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Brucellosis

Volume 656: debated on Friday 30 March 1962

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Motion made, and Question proposed, That this House do now adjourn.—[ Mr. Chichester-Clark.]

4.3 p.m.

The question which I wish to raise on the Adjournment may not appear to be a very interesting or exciting one, but as it affects public health I am sure that the House will accord it a due degree of importance.

Undulant fever in human beings is caused by milk from cows suffering from brucellosis. The problem has attracted a great deal of attention in public health circles. I find that there is quite a little library already about it. There is, indeed, a great dead of concern among medical officers of health.

The Public Health Laboratory service has estimated that at least 15 per cent. of the dairy herds in England and Wales are infected. We have not got official figures on that, but the Minister said earlier this month that he was collecting up-to-date information, and perhaps the Joint Parliamentary Secretary will be able to give us some more today. We have, however, one official figure, and that is that there were 101 cases of brucellosis last year. The Parliamentary Secretary to the Ministry of Health told us so on 12th March, and she added, somewhat complacently I thought, that medical officers of health had full powers to control the sale for human consumption of milk infected or suspected of this disease.

Unfortunately, it does not seem to be quite as simple as all that. I am informed that diagnosis of the disease is very difficult, that it takes some weeks to identify a culture from the milk and that two separate cultures are necessary, extending over several weeks, before a medical officer of health can say definitely whether or not brucellosis exists. The big point is that while doubt exists, the infected cow or the cow suspected of infection can be sold and sent to another district, and then the whole process has to start all over again.

In a letter dated 10th January, the Minister referred me to an Order of 1922 with a very peculiar name—the Epizootic Abortion Order—and I must confess that I did not know what the word "epizootic" meant until then. I now know that it is connected with abortion, and has no direct connection with brucellosis, as far as I am aware. The point is that under that Order there is a prohibition of the sale of such animals, and I am wondering why there cannot be a similar prohibition in this case.

Should there be some control over the movement of cattle infected or suspected of being infected with this disease? The Minister told me on 1st March, in reply to a Question, that he did not think that would be useful, and the Joint Parliamentary Secretary, in a letter of 10th January, said that he saw no hope that he would be able to introduce movement control, because, he said, infected animals rarely show clinical symptoms unless they abort. But my information is that public health inspectors get regular samples of milk and that they do from time to time spot in these samples what they suspect to be traces of this disease. I should have thought that it was reasonable that when they have suspicions of that kind they should have power to take some action. I should say that this is a case of safety first.

Medical officers of health, I gather from certain articles to which the attention of the Joint Parliamentary Secretary has been drawn, feel frustrated, and wonder whether they and the bacteriologists in the laboratories are wasting their time in taking these samples, analysing them, studying the cultures for several weeks, and then finding that the animal concerned has been sold and moved away, so that they do not even know where it has gone. Unfortunately, farmers are not required to notify this disease.

The Urban District Councils' Association and the County Councils' Association have made representations to the Ministry on whether there should not be compulsory notification under the Milk and Dairies Regulations, 1959, but so far without success. These Regulations provide that where a medical officer of health of a district is in possession of evidence which satisfies him, he can take certain action. There is another provision which says that if, without being in possession of such evidence, he has reasonable grounds, he can take certain action, but the snag seems to be that if certain action is taken under this Order, a question of compensation is involved if a mistake happens to be made.

Even if the authorities concerned do not make a mistake, they might still be involved in heavy compensation in certain circumstances, and medical officers of health are, therefore, very chary about using their powers under this Order, because they regard the wording of the Order as not being sufficiently definite to enable them to take action without running financial and other risks. Therefore, very few local authorities have made undulant fever a notifiable disease. I am asking the Minister whether he thinks that this is a safe thing in the interests of public health.

Another suggestion which I have made in a Question, and which has been made from other quarters, is that all milk should be pasteurised. The Joint Parliamentary Secretary said last December in the House that compulsory pasteurisation would not be practicable because of the difficulty of supplies in rural areas. I do not see very much strength in that. Could he not at least consider compulsory pasteurisation in an area in which the disease is suspected, or has even been discovered? Would he not go as far as that?

We have been told, in answer to Questions, that 94 per cent. of the milk sold retail in England and Wales is already pasteurised, and presumably the danger lies in the remaining 6 per cent. What insuperable obstacle is there in dealing with the remaining 6 per cent? There may be some temporary difficulties in certain areas, but surely they could be overcome.

