• Influenza activity is increasing across the UK

• A national active surveillance system for VTEC in England

• MRSA bloodstream infections continue to fall
  
  
• Case of imported rabies in the UK
  
  
• Group A streptococcal infections: seasonal activity 2008/09
  
  
• Corrigendum: Zoonoses report in HPR 2(50), 12 December 2008.
  

 

Influenza activity is increasing across the UK

Influenza activity has started earlier this season compared to recent years. Epidemiological, clinical and virological indicators show that influenza viruses are circulating in the community at moderate levels. Infuenza is now widespread across parts of the UK and continues to increase.

Figures from the Royal College of General Practitioners (RCGP) sentinel surveillance scheme have shown that GP consultation rates for influenza-like-illness (ILI) in England and Wales increased to 39.5 per 100,000 in week 50, exceeding the baseline threshold level of 30 per 100,000 (see figure). The ILI consultation rates are highest in people aged 15-44 years at 54.4 per 100,000 and in central (56 per 100,000) and southern England (36 per 100,000) [1]. ILI consultation rates have also increased but remain within baseline levels in Scotland and Wales. In Northern Ireland the rate has greatly increased but thresholds have not yet been set [1]. In week 50, the proportion of fever calls to NHS Direct in those 5-14 years of age had risen to 11.5%, exceeding the 9% threshold for over a week. These are the highest levels since winter 2003/4 [2].

The percentage of ILI cases with laboratory confirmed influenza through GP sentinel schemes in England and Wales exceeded the threshold of 30% in week 48 and is currently at 50.6%. A total of 403 samples have tested positive for influenza in the Respiratory Virus Unit (RVU) influenza reference laboratory at the HPA's Centre for Infections (CfI) since week 40. The vast majority of circulating influenza has been influenza A(H3) with 359 (89.1%) isolates. A further 34 (8.4%) influenza A(H1) and 10 (2.5%) influenza B isolates have been detected. All 42 A(H3) isolates tested since week 40/08 have been sensitive to oseltamivir and zanamivir but resistant to amantadine. Of the 28 A(H1) specimens tested, 27 are resistant to oseltamivir but sensitive to zanamivir and amantadine. Viruses characterised at RVU show that the current seasonal influenza vaccine is well matched to circulating strains [1] and should provide good protection. The number of influenza positive detections from other NHS and HPA laboratories in England and Wales has increased in the past few weeks and almost doubled from week 49 to week 50. Similar patterns have been seen in Scotland and Northern Ireland [1].

So far this season 32 outbreaks of respiratory illness have been reported, of which 18 (56.3%) have been confirmed as influenza. Several others are still being investigated. The outbreaks have occurred in various institutions including schools, care homes, hospitals and army barracks [1]. CfI welcomes further outbreak reports to respcdsc@hpa.org.uk.

Based on advice from the HPA that clinical, epidemiological and virological indicators were showing that influenza viruses were circulating within the community, on 12 December the Department of Health issued recommendations for the use of antivirals for treatment and prophylaxis of influenza according to NICE guidance [3].

The best method of preventing influenza remains vaccination. The proportion of those over 65 years of age vaccinated this season in England has now reached 72% and for those under 65 years of age in a clinical risk group, it is 44% [1]. Vaccine uptake amongst health care workers in direct contact with patients has been historically low (13.4% in the 2007/08 season) [4]. It is important to ensure these groups receive their influenza vaccination [5].

Figure. Royal College of General Practitioners influenza-like-illness rate in the 2008/09 season and recent years

References

1. HPA weekly influenza report week 51, published 17 December 2008. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1229502460226.
2. NHS Direct Syndromic Surveillance Bulletin 362, published 17 December 2008. Available at: http://www.hpa.org.uk/hpr/infections/NHS_Direct_Bulletin.pdf.
3. National Institute of Clinical Excellence guidance: Influenza (prophylaxis) - amantadine, oseltamivir and zanamivir, issued 24 September 2008. Available at: http://www.nice.org.uk/Guidance/TA158.
4. Summary: National Influenza Vaccine uptake for Healthcare Workers for England, winter season 2007/08. Available at: http://www.immunisation.nhs.uk/files/flu_vaccine_uptake0708_summary.pdf.
5. Chief Medical Officer's letter: The influenza immunisation programme 2008/09, published 31 March 2008. Available at: http://www.dh.gov.uk/en/Publicationsandstatistics/
Lettersandcirculars/Professionalletters/Chiefmedicalofficerletters/DH_083812.

A national active surveillance system for VTEC in England

Vero cytotoxin-producing Escherichia coli (VTEC) can cause severe gastrointestinal disease in humans. The disease spectrum ranges from asymptomatic carriage or mild diarrhoeal disease through haemorrhagic colitis to haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) [1]. In England, VTEC of serogroup O157 are routinely tested for in clinical laboratories and form over 99% of VTEC isolated annually.

