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Highly Pathogenic Avian Influenza A/H5N1 ? update and overview of 2006

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  • Highly Pathogenic Avian Influenza A/H5N1 ? update and overview of 2006

    Highly Pathogenic Avian Influenza A/H5N1
    Update and overview of 2006

    This is the last weekly release of 2006.
    Eurosurveillance will return on Thursday 4 January 2007.
    From the Eurosurveillance editorial team in England, France and Sweden, we wish all our readers a merry Christmas, a happy New Year, and a peaceful holiday.
    Highly Pathogenic Avian Influenza A/H5N1 ? update and overview of 2006 Influenza team (

    European Centre for Disease Surveillance and Control, Stockholm, Sweden

    Avian influenza 2006: human situation

    As of 29 November 2006, 258 human H5N1 infections that meet its strict laboratory criteria have been reported to the World Health Organization (WHO) since reporting began for 2003. Of these 258 cases, 154 patients have died (60%) and there has been no decline in that high mortality rate over time [1,2].

    There has been a disproportionate concentration of infections in children and young adults, even allowing for the relatively young populations in the ten countries where human infections have occurred, and there is an over-representation of females among patients aged 10-29 years [2].

    This is thought to be related to the fact that it is usually young people and women who look after domestic poultry.

    There is some evidence of familial clustering which may suggest a genetic susceptibility [3,4].

    Asymptomatic and mild infections do occur but appear to be very rare, although more sero-epidemiology around confirmed cases is needed to confirm this impression [3-6].

    In the second half of 2006, there was a steep decline in the number of case reports, although similar declines occurred in 2004 and 2005, but were then followed by resurgences (Figure 1) [1,2].

    Critically, human to human transmission, as indicated by cluster size, is still extremely inefficient, as it was a decade ago when the first human to human transmission took place in Hong Kong [3-5].

    Figure 1. No. of confirmed human cases of H5N1 infection reported to WHO by month of onset, 1 December 2003 ? 11 December 2006

    Based on reports to WHO published at using method used by WHO and described in Reference 2

    Animals still source of human infections

    In 2003, highly pathogenic avian influenza viruses type A/H5N1 (Asian strain) re-emerged and spread rapidly, infecting poultry and some humans in a number of southeast Asian countries, particularly Vietnam, Thailand, Cambodia and Indonesia [7].

    The mechanism for this spread remains unclear although it is suspected that it was as much related to trade of poultry and poultry products as the movements of wild birds.

    An exceptional multi-species epizootic at Qinghai Lake in northwest China in May 2005 seemed to demonstrate a role of wild birds in the spread of the viruses beyond Asia [8].

    From Qinghai, the virus spread to Central Asia, Europe and some African countries with human cases reported in Turkey, Iraq, Azerbaijan, Djibouti and Egypt [1,2,7]. Now, at the end of 2006, the virus has been confirmed in birds in over 50 countries, with birds (almost entirely domestic poultry) being the source of human infections in ten of these [2,7,9].

    Some countries are facing up to endemic infection in their national poultry flock and consequent ongoing risks to humans with domestic poultry, while others are barely affected.

    At a recent world conference on avian influenza and pandemic preparedness [footnote], field reports on efforts to control avian influenza were presented by national and international authorities.

    There is evidence that H5N1 viruses have now become entrenched in backyard poultry in Indonesia, and perhaps also Egypt [10,11].

    Large scale programmes of poultry immunisation have been underway in China and Vietnam where, since 2005 and until an outbreak in the Mekong Delta this week in Vietnam [12], poultry outbreaks had stopped being reported [9].

    The scale of immunisation in China, with potentially 14 billion poultry needing to be vaccinated twice annually (in spring and autumn), is the largest immunisation programme against avian influenza ever attempted anywhere in the world.

    In the European Union (EU), the virus has not become established in poultry nor have there been there any human infections even though the virus was found in wild birds in at least fifteen countries in the spring of 2006 (Figure 2).

    Some cats and a pine marten that fed on infected birds were also infected [13].

    The bird movements to the EU may have been exceptional following an unusually cold spell of weather in Russia and Central Asia in early 2006.

    After the spring wave, there have only been confirmation of sporadic H5N1 infections in birds in Spain and Germany (Figure 2).

    Figure 2. Highly pathogenic avian influenza cases in wild birds in the EU member states notified to the European Commission in 2006.

    Based on reports through reports to the European Commission Animal Disease Notification System (ADNS) as cited in Reference 14. Cases are almost entirely due to A/H5N1.
    The successful protection of domestic birds in EU countries was primarily due the robust and consistent application of veterinary measures directed under EU legislation.

    As a consequence, only five poultry outbreaks occurred in the EU and these were rapidly contained [14,15].

    However, the continuing sporadic reports demonstrate that the virus may still sometimes be present and therefore, routine biosecurity measures and early warning systems cannot be relaxed.

    There were major outbreaks of infection in wild birds and domestic poultry in the Danube delta in 2005 and 2006, and the Romanian authorities successfully contained these.

    There will be an additional challenge for EU authorities if it occurs here again after Romania joins the European Union next month.

