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Volume 3 No 7; 20 February 2009

Post mortem finding of asymptomatic variant Creutzfeldt-Jakob Disease abnormal prion protein in a person with haemophilia

A person with haemophilia has been found to have evidence of the abnormal prion protein that causes variant Creutzfeldt-Jakob Disease (vCJD) only in their spleen at post mortem. The post mortem was carried out as part of a study jointly co-ordinated by the UK Haemophilia Centre Doctors Organisation (UKHCDO) and the National CJD Surveillance Unit.

This haemophilia patient had been treated in the 1990s with several batches of UK sourced clotting factors, including one batch of Factor VIII that was manufactured using plasma from a donor who went on to develop vCJD. The plasma donor developed symptoms of vCJD six months after donating the plasma in 1996. The haemophilia patient, who was over 70 years old, died of a condition unrelated to vCJD, 11 years and one month after receiving the batch of implicated Factor VIII. The patient had no signs or symptoms of vCJD or other neurological disease when alive.

A final view as to how vCJD abnormal prion protein was transmitted to this haemophilia patient has yet to be reached because investigations are continuing to determine the most likely route of transmission. This is the first time that vCJD abnormal prion protein has been found in a patient with haemophilia, or any patient treated with plasma products.

All patients with bleeding disorders [1] who have been treated with UK-sourced pooled factor concentrates or antithrombin [2] between 1980 and 2001 [3] are classified as 'at risk of vCJD for public health purposes'. Special infection control precautions and other safety measures apply to these patients. This new finding does not change this advice.

This case does not change the public health vCJD 'at risk' status or management of any patients with bleeding disorders.

All haemophilia centre doctors were informed on Monday 16 February 2009 and asked to send a letter to their patients with bleeding disorders. Further information is available at http://www.hpa.org.uk/vcjdplasmaproducts.

Notes

1. Defined here as congenital and acquired haemophilia (Haemophilia A and Haemophilia B), Von Willebrand Disease, other congenital bleeding disorders and congenital antithrombin III deficiency.

2. ie clotting factors and antithrombin made from pooled plasma. These include factor VIII, factor IX, factor VII, factor XI, factor XIII and prothrombin complex concentrates as well as antithrombin.

3. The start date of 1980 is when BSE is thought to have entered the human food chain. The end date of 2001 is the last possible expiry date of any product manufactured by the UK fractionators that was sourced from UK donors until 1998.

Multi-agency response to Wiltshire mine fire

A co-ordinated multi-agency response to an underground fire that burned for five days in a former mine in the south west of England successfully minimised the impact on the local community and ensured there was no risk to public health associated with the release of combustion products to atmosphere.

The HPA’s Avon, Gloucestershire and Wiltshire Health Protection Unit was alerted late morning on 11 February to a fire in a former underground mine at Corsham, Wiltshire, now used as a storage facility for MOD supplies, notably naval equipment. Employees had been evacuated, and emergency responders were on scene, including the specialist Mines Rescue Service.

Due to heavy smoke logging and accessibility problems in the former mine, Wiltshire Fire and Rescue Service withdrew for safety purposes as the fire burnt underground. The presence of white asbestos was confirmed early in the incident but there was also concern that some of the stored electronic equipment, such as transformers, may have been involved in the fire, generating various toxins. The fire service eventually managed to contain the fire within the underground area by closing off all the access points and ventilation outlets.

Continuous chemical meteorological reports and plume modelling were generated throughout by the Met Office (the United Kingdom's national weather service) and a number of multi-agency teleconferences, involving HPA local, regional experts, including from the Chemical Hazards and Poisons Division, culminated in advice that the smoke plume should only be released from the mine after careful consideration of the wind direction, the potential for public exposure and wider environmental effects. Press statements and messages for the public were disseminated regularly through local media channels.

To help extinguish the fire, the Fire Service pumped liquid nitrogen into the mine compartments over a nine hour period, reducing the ambient temperature and level of oxygen. Analysis was carried out on the underground air space which showed minimal asbestos levels but high particulate content. It was agreed that the mine could be vented, depending upon the temperature of the contained combustion products and local weather conditions.

The Environment Agency (EA) mobilised a team to monitor particulates on site and in the direction of the plume while venting was carried out from the evening of Sunday 15 February. Local residents were advised directly to remains indoors while the smoke was released from the mine. The Director of Public Health for Wiltshire, who was on site during the venting, reported that particulates were very low, both on site and around the local residential properties. Environmental asbestos sampling was undertaken 24 hours later and continues to be taken at the above-ground venting points.

Initial views on the incident, prior to full de-brief, were that multi-agency communications and co-ordination were smooth and effective. Public health implications from potential release of the products of combustion to air were minimal and good risk communication ensured that local anxieties were minimised.

Input and assistance from the Met Office was excellent throughout the five days of the incident and has provided a platform for joint working to enhance future responses to large incidents.

Local authority capacity and capability to monitor for particulates in this type of incident will be discussed further as non-major incidents normally fall below the trigger level of the current EA agreement to mobilise modelling and sampling resources.