In the course of doing some homework on the subject I have found that in the State of New York the sale of raw milk is prohibited unless on medical prescription, and even then it must come from brucellosis-free herds. I found that some years ago, when our Armed Forces were faced with an outbreak of undulant fever in Malta—I believe that it was known as the Malta fever—they dealt with it by prohibiting the sale of raw goats' milk, and I imagine that what was important in Malta should equally be important for the British public.

The only remedy mentioned in the House by the Minister is vaccination. He told us the other day that a new scheme of free vaccination is to start on 1st May, but I am advised that while the vaccination is good for the calves, it is not in itself sufficient protection in respect of brucellosis, because it does not prevent the parent cow from transmitting the disease. I will quote a few words from a textbook on bacteriology by Topley and Wilson, page 1355 of the second edition:
"Vaccination does not appear to diminish the carrier rate or to prevent organisms from being excreted in the milk, and it therefore does not make it safe for human consumption"
I speak with all due deference, having no veterinary knowledge at all, but it seems to me that the few pieces of evidence which I have been able to gather should give the Minister food for thought and should make him consider very carefully whether he has done sufficient to protect the public health against this disease. The suggestion which I made the other week that the sale of infected milk should be prohibited has also been turned down. Apparently that could be done under Section 31 of the Food and Drugs Act, 1955. When I asked why it has not been done I was told that it is difficult to apply because it has to be proved in court that the farmer had knowledge of a diseased condition and that, in practice, it is virtually impossible to apply this provision. Perhaps the Minister will look at that.

I suggest, in brief, that whatever the difficulties, milk, which is the only raw food fed to children, should have special care given to it. It has long been known to be a carrier of disease. We have been told that the poliomyelitis virus can survive in milk. Years ago, when it was found that there was a possibility of tuberculosis being conveyed by milk, the Ministry took very effective action. I am asking that similar action, although perhaps not quite as drastic, should be taken in respect of brucellosis.

I call the Minister's attention to the fact that this disease has been banished from dairy herds in Norway, Sweden and Denmark. I ask him to consider how and why those countries have been able to deal effectively with the disease. I realise that there are difficulties, but there is an old saying, "Where there's a will there's a way."

4.15 p.m.

I am obliged to the hon. Member for Accrington (Mr. H. Hynd) and to my hon. Friend the Parliamentary Secretary for giving me a few minutes in which to intervene in the debate. Earlier this month I put a series of Questions to the Minister of Health and the Minister of Agriculture, some of which have been quoted this afternoon, on the subject of brucellosis.

The Questions arose from an interview which I had with a young man, a constituent of mine, who had not only contracted this disease, but had also conducted a most careful research into the incidence of the brucella germ. He was kind enough to put his records at my disposal and I use them as the main source for my few remarks this afternoon. I should like to put before the House one or two points which emerge from this piece of research.

First, only heat-treated milk is safe. That clearly emerges. The brucella germ may be present in T.T. raw milk. Secondly, although about 95 per cent. of milk is heat-treated and only about 6 per cent. of T.T. milk may contain the brucella germ, it means that there may be between 300 and 400 occasions when it is safe to drink raw milk, but one occasion when one may drink a pint of milk which contains brucella germs. That does not mean that the person drinking the milk need necessarily contract the disease, but there is always a danger. Those who obey the injunction "Drinka pinta milka day" and who drink raw T.T. milk may, once a year, drink a pint of milk containing this germ.

The extent of brucellosis in human beings is not known. In answer to a Question put to my right hon. Friend the Minister of Health, I received an answer saying that 101 cases in England and Wales were reported in 1961, but since the disease is not a notifiable disease—it is not obligatory to report it—its extent cannot be established.

One serious trouble arising from the disease is that it is not easily diagnosed. My constituent contracted undulant fever in July, 1961, but his condition was not correctly diagnosed until December of that year. Clearly, by that time, it was far too late for the medical officer of health to trace the source of the infected milk.

I appreciate that what I have been saying has been for my right hon. Friend the Minister of Health and not my hon. Friend. But I now come to some matters which are for my hon. Friend. A number of dairymen have been in touch with me since I put down these Questions and the consensus of opinion seems to be that the public should be made aware of the fact that our T.T. milk is not safe, and nor is goats' milk, to which the hon. Member for Accrington alluded. I hope that my hon. Friend will put that to the Milk Marketing Board so that it may make it clear in its advertising.

