Cryptosporidiosis in North Wales

In my statement on 29th November concerning Cryptosporidiosis in North Wales, I said that I would bring to Members’ attention any significant new developments with regard to public health.  At 12 noon on Monday 12th December the total number of Cryptosporidium cases confirmed since 1st October was 192.  This is an increase of 105 over the number given in my first statement on 29th November and 69 over the number given in my statement on 2 December.  All existing channels of investigation are continuing – including heightened disease surveillance, regular water testing and DNA analysis of isolated organisms from both human and environmental specimens.

Because secondary spread of cryptosporidium from one person to another is often found, thorough hand washing has been advised after going to the toilet and before preparing or eating food. People with water supplied by the Cwellyn reservoir should continue to boil, and then cool their water prior to consumption.

Dedicated help lines at NHS Direct remain open for people who have questions or concerns about their health: NHS Direct 0845 850 9859 or 0845 600 6086 (open 9-6 weekdays, and 9-5 weekends). The information supplied by NHS Direct is regularly updated.  A Welsh Water helpline is open for people who wish to check if they are affected by the ‘Boil Water Notice’: Welsh Water 0800 052 0130 (open 24 hours).  Information is also available on the NHS Direct website at www.nhsdirect.nhs.uk or the National Public Health Service for Wales (NPHS) website at www.nphs.wales.nhs.uk.

Dwr Cymru Welsh Water is writing to 9,000 customers in North West Wales who no longer need to boil drinking water from the tap during the current cryptosporidium outbreak.  They include customers whose supply has been switched from the Cwellyn water treatment works to other sources, and those who received boiling order letters although they live outside the area supplied by the works. These customers will shortly receive letters advising them that they no longer need to boil tap water.  However, the company is asking customers to continue boiling their tap water until January 9th – unless they receive an ‘All Clear Notice’ letter.

Members have asked questions about responsibilities and communications from the point of view of public health.  The position is that the NPHS has a duty to protect local populations, which in an outbreak situation is achieved by heightened surveillance, risk containment and risk management. The NPHS is responsible for the surveillance of cryptosporidium.  In a typical year, there will be 300 cases reported across Wales with higher incidence in the autumn and spring.  Across the UK, there has been a higher than normal increase this autumn. Anglesey and Gwynedd were no different in this respect.  However, in the first week of November, there was an increase which was greater than that found elsewhere. On this basis, on 4th November, the NPHS called a meeting of an Incident Management Team drawn from all relevant authorities, including the Gwynedd and Anglesey Local Health Boards.

In line with the surveillance findings described above, the NPHS wrote to every GP in Anglesey and Gwynedd on 4th November. The letter advised GPs of the recent increase in cases of cryptosporidiosis and asked them to refer samples from possible cases to the laboratory. (NPHS laboratories routinely test all samples from patients with diarrhoea for cryptosporidium).

On 23rd November, GPs and specific clinician groups (paediatricians, haematologists, renal physicians and oncologists) at NWW NHS Trust were advised of the need for immuno-compromised patients to boil water direct by letter from Dr Mark Walker, Consultant in Communicable Disease Control for the NPHS.  Attention was drawn to existing CMO advice that patients with severely impaired immune systems should routinely boil drinking water, from whatever source.  They were asked to contact patients with severely impaired immune systems to tell them to boil their drinking water before use. For most of these people, this is advice that they would have received as standard everyday practice.  This advice was re-emphasised at this stage because investigations over the previous two weeks had shown that there was a possibility of there being cryptosporidium in the water supply.  At this stage there was insufficient evidence to justify advising the wider public to boil their water and it was not certain that the water was the source.

Whilst cryptosporidiosis is an unpleasant diarrhoeal illness, it is self-limiting and without long term complications in most people. The most vulnerable group of individuals are those whose immune systems are compromised (such as people with HIV/AIDS, or those taking high dose steroids). These people were proactively sought and advised.  Dr Walker has liaised personally with the Medical Director of NWW Hospital Trust and with the NWW NHS Trust Corporate Communications Manager, throughout the outbreak.  The Hospital Infection Control Team continues to provide on site advice in relation to hospital patient care.

Elderly people, whether in nursing homes or the community, and children, can suffer adversely from cryptosporidiosis because they are more susceptible to dehydration secondary to diarrhoeal illness. Advice sheets were prepared and circulated to all members of the Outbreak Control Team for distribution to residential homes and other institutions.  The majority of cases of cryptosporidiosis in the outbreak have been seen in the 15 to 44 year age group. Less than 10% of cases are aged over 65 years. Immediate risk containment in this outbreak could not therefore be achieved through targeting old people’s homes. Nevertheless, the NPHS proactively included specific reference to the susceptibility of older people to early dehydration in the event of any diarrhoeal illness, and advice for them to seek healthcare early.

The Incident Management Team was reconstituted as an Outbreak Control Team on 29th November when it was clear it was dealing with an outbreak. The work of the group is ongoing and is led by Dr Mark Walker,   It has wide organisational and specialist membership and includes representatives from the National Public Health Service for Wales, Anglesey County Council, Gwynedd County Council, Anglesey Local Health Board, Gwynedd Local Health Board, the Environment Agency Wales, the Drinking Water Inspectorate and Welsh Water.

The Outbreak Control Team is an advisory body only and has no statutory powers itself.  However the individual constituent representatives between them hold considerable authority to ensure public safety.  This includes the capacity for the issuing of specific prohibition or remedial work orders by environmental health officers of the local council or carrying out epidemiological investigation through the regional and local communicable disease surveillance teams. Welsh Water has statutory responsibility for the issuing of boil water notices.  In practice the Outbreak Control Team has sufficient expertise and broad authority to ensure relevant actions are taken.
In this outbreak the NPHS has played a central role on the public health side, leading both the incident management and outbreak control teams and providing epidemiological and communications expertise.  Further NPHS input is provided through the North Wales Local Health Protection Team, the Communicable Disease Surveillance Centre and the on-call Public Health service. The NPHS maintains a significant advocacy and liaison role with diverse partner organisations and through pre-existing links through the Communicable Disease Consultants with Local Council Public Protection Units and their environmental health officers working in the field.  A report is always produced in the event of any declared major outbreak. The current cryptosporidiosis outbreak in North Wales is no exception. Contents routinely include a chronological report of events including those with partner agencies.

It is my intention to release a further written statement next week.