Review/Oorsig Volume 22, Issue 01 - Page 18

Oorsig/Review Clostridium Diseases Sample Collection for Effective Disease Diagnostics Dr Rick Last – BVSc, M.Med.Vet (Pathology) Specialist Veterinary Pathologist Clostridial Myositis Gross Examination “Uncut version” (prior to skinning) • • • • • • Assessment of the degree of autolysis Subcutaneous crepitation – present / absent Visible swelling of musculature – present / absent Describe distribution of lesions (schematic representation) Haemorrhagic exudates from body cavities Blood smear to exclude anthrax • Clostridial Fluorescent Antibody Test (FAT) Smear preparation Fully cut version (after skinning) • • • • • • • • • • Skin carcass evaluate subcutaneous tissues – oedema / emphysema / haemorrhage Odour Cut into affected site – emphysema vs oedema syndrome Evidence of myositis / necrosis Select site for smears / fluid / tissue collection Collect batches of samples from the same site. NB enables more critical comparison of gross pathology vs cytology vs FAT vs culture vs histopathology Role of Clostridium perfringens in 18 clostridial myositis syndromes are not to be ignored. Consider differentials (anthrax, necrotizing fasciitis) • • • Minimum of 6 smears allows for individual smear FAT (preferred), Diff-Quick® another special stain (Giemsa, Gram etc) All smears collected from same site Following glass slide impression from muscle, smear onto a second slide to avoid thick smears (most important for the 2 non- FAT smears) Allow adequate time for smears to dry prior to packing for the laboratory. Smears packed before they are adequately dry, have artefactual changes which can interfere with interpretation of the cytology and FAT. After drying wrap each smear in paper- towel using a continuous wrap, then fold over ends and strap with tape.