To the Organizers of the International Conference on the Prevention and Control of Foot and Mouth Disease, 12-13 December 2001,
In the lecturer's paper to be given by Dr. Kris De Clercq during the International Conference on the Prevention and Control of Foot and Mouth Disease, 12-13 December 2001, Charlemagne Brussels, there is the paragraph:
"However, there is growing circumstantial evidence from Africa that transmission can occur from carrier cattle and buffalo to susceptible cattle with which they have close contact (Thomson, 1997)",
on which I wish to make the following comments.
1. The lecturer creates the impression that the circumstantial evidence is growing. This is not the case; it is just one more anecdote that under special unknown circumstances unvaccinated persistently FMD-infected animals "in rare instances can transmit the virus to susceptible contact animals". (Thomson, 1996, 64th General Session OIE).
2. A SAT-2 type virus caused FMD in the Zimbabwe episode. The SAT serotype viruses differ in many aspects from the classical A, O and C serotypes and have developed an intimate relationship with wildlife, in particularly with the Cape buffalo. However, it is unknown whether this relationship depends on the SAT virus, on the buffalo, or both. I believe that it is unknown whether the "classical" serotypes would also act like the SAT viruses in the buffalo or that SAT viruses possess special characteristics that make it such a good "carrier" virus in the buffalo. These are very interesting scientific issues, but should not confuse the audience by stating "that the evidence is growing ".
I am attaching to this e-mail a list of points that I developed jointly with Dr. Simon Barteling, that might be useful in considering the prevention, control and eradication of FMD. You will see from this list, which reflects a thorough study, that over the last hundred years there are only a few cases where circumstantial evidence suggests the introduction of new disease by carriers. This circumstantial evidence does not exist for vaccinated carriers.
I hope that you will make these comments known to the participants of the meeting.
Dr. Paul Sutmoller PhD, DVM December 8, 2001
Animal Health Consultant
USA: 1502 Largo Road, Richmond VA 23233
The Netherlands: Duinschooten 12, Bung. 127, 2211 ZC Noordwijkerhout