AVIS - Foot and Mouth Disease

Collection of samples

Blood

Serum

For antibody detection, blood should be collected into plain tubes without anticoagulant and allowed to clot. The sample should be centrifuged and the serum decanted into sterile tubes. Whole, clotted blood should not be sent unseparated and should certainly not be frozen as both procedures result in haemolysis which reduces the reliability of diagnostic tests.

A minimum of 4 ml is essential. Should lesser amounts be submitted there is a risk that re-sampling may be required with subsequent delay. It is essential that sterile containers be used. If sera have been collected under sterile conditions they can normally travel satisfactorily without refrigeration.

Detection of antibody to FMDV is useful:

• to certify freedom from previous exposure to FMD virus or antigen for the purpose of international trade.

• to detect previous, undetected infection with FMD virus as part of serological surveillance during control and eradication programmes.

• during national or regional surveillance programmes.

• to detect evidence of seroconversion or change in titre when the first sample from an animal(s) gives an inconclusive result.

• to assess the effectiveness of a vaccine or vaccination campaign.

A detailed consideration of the structure of serological surveillance programmes is beyond the scope of this module, but the FAO/EC European Commission for the Control of FMD has issued guidelines for the design and implementation of serological surveillance.