Incidence is highest in children, who account for over 40% of all laboratory-confirmed cases, and a third of all cases are admitted to hospital as a result of their illness [2]. The case-fatality rate has been estimated at approximately two percent for all cases [2].

Our current understanding of the epidemiology of VTEC infection is incomplete. Following a number of high profile outbreaks in the 1990s, VTEC O157 infection was thought to be mainly a foodborne disease. However, most cases are not linked to identified outbreaks and case-control studies of sporadic cases conducted in the United Kingdom in the early to mid-1990s demonstrated that contact with the environment, and with animals and/or their excreta in particular, was commonly associated with illness [3-5] . Ten years on, the impact of these and emerging risk factors for apparent sporadic infections need to be assessed.

Significant local resources are channelled into the investigation of individual cases of VTEC O157 infection each year. However, variations in practice mean that the epidemiological data collected are not readily comparable. Hence disseminated local outbreaks, or those occurring across several regions, might not be recognised, or their investigation might be slowed down, potentially delaying the introduction of control measures.

To better understand the epidemiology of VTEC infection and to assess its impact more accurately, an active national surveillance system for VTEC infection in England is to be introduced. The protocol and questionnaire were developed by a multidisciplinary collaborative group drawn from specialists and practitioners based in the HPA Centre for Infections, Local and Regional Services and Regional Microbiology Network. The scheme will commence on 1 January 2009 and will run for five years in the first instance. The aims and objectives are to:

a) Assemble a standard core clinical, epidemiological and microbiological dataset on all primary indigenous VTEC cases; and

b) Create a comprehensive epidemiological and microbiological database which will enable:
•  improved outbreak recognition to facilitate public health investigations;
•  improved access to surveillance data to all those working across the public/environmental health spectrum to assist in the control of infection at local, regional and national levels;
•  elucidation of the epidemiology of VTEC in England;
•  markers of disease severity including hospitalisations, severe complications and death to be systematically recorded so that the burden of VTEC infection in England can be more accurately assessed;
•  examination of the relationship between geographic variables and disease occurrence; and
•  the clinical manifestations and exposure histories from patients infected with different strain types of VTEC to be compared.

The questionnaire, protocol and case-classification algorithm can be found on the Health Protection Agency website [6]. Health Protection Units are requested to fax the complete questionnaire to us once it has been filled in. Hospital microbiologists are requested to continue to send all presumptive VTEC O157 isolates to the national reference laboratory, as well as stool specimens from cases where VTEC infection is suspected but VTEC O157 has not been isolated. For further information on this surveillance scheme please contact Dr Naomi Boxall (naomi.boxall@hpa.org.uk; tel. 020 8327 6214) or Dr Iain Gillespie (iain.gillespie@hpa.org.uk; tel. 020 8200 7486). For further information on VTEC/VTEc O157 strain characterisation please contact Dr Geraldine Smith (Geraldine.Smith@hpa.org.uk; tel 020 8327 6146).

References

1. Karmali MA. Infection by verocytotoxin-producing Escherichia coli. Clin Microbiol Rev 1989; 2:15-38.
2. Adak GK, Long SM, and O'Brien SJ. Trends in indigenous foodborne disease and deaths, England and Wales : 1992 to 2000. Gut 2002; 51:832-41.
3. Parry SM, Salmon RL, Willshaw GA, and Cheasty T. Risk factors for and prevention of sporadic infections with vero cytotoxin (shiga toxin) producing Escherichia coli O157. Lancet 1998; 351:1019-22.
4. O'Brien SJ, Adak GK, and Gilham C. Contact with farming environment as a major risk factor for Shiga toxin (Vero cytotoxin)-producing Escherichia coli O157 infection in humans. Emerg Infect Dis 2001; 7:1049-51.
5. Locking ME, O'Brien SJ, Reilly WJ et al. Risk factors for sporadic cases of Escherichia coli O157 infection: the importance of contact with animal excreta. Epidemiol Infect 2001; 127:215-20.
6. http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1194947412840.

MRSA bloodstream infections in England, July to September 2008

The latest quarterly HPA report on MRSA bloodstream infections in England [1] has shown a fall by 13% in the third quarter of this year (compared with the previous quarter) to a level 33% below the corresponding quarter of 2007.

Mandatory surveillance results show that there were 725 cases reported in England during the July to September 2008 quarter compared with 837 between April and June 2008 and 1,082 between July and September 2007.

The next set of quarterly data on MRSA bloodstream infections (October to December 2008) will be published on March 19 2009. Quarterly figures for C. difficile infections (July to September 2008) will be published on January 15 2009.   

MRSA bloodstream infection figures - a summary of cases reported under mandatory surveillance in England

Quarter	Number of MRSA bloodstream infection reports
April 2006 - June 2006	1,742
July 2006 - September 2006	1,651
October 2006 - December 2006	1,543
January 2007 - March 2007	1,447
April 2007 - June 2007	1,306
July - September 2007	1,082
October - December 2007	1,091
January 2008 - March 2008	969
April 2008 - June 2008	837
July 2008 - September 2008	725

Note: Data are collected at Trust level and are not published by the HPA for individual hospitals within a Trust.