    Continuing evolution of the viruses

    There remains the risk of emergence of a human pandemic strain through either mutation of the H5N1 virus or incorporation of part of its genome, through recombination, into a human influenza virus [7,16].

    As well as extending their range geographically the H5N1 viruses have diversified genetically into clades and sub-clades. Clade 1 dominated in 2003-2004, then clade 2 became more important. Clade 2 has subsequently developed into three distinct sub-clades [7,17,18]. The balance between the types of virus continues to change, for reasons that are not clear. For example, since 2005, the Fujian-like virus (clade 2, sub-clade 3) has become the dominant type found in surveillance of market poultry across southern China [17].

    Fortunately, despite genetic changes, there has been no evidence of significant change in the viruses? effects on humans.

    The genetic differences and the fact that the virus is continuing to change are, however, important considerations since the clades have different antiviral resistance profiles and continuing genetic change will alter the necessary composition of human H5N1 vaccines referred to as ?pre-pandemic vaccines? [7,18].

    Two countries have already committed to purchasing these vaccines and others are considering to do so, although it is by no means clear that an H5 based pandemic is inevitable[7,16].


    There are many important unknown factors relating to the spread of H5N1, including the current distribution of the viruses.

    The pattern of H5N1 infection in Africa remains elusive because surveillance is especially weak there, apart from Egypt and some parts of Nigeria [11,19].

    The picture is also incomplete in eastern Asia - following two human cases in summer 2006, the situation has improved in Thailand, but the risk remains [20]

    A good picture of the zoonotic situation in China is currently not available and it is also still unclear whether the H5N1 vaccination programmes in China and Vietnam have been successful in eliminating or just reducing the level of infection in poultry, and whether low levels of circulating viruses pose a significant human risk [7,21]

    One negative consequence of any success of vaccination programmes is that surveillance for sporadic human cases is made more difficult, since now, when atypical pneumonias occur, there is rarely the marker of local poultry deaths to inform decisions on whether to test the patient for H5N1 virus.

    The relative role of the commercial movement of animals and wild birds in the international spread and local distribution of H5N1 viruses remains controversial.

    However, it is local preparedness and response that are most crucial in determining the outcome in terms of domestic animal and human health when countries are challenged by the virus.

    Nationally organised veterinary services, which would enable effective surveillance/early warning and biosecurity systems, are crucial so that authorities can respond promptly when infections are first suspected in either birds or humans.

    Where biosecurity is poor and veterinary services ineffective, viruses can become endemic and the situation can be complicated by the virus cycling between poultry and wild birds [10,11,17].

    One challenge developing countries face is a lack of financial support for the veterinary services and biosecurity measures, even though avian influenza has demonstrated that it is truly an international problem.

    There has been some progress towards a solution for the financial issues by the involvement of the World Bank, the European Commission and the United Nations System Influenza Coordinator

    (, which have mobilised and released donations that had been pledged by national and international donors [22].
    The data indicate that H5N1 avian viruses remain poorly adapted to humans.

    With a high enough viral challenge and perhaps some genetic host susceptibility the viruses can infect humans, in which case they are then often lethally pathogenic, although they are still unable to transmit efficiently between humans [2-5,16].

    The H5N1 viruses have been around for nearly a decade and it might be tempting to conclude that if they were going to proceed to form or contribute to a pandemic strain, they would have done so by now.

    However, it should be remembered that it is thought that the avian influenza virus which contributed to the 1918-19 ?Spanish Influenza? H1N1 pandemic strain had been around for some years before it became part of a virus that could efficiently transmit between humans and so be a successful pandemic strain [23].

    Apart from the threat from H5N1 there are still many issues around influenza pandemic preparedness (irrespective of the virus type) which need urgent attention.

    One key area is how authorities in developing countries should best focus their efforts with preparedness, given often very limited resources and many more immediate competing priorities.

    So far, most discussion, ideas and research have been more suited to settings in better resourced nations.

    This area needs a multi-sector approach as medical services will not have the most to offer in poorer countries when it comes to preparing for a pandemic.

    It is hoped that the next world meeting, planned for New Delhi in late 2007 (and intervening technical meetings), will provide opportunities to tackle preparedness in developing nations as well as dealing with avian influenza.

    Footnote. The Bamako conference organised by the African Union, the Interafrican Bureau for Animal Resources and the European Union. International Conference on Avian and Human Pandemic Influenza, (Ministerial Meeting and Pledging Conference) 6-8 December 2006, Bamako.

    Documentation and presentations at the conference are viewable at :

