype, October 2010.

The number of sporadic cases of Cryptosporidium identified in the Stockholm county area increased above the expected limit during October 2010. Additionally, two food-borne outbreaks of cryptosporidiosis occurred in two other Swedish cities: Umeå (4 October) and Örebro (9 October). The outbreak investigations did not reveal any responsible food item, however fresh herbs were suspected. Thirty stool samples, originating from all three events, tested positive for Cryptosporidium oocysts. Polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) revealed that 27 individuals were infected with C. parvum, two with C. hominis, and one with C. felis. Using sequence analysis of the GP60 glycoprotein gene, a polymorphic marker with high intra-species diversity, we identified the same C. parvum subtype IIdA24G1 in samples from both the Umeå outbreak and the Stockholm area cases, thus indicating a possible outbreak in the Stockholm area and establishing a link between these two events. C. parvum IIdA24G1 has not previously been described in connection with a food-borne outbreak. For the outbreak in Örebro, another subtype was identified: C. parvum IIdA20G1e. These findings demonstrate that subtyping C. parvum isolates using GP60 gene amplification can be used to link cases in an outbreak investigation and we recommend its use in future similar events.

Investigations and actions taken during 2011 due to the first finding of Echinococcus multilocularis in Sweden.

Echinococcus multilocularis is a parasite that can cause alveolar echinococcosis disease. After the first positive finding of E. multilocularis in Sweden in 2011, a consulting group with representatives from relevant authorities was summoned. In this group, all relevant information was shared, strategies for information dissemination and any actions to be taken due to the finding of E. multilocularis were discussed and decided. The present paper describes the actions taken during 2011 and the results thereof, including surveillance in animals, risk assessment for humans to become infected and recommendations given to the public. Further discussion about whether the parasite was introduced, and if so, how, as well as possible future development of the infection in animals and humans in Sweden and future actions are included.

Q fever outbreak in Cheltenham, United Kingdom, in 2007 and the use of dispersion modelling to investigate the possibility of airborne spread.

We describe the investigation of an outbreak of Q fever in the town of Cheltenham, England. The outbreak was detected in June 2007, and prospective and retrospective case finding identified 30 confirmed or probable human cases. The investigation identified windborne spread of Coxiella burnetii from nearby sheep farms as the most likely source of infection. A telephone survey was conducted to identify risk practices at local farms. Subsequently the atmospheric dispersion model NAME was used to identify whether air from the identified farms with high risk practices had been carried into Cheltenham town centre during the risk period. Three high risk farms were identified and the modelling showed that air from all of these farms was carried over Cheltenham in the estimated risk period. The investigation resulted in an information campaign to farmers and production of improved advice for livestock farmers on reducing the risks of transmitting Q fever to humans.

No evidence of transmission of H5N1 highly pathogenic avian influenza to humans after unprotected contact with infected wild swans.

Highly pathogenic avian influenza (HPAI) subtype H5N1 remains a public health threat as long as it circulates in wild and domestic birds. Information on the transmissibility of H5N1 HPAI from wild birds is needed for evidence-based public health advice. We investigated if transmission of H5N1 HPAI had taken place in people that had unprotected contact with infected wild mute swans during an incident at the Abbotsbury Swannery in Dorset, England. Thirteen people who had been exposed to infected swans were contacted and actively followed up for symptoms. Serology was taken after 30 days. We did not find evidence of transmission of H5N1 HPAI to humans during the incident. The incident provided a rare opportunity to study the transmissibility of the virus from wild birds to humans.

Compliance and side effects of prophylactic oseltamivir treatment in a school in South West England.

School closure along with mass prophylactic oseltamivir treatment of pupils have been used in England and elsewhere to contain school outbreaks of influenza A(H1N1)v. We evaluated the protective effect, compliance with and side effects of oseltamivir chemoprophylactic treatment with a ten-day course of 1x 75mg given to 11-12-year-old pupils in one school year in a secondary school in South West England closed for ten days in response to a symptomatic laboratory-confirmed pupil. We distributed a questionnaire to pupils in the affected school year in class after the school had re-opened. Questions included symptoms of flu-like illness, compliance with chemoprophylaxis and side effects. All present on the day, 248 (93.2%) participated. Compliance with chemoprophylaxis was high, 77% took the full course, 91% took at least seven days. Fifty-one percent experienced symptoms such as feeling sick (31.2%), headaches (24.3%) and stomach ache (21.1%). Although some children were ill with flu-like symptoms, those tested did not have A(H1N1)v infection. Compliance with oseltamivir chemoprophylaxis was high, although likely side effects were common. The burden of side effects needs to be considered when deciding on mass oseltamivir chemoprophylaxis in children especially given that the symptoms of A(H1N1)v influenza are generally mild.

Multiple gene segment reassortment between Eurasian and American lineages of influenza A virus (H6N2) in Guillemot (Uria aalge).

Guillemots banded in the northern Baltic Sea were screened for influenza A virus (IAV). Three out of 26 sampled birds tested positive by RT-PCR. Two of these were characterized as subtype H6N2. Phylogenetic analyses showed that five gene segments belonged to the American avian lineage of IAVs, whereas three gene segments belonged to the Eurasian lineage. Our findings indicate that avian IAVs may have a taxonomically wider reservoir spectrum than previously known and we present the first report of a chimeric avian IAV with genes of American and Eurasian origin in Europe.