1. Reports of MRSA bloodstream infections for individual Trusts are available at
http://www.hpa.org.uk/webw/HPAweb&Page&HPAwebAutoListName/Page/1191942126522?p=1191942126522

Case of imported rabies in the UK

A case of imported human rabies has been identified in Northern Ireland. The diagnosis was confirmed by tests on samples sent to the United Kingdom National Reference Laboratory for Rabies at the Veterinary Laboratory Agency, Weybridge, Surrey. The case had worked as a volunteer with animals in South Africa for short periods during the past two years, and had close contact with various animals including dogs. Rabies is endemic in South Africa where bites from infected dogs are the main source of rabies in humans.

In the last 10 years there have been three previous cases of imported human rabies in the UK.

Although an estimated 55,000 cases of classical rabies occur worldwide each year, there has never been a virologically confirmed case of natural human to human transmission of rabies. Despite the lack of evidence for human to human transmission, some people who have been exposed to the secretions of a patient with rabies may be offered post-exposure immunisation, purely as a precautionary measure.

If bitten, scratched, or licked by a warm blooded animal in a rabies-endemic country, people should wash the wound or site of exposure (e.g. mucous membrane) with plenty of soap and water and seek medical advice without delay, even if previously vaccinated. If they do not seek medical treatment while abroad, they should still seek it when they come home, even if some time after the event.

Following exposure an individual risk assessment should be undertaken to determine the need for post-exposure prophylaxis (PEP) with rabies vaccine and/or immunoglobulin. PEP is highly effective in preventing rabies if given promptly and there have been no cases of rabies in the UK in people who have received rabies post exposure prophylaxis.

Travellers should always be advised to seek travel health advice well in advance of their visit overseas to ensure that the risks of all travel associated illness, not just rabies, have been explained. Although rabies vaccine is not routinely advised for all travellers, pre-exposure immunisation is recommended for those:

• working abroad (eg veterinary staff or zoologists) who by the nature of their work are at risk of contact with rabid animals.
• living in or travelling for more than one month to rabies-enzootic areas unless there is reliable access to prompt, safe medical care .
• travelling for less than one month to enzootic areas but who may be exposed to rabies because of their travel activities;
• who would have limited access to post-exposure medical care.

This advice should be specifically brought to the attention of those planning to do voluntary work with animals in rabies-endemic areas.

 

Further information on rabies prevention for the traveller is available from the National Travel Health Network and Centre at http://www.nathnac.org/pro/factsheets/rabies.htm.

Detailed information on rabies is available in chapter 27 of the Green Book [1].

References

1. DH. Immunisation against infectious disease ("the Green Book"). Available at: http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/DH_4097254.

Group A streptococcal infections: seasonal activity 2008/09

 

 

 

 

 

 

 

 

Surveillance data for invasive and non-invasive group A streptococcal (Streptococcus pyogenes) infections are indicating higher levels of incidence than seen since the last peak year, 2003. A total of 79 bacteraemia reports have been received to date through routine laboratory reporting (England, Wales and Northern Ireland) for the month of November, higher than 2005-2007 and likely to rise further with delayed reports, with increases seen across several regions. Scarlet fever notifications are also elevated: 166 for weeks 45-48 (England), higher than for 2004-2007, with increases seen across several regions during October and November. Primary care surveillance data for pharyngitis/scarlet fever similarly indicate higher incidence compared to the previous season [1].

Further seasonal updates will be published in the Health Protection Report. Clinicians, microbiologists and HPUs should be mindful of these early indications that 2008/09 could be a peak year for group A streptococcal infections and maintain a high index of suspicion in relevant patients. Invasive disease isolates and those from suspected clusters or outbreaks should be submitted to the Respiratory and Systemic Infection Laboratory at the Health Protection Agency, Centre for Infections, 61 Colindale Avenue, London NW9 5HT. Guidelines for the management of close community contacts of invasive group A streptococcal disease are available on the Agency's website at [2].

1. QSurveillance Weekly Bulletin No 213, Week commencing 8th December 2008 (Week 50, 2008). Available at: http://www.hpa.org.uk/hpr/infections/Qresearch.pdf.
2. Interim UK guidelines for management of close community contacts of invasive group A streptococcal disease. Available at: http://www.hpa.org.uk/cdph/issues/CDPHvol7/No4/guidelines1_4_04.pdf

Corrigendum: Zoonoses report in HPR, 2(50), 12 December 2008)

In last week's report "Toxoplasma gondii infections diagnosed by the Toxoplasma Reference Unit , England and Wales: weeks 27-39/08", the data tables, and some of the text, had not been properly updated due to a production error.
Please refer to the latest version online, or download the amended PDF file at: http://www.hpa.org.uk/hpr/archives/2008/hpr5008.pdf