Research and analysis

HPR volume 10 issue 25: news (5 August)

Updated 16 December 2016

1. Hepatitis C in the UK annual report

Preliminary data indicate that mortality attributable to hepatitis C-related end-stage liver disease and liver cancer fell in the UK for the first time in 2015 (having more than doubled over the previous decade) [1]. This suggests that improved access to treatments may be having a positive impact in controlling a virus with which more than 200,000 people in the UK are chronically infected.

However, there is no evidence to suggest that incidence of infection is falling: data from UK surveys of PWID – the principal risk group – suggest that numbers of new HCV infections have remained relatively stable over recent years. Both estimated rates of infection in PWID, and prevalence of infection in recent initiates to drug use, were similar in 2015 (8/100 person years and 26% respectively) to those observed in 2011 (7/100 person years) and 2008 (24%).

If improved access to treatments continues and contributes to reduction in mortality, the World Health Assembly’s recently adopted Global Health Sector Strategy (GHSS) on viral hepatitis for the period 2016 to 2021 [2], calling for a 10% reduction in hepatitis C deaths by 2020, should be achievable in the UK. However, the WHO GHSS call to reduce new cases of chronic HCV by 30% by 2020, and 90% by 2030, represents a significant challenge for UK health services.

These are among the conclusions of PHE’s eighth annual Hepatitis C in the UK report, published on World Hepatitis Day, 28 July 2016 [1].

In a press release [3] announcing the publication Dr Helen Harris, hepatitis C expert at PHE, stated:

With more patients being tested and improved treatments, there is genuine hope that we are seeing an impact on the number of deaths from hepatitis C related end-stage liver disease and liver cancer. However it’s not enough to just treat the liver damage caused by the virus, we also need to prevent infection in the first place, and continue to highlight the importance of prevention and testing.

Many people may be unaware of their infection because they have only mild or no symptoms. If we don’t do more to identify these people, they are likely to remain unaware of their risk until they present with advanced disease. Health care professionals in primary care and other settings should therefore consider hepatitis C testing in people who may be at risk. Those most at risk are people who have ever injected drugs, had a blood transfusion before the introduction of screening of the blood supply in 1991, and people born or brought up in countries with a high prevalence of hepatitis C.

1.1 References

1. PHE, HP Scotland, PH Wales, HSC Northern Ireland, (July 2015). Hepatitis C in the UK: 2016 report. See also the Hepatitis C: guidance, data and analysis health protection guidance collection.

2. “Sixty-ninth World Health Assembly closes: HIV, viral hepatitis and sexually transmitted infections”, WHO news release (28 May 2016).

3. “Annual hepatitis C in the UK report”, PHE press release (28 July 2016).

2. Cyclospora outbreak related to travel to Mexico

As of 5 August 2016, 204 confirmed and probable cases of cyclospora infection have been reported in the UK since 1 June 2016, of which 148 (73%) were associated with travel to Mexico (travel history is pending for 53 cases). Cases have stayed at 24 different hotels and resorts in Mexico, but predominantly on the Riviera Maya coast. Cases are equally distributed between males and females, and the range of ages affected is 12-76 years. UK public health authorities have shared information with the Mexican authorities and the travel industry to support investigations in Mexico.

A similar increase in cyclospora cases in travellers returning from Mexico was detected last year, with a total of 79 cases reported in UK travellers between 1 June and 22 September 2015. Those cases had stayed at a range of hotels and resorts in the Riviera Maya and it was suggested that the source may be a food product that was distributed to several hotels in the region [1].

Most cyclospora cases in the UK in recent years have been reported between weeks 23 and 33 (in June and July), which coincides with the summer holiday period. Typically, around 30 cases are reported each year in the UK, with various tropical and subtropical countries of travel reported [1]. In 2015, there was a multistate outbreak in the USA in which fresh cilantro (coriander) from Puebla, Mexico, was implicated as the cause of cluster-associated cases in three states [2]; large outbreaks in Texas in 2013 and 2014 were also associated with Mexican salad products [3, 4].

Cyclospora cayetanensis is a coccidian protozoan parasite that infects humans and other primates. Infection is characterised by diarrhoea, fatigue, muscle pain, anorexia, weight loss, abdominal cramping and flatulence, nausea and low-grade fever, and is commonly acquired from food or water contaminated by cyclospora oocysts [5, 6]. The oocysts of this organism are not infectious until approximately 10 days after they are passed in faeces, therefore direct person-to-person transmission does not occur. The foods previously involved in cyclospora outbreaks include soft fruits, such as raspberries, and salad products such as coriander, basil and lettuce.