Another matter for my hon. Friend is a correct description of milk when it is sold by carton, particularly from a vending machine. At present, it is not obligatory to state whether the milk has been heat-treated. It is frequently described as "T.T. tested" and the person buying the milk from the machine is probably unaware of the risk which he may undergo by drinking T.T. raw milk.

Clearly, the only sensible way of eradicating brucellosis is by universal pasteurisation, and I hope that we shall hear from my hon. Friend something which will prove to us that a positive and realistic approach has been made to this problem, although there may be small areas in the country where that may be impracticable.

4.19 p.m.

The Joint Parliamentary Secretary to the Ministry of Agriculture, Fisheries and Food
(Mr. W. M. F. Vane)

The hon. Member for Accrington (Mr. H. Hynd) has a special interest in this matter as has been shown by the Questions he has asked in the House and correspondence which I have had with him. I am glad to have this opportunity to give him rather fuller information. I hope that he will welcome much of what I have to say, if not everything.

My hon. Friend the Member for Southampton, Test (Mr. J. Howard) was right to say that much of what has been said in the last twenty minutes is more a responsibility for my right hon. Friend the Minister of Health than for me, but I will try to forget that and answer as much as I can, and hope that I will not be misleading anyone, because I know that the general interest is very great. I thank the hon. Gentleman for giving me advance notice of some of the points that he was going to raise this afternoon.

This disease, brucellosis, is causing increasing concern in some quarters, and it is right that a cattle disease which has public health significance should cause us special concern. Much has been done to control animal diseases in this country. The hon. Gentleman referred to the tuberculosis eradication scheme which has had a great success. We are in the early stages of something similar here.

We are not, however, content to rest on our achievements. We recognise that there are many other problems to tackle, and one of the major problems is brucellosis. I hope that what I describe will be regarded as an important step forward, even though the hon. Gentleman may think that we are not going as far or as fast as he would like.

We know that brucellosis is widespread in cattle in this country. I should not like to say that any area is completely clear of it. The hon. Gentleman referred to compulsory pasteurisation in certain areas where the disease was suspect. At the moment we must say that it is generally suspect, but to find out much more—and I do not want to be alarmist or unduly complacent—we are carrying out a much more elaborate survey than has ever been undertaken before. It covers many herds up and down the country. A considerable mass of information has been collected, and, as the hon. Gentleman knows, when dealing with samples it is a mistake to start guessing at what the results will be before the mass of information has been properly examined.

The preliminary results tend to show a wide variation, not only between different parts of the country, but between neighbouring herds, and this substantiates the fact that we have ahead of us a task which needs to be tackled. I hope that it will not be too long before we can give more precise information. I do not therefore want to mislead hon. Members now.

The hon. Gentleman referred to two difficulties about the disease. It is not readily identifiable, and in many cases apparently healthy cattle can be harbouring the organism to a lesser or greater extent and, secondly, there is no known cure.

When a disease is readily recognisable from clinical symptoms, we can stop its spread by a slaughter policy, provided we have power to do so and to pay compensation. That is what we do with foot-and-mouth disease, but with brucellosis such a system would clearly be futile, because we should be doing no more than eliminating the odd carrier, leaving many others untouched. That is why the prohibition to which the hon. Gentleman referred is not really workable in practice. It would mean exercising tremendous sanctions against farmers, and then we should be deceiving ourselves that we were tackling the real problem.

There is no cure for the disease and we would therefore have to institute a slaughter policy, but before we could make a slaughter policy effective we should have to be more certain about identification. Radical treatment would be necessary but with our continuing commitments for testing cattle for tuberculosis—and we do not want to slip back after all we have achieved—we have to make the best use of our veterinary resources. We cannot give top priority to everything, and a full-scale brucellosis eradication scheme involving the testing of all herds in the country and the removal of all reacting animals would be extremely difficult to undertake at this stage.

We have to establish the size of the problem and then contain and reduce it. After doing that we can consider further steps. Cattle can be protected against abortion by vaccination, and we believe that given time and co-operation from farmers we can reduce the incidence of brucellosis very considerably. That is why we are offering all farmers a free calf vaccination service as from 1st May next. There has been a calf vaccination service, but it has not been free. This will be a voluntary scheme confined to calves within a limited age range, but I am confident that farmers will recognise the benefits of it, and we hope to improve upon the current large number of calves vaccinated with Strain 19.

That deals only with calves and not with the effects of the milk that the animals can still produce.