    1. WHO. Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO. 29 November 2006. (
    2. WHO. Epidemiology of WHO confirmed human A(H5N1) confirmed cases. Wkly Epid Rep 2006; 81: 249-257
    3. Oner AF, Bay A, Arslan S, Akdeniz H, Sahin HA, Cesur Y et al. Avian Influenza A (H5N1) Infection in Eastern Turkey in 2006. NEJM. 2006; 355: 2179-2185
    4. Kandun IN, Wibisono H, Sedyaningsih ER, Yusharmen, Hadisoedarsuno W, Purba W et al. Three Indonesian Clusters of H5N1 Virus Infection in 2005. NEJM 2006; 355: 2186-2194
    5. Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5. Avian Influenza A (H5N1) Infection in Humans. NEJM 2005; 353:1374-1385.
    6. Nicoll A Human H5N1 infections: so many cases ? why so little knowledge? Euro Surveill 2006;11(5):74-5 (
    7. Webster RG,Govorkova EA. H5N1 Influenza ? Continuing evolution and spread NEJM. 2006; 355: 2174-7 (
    8. FAO. Animal Health Special Report. Wild birds and avian influenza? (
    9. OIE. Update on avian influenza (H5). 19 December 2006 (
    10. FAO. Indonesia struggles to contain H5N1 bird flu: coordinated donor funding plays major role in the fight against bird flu.6 December 2006 (
    11. Ministry of Health and Population, Egypt. Recent and foreseeable developments in the avian influenza epidemic: Egypt. Presentation at International Conference on Avian and Human Pandemic Influenza, 6-8 December 2006, Bamako (
    12. OIE. Immediate notification, Vietnam. 19 December 2006 (
    13. Influenza team. H5N1 infections in cats ? public health implications. Euro Surveill 2006;11(4):E060413.4. Available from:
    14. European Commission. DG Health and Consumer Protection. Avian influenza ? Regional response in the European Union. Presentation at International Conference on Avian and Human Pandemic Influenza, 6-8 December 2006, Bamako
    15. European Commission, Avian Influenza. Emergency and control measures
    16. ECDC. The Public Health Risk from Highly Pathogenic Avian Influenza Viruses Emerging in Europe with Specific Reference to type A/H5N1. 1 June 2006 (
    17. WHO Influenza research at the human and animal interface ? Report of a WHO working group, 21-22 September 2006. WHO/CDS/EPR/GIP/2006.3 Geneva, Switzerland.
    18. WHO Global Influenza Program Surveillance Network. Evolution of H5N1 avian influenza viruses in Asia. Emerg Infect Dis. 2005; 11(10): 1515-21. (
    19. Maina JA. Current status of highly pathogenic avian influenza in Nigeria. Presentation at International Conference on Avian and Human Pandemic Influenza, 6-8 December 2006, Bamako (
    20. WHO Thailand. Avian Influenza Surveillance Daily Report. Avian Report. (
    21. Smith GJD, Fan XH, Wang J, Li KS, Qin K, Zhang JX et al . Emergence and predominance of an H5N1 influenza variant in China. PNAS 2006; 103(45): 16936-16941 Published online before print October 30, 2006 (
    22. International Pledging Conference on Avian and Human Influenza in Beijing. 17-18 January 2006. (,,contentMDK:20765526~menuPK:2077305~pagePK:41367 ~piPK:51533~theSitePK:40941,00.html)
    23. Reid AH and Taubenberger JK. The origin of the 1918 pandemic influenza virus: a continuing enigma. J Gen Virol 2003 84 2285-229
    <HR>Soft tissue infections in Belgian rugby players due to Streptococcus pyogenes emm type 81

    S Quoilin<SUP>1</SUP> (, N Lambion<SUP>2</SUP>, R Mak<SUP>3</SUP>, O Denis<SUP>4</SUP>, C Lammens<SUP>5</SUP>, M Struelens<SUP>4</SUP>, S Maes<SUP>1</SUP>, H Goossens<SUP>5</SUP>
    <SUP>1</SUP>Scientific Institute of Public Health, Brussels, Belgium
    <SUP>2</SUP>Health Inspectorate, French Community, Brabant Wallon, Belgium
    <SUP>3</SUP>Health Inspectorate, Flemish Community, Oost Vlaanderen , Belgium
    <SUP>4</SUP>National Reference Laboratory for MRSA and Staphylococcus, Erasmus University Hospital, Brussels, Belgium
    <SUP>5</SUP>National Reference Laboratory for Streptococcus pyogenes, University Hospital of Antwerp, Belgium

    On 16 October 2006, about 20 cases of infected skin lesions in rugby players from four different clubs were reported to the health inspectorates of the French and Flemish Communities in Belgium by the director of a rugby club. One of the affected rugby players had been admitted to hospital in early October for treatment of deep skin infections with adenopathia and perineal lesions and two other rugby players were on sick leave for one week, although they were not sufficiently ill to be admitted to hospital. The onset of the outbreak was believed to be mid-September. In order to confirm the information a health inspector contacted all directors of the clubs involved and from these, identified 37 suspected cases on the basis of clinical signs. Because of the severity of the lesions and the spread observed among rugby players following each match, epidemiological and microbiological investigations began on 20 October 2006 to identify the cause of the outbreak. A total of 376 rugby players were interviewed and nose and throat swabs were also obtained. Thirty one of these rugby players were observed to have infected wounds, and swabs were taken from all 31 wounds. Five wounds were found to be infected with Streptococcus pyogenes emm type 81. Further analysis of clinical and environmental samples is ongoing.

    Epidemiological investigation

    A description of the situation and an interview with one of the directors of the clubs as well as a visit of the sports facilities were performed, followed by interviews with all the rugby players from the four clubs (A, B, C, D) involved. The questionnaire was self-administered and checked by the interviewers in the presence of the interviewees. The interviewers also took clinical samples for microbiological examination.

