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Volume 4 No 19; 14 May 2010

HPR Home | Archives | 2010 news

Hepatitis C diagnosis increasing but awareness-raising and rates of testing need to be sustained
Cryptosporidiosis linked to open farm visits: a reminder of the hazard
Increase in reported foodborne outbreaks in 2009
Open consultation on new public health guidelines on the management and control of group A streptococcal infections in hospitals in the UK

Hepatitis C diagnosis increasing but awareness-raising and rates of testing need to be sustained

It is estimated that around 185,000 individuals in the UK are chronically infected with hepatitis C (HCV) and at least 130,000 of these are living in England [1]. Although improved access to testing in recent years may have contributed to a falling proportion of those tested today being found to be anti-HCV positive, public awareness campaigns need to be maintained in order that "hard to reach" groups can be diagnosed and treated.

The most recent evidence suggests that much of the incident infection is now concentrated in marginalised populations, with injecting drug users (IDUs) at greatest risk of acquiring infection, and some minority ethnic populations having higher rates of infection than the white, UK-born population [1,2].

Laboratory reported infections

There has been a steady increase in the number of laboratory-confirmed diagnoses of hepatitis C infection that are reported to the HPA, from all regions in England, each year since 1995 (see table).

Laboratory reports of hepatitis C infection by English region: 1995-2009

Region	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	Total
East Midlands	128	151	182	181	196	189	151	241	322	380	466	278	398	636	563	4462
Eastern	125	224	374	541	565	552	430	351	408	522	584	620	617	680	605	7198
London	203	263	257	334	299	263	316	331	388	744	811	1189	1016	972	861	8247
North East	2	13	40	58	110	130	113	136	228	238	281	243	138	163	241	2134
North West	206	135	110	626	1054	896	1061	1367	1998	1839	1487	1359	1743	1679	2194	17754
South East	314	584	662	928	800	601	569	531	492	404	322	387	816	947	1128	9485
South West	312	411	477	443	713	851	722	831	697	929	684	858	1038	1103	1003	11072
West Midlands	36	145	225	559	638	612	551	666	514	554	582	511	625	698	875	7791
Yorks. & Humber.	66	77	156	141	236	392	236	305	473	584	976	1428	1370	1318	1093	8851
TOTAL	1392	2003	2483	3811	4611	4486	4149	4759	5520	6194	6193	6873	7761	8196	8563	76994

Although the number of monthly reports has fluctuated, the annual total of reports has been increasing steadily since 1997 (figure 1). In 2009, the number of laboratory confirmed diagnoses reported was 8,563, a rise of four and a half per cent on the previous year and a rise of almost 40 per cent on the number reported in 2004 when the HCV Action Plan was launched [3].

Between April and December 2009, however, the five-month-averaged level of laboratory reports showed a decrease. This may be due to reporting delay or could suggest that the rate of testing is no longer increasing.

Figure 1. Five month moving average of laboratory reports of hepatitis C infection from England: January 1996 - January 2010

The steady increase in annual diagnoses of recent years is likely to be a reflection of increased awareness and testing; Department of Health, NHS and voluntary sector awareness campaigns are likely to have contributed to this increase.

Sentinel surveillance data

Although laboratory reports underestimate the true numbers of infections in England, they should provide a reliable indication of trends in national testing. Trends in testing can also be analysed using data from sentinel laboratories participating in the Sentinel Surveillance of Hepatitis Testing Study [4]. Figure 2 shows the number of people tested for anti-HCV and the proportion testing positive by year in 18 sentinel laboratories with complete data from January 2005 to the end of December 2009. These data also support the view that testing has continued to increase over the last three years but that the rate of testing is levelling off (figure 2).

Figure 2. HCV tested and percentage positive by year: 2005-2009* - data from 18 centres in the Sentinel Surveillance of Hepatitis Testing Study

As in previous years, the proportion of people tested who were found to be anti-HCV positive continues to decline. This falling yield of positives - as hepatitis C testing/screening is being extended - is consistent with improved access to testing for groups at relatively lower risk of infection. The falling rate of testing may partly be the result of testing saturation, since groups of patients tested in earlier years are those relatively easy to access, whereas the remaining individuals at risk are harder to identify. If these hard-to-reach groups are to be diagnosed and treated, it is important that awareness of the infection is raised within the general population and individuals at risk are encouraged to come forward for testing - which is the aim of the Department of Health's Get tested. Get treated campaign [5].

The continued increase in deaths, transplants and hospital admissions from HCV-related end stage liver disease [1] shows that there is no room for complacency when dealing with this infection. A national action plan to help tackle HCV infection is in place [3] and actions are focused in four main areas:

preventing new infections
increasing awareness of the infection among the public and healthcare professionals
increasing diagnosis
getting diagnosed individuals into treatment and care.

