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Archivo: 1999 Session - Appendix 9



Appendix 9 (a) - Foot and Mouth Disease serosurveillance in Morocco

E.Blanco, D.Condes, RF.Senso and JM Sanchez-Vizca‘no



Between January and March of 1999 three outbreaks of foot-and-mouth disease (FMD) were declared in Morocco. One of them was located close to the Algerian border and the other two in the center of the country. In the Middle East and North-Africa small ruminants make up the most import livestock species. Sheep can be particularly dangerous as FMD can spread unnoticed since the clinical signs can be very mild or absent.
In order to check the serology against FMD in the sheep population of Morocco 335 sheep serum recovered from the three outbreaks declared were analysed. The presence of antibodies against structural proteins were measured using an indirect ELISA developed by WRL (Pirbright). Serum corresponding to the third outbreak located in the center resulted positive, which proves that the animals had contact with FMDV antigen.
Furthermore, the detection of antibodies against the non-structural protein 3ABC gives evidence of infection.




Appendix 9 (b) -Experiences with non-structural protein ELISA's for serosurveillance

E.Blanco, D.Condes, Pedemonte.A, Sobrino.F and JM.Sanchez-Vizca‘no



Differentation between vaccinated and infected animals is important during serological surveys to detect evidence of infection, as a follow-up to ring vaccination in FMD-free countries. The recent advances in testing antibody against Non-structural proteins has allowed to differentiate these two categories.
We designed an indirect ELISA trapping directly the non-structural 3ABC polypeptide expressed in E.coli. About 30 field sera from native, vaccinated and infected cattle from Argentina were examinated using this ELISA. The sensitivity and specificity of the assay allowed to detect all the infected animals and establishing the properly threshold was possible to differentiate vaccinated (one, two or more times) from infected animals.
By this ELISA were analyzed the presence of non-structural antibodies in sheep samples from the outbreaks which had occurred in Morocco during 1999. For the first time an ELISA using non-structural proteins was used to check the presence of antibodies against these proteins in other species different from cattle or pigs.