    The questionnaire asked about demographic data, presence of wounds and their description, matches played in, potential risk factors (e.g. position played, sharing of personal items or equipment), knowledge of secondary cases among close contacts (e.g. household members, contacts in other sport activities). During the visit of sports facilities, environmental samples were taken from various surfaces by investigators to assess possible environmental contamination.

    Three of the affected clubs were located in the Walloon Region (clubs A, B and C), and one in the Flemish Region (club D).

    The majority of the interviewed rugby players were male (only one woman among the 376 interviewees) and aged between 14 and 63 years (median 19 years). The index patient, a member of club A, came back from a rugby tour, played during the week 5-12 September, in Malaysia, with signs of infected skin lesions. Several days later, further cases appeared in rugby players in the same club (A).

    These players had not traveled to Malaysia. All presented with purulent wounds, and reported that symptoms had taken ?a long time? to disappear, even when treated with antibiotics (no information on the treatment is available).

    Further skin infections in players from the clubs B, C and D began to occur after a matches against club A: Club C on 17 September (11 cases), club B on 08 October (7 cases), club D (2 cases) on 15 October. Wounds were on parts of the body that were normally uncovered, and so it was hypothesised that the possible mode of transmission was direct skin contact between players.

    Early in the investigation, it became obvious that contact tracing would be complicated by several factors. Firstly, the rugby players were not formally affiliated to a club, and so they were free to train and/or play with other rugby clubs as well.

    They also did not need formal permission from their original club to play in teams in other countries. In addition, the four clubs involved had played in six tournaments since 20 August 2006: two in Belgium with teams from the Netherlands and from the United Kingdom, and one in each of the Netherlands, Malaysia, Luxembourg and Poland.

    These tournaments involved at least 28 teams (15 players per team) from 10 countries. Ten teams were from the Netherlands, and two teams were from outside Europe (Malaysia and New Zealand).

    Furthermore, possible contacts with four additional teams in France (2 teams), Germany (1 team) and the Netherlands (1 team) were noted by the investigators.

    On 27 October (follow-up 6 November) Belgium alerted the other national public health authorities in Europe to the cases through the Early Warning and Response System. No cases have been identified from other countries.

    Laboratory investigations

    After the initial investigation, there were two alternate bacteriological hypotheses regarding the outbreak: community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) as a cause, as described in the international literature [1,2] or an outbreak due to group A Streptococcus [3,4]. Nose and throat swabs from 376 players belonging to the four affected Belgian clubs were taken, to identify the pathogen and any asymptomatic carriers. Additional wound swabs were taken from the 31 players presenting with an infected wound. Initial laboratory findings indicated a probable outbreak due to group A Streptococcus. Further investigation at the National Reference Laboratory for group A Streptococcus revealed Streptococcus pyogenes emm type 81 in the wounds from five rugby players, one of them had also positive results for the throat swab, all other throat swabs were negative. In Belgium, this emm type is very rarely identified: it was identified in only two out of 1285 S. pyogenes strains collected and serotyped by the National Reference Laboratory between January 2000 and October 2006. Recent Strep-EURO enhanced surveillance showed this S. pyogenes emm type within the top 14 types (Efstratiou A, personal communication, December 2006). Cases have also been found in Poland, where it has been associated with streptococcal toxic shock syndrome and necrotising fasciitis [5]. Simultaneous examination of the 31 wound swabs at the National Reference Laboratory for MRSA and Staphylococcus detected an oxacillin susceptible S. aureus (MSSA) in three players. Molecular typing of the isolates showed the strains found were unrelated. Analysis of the nasal swabs did not reveal presence of community acquired S. aureus. Since all environmental samples taken in club A were negative, and sports facilities were disinfected in the other three clubs, the samples were not examined further.

    Preventive measures

    In order to prevent further spread of the infections, the Community Health Inspectorates advised the Belgian Rugby Federation and the clubs involved on preventive measures. The recommendations included temporary and general advice.

    Temporary measures

    ? No matches at a national and/or international level for the clubs involved until 1 November 2006.
    ? Training sessions allowed only if restricted to members of one club and if excluding players with wound infections until complete healing of wound.


    <TABLE cellSpacing=0 cellPadding=0 width=969 border=0><TBODY><TR><TD width=969>
    • No sharing of towels or clothing
    • Regular washing of sports clothing.
    • Disinfection of toilet and washing areas, locker rooms, training rooms and physiotherapy room, including gym and physiotherapy equipment.

    <TABLE cellSpacing=0 cellPadding=0 width=969 border=0><TBODY><TR><TD width=969 bgColor=#ffffff>
    • Covering all wounds during training and matches. Before training and matches, it is the trainer?s responsibility to check the players and to exclude them in case of infected wounds. On the field, decisions about new injuries gained during the current match are the responsibility of the referee.
    </TD></TR><TR><TD bgColor=#ffffff>
    • Players presenting with a wound infection should visit a physician, and the case be notified to public health authorities. A swab from the wound should be taken before starting antibiotic treatment and be sent for microbiological testing, preferably to the National Reference Laboratory for Streptococcus.
    </TD></TR><TR><TD bgColor=#ffffff>
    • After each training or match, players must wash all over using soap and hot water.
    </TD></TR><TR><TD bgColor=#ffffff>
    • After each training or match, wounds must be checked and correctly disinfected.