Activity in these action areas must be sustained and enhanced if the predicted future burden of HCV-related disease [6] is to be averted. The HPA has drawn up 12 public health recommendations to help achieve this, which can be found in the Hepatitis C in the UK report [1].

References

1. Hepatitis C in the UK - HPA report 2009. Available at: http://www.hpa.org.uk/web/HPAweb&HPAwebStandard/HPAweb_C/1259152221168.

2. "Hepatitis C diagnoses increasing in the UK", Health Protection Report 3(49): news. Available at: http://www.hpa.org.uk/hpr/archives/2009/news4909.htm#hcv.

3. Hepatitis C Action Plan for England. Department of Health, July 2004. Available at: www.dh.gov.uk/assetRoot/04/08/47/13/04084713.pdf.

4. Health Protection Agency. Quarterly report from the sentinel surveillance study of hepatitis testing in England: data for October to December 2009 (quarter 4). Health Protection Report 4(16): immunisation. Available at: http://www.hpa.org.uk/hpr/infections/immunisation.htm#sntnlQ4.

5. Hepatitis C - Get tested. Get treated campaign. Available at: http://www.nhs.uk/hepatitisc/hcp/Pages/default.aspx.

6. Sweeting MJ, De Angelis D, Brant L, Harris HE, Mann AG, Ramsay ME. The burden of hepatitis C in England. J Viral Hepat 2007; 14: 570-6.

Cryptosporidiosis linked to open farm visits: a reminder of the hazards

Cryptosporidiosis is a common gastrointestinal illness that is transmitted from infected persons, animals, or contaminated water or food. It is most common in children under five, but can affect anyone, particularly those who are immunocompromised. This article reports on outbreaks of cryptosporidiosis associated with open farms and provides a reminder of the risk to visitors of becoming infected from Cryptosporidium and other zoonotic organisms and the importance of hygiene control measures in open farm settings.

Between 1992 and 2009, 54 outbreaks of infectious intestinal disease (IID) associated with open farms in England and Wales were reported, of which 56% (30) were caused by Escherichia coli O157 (VTEC O157), an organism that attracted attention following the large outbreak that occurred in August to September 2009 [1]. However, 40% (22) of outbreaks during this period were caused by Cryptosporidium spp.- with a total of 1072 people affected, of whom 307 had laboratory confirmed infections, and 29 were hospitalised. The remaining two outbreaks were caused by Salmonella Typhimurium.

Contributory factors reported in these outbreaks of cryptosporidiosis included: direct contact with pre-weaned animals (eg lambs, calves, kid goats); direct contact with animal faeces (eg scouring lambs, a recognised risk factor for cryptosporidiosis); inadequate hand washing facilities; and reliance of alcohol-based hand gels and sanitizers which are not effective against Cryptosporidium.

Seasonality of patterns of farm-related infection

Open farm outbreaks caused by Cryptosporidium and VTEC O157 display a seasonal pattern; outbreaks of cryptosporidiosis occurred more often in springtime in comparison to outbreaks of VTEC O157 which occurred more frequently during the summer months and especially in August (see figure). Over the springtime of 2010, two outbreaks of cryptosporidiosis associated with open farm visits have been reported to the Health Protection Agency in England.

Despite the two separate seasonal peaks of infection, care needs to be exercised throughout the year. The importance of careful attention to hygiene and supervision of children when visiting farms, and the need for appropriate facilities, such as those for hand washing, are covered in the Health and Safety Executive (HSE) standards which the operators of open farms, including 'petting farms' are expected to meet [2]. More recently a good practice reminder on managing the risks from VTEC O157 in an open farm context has been published by the HPA, HSE and the Local Authorities Co-ordinators of Regulatory Services [3]. Guidance on the control of VTEC O157 infections for farms open to public access applies equally to most gastrointestinal pathogens.

Outbreaks of cryptosporidiosis, VTEC O157and S. Typhimurium linked to open/petting farm settings, England and Wales (1992-2009)

Outbreaks of cryptosporidiosis, VTEC O157and S. Typhimurium linked to open/petting farm settings, England and Wales (1992-2009)

References

1. Health Protection Agency. Investigation of cases of E. coli O157 at Surrey Farm, 12 September 2009. Available at: http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1252660019696?p=1231252394302

2. Health and Safety Executive (HSE). Avoiding ill health at open farms - advice to farmers (with teachers supplement). Available at: http://www.hse.gov.uk/pubns/ais23.pdf.

3. HSE, Local Authorities Coordinators of Regulatory Services and HPA. Understanding and managing the risks from E. coli O157 in an open farm context. 23 March 2010. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1267551712693.

