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March 1997 news from S. Dealler

Steven Dealler's Web site: has the text of :
A matter for debate: the risk of bovine spongiform encephalopathy to humans posed by blood transfusion in UK"
Transfusion Medicine 1996;6:217-222.
(Transfusion Medicine is a peer reviewed scientific journal of blood transfusion in the UK. Dr. Dealler submitted the article in 1994!)

Below are some items from Dealler's March 1997 gossip section and from an Open Letter to opposition parties about problems they might inherit upon taking office. The webmaster has selected and grouped related items.

Paul Brown announcing that nv-CJD in mice is transmissible in the mouse plasma to another mouse. The big problem with this is that human gamma globulins are made from plasma and actually in a way that might concentrate the prion. As such 300,000 inoculations per year up to 1995 and then 160,000 inoculations may well have taken place using gamma globs that are partly derived from infected blood. Horror is basically spreading through the blood transfusion service. I think that everyone can see that blood transfusion may not be a very clever thing in the UK and that people may actually start turning it down. The fact that Paul Brown is saying all this to the WHO will probably not do very much at the meeting but the transfusion people in Europe may consider stopping UK donors from giving blood in their country. The gamma globulins problem is unlikely to abate even though the DofH are as usual going to tell everyone that all is fine.

For some reason the DofH seems to have remained totally silent about the risks of blood transfusion. The Nature article predicted a maximum of 85,000 cases of nv-CJD currently incubating the disease (this may well be an underestimate). It would be expected that their blood would be currently infective and, as this group are just the ones that donate blood it should be assumed (as it is in other countries) that their blood is dangerous. This would suggest that one in every 200 pints of blood donated currently comes from a person infected with nv-CJD.

The US is likely to ban UK donors of blood and the EU countries to ban the export of UK blood products, specifically because of BSE. There can be no proof at the current time of the number of blood donors infected with nv-CJD and no proof that it is transmitted*. However, because of the sheer numbers of people involved it should be assumed to be infective, accelerated research put into looking for methods to diagnose the condition before symptoms appear (i.e. in donors) and the use of blood in the UK (it is grossly over-used here) limited to when necessary. *Statistics from human studies of CJD are quite inadequate currently and anecdotal evidence has appeared to indicate both that it is a risk and that it is not.

The major finding that mouse inoculation was very insensitive method to test for BSE in tissue was released at a lecture in Liverpool in June 1996 but has not been released either in scientific literature or in Government data. This must be admitted officially. The finding was that between 1000 and 10,000 infective units (one IU is the amount needed to infect another cow) was needed to infect a mouse. This meant that, as only 3mg of beef tissue could be injected into the mouse, all we can say when we find that the mouse does NOT die of BSE is that there is less than 3,000,000 IU per gram of that tissue. This was not made clear in information to the House of Commons or to the EC. It was simply indicated that the mouse inoculated with muscle (for instance) did not die. It was not indicated just how little this meant as an indicator of the amount of infection in the tissue.

Pathological changes in bovine muscle with BSE. It was announced in the House of Commons yesterday by David Hinchliffe that changes were seen under the microscope but that the information was not permitted to be let out. Considering infectivity had been found in the TSEs muscle of mink, goats and hamsters, this would surely have been important at the time. Hinchliffe made it clear that he felt that the denying and ignoring of information was very bad.

Milk and BSE . Don't forget that the SEAC will present a report on 7th of March and the EU Standing Veterinary Committee will submit a report on 4/5 March on meeetings held on 17 Feb. Nothing has come through to me about these. If anyone has any further data I would be glad to hear it.

Mites involved in the UK? MAFF have admitted to considering research into the exposure of British sheep and cattle to mites and the replication of scrapie and BSE prions in mites (not funding it of course yet). What they have not admitted however to the MP that asked the question is that the work has been already started and that they have already found the mites in the BSE fields

Vertical transmission rates corrected. Anderson's group in Oxford, who appear to be getting much better at understanding the biology of the disease now have produced a document for the EC and MAFF calculating the risks of vertical transmission. 10 per cent VT seen in the experimental group (compared with the control group), 7.8 per cent are associated with a factor that makes them more likely to develop it, but the overall rate of transmission was 1 per cent. (i.e. less than 1% of cattle would develop BSE from vertical transmission and this would be a useful figure for calculating the fall in the number of cases of BSE by generation). BUT the data has not been published and worries are being seen from other groups that this 1 percent figure might be too inaccurate to be useful. The confidence intervals on it might be so wide as to make it unhelpful.

The vertical transmission rate of BSE has now been declared as 7.8% in the last 6 months of the incubation period of BSE in the mother. This data has been submitted to SEAC but not published. No confidence intervals appear to have been included in this sort of data as should be present in statistical data. What are the findings? What are the confidence intervals?

MAFF wants the chicken. MAFF have contacted Narang and demanded the chicken that might have a TSE. It is not really clear how he can give it to them as it is probably in a bucket of formalin in a path lab out of his control now. The worry that has come from European groups is that Narang spoke too soon and should not have done so. Europeans contact MAFF about chicken with 'TSE'. Following the Mail on Sunday report of the chicken that might be infected various countries (incoluding Holland) have come back to MAFF with requests of information and suggeting that they may ban the UK poultry. MAFF think that they would not get away with this as it would be against EC rules but they Europeans think that they were duped the first time by MAFF and so why should they believe MAFF again.

. The number of cases of BSE do not seem to be dropping towards zero. This work was published by MAFF epidemiology group about 9 months ago as a graph in their 6 monthly document and was probably not noticed because of its complexity.... For every case of BSE seen we eat about 7 infected cattle (although this has changed a bit due to the thirty month slaughter policy). How many infected cattle would be being slaughtered, eaten, incinerated etc in the years to 2001 and the confidence intervals.

The incubation period of any transmissible spongiform encephalopathy depends on the dose of infection present in the initial food that caused the disease. The more infection eaten, the shorter the incubation period. For some reason the incubation period (when other factors are taken into account) of BSE in the UK seems to be dropping. How could this be? After all, by rights the cattle dying now would have eaten infection after the feed ban! It is as if the few numbers are actually eating more BSE. One explanation is underreporting by farmers (British Food Journal, 1995) but there may be others. MAFF has not put forward any reasonable explanations but some of them suggest that the disease may be becoming endemic.

The storing of cattle remains; not possible to get rid of them? The storing costs currently 250,000 per week and is rising. The only place that can get rid of the material according to the EC regulations is ReChem in Southampton but that can only deal with 2000 tons per annum. Even if the 9 further places get the OK to deal with it, the rate at which new carcasses arise will be faster than all of these places can get rid of them. It seems as if this is a problem that is being stored until after the election was the viewpoint of a number of the MPs.

The thing to remember about all TSEs is that by the time you find out what is happening it is always too late to do anything about it. In other words you have to take action before proof is available; before scientific certainty. You have to take pessimistic guesses. The reason for this is simply that this sort of disease can affect a large proportion of a population and so if you take optimistic guesses and are wrong, the effect can be extremely damaging for the whole country. What happened was that MAFF took optimistic guesses and kept other groups out from the subject using many methods. What Labour will find is that a lot of the optimistic guesses have turned out to be wrong and so the effects we are now seeing start to build up may be quite severe.

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