There may be substantial under-ascertainment and reporting of cyclospora cases, because not all patients are tested, and not all positives are reported by laboratories. In addition, these organisms can be difficult to spot and recognise in unstained wet films or concentrates. Faecal samples can be examined using a wet preparation and concentration technique. Any structures resembling cyclospora are further examined under UV light for parasite autofluorescence or confirmed using modified Ziehl-Neelson stain and accurate measurement [7].

In view of the ongoing outbreak, PHE recommends that cyclospora is considered as a possible cause of gastrointestinal infection in patients returning from Mexico. Cases should be reported to the local Health Protection Team. Positive samples should be referred to the appropriate reference laboratory for confirmation: National Parasitology Reference Laboratory, Hospital for Tropical Diseases in London (England), the Scottish Parasite Diagnostic and Reference Laboratory in Glasgow (Scotland) or the Cryptosporidium Reference Unit in Swansea (Wales).

Health advice for travellers to Mexico, including advice on food and water hygiene, can be found on the NaTHNaC website.

2.1 References

1. Nichols GL, Freedman J, Pollock KG, Rumble C, Chalmers RM, Chiodini P, et al (2015). Cyclospora infection linked to travel to Mexico, June to September 2015. Euro Surveill. 20(43).
2. Centers for Disease Control and Prevention (2016). Cyclosporiasis outbreak investigations: United States, 2015.
3. Abanyie F, Harvey RR, Harris JR, Wiegand RE, Gaul L, Desvignes-Kendrick M, et al (2015). 2013 multistate outbreaks of Cyclospora cayetanensis infections associated with fresh produce: focus on the Texas investigations.
4. Centers for Disease Control and Prevention (2013). Outbreaks of cyclosporiasis: United States, June-August 2013. Morbidity and Mortality Weekly Report 62(43): 862.
5. Ortega YR, Sanchez R (2010). Update on Cyclospora cayetanensis, a food-borne and waterborne parasite. Clinical Microbiology Reviews 23(1): 218-234.
6. Chacin-Bonilla L (2010). Epidemiology of Cyclospora cayetanensis: a review focusing in endemic areas. Acta tropica 115(3): 181-193.
7. PHE-SMI B31. UK Standards for Microbiology Investigations:Investigation of specimens other than blood for parasites.

3. Measles associated with summer festivals

Since June 2016 a significant number of measles cases have been confirmed in teenagers and young adults who attended or worked at music and arts festivals around England. This follows an increase in measles this year with 234 cases confirmed between January and June 2016, compared with 54 cases reported for the same period last year [1]. Measles is extremely infectious and events like festivals, where people are mixing closely with each other, provide the ideal place for the infection to spread.

Public Heath England (PHE) is currently aware of 36 reported measles cases linked to at least eight music and arts festivals across England this summer (mid-June to end July) (see table). Thirty (83%) of these cases are laboratory confirmed, and six are considered likely to be measles on the basis of their clinical and epidemiological features.

Cases have been identified across England as well as Wales (2) and Scotland (1). Most cases reside in the South West (12) and London (9) regions with the South East (6), West Midlands (4), East of England (2) and North West (1) all reporting linked cases.

The vast majority of cases were unvaccinated (30) or partially vaccinated (3)* teenagers and young adults, with a median age of the 20 years (range: 11 to 42 years). PHE is aware of at least three cases who attended festivals despite being symptomatic.

The current data are provisional, and it is likely that more cases linked to festivals will be identified as investigations are ongoing.

PHE is reminding teenagers and young people who are unsure about their vaccination status to check with their GP and make an appointment, if needed, to ensure they receive the two doses of MMR vaccine required. All age groups are urged to be aware of the symptoms of measles and not to attend festivals if they are unwell. Young people planning to attend other festivals over the summer are in particular urged to follow this advice.

3.1 Number of measles cases linked to festivals in June and July 2016

Name of festival	Postcode	Start date	End date	Number of linked cases **
Glastonbury festival	BA4 4BY	23/6/2016	26/6/2016	16
NASS festival	BA4 6QN	7/07/2016	9/7/2016	7
Triplicity Music and Arts Festival	EX35 6PU	15/06/2016	18/06/2016	6
Tewkesbury Medieval Festival	GL20 5TU	9/07/2016	10/07/2016	3
Nozstock Festival, the Hidden Valley	HR7 4LS	22/07/2016	24/07/2016	2
Noisily Festival	LE7 9EH	7/07/2016	10/07/2016	2
Secret Garden Party festival	PE28 2LA	21/07/2017	24/07/2016	1
Yeovil Show	BA22 9TA	16/072016	17/07/2016	1

* The vaccination status of three of the cases was not known.

** Some cases are linked to more than one festival.

3.2 Reference

1. “Laboratory-confirmed cases of measles, mumps and rubella, England: April to June 2016”, HPR 10(25). See MMR: laboratory-confirmed cases in 2016