Infectious Disease Testing


Chapter 21
Infectious Disease Testing


The best sample for infectious disease testing is usually fresh tissue, body fluids, or swabs from areas of interest. However, many tests can be done on frozen tissue, and some testing, such as immunohistochemistry and polymerase chain reaction (PCR), can be done on formalin-fixed tissue. Samples for these tests, unlike the samples for histopathology, do not need to be kept small, and often, the ideal sample is a 3–4 cm cube of tissue. For intestine, the ideal sample is a tied off loop, with contents (Figure 21.1). The Animal Health Diagnostic Center at Cornell University has published diagnostic plans for various animal conditions summarized in Tables 21.1–21.4. These plans should be modified based on the history and clinical presentation.

Intestine segments for ancillary testing sit on a gridded surface, some with ends tied off, retaining intestinal contents.

Figure 21.1 The ideal sample of intestine for ancillary testing is a segment, including intestinal contents, with the ends tied off (Gerald E. Duhamel).


Table 21.1 Infectious disease testing: Diarrhea.






























































Sample Tests

Carnivore Ox Sheep/goat Pig Equid Camelid
Tied off loop of bowel Aerobic culture + E. coli genotyping/toxin testing if indicated
Anaerobic culture + Clostridium sp. genotyping/toxin testing if indicated
Salmonella sp. culture
C. jejuni culture

Lawsonia sp. PCR
Virus isolation
Rotavirus FA (young animals)
Coronavirus FA, PCR
Parvovirus PCR, FA BVD PCR
PRRS, Circovirus FA
Feces Salmonella sp. culture

Johne’s culture or PCR Yersinia sp. culture Lawsonia sp. PCR




PHF PCR
Rotavirus (young animals)
Fecal Floatation
Giardia sp., Cryptosporidium sp. ELISA



Ear notch
BVD ELISA


Rectal swab Trichomonas fecal exam (cat)




Table 21.2 Infectious disease testing: Respiratory disease.




















































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Related posts:

  1. IV: Additional Testing
  2. V: Special Cases
  3. The Cardiovascular System
  4. Reptiles

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Feb 1, 2026 | Posted by in GENERAL | Comments Off on Infectious Disease Testing

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Tissue Tests

Carnivore Ox Sheep/Goat Pig Horse Camelid
Lung (Nasal swab is suitable for some tests) Aerobic culture (Anaerobic with pulmonary abscess)
Mycoplasma culture
Chlamydia PCR
Chlamydia PCR

Chlamydia PCR
Virus Isolation

BRSV PCR

BRSV PCR
Distemper PCR (dogs) BVDV PCR
Circovirus FA
Coronavirus PCR (dogs) Coronavirus PCR
Coronavirus PCR
Coronavirus PCR
Parainfluenza PCR (dogs) Parainfluenza PCR PRRS FA
Pneumovirus (dogs)



Adenovirus PCR (dogs)

Adenovirus PCR
Calicivirus FA (cats)