J Scudamore Esq
Chief Veterinary Officer
Ministry of Agriculture Fisheries & Food
1A Page Street
tel: 0117 939 2000
Our ref: SL02/WN01/24393.1/LEACH
25 May 2001
When telephoning please ask for: Simon Leach
Camelids and Foot and Mouth Disease
We act on behalf of British Camelids Limited, generally known as the British Llama and Alpaca Association (BLAA), the breed society founded in 1987 and representing owners of all 4 species of camelids in Great Britain and CAUSAL (Campaign Against Unnecessary Slaughter of Alpacas and Llamas), a group consisting of a number of camelid owners. We have been instructed to write to you in connection with the treatment of camelids in the current epidemic of foot and mouth disease ("FMD"), and specifically dealing with the following issues:
(a) The susceptibility of camelids to FMD;
(b) The risk (if any) of camelids as carriers of foot and mouth disease virus ("FMDV");
(c) Proposals for dealing with camelids.
We have seen copies of the letter dated 13th March, signed on behalf of various camelid owners by Mary Marshall and Laurie Humble which was addressed to Miss Smith and Mr Landeg, Heads of Division respectively of Animal Identification and International Trade and Veterinary Exotic Diseases. The purpose of that letter was to invite you to consider the possibility of quarantine in cases where camelids would otherwise be slaughtered. The letter referred you to a number of research studies on the resistance of camelids to infection, whether camelids were carriers of FMDV and indeed provided you with a list of the relevant articles and studies.
We have also seen your reply dated 18th April written by Celia Webber in the Animal Disease Control Division. That reply is disappointing and glosses over the substance of the points made in the letter of 13th March. Your position as stated in your letter can be summarised as follows:
(a) Camelids ruminate and are therefore within the definition of susceptible animals;
(b) Although of low susceptibility, they will still be slaughtered if they are on infected premises or deemed to be a dangerous contact;
(c) Your letter was silent about the important point of whether camelids are carriers of FMDV and the risks of them transmitting disease to other susceptible species.
In dealing with the issues outlined at the start of this letter, we shall in effect be replying to the points raised in your letter of 18th April. We shall also refer to the considerable body of scientific evidence on these issues, some specific points arising from the treatment of camelids during the current epidemic and then review this in the light of your current policy for dealing with the epidemic, particularly on contiguous premises. For ease of reference we shall use numbered paragraphs:
We have considered a number of the articles/studies on the susceptibility of camelids to FMD. The evidence from those articles/studies can, in our view, be fairly summarised as follows:
(a) Although exceptionally, it appears possible that camelids can be infected with FMDV by direct contact, they have low susceptibility to FMDV;
(b) Where camelids are infected with FMDV, symptoms are relatively mild compared to other susceptible animals, e.g. they may develop minor lesions, fever and some lameness. This has led experts to believe that camelids are therefore much more resistant to FMDV than most other susceptible species;
(c) Even where camelids have been infected with FMDV, the virus has not been detectable 14 days post exposure;
(d) The available evidence (see below) also supports the conclusion that there is a very low risk, if any, of camelids transmitting the disease to other susceptible species. This conclusion is based on studies where susceptible animals, typically cattle, sheep, goats and pigs have been placed in direct contact with experimentally infected llamas and alpacas;
(e) Camelids do not therefore present a serious epidemiological risk.
Below, we have developed this argument further by specific reference to some of the articles/studies, not least because they look at bovines and ovines as well as camelids.
In "Susceptibility of Llamas to Infection with Foot and Mouth Disease Virus" (J. Vet Med B. 42,595-599), Fondevila et al reported on an experimental trial of the susceptibility of llamas to FMD natural exposure in a biocontainment facility in Argentina. The study considered the ability of FMDV to infect susceptible llamas exposed either directly to affected livestock or indirectly to llamas that had been directly exposed to affected livestock. The llamas were exposed by cohabitation to FMD strains A-79, C-3 and O-1. 30 llamas were exposed to FMDV infected pigs. Only 3 showed any evidence of infection and only 2 (exposed to the O-1 strain) showed any clinical signs of infection. Those clinical signs were extremely mild.
More importantly, FMDV could not be recovered from any specimens obtained from the infected llamas beyond 14 days post exposure to FMDV.
Further, 10 cattle, 10 sheep, 10 goats, 10 pigs and 30 other llamas were exposed to the 30 llamas that had been exposed to the FMDV infected pigs. None of these animals showed any clinical signs of disease (our emphasis). The study concluded that there was no evidence of virus transmission between the directly exposed llamas and the indirectly exposed llamas or between both groups of llamas and susceptible domestic livestock because of:
(a) the lack of clinical signs;
(b) by virus isolation;
(c) by serology results.
The authors concluded that this was further evidence of the resistance of llamas to FMD infection and that they play a minor role, if any, in transmitting the virus to domestic livestock (our emphasis).