I was coming to that point later, but as the hon. Member has now mentioned it I can say that undulant fever is not only developed by a man or woman through drinking milk. There are other sources of infection, by contact and there may be cases over and above the 101 mentioned by the hon. Member as having been diagnosed. It is wrong to suppose that the ingestion of milk in which brucella is present will always cause undulant fever. We must not exaggerate the situation and it would be wrong if this debate gave that impression.

It is true that some cows may be giving milk which is to some extent infected. But the greater part of that milk is being pasteurised at the moment. It is true that a small fraction of our milk is not subject to heat treatment but if we insisted that even that small fraction should be heat treated we should not only cause a good deal of disruption in the supply of milk but we should be depriving some people in remote districts of any supply of milk at all.

My hon. Friend the Member for Southampton, Test spoke of T.T. milk in vending machines. In specified areas only milk of special designation can be sold and T.T. is one such milk. This is milk from an attested herd, free from tuberculosis. That does not imply that it is free from brucella. That point is not always appreciated but we hope that, given a little time, we shall build up a national herd which is strongly resistant to brucellosis. The life of a commercial cow is not very long, and the older cattle will be dying all the time. This means that at the same time as we are building up strongly resistant dairy herds, which will be greatly limiting the opportunities for the disease to be passed from one animal to another. There will be less abortion and therefore less chance of infection spreading from one beast to another.

Veterinary surgeons will I know do their best to persuade all their clients to take part in this vaccination scheme. Vaccination must be done at the right time, and it will have a great effect if it is widely taken up.

Does vaccination give immunity throughout the life of the animal?

We cannot guarantee that it will give lifelong immunity, but I am advised that it should have effect at least throughout five pregnancies, which is probably longer than the average commercial expectation of life of a cow in the national dairy herd.

I do not for a moment under-estimate the danger of brucellosis in cattle, or its public health significance, but we must maintain a sense of proportion. It is fair to say that this problem is nothing like as big as the tuberculosis problem, which we have tackled, and on which we have made so much progress. Our veterinary surgeons deserve a great deal of credit for this. This scheme, in a way, is the early pattern of the same sort of operation. Although we can make no commitments as to what form the later stages may take. It may already be said that with good husbandry, plus vaccination, brucellosis is nothing like the problem it was even a few years ago. This is a heartening sign. If we can get this taken up far more widely we should be able to achieve the sort of progress for which the hon. Member is looking.

The best line of attack from the public health standpoint is to deal with the disease at its source, which is the infected cow which can pass it to the milk. We want to eliminate every conceivable risk to health due to brucellosis in cattle, but that ideal is not attainable tomorrow or the day after tomorrow. We must not forget that.

About 94 per cent. of all milk sold by retail in England and Wales is heat-treated, but even if we had a rule that no milk other than heat-treated milk should be sold by retail, it would not stop a number of people in country districts from drinking raw milk which has been obtained the easiest way, probably from a farm round the corner. So whatever regulations we might pass they would not completely prevent a large number of people from obtaining such milk.

Medical officers of health have powers, and use them to deal with milk which they believe to be suspect. It would be wrong to assume that all cases of infection come from drinking milk. There are other ways of passing the infection by contact. Therefore, even if the heat treatment were 100 per cent. there would still be means for the infection to pass.

The hon. Member for Accrington referred to what happened in Malta. There they had the more dangerous form of brucellosis, which we have not had. He also spoke of Scandinavia and we must admit that the Scandinavians are ahead of us. But they have not yet got so far as achieving nil returns from their tests. We are treating this matter seriously and we are convinced that the first step must be to reduce the incidence of the disease to a much lower level in our herds, at the same time building up herds protected against the reintroduction of infection. When we have done that we shall be able to consider the next step. Meanwhile, I think it right that we should treat this as a serious problem, although we must keep it in proportion. This is what we are doing, and I hope that it will not be long before somebody can come to this Dispatch Box and report that the campaign which we are now starting has had a measure of success—

When the hon. Member refers to medical officers and their powers, does he mean that they have powers under the Milk and Dairies (General) Regulations, 1959?

Yes, under the Regulations of 1959 they can examine milk and if they find that for any reason it contains a hazard to health they can order how the milk should be disposed of. I hope that the free vaccination service will soon have a marked effect in the direction which we desire, and that it will not be long before we are in a position to consider the next step forward.

Question put and agreed to.

Adjourned accordingly at twenty-seven minutes to Five o'clock.