Page 356 - The Veterinary Laboratory and Field Manual 3rd Edition

Serology and immunology 325

positive sera from vaccinated animals or from Endnotes
animals that tested positive in gold standard
tests can also be used. 1 See also the OIE Standards for diagnosing NCD
The results for serological tests are usually available on line, http://www.oie.int/fileadmin/
expected to fall within a set range but occasion- Home/eng/Health_standards/tahm/2.03.14_
ally there may be an unexpected result (very NEWCASTLE_DIS.pdf.
high or very low), in these cases it is necessary
to re-test the sample. For the diagnosis of infec- Bibliography
tious diseases most laboratories will request two
samples collected over a 10–14 day period. This Hendrix, C.M., Sirois, M. (2002) Laboratory
is to check for a rising antibody titre suggestive Procedures for Veterinary Technicians, 5th edn.
of active infection vs. previous exposure or vac- Mosby, Maryland Heights, MO.
cination. Interpretation of diagnostic and survey Kememy, D.M. (1991) A Practical Guide to ELISA.
results often requires a lot of experience so it is Pergammon Press, Oxford.
necessary to discuss the results with the senior OIE (2008) Quality Standard and Guidelines for
Veterinary Laboratories: Infectious Diseases.
laboratory technician or veterinary officer in Various Authors. World Organisation for Animal
charge before they are passed to the submitting Health (OIE), Paris, France.
officer and/or owner of the animal. OIE Manual of Diagnostic Tests and Vaccines for
Terrestrial Animals. http://www.oie.int/standard-
setting/terrestrial-manual/access-online/.
OIE Manual of Diagnostic Tests and Vaccines for
6.5 Epidemiology and sampling Terrestrial Animals. Chapter 1.1.2 Collection,
plans submission and storage of diagnostic speci-
mens. http://www.oie.int/fileadmin/Home/eng/
Serology is a valuable tool for diagnostic work Health_standards/tahm/1.01.02_COLLECTION_
and for general disease surveillance and screen- DIAG_SPECIMENS.pdf.
ing programmes. Serological surveys require OIE Manual of Diagnostic Tests and Vaccines for
Terrestrial Animals. Chapter 1.1.3 Transport of
careful planning with a sampling plan based on biological materials. http://www.oie.int/filead-
a good understanding of the pathogenic agent min/Home/eng/Health_standards/tahm/1.01.03_
involved, the disease process and the epidemi- TRANSPORT.pdf.
ology of the disease(s) to be tested for. More OIE Manual of Diagnostic Tests and Vaccines for
information about the principles of epidemi- Terrestrial Animals. Chapter 1.1.6 Principles and
ology are outlined in Chapter 9 and are well methods of validation of diagnostic assays for infec-
tious diseases.
described in the reference texts given at the end OIE Manual of Diagnostic Tests and Vaccines for
of this section. In most cases the design of a sero- Terrestrial Animals. Chapter 1.1.7 Standards for
logical survey will involve input from a range of high throughput sequencing, bioinformatics and
staff with complementary expertise. The degree computational genomics. http://www.oie.int/
of test sensitivity and specificity required will fileadmin/Home/eng/Health_standards/tahm/
1.01.07_HTS_BGC.pdf.
depend on the nature of the disease and the Quinn, P.J., Carter, M.E., Markey, B.K. and Carter, G.R.
purpose of the screening. It is important that all (1993) Clinical Veterinary Microbiology. Mosby,
associated staff understand how serological tests Maryland Heights, MO.
are chosen and that they are able to understand Tizard, I. (2008) Veterinary Immunology, 7th edn.
the procedures involved in assessing the reliabil- W.B. Saunders Co., Philadelphia, PA.
ity of the results.

Vet Lab.indb 325 26/03/2019 10:26