The Fondevila study confirms the results of an early study by Lubroth et al "Foot and mouth disease virus in the llama (Lama glama): diagnosis, transmission and susceptibility." Vet. Diagn. Invest. 2: 197-203 (1990), where FMDV was not isolated in llamas beyond the first week post infection, a point described by the authors as "of paramount importance".
Research was also undertaken as to the number FMD of cases reported in published world literature by Dr Murray Fowler, (Professor Emeritus of Zoological Medicine at the Department of Epidemiology at the Veterinary College at the University of California, Davis). The research is published as "Prevalence of Selected Diseases of Llamas and Alpacas", Proceedings 103 Annual Meeting of the United States Animal Health Association, San Diego, California, October 7-14, 1999.
From the research into published world literature, in the section on FMD, the authors make the following comment:
"Studies conducted at Plum Island and in Argentina show that camelids may be infected with a virus experimentally by scarification of the tongue, intradermal inoculation of the tongue, IM and IV, but not by cohabitation with FMD infected animals. Llamas were quite resistant to infection and do not retain the virus for more than 14 days. Clinical signs were mild. Natural disease has been described in alpacas following a disease epizootic in cattle in Peru."
They conclude as follows:
"Camelids are not a reservoir or carriers of any of the diseases listed above. When exposed to some of the above listed diseases, camelids may mount an immune response without developing clinical disease (FMD, VS, BVD and bluetongue). Camelids are not of zoonotic concern for any of the foregoing diseases."
In a short article in March 2001 "Foot and Mouth Disease: Are Llamas and Alpacas at Risk? (available by e-mail), Professor David Anderson (Department of Veterinary Clinical Sciences of the College of Veterinary Medicine at Ohio State University) commented on the studies by Fondevila and Lubroth (referred to above) as follows:
"Based on these studies, a policy of livestock separation (to diminish high concentration, cohabitation exposure risk) and quarantine of all camelids with no movement or visitation would seem reasonable and prudent."
The existing body of scientific evidence therefore demonstrates that camelids:
(a) have much greater resistance to infection of FMDV than cattle, sheep, goats and pigs;
(b) do not carry FMDV after 14 days post exposure.
During the existing epidemic, our clients have become aware of the small number of cases (thought to be 12) where llamas and alpacas have been slaughtered along with other susceptible livestock. From the inquiries that they have made, our clients believe that where samples have been taken from the slaughtered camelids (whether blood samples or tissue samples), they have not tested positive for FMDV. If that is the case, it is entirely consistent with the body of scientific evidence to which we have referred above. If our clients' understanding of the position is wrong, and there have been any positive tests on the camelids slaughtered, then we should be grateful if you could let us have details of the owner and premises affected, whether it was a confirmed case or contiguous premises or dangerous contact, the number of samples taken and whether it was the blood or tissue samples that tested positive. Our clients should at least be given the opportunity of considering that information and responding to it but as we say, our clients believe that, to date, the tests on camelids have been negative.
Our clients have also instructed us that they are aware of cases in different regions of the country where exceptions have been made for camelids and they have been quarantined. In one case, we understand that the camelids have been quarantined for some weeks and our clients believe there is no evidence to show that they have become infected. Again, not only would that be consistent with the scientific evidence referred to above but would demonstrate a recognition on your part that in principle, camelids can be exempted from slaughter. It is in this overall context that we now turn to consider your stated policy on FMD.
We do not propose to set out all of the policy in detail, not least because it is your policy and it should be unnecessary for us to set out all of the detail. It can be conveniently summarised as follows:
(a) on infected premises to slaughter all susceptible animals within 24 hours;
(b) on contiguous premises, to slaughter susceptible animals within 48 hours subject to limited exceptions;
(c) in Cumbria and Dumfries and Galloway, to slaughter sheep and goats within 3 kilometres of infected premises again, subject to limited exceptions.
We should make it clear on behalf of our clients that they reserve their position entirely as to whether or not such a policy is legal and the proposals in this letter are without prejudice to their arguments as to legality of the policy.
The revised slaughter policy on contiguous premises, as set out in the Joint Instructions to Regional Operations Directors and Divisional Veterinary Managers dated 27 April broadens existing areas of discretion for local veterinary judgement in the light of the developing FMD situation. The policy sets out some of the factors a vet should take into account in carrying out a risk assessment.
Paragraph 8 of the instructions dated 27 April outlines the advice given by the Chief Veterinary Officer on distinguishing between species and the differential risk of disease transmission posed by the different susceptible species. There is no specific reference to camelids in this paragraph. Given its importance, paragraph 8 is worth setting out in full:
"The Chief Veterinary Officer has provided advice to Ministers on the differential risk of disease transmission posed by the different susceptible species. In summary, pre-emptive culling of sheep (as "silent shedders" of virus which cannot reliably be detected, especially early in the disease) and pigs (as major shedders of virus) which are judged to have been exposed to infection remains essential. A somewhat greater risk of infection can be accepted in cattle (clear and relatively early indicators of disease, with lower onward transmission risks than pigs), provided they are kept under adequate biosecurity, and monitored for signs of disease."
