Collection and Submission of Specimens

 

Specimens

An accurate diagnosis depends on the availability of proper specimens. It is therefore essential that the specimens should be collected and submitted as outlined in this manual. They should be sent to the ARC-OVR as quickly as possible and, when necessary, a courier service must be used. Specimens can be submitted after hours, preferably with prior notification of the section involved, and in such cases they should be delivered at the security office.

Specimens for the diagnosis of Foot-and-mouth disease and African swine fever must always be delivered or sent directly to the Transboundary Animal Diseases (TAD).

Address to deliver specimens:

Specimens must be kept cool during transport and should be refrigerated first at 4°C and then sent packed on frozen cool packs. 

Fish should be sent alive where possible.

Suitable containers for the submission of specimens as well as swabs for bacteriological cultures and virological isolations are available from the OVR. For further information please contact the Registration Office + 27 (0) 12 529 9274/3/2.

General Information on Sample Submission

It may be necessary, to provide additional cooling in the remote and hotter areas of the country, to ensure that, samples reach the laboratory in good condition. Samples need to reach the laboratory within 2 days of collection and no later than 12:00 on Fridays. Laboratory closed: Weekends and Public holidays.

Virology: General Requirements

Specimen for virus isolation:
Specimens should be collected early in the acute phase of the illness. They should be fresh, and if possible collected aseptically with no preservative or fixative added. Swabs taken from clinically ill animals should be placed directly into a viral transport medium. These specimens should be refrigerated, not frozen, as soon as collected. Note that swabs for Chlamydia isolation must be placed in a chlamydia transport medium.

Serological diagnosis:
For many diseases it is imperative that paired serum samples be submitted for detecting viral infections since only the demonstration of a significant increase in antibody level (generally a four-old rise in titre) is meaningful. The first sample should be collected early in the acute phase and the second taken during convalescence three weeks later. The first sample can be retained frozen until the follow-up sample has been taken and they can then be submitted, clearly marked, at the same time. In the case of congenital deformities in neonatal calves and lambs as well as the weak-calf syndrome pre-colostral serum is essential. Paired serum samples have only limited value in the case of abortions unless an abortion storm is involved.

Blood:
Commercially available vacuum tubes should be used, and heparin rather than EDTA is preferred as anticoagulant. Blood should be kept at 4°C (not frozen), should be taken during the febrile stage of the illness and should be submitted on frozen cool packs as soon as possible.

Blood for serological testing should be collected in red top vacuum tubes and allowed to clot at room temperature (between 18-24°C). If there is an unavoidable delay (more than 5 days) before dispatch or a long transit time, the clot should be removed as aseptically as possible. It is preferable to decant the serum into a new tube. Serum should be stored at 4°C and sent to the laboratory, packed on frozen cool packs.

Faecal specimens for electron microscopy:
Either faeces or colonic contents may be submitted; rectal swabs are not suitable. Specimens must be collected within hours of the onset of diarrhoea and, where possible, directly from the animal. The specimens should be kept at 4°C and sent on frozen cool packs.