Increase in reported foodborne outbreaks in 2009

With the introduction of the European Food Safety Authority (EFSA) statutory reporting, the investigation and reporting of foodborne outbreaks within the European Union became mandatory from 2007 (Directive 2003/99/EC) [1]. The Health Protection Agency has operated a system of surveillance for general outbreaks* of infectious intestinal disease (foodborne and non-foodborne) in England and Wales since 1992 (GSURV) [2]. In order to align with statutory requirements as well as modernising the system by enhancing and improving the capture of outbreak information, a stand alone surveillance system from GSURV: eFOSS (HPA electronic Foodborne and non-foodborne gastrointestinal Outbreak Surveillance System), commenced in 2009. Two surveillance forms are used: one for foodborne outbreaks and another for non-foodborne gastrointestinal outbreaks that seek data on the outbreak, including details of setting, mode of transmission, causative organism and details of epidemiological and laboratory investigations. Such data forms a national minimum dataset for analysis and reporting.

In 2009, 92 outbreaks of foodborne transmission were reported to eFOSS, the highest number reported since 2001. In total, 3,410 people were affected and of these, there were 1,090 laboratory confirmed cases, 109 hospitalisations and eight deaths. The majority were reported from London (19) with fewest reported from the East Midlands (3); four national outbreaks were also reported. Outbreaks caused by salmonellas and norovirus were the most commonly reported pathogens in 2009 (28/92, 30% and 17/92, 18%, respectively) while Campylobacter was the next most common (13/92, 14%) (see table 1).

Table 1. Foodborne outbreaks reported to eFOSS in 2009, by pathogen/toxin

Pathogen/toxin	No. of foodborne outbreaks
Salmonella spp.	28 (30%)
Norovirus	17 (18%)
Campylobacter spp.	13 (14%)
Unknown	8 (9%)
VTEC O157	7 (8%)
Scombrotoxin	5 (6%)
Clostridium perfringens	3 (3%)
Staphylococcus aureus	3 (3%)
Bacillus spp.	2 (2%)
Other viral	2 (2%)
Shigella spp.	2 (2%)
Listeria monocytogenes	1 (1%)
Mixed	1 (1%)
Total	92

Foodborne outbreaks more often occurred in the food service sector (73/92, 79%), followed by institutional/residential (9/92, 10%), retail (6/92, 7%), and 'other' settings (eg private household and community) (3/92, 3%). Of the food service sector associated outbreaks, restaurant and takeaway premises accounted for almost two-thirds (47, 64%) of these, with the majority serving Chinese (12/47, 26%), mixed (8/47, 17%) or Indian cuisines (6/47, 13%). Specifically by pathogen, 82% (23/28), 88% (14/17), and 84% (11/13) of Salmonella , norovirus and Campylobacter outbreaks, respectively, were linked to food service premises. Escherichia coli O157 (VTEC O157) outbreaks were in the main also linked to food service (3/7, 43%) and retail premises (2/7, 29%).

In 76% (70/92) of the outbreaks, a food vehicle was identified. Poultry meat was most frequently identified (22/92, 24%), followed by composite/mixed foods (14/92, 15%) and crustacea and shellfish (12/92, 13%) (table 2). Consumption of oysters (12/92, 13%) and poultry liver pate/parfait (9/92, 10%) were the most common specific foods identified in outbreaks during 2009. Salmonella outbreaks were most frequently linked with consumption of poultry meat (26%), composite/mixed foods (23%) and eggs (17%) (table 2). From 17 norovirus outbreaks, 12 (70%) were linked to consumption of oysters (crustacea/shellfish category) and 90% of Campylobacter associated food vehicles were poultry meat. VTEC O157 outbreaks were most frequently linked with red meat (57%) and in the 'other' pathogen/toxin category (Table 2) all outbreaks linked to consumption of finfish (all tuna) were attributed to scombrotoxin. The evidence implicating a food vehicle in these outbreaks included analytical epidemiology plus microbiological in 1% (1/92), microbiological evidence alone in 24% (22/92), analytical epidemiology alone in 11% (10/92) and descriptive epidemiology in 40% (37/92).