Therefore, cattle are distinguished from the other susceptible species because they are considered to be at a lower risk of onward transmission of FMDV and that, in conjunction with consideration of the biosecurity measures, and monitoring can justify an exemption from the decision to slaughter.
The scientific evidence that we have referred to above demonstrates that camelids have what might be described as their own in-built biosecurity. They are much less susceptible to FMD than cattle, sheep, pigs etc and importantly, present a much lower risk of onward transmission than other susceptible species (assuming that they present any such risk).
Therefore, if one considers your policy in the light of the scientific evidence on camelids, then if there is to be consistency of approach, camelids should also be considered to be exceptions from slaughter. We are sure that you will agree the importance of showing consistency in approach.
Having regard to the legislative framework and your powers under the Animal Health Act 1981, a reasoned and proportionate approach is required. In that context, our clients invite you to adopt the following approach on camelids:
(a) camelids on an infected premises or contiguous premises or treated as dangerous contacts or, if in Cumbria, within 3 kilometres of an infected premises should be quarantined for a minimum period of 14 days;
(b) quarantine could involve housing the camelids in a separate building (if a suitable building is available to the owner) or by fencing off part of a field and, for example, keeping them at least 50 metres from any other susceptible species. (This would be consistent with the guidance you have issued on the policy of exempting rare breeds of sheep/goats from slaughter);
(c) blood samples should be taken from the camelids;
(d) if those samples test positive for FMDV, the appropriate course is to wait until 14 days has expired and then re-test. Only if the re-test for antigens is positive should slaughter of the camelid(s) be considered. This would be consistent with the existing scientific evidence on the risks of onward transmission to other susceptible species;
(e) that all appropriate biosecurity measures will be taken. Again, the details of this could be based on the guidance that you have already issued both generally and specifically in connection with rare breeds of sheep/goats.
Our clients' suggested approach should be considered further in the light of the scientific evidence now available which deals specifically with the current epidemic of FMD. In this context, we refer you to an article by Donaldson et al "Relative risks of the uncontrollable (airborne) spread of FMD by different species" The Veterinary Record May 12th 2001 and the conclusions that are reached especially on contiguous premises are pages 603 604, part of which is set out below:
"when disease is diagnosed and movement control is fully implemented around an infected premises, the animals on contiguous premises should not be at risk from uncontrollable spread, that is from airborne spread, unless (a) there are pigs or very large numbers of cattle or sheep on the affected premises with early clinical signs, and (b) the concentration of virus and plume was at the same or higher concentration from the threshold concentration required to infect them. Under those "ideal" circumstances for airborne spread, the species at risk downwind would be sheep and cattle. The action taken on contiguous premises should, therefore, be determined by the species at risk on those premises (our emphasis). For cattle, intensified clinical surveillance should be an appropriate alternative to immediate culling, since FMD in that species is easily recognised and any cases should be quickly identified and eliminated before there was a risk of infectious plumes of virus being generated. These recommendations for contiguous premises should not override the requirement for clinical surveillance, possibly supplemented by serological investigations in other holdings within a 3 kilometre protection and 10 kilometre surveillance areas and the controlled area, if declared."
Within the last month, not only have you revised your slaughter policy on contiguous premises but you have also recognised the principle of exemptions for rare breeds. Given that the decision on whether or not to slaughter is a discretionary one, it is not surprising to find that there is a principle of exemptions from slaughter, albeit in limited circumstances. That is now well established.
In our clients' view, the argument for the exemption of camelids is not only supported by the scientific evidence but is inherent in your own policy. Of course, the matter would still be based on local veterinary judgement and that would include consideration of the species at risk, the local circumstances and whether clinical and/or serological surveillance is appropriate. Put another way, if you are prepared to exempt cattle, what good reason do you have for not exempting camelids?
Should you take a contrary view to this argument, then please specify your reasons so that our clients will be given the opportunity of considering them and responding as appropriate.
We have sent a copy of this letter to Mr Mayur Patel, your Head of Civil Litigation, for information.
In our view, it will be in the interests of all parties for there to be an early reply to this letter. Although we anticipate that you will have access to the various articles/studies referred to both in this letter and in the earlier letter of 13 March, should you like to see copies of any of the articles referred to, then we are more than happy to provide them. Equally, if it would assist you to discuss these matters with us, either over the telephone or in a meeting then we are more than willing to do so. We know that our clients would also be more than willing to attend a meeting if that is going to assist. The Secretary of the British Veterinary Camelid Society has indicated that he, and the President of the Society would be willing to join any meeting. We think that illustrates that our clients are prepared to take a constructive approach on this issue and we look forward to receiving a reasoned reply.
c.c. Ministry of Agriculture Fisheries & Food, Legal Department, 55 Whitehall, London SW1A 2EY