    There were several possible problems in an outbreak investigation:

    1. There was a delay between the onset of the outbreak and notification to the health inspectorate, because the Belgian Rugby Federation did not immediately recognise the potential public health threat, and this led to the occurrence of infected wounds in at least 37 players.

    2. The large number of national and international contacts of the rugby players complicated contract tracing. Players from about 10 different countries were involved. Because of the possibility of an international spread the Belgian authorities informed EU member states about the outbreak twice (27 October and 6 November) via the Early Warning and Response System. To date, no further skin infections in rugby players from other countries have been notified to the Belgian authorities.

    3. Of the 31 swabs taken from wound infections, only five bacteriological results were positive, probably because the samples were taken at a late stage when most of the wounds were already beginning to heal, and because most of players from whom a sample was obtained were already receiving antibiotic treatment.

    Some players received antibiotics prescribed by their general practitioner without samples being taken from their wounds. Other players reported taking ?prophylactic? antibiotics although they had no infected wounds, because they were worried. This highlights the necessity to remind healthcare staff and the public about good practice on the use of antibiotics.

    Regardless of these problems the investigation was facilitated by the excellent cooperation between laboratories, the Scientific Institute of Public Health in Brussels, rugby clubs and the French and Flemish Community health authorities. Releasing early recommendations for the affected clubs and collaborating closely with the Belgian Rugby Federation was helpful in preventing a spread of the infections. An analysis of all findings, when completed, will describe the attack rate and risk factors which will be useful in controlling and preventing future outbreaks.

    The authors would like to thank all presidents of the clubs involved and the president of the Belgian Rugby Federation for their collaboration.

    1. Kazakova SV, Hageman JC, Matava M, Srinivasan A, Phelan L, Garfinkel B, et al. A clone of methicillin-resistant Staphylococcus aureus among professional football players. N Engl J Med. 2005 Feb 3;352(5):468-75.
    2. Centers for Disease Control and Prevention (CDC). Methicillin-resistant staphylococcus aureus infections among competitive sports participants--Colorado, Indiana, Pennsylvania, and Los Angeles County, 2000-2003. MMWR weekly. 2003 Aug 22;52(33):793-5. (
    3. Manning SE, Lee E, Bambino M, Ackelsberg J, Weiss D, Sathyakumar C, et al. Invasive Group A Streptococcal Infection in High School Football Players, New York City, 2003. Emerg Infect Dis 2005; 11(1): 146-149. (
    4. Falck G. Group A streptococcal skin infections after indoor association football tournament. Lancet. 1996 Mar 23;347(9004):840-1.
    5. Szczypa K, Sadowy E, Izdebski R, Strakova L, Hryniewicz W. Group A streptococci from invasive disease episodes in Poland are remarkably divergent at the molecular level. J Clin Microbiol. 2006 Nov;44(11):3975-9. Epub 2006 Sep 6.
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    <HR>Epidemic intelligence during mass gatherings
    R Kaiser, D Coulombier (
    European Centre for Disease Prevention and Control, Stockholm, Sweden

    Public health is an important aspect of the planning for mass gatherings which include major sport events (e.g. the Olympic Games, the FIFA World Cup), other spectator events (e.g. air shows, concerts), and political or business (e.g. conferences, trade fairs) or religious events (e.g. the Hajj).

    The sizes of mass gatherings vary: for example, there were around 3.2 million spectators during the FIFA World Cup in Germany in 2006, compared with 5000 demonstrators who set up a camp close to the 2005 G8 Summit in Gleneagles in Scotland [1,2].

    The particularly high population density at a mass gathering event may facilitate transmission of infectious diseases, or attract deliberate releases of chemical, biological or radioactive agents, or bomb attacks [3,4].

    Visitors may come to the gathering with infections (such as undetected tuberculosis) or may be susceptible to pathogens circulating at the location of the event (for example, unvaccinated people who travel to a country where there is a measles outbreak).

    An example of an acute outbreak at a mass gathering is the norovirus outbreak at an international scout summer camp in the Netherlands in 2004 [5].

    Furthermore, gatherings with international participants potentially pose specific challenges for implementing control measures, such as contact tracing in case of an outbreak.

    Finally, when events attract a high level of media attention, health authorities need to be prepared to issue timely communications to the responsible institutions and, possibly, the general public, in case of a potential or actual public health threat (not only outbreaks).

    As part of the medical service preparations for a mass gathering event, health authorities frequently enhance their surveillance systems to enable earlier warning of potential public health threats.

    ?Epidemic intelligence? can be defined as all the activities related to early identification of potential health threats, their verification, assessment and investigation, carried out in order to recommend public health measures to control them [6].

    In order to detect all potential threats, epidemic intelligence should also include non-communicable health hazards.