Table 2. Foodborne outbreaks in 2009, implicated food vehicle by pathogen*

Food vehicle	Salmonella spp.	Norovirus	*Campylo-bacter*	VTEC O157	*L. mono-cytogenes*	Other^	Unknown	Total
Poultry meat	9	-	9	-	1	2	1	22
Red meat	2	-	-	4	1	2	-	9
Finfish	-	-	-	-	-	5	-	5
Crustacea & shellfish	-	12	-	-	-	-	-	12
Vegetables & fruit	3	-	-	-	-	1	-	4
Dessert, cakes, confectionery	3	-	1	-	-	-	1	5
Milk & dairy products	-	-	-	1	-	-	-	1
Condiments & sauces	2	-	-	1	-	1	-	4
Composite / mixed foods	8	-	-	1	-	4	1	14
Eggs & egg dishes	6	-	-	-	-	-	-	6
Rice	2	-	-	-	-	1	-	3
Total	35	12	10	7	2	16	3	85

Factors that contributed to the outbreak were reported in 77% (71/92) of the foodborne outbreaks. Cross contamination was the most commonly reported factor (29%, 28/98) in the outbreaks followed by inadequate heat treatment/cooking (22%, 22/98), poor storage (ie storage too warm or too long) (17%, 16/92), an infected food handler (10%, 10/98), poor hand-washing facilities (9%, 9/98), poor personal hygiene (7%, 8/98) and inadequate chilling (4%, 4/98). Salmonella outbreaks were most frequently caused by a cross contamination event (39%) or inadequate heat treatment of the implicated food (24%), as were Campylobacter outbreaks (46% and 46% respectively) and VTEC O157 outbreaks (29% and 43%, respectively). The main contributory factor reported for norovirus foodborne outbreaks included infected food handlers (57%).

The existence of comprehensive foodborne outbreak data in England and Wales collected for almost two decades allows trends in foodborne disease against interventions taken place to be tracked and provides a useful resource for source attribution of foodborne infections. Following the implementation of measures to improve communication and data capture, the annual number of general foodborne outbreaks in 2009 reported to eFOSS increased from previous years to 92 (figure 1). Interestingly however, was that the number of outbreaks caused by specific pathogens mirrored reported increases in laboratory confirmed cases in 2009, the exception being Salmonella where a decrease occurred in 2009. However, over half of the Salmonella outbreaks reported in 2009 (61%, 17/28) were caused by S. Enteritidis PT 14b which were linked to raw shell eggs supplied by an approved establishment in Spain and used in food service premises [3].

Number of general foodborne outbreaks reported from 1992 to 2009, showing changes in numbers of outbreaks attributed to the major pathogen

Number of general foodborne outbreaks reported from 1992 to 2009, showing changes in numbers of outbreaks attributed to the major pathogen

Evidence from reported foodborne outbreaks during 2009 has shown that almost 80% of outbreaks were linked specifically to food service premises, and that these were related to cross contamination in the kitchen and/or inadequate cooking of the food. Caterers need to adopt appropriate control measures and follow food safety advice provided by the Food Standards Agency [4]. Improving hygiene and lowering the risk of introducing Salmonella and other pathogens into the food service sector are needed in order to reduce the risk of infection.

* A general outbreak is an incident in which two or more people, from more than one household, or residents of an institution, thought to have a common exposure, experience a similar illness or proven infection (at least one of them having been ill).

References

1. European Food Safety Authority. Report from the Task Force on Zoonoses Data Collection on harmonising the reporting of food-borne outbreaks through the Community reporting system in accordance with Directive 2003/99/EC. The EFSA Journal 2007; 123: 1-16.

2. Cowden JM, et al. Outbreaks of foodborne infectious intestinal disease in England and Wales: 1992 and 1993. Commun.Dis.Rep. CDR Rev. 1995; 5: R109-R117.

3. HPA. S. Enteritidis infections in England in 2009: national case control study report. Health Protection Report 4(6) (12 February 2010). Available at: http://www.hpa.org.uk/hpr/archives/2010/news0610.htm#pt14b.

4. Food Standards Agency. Safer Food, Better Business. Available at: http://www.food.gov.uk/foodindustry/regulation/hygleg/hyglegresources/sfbb/.

Open consultation on new public health guidelines on the management and control of group A streptococcal infections in hospitals in the UK

A newly drafted evidence-based guideline for the prevention and control of group A streptococcal infections in hospital settings is now open for consultation. The guideline has been drafted by a working group with comprehensive representation from clinical and public health professional bodies across the UK, as well as patient support group representation. The draft guideline provides recommendations for hospital infection prevention and control teams and health protection specialists on measures to minimise the further spread of group A streptococci in hospitals, including within maternity units, and investigations to be undertaken where an outbreak is suspected.

The draft guideline is currently open for consultation through the HPA website: http://www.hpa.org.uk/ConsultationsAndFeedback/

Comments on the guideline are welcomed and should be sent to gas.guidance@hpa.org.uk. Healthcare professionals are asked to channel their comments through their respective professional body for compilation. The closing date for receipt of comments is 6 August 2010.

Further information on group A streptococcal infection can be found on the HPA website at: Home > Topics > Infectious Diseases > Infections A-Z > Group A Streptococcal Infections.