Parasitology - Diagnostic techniques

Question 1

Qualitative flotation test

Answer 1

• Performed on faeces to recover and identify parasite eggs and oocytes
• Sieve containing faeces is mixed with saturated salt solution to transfer eggs/oocytes to salt solution
• Salt solution is transferred to a centrifuge tube and more salt solution is added until a meniscus bulges on top of the tube
• Cover slip placed over meniscus and left for 5 mins then examined under microscope

Question 2

Quantitative faecal egg counts

Answer 2

• Samples collected directly from the rectum
• Samples are measured
• mixed with saturated salt solution
• sieved and transferred to counting slide
• examined under microscope to count the eggs
• Eggs per gram calculated

Question 3

Direct fluorescent antigen test

Answer 3

• Directly tests the presence of an antigen with the tagged antibody

Question 4

Tritichomonas culture

Answer 4

Sample must be inoculated into pouch within 0.5 hour of collection –> allowed to grow then examined under microscope