    When is epidemic intelligence needed? The difficulties of defining mass gatherings

    The following challenges exist when determining which mass gathering events require epidemic intelligence gathering:

    <TABLE cellSpacing=0 cellPadding=0 width=934 border=0><TBODY><TR><TD width=934>
    • It is difficult to define what a mass gathering is, and to categorise different types in relation to their potential risks to public health. As far as epidemic intelligence and public health are concerned, mass gatherings need to be differentiated from humanitarian emergencies. Mass gatherings are non-emergency events where there is generally time for appropriate planning, while humanitarian emergencies require different resources and approaches.
    • There can be similar visitor numbers and health risks at organised mass gatherings that attract media attention (such as the Olympics) and those that do not, such as trade fairs, international airports or mass tourism settings where large numbers of people gather every day. However, there is low awareness of the potential need for epidemic intelligence during the non-organised gatherings.
    </TD></TR></TBODY></TABLE>The lack of a definition of mass gatherings, and low awareness within organising committees, may be the main reasons why public health preparedness has not been a major priority for such events.

    However, there are indications that this may have changed after the terrorist attacks in New York on 11 September 2001 and the emergence of SARS and avian influenza.

    Public health authorities have been involved in planning for the major sports events in Europe in 2006, the Torino Winter Olympics [7] and the FIFA World Cup in Germany [1].

    The following points should be considered for prioritising the need for epidemic intelligence and public health planning before a mass gathering event.

    <TABLE cellSpacing=0 cellPadding=0 width=935 border=0><TBODY><TR><TD width=935>
    • number of people expected to gather;
    • kinds of people gathering for the event (ages, nationalities and other characteristics; for example, summer camps will attract adolescents and young adults from the country where the event is held, while an international event like the Hajj attracts people from all over the globe and a wide range of socioeconomic classes);
    • duration of the event;
    • expected public attention or political importance (the event may attract deliberate releases and constitute a reason to invest in preparedness);
    • potential spread of infection or other effects to other sites in the community.
    </TD></TR></TBODY></TABLE>Planning epidemic intelligence during mass gathering events

    The planning process for epidemic intelligence during mass gatherings should include the following steps:

    <TABLE cellSpacing=0 cellPadding=0 width=933 border=0><TBODY><TR><TD width=933>
    • Gathering of experience from previous events, thorough review of the literature, participation in the planning of events, or consultations;
    • Assessing potential public health risks during the mass gathering and the capacity of the existing surveillance and response structures to detect and control them. The risk assessment should take into account the accessibility of the event site, the type of venue (e.g. outdoors or indoors, stadium or larger, less well-defined space), the likely demographics, risk factors and susceptibility of the people attending, environmental factors (such as weather conditions, food handling, water quality and sewage disposal), and communicable and non-infectious hazards of concern;
    • Defining the epidemic intelligence objective during the mass gathering. An example for the general objective for epidemic intelligence during a mass gathering is to quickly detect emerging disease outbreaks or unusual patterns of disease or injury that might require rapid intervention immediately before, during or after the event[8];
    • Developing an epidemic intelligence strategy, including a budget and human resources plan, and establishing a network with national and international stakeholders if necessary;
    • Developing reporting and analysis systems with backup mechanism in case of network failure;
    • Testing epidemic intelligence during smaller events and/or exercises.
    </TD></TR></TBODY></TABLE>Surveillance methods during mass gatherings

    The routine collection of surveillance data can be enhanced and the scope of surveillance widened in different ways, according to the nature of the event:

    1. Enhancing existing surveillance systems

    Enhancing existing surveillance systems usually consists of improving the completeness of case reporting by requesting that the sources of information (e.g. clinics) provide more timely and complete reporting and adjusting the flow of data to ensure timely notification to enable health authorities to trigger appropriate control measures if necessary.

    Systems relying on a sample of sources (sentinel), such as the one for influenza-like illnesses, can be used for additional conditions (e.g. diarrhoeal diseases).

    Enhancement activities are usually limited to cities or the administrative areas involved in the mass gathering.

    2. Developing an additional community-based system

    Additional temporary community-based surveillance may use syndromic case definitions for conditions presenting a potential risk, e.g. for diarrhoeal diseases or lower respiratory syndromes.

    Syndromic surveillance involves the collection and analysis of data on clinical case features, such as signs and symptoms that are present (and available for analysis) before a definitive diagnosis [9].

    Syndromic surveillance systems, although less specific, have the advantage of more rapid reporting, especially if information is actively obtained, which is directly entered into an electronic system, and automatically categorised.

    Such systems have been implemented in emergency medical departments [7,10] and sometimes general practices when the information systems allowed it. The added value of such systems has not been shown and should be studied.

    While more traditional existing surveillance systems are well connected to response systems, additional syndromic systems may cause problems if actions resulting from a generated signal are not clearly defined and assigned in advance.

    3. Setting-up venue/event-specific surveillance systems

    Some mass gatherings have clinics onsite at venues or specific locations (e.g. an Olympic village or media centre). Managing these facilities is usually the responsibility of the organising committee.

    There should be daily reporting to public health authorities of activity (number of consultations) classified according to a predefined short list of syndromes.

    Additional approaches may include collection of unusual types of surveillance data [11], e.g. sales of over-the-counter drugs, increase in health-related web queries, or number of orders for blood cultures, stool cultures, or chest x rays.

    Detection algorithms and thresholds

    Systems can be set up to automatically detect abnormalities in the surveillance data [11].

    Automated tests should be complemented by human visual assessment of changes over time (?eyeballing?).

    An alarm may be triggered if an observed case count exceeds the 90% or 95% confidence interval of the predicted count. Historical baseline data are usually not available for mass gatherings.

    Therefore, departure from the expected may rely on detection of short term changes, such as comparing cases observed on a given day to the average of previous seven days, using a Poisson test, or the percentage of visits for one syndrome compared to the average of visits during the previous seven days, using a binomial test.

    Planning should take into consideration the potential nature of any alerts and the type of transmissions, sensitivity and specificity of the analysis algorithms, control for seasonal and daily trends (e.g. higher case numbers in emergency departments during the weekend), availability of historical data as a baseline, and resulting denominator issues due to the temporary population changes during the event. Existing statistical resources and available software may also be useful.

    Dissemination of information

    The potential need to prepare a daily report on the epidemiological situation for decision makers and the public has considerable implications for planning of the epidemic intelligence process during the mass gathering event.

    Some public health planners during previous mass gatherings limited access to reports to partner organisations only, whereas others made the reports (sometimes including the underlying data) generally available (e.g. on the event?s website) [12].

    During a crisis, a high level of transparency, including daily reporting, may contribute to general awareness raising and building of trust between the responsible authorities and the public.

    Future developments

    In 2006, the European Centre for Disease Prevention and Control (ECDC) worked in close collaboration with national health authorities during the Winter Olympics in Torino and the FIFA World Cup in Germany, providing event-based surveillance and back up support in case of a crisis.

    The ECDC will continue to collaborate with European national health authorities and international partners on public health preparedness during mass gatherings.

    Monitoring and evaluation are needed to increase knowledge of the potential benefits of different models of epidemic intelligence and their cost-effectiveness during mass gatherings.

    This article is based on discussions during a recent epidemic intelligence consultation organized and held by the European Centre for Prevention and Disease Control (ECDC) on 6-8 November 2006 in Stockholm and brought together national epidemic intelligence and surveillance experts from EU countries plus Iceland, Norway, and Switzerland, as well as representatives from the European Commission, World Health Organisation, Health Canada and the Caribbean Epidemiology Centre.

    1. Josephsen J, Schenkel K, Benzler J, Krause G, Preparations for infectious disease surveillance during the football World Cup tournament, Germany 2006. Euro Surveill 2006;11(4):E060427.2. Available from:
    2. The Health of the Population of Forth Valley 2005-2006. Available from:
    3. Editorial team. Hajj 2007: vaccination requirements and travel advice issued. Euro Surveill 2006;11(11):E061130.1. Available from:
    4. Meehan P, Toomey KE, Drinnon J, Cunningham S, Anderson N, Baker E. Public Health Response for the 1996 Olympic Games JAMA. 1998;279:1469-1473.
    5. Norovirus outbreak at an international scout jamboree in the Netherlands, July-August 2004: international alert. Eurosurveillance Weekly [1812-075X]. 2004 Aug 12;8(33) 040812. Available from:
    6. Kaiser R, Coulombier D, Baldari M, Morgan D, Paquet C. What is epidemic intelligence, and how is it being improved in Europe?. Euro Surveill 2006;11(2):E060202.4. Available from:
    7. Epidemiological Consultation Team. Surveillance system in place for the 2006 Winter Olympic Games, Torino, Italy, 2006. Euro Surveill 2006;11(2):E060209.4. Available from:
    8. Jorm LR, Thackway SV, Churches TR, Hills MW. Watching the Games: public health surveillance for the Sydney 2000 Olympic Games. J Epidemiol Community Health. 2003 Feb;57(2):102-8.
    9. Lewis MD, Pavlin JA, Mansfield JL, O'Brien S, Boomsma LG, Elbert Y, Kelley PW. Disease outbreak detection system using syndromic data in the greater Washington DC area. Am J Prev Med. 2002 Oct;23(3):180-6
    10. Hadjichristodoulou C, Mouchtouri V, Soteriades ES, Vaitsi V, Kolonia V, Vasilogiannacopoulos AP, Kremastinou J. Mass gathering preparedness: the experience of the Athens 2004 Olympic and Para-Olympic Games. J Environ Health. 2005 May;67(9):52-7.
    11. Gesteland PH, Gardner RM, Tsui FC, Espino JU, Rolfs RT, James BC, Chapman WW, Moore AW, Wagner MM. Automated syndromic surveillance for the 2002 Winter Olympics. J Am Med Inform Assoc. 2003 Nov-Dec;10(6):547-54
    12. Coulombier D. Surveillance for the World Cup, France, 1998 . Eurosurveillance Weekly [1812-075X]. 1998 Jun 11;6(24) 980611. Available from:
    <HR>Cooperation between animal and human health sectors is key to the detection, surveillance, and control of emerging disease: IMED 2007 meeting in Vienna, February 2007
    L Madoff (
    Harvard Medical School, Boston, MA, USA

    For many years, scientists have recognised the overrepresentation of zoonoses among emerging and re-emerging human diseases.

    Many factors affect the likelihood that a pathogen will emerge (the broad definition of an emerging infectious pathogen used by the US Centers for Disease Control and Prevention is one ?whose incidence in humans has increased within the past two decades or threatens to increase in the near future [1]), but it was suggested over 10 years ago that emerging pathogens were very frequently zoonotic [2].

    More recent work has confirmed that as many as 60% of the more than 1400 recognised human pathogens jump between species [3].

    Despite this knowledge, and many dramatic recent examples such as Ebola virus, Lyme disease and SARS, the worlds of veterinary and human health, including public health, remain quite separate.

    Schools and other training institutions, healthcare facilities, NGOs, public health agencies at all administrative levels, professional and scientific organisations, and journals nearly all remain segregated by their interests in either human or veterinary health.

    One of the rare examples that deals with both is ProMED-mail (the Program for Monitoring Emerging Diseases,, an internet-based service devoted to the early detection of infectious disease outbreaks around the world, which has explicitly included animal diseases as part of its purview [4].

    ProMED reports on human diseases, zoonotic diseases and diseases that affect sources of human nutrition (both plants and livestock animals).

    As such, ProMED has always included the veterinary community, both among its staff and as participants in its reporting system. Currently, four of ProMED?s 11 subject area moderators are veterinarians.

    Over 20% of ProMED?s 37 000 participants subscribe to one or more of its email lists specialising in animal health issues. A recent retrospective study of ProMED from 1996-2004 showed that over 10 000 reports during this 9 year interval concerned animal health issues [5].

    Approximately 30% of these related to zoonotic disease in humans, the remainder dealt strictly with animal disease outbreaks both in wildlife and domesticated animals including livestock.

    Nearly half of the animal diseases reported were caused by viral pathogens, the most likely category to emerge or re-emerge.

    To help address the animal health/human health divide, the International Meeting on Emerging Diseases and Surveillance (IMED 2007) is being held in Vienna from 23 to 25 February 2007.

    The meeting will fully embrace the ?one medicine? concept, which considers health without regard to species differences and recognises the commonality of human and veterinary health interests. Virtually every session at IMED 2007 will include representatives of both the human health and veterinary communities.

    Topics will include emerging zoonoses; models of disease surveillance, detection, and reporting; emerging vectorborne diseases in humans and animals; and vaccines against emerging diseases.

    The meeting is aimed at physicians, veterinarians, public health workers, microbiologists and other scientists, as well as journalists and other non-scientists who recognise the importance of emerging infectious diseases in humans and animals and the surveillance of these diseases.

    They will come away with specialised knowledge of some of the most important emerging diseases, their surveillance, prevention, and control, and a better appreciation of the complexities of the animal-human ecosystem.

    The organisers believe that greater cooperation between the animal and human health worlds will lead to a healthier world.

    Plenaries will include Surveillance of Emerging Diseases in the 21st Century, Drivers of Disease: Human-Wildlife Linkages, and Marburg the Angola Experience.

    The deadline for discounted early registration is 22 December 2006, and more information is available at

    IMED 2007 will be sponsored by the World Organisation for Animal Health (OIE), ProMED-mail (The Program for Monitoring Emerging Diseases), the European Commission, the European Centre for Disease Prevention and Control, and the World Health Organization Regional Office for Europe.

    1. Lederberg J, Shope RE, Oaks, Jr., SE (eds); Committee on Emerging Microbial Threats to Health, Institute of Medicine. Emerging Infections: Microbial Threats to Health in the United States. Washington D.C.: Institute of Medicine of the National Academies; 1992.
    2. Morse SS.Factors in the emergence of infectious diseases. 1: Emerg Infect Dis. 1995 Jan-Mar;1(1):7-15. (
    3. Woolhouse ME, Gowtage-Sequeria S. Host range and emerging and reemerging pathogens. Emerg Infect Dis 2005; 11(12): 1842-7. (
    4. Madoff LC, Woodall JP. The internet and the global monitoring of emerging diseases: lessons from the first 10 years of ProMED-mail. Arch Med Res 2005; 36(6): 724-30.
    5. Cowen P, Garland T, Hugh-Jones ME, Shimshony A, Handysides S, Kaye D, Madoff LC, Pollack MP, Woodall J. Evaluation of ProMED-mail as an electronic early warning system for emerging animal diseases: 1996 to 2004. J Am Vet Med Assoc 2006; 229(7): 1090-9.

    Citation style for articles

    - Article 1 : Influenza team. Highly Pathogenic Avian Influenza A/H5N1 ? update and overview of 2006. Euro Surveill 2006;11(12):E061221.1. Available from:

    - Article 2 : Quoilin S, Lambion N, Mak R, Denis O, Lammens C, Struelens M, Maes S, Goossens H. Soft tissue infections in Belgian rugby players due to Streptococcus pyogenes emm type 81. Euro Surveill 2006;11(12):E061221.2. Available from:

    - Article 3 : Kaiser R, Coulombier D. Epidemic intelligence during mass gatherings. Euro Surveill 2006;11(12):E061221.3. Available from:

    - Article 4 : Madoff L. Cooperation between animal and human health sectors is key to the detection, surveillance, and control of emerging disease: IMED 2007 meeting in Vienna, February 2007. Euro Surveill 2006;11(12):E061221.4. Available from: