Molecular diagnostic assays detect nucleic acid (DNA or RNA) of infectious
disease agents within test specimens. Test specimens may be swabs, fluids,
blood, or tissues. A test simply designated as “PCR” is a
polymerase-chain-reaction test to detect DNA and is composed of 3 basic
parts:
RT-PCR is a reverse-transcriptase PCR test to detect RNA and is
composed of the same 3 basic parts as PCR and an additional step using
reverse-transcriptase enzyme to synthesize complementary DNA from the target
RNA. The complementary DNA is then run in the PCR test.
Nested PCR is a modification that uses 2 sets of nucleotide primers
and 2 complete cycles of amplification; the second cycle of amplification
further amplifies a target fragment of DNA originating within an already
amplified larger target fragment of DNA. Nested PCR results in higher
sensitivity than simple PCR or RT-PCR and is used for diseases that have
very little target nucleic acid in tissue samples.
Real Time PCR (also called quantitative PCR) is the same as PCR
except that it simultaneously amplifies and quantitates the amount of DNA
after each PCR cycle. It is based on the detection and quantitation of
fluorescence of a reporter dye attached to DNA probe which is specific for
the amplified DNA of interest (target) The test is very specific and about
10,000 more sensitive than conventional PCR in detecting DNA.
Preferred specimens for each test are listed in the table below.
Under special circumstances, we may test other specimens; however,
please contact the lab before submitting these. Submit all samples
as quickly as possible and keep them chilled during transport to the
lab for best results (refer to “WADDL Sample
Submission”). Formalin can degrade DNA or RNA over time, so
paraffin-embedding should be done as quickly as possible for best
results from fixed tissues.
|
Test |
Fees |
Specimen |
Turnaround
(days) |
Comments |
|
Ave. |
Max. |
| Anaplasma marginale |
fee schedule |
|
3 |
8 |
|
| Avian influenza |
fee schedule |
Tracheal or cloacal swabs (up to 5 pooled samples) in 2
ml BHI. Fresh lung, spleen, or intestine (no pooling for
fresh tissue). Whole bird. |
2 |
7 |
NAHLN Assay
Contact Lab |
| Avian paramyxovirus (Newcastle's Disease) |
fee schedule |
Tracheal or cloacal swabs (up to 5 pooled samples) in 2
ml BHI. Fresh lung, spleen, brain, or intestine (no pooling
for fresh tissue). Whole bird. |
2 |
7 |
NAHLN Assay
Contact Lab |
| Bluetongue virus |
fee schedule |
EDTA blood, fresh tissue (lung, spleen) fixed tissue
block |
3 |
7 |
|
| BVD (blood) |
fee schedule |
EDTA blood |
3 |
6 |
Pooled testing of EDTA samples
available; contact lab |
| BVD (ear notch) |
|
Ear notch skin |
3 |
6 |
See BVD-PI (Persistent Infection)
Ear Notch Testing Program |
| BVD (milk or tissue) |
fee schedule |
milk, fresh tissue (lung, spleen) fixed tissue block |
3 |
7 |
|
| Classical swine fever (CSF, Hog Cholera) |
fee schedule |
|
2 |
7 |
NAHLN Assay
Contact Lab |
| Enzootic hemorrhagic disease virus (EHD)
|
fee schedule |
EDTA blood, fresh tissue (lung, spleen) fixed tissue
block |
3 |
7 |
|
| Canine influenza virus |
fee schedule |
Tracheal wash, BAL, fresh tissue, nasal swab,
oropharyngeal swab, fixed tissue block |
2 |
7 |
Lung or bronchial lymph nodes are best tissues |
|
Clostridium perfringens |
fee schedule |
Feces, intestinal tract tissue, isolate |
3 |
7 |
Genotyping is done from bacterial isolates. Detection of
types A, B, C, D, E, Beta 2, and enterotoxin gene |
|
E. coli virulence |
fee schedule |
Feces, intestinal tract tissue, isolate |
3 |
6 |
Assay is performed from bacterial isolates. Routine
assay detects F5(K99), F41, eaeA (intimin), stx1, and stx2
genes. |
|
Equine Herpesvirus-1 (EHV-1) neuropathogenic and wild type |
fee schedule |
EDTA blood, nasal swab, lung tissue |
1 |
7 |
Shipping: Ice pack |
| Flavobacterium psychrophilum |
fee schedule |
Tissue, isolate on slant or plate |
2 |
7 |
Assay is performed from bacterial isolates. |
| Francisella Tularensis
(Tularemia) |
fee schedule |
EDTA blood Culture isolate |
2 |
7 |
Zoonotic Disease Surveillance Program
Contact Lab |
| Fungal identification by universal primers and
sequencing |
fee schedule |
Fixed tissue block (affected organ), fresh tissue,
isolate on SAB slant |
7 |
20 |
|
|
Helicobacter spp. |
fee schedule |
|
3 |
7 |
|
| Malignant Catarrhal Fever virus (MCF) |
fee schedule |
EDTA blood, Fresh or fixed tissues. Lymphoid tissues
such as spleen, lymph nodes, lung, or kidney are best. Liver
and intestine may be tested, but sometimes contain PCR
inhibitors. Brain may be tested, but false negatives may
occur due to very low viral replication in the brain. |
2 |
7 |
Species being tested and clinical history is essential
for the lab to perform the proper assay. Real time PCR
specific for ovine herpesvirus-2 is used for clinical cases
only. Nested PCR is used for non-clinical carrier species or
for other MCF viruses. |
| Mycobacterium avium |
fee schedule |
Fresh of fixed tissues, culture |
3 |
7 |
|
|
Mycobacterium avium/ M. genavense
duplex |
fee schedule |
Fresh of fixed tissues, culture |
3 |
7 |
For birds or other species where one of these
Mycobacterium species is suspected. |
|
M. avium ssp. paratuberculosis (Johnes) |
fee schedule |
Culture slant |
3 |
7 |
Assay is performed from bacterial isolate |
|
Mycobacterium spp. identification by universal
primers and sequencing |
fee schedule |
|
7 |
20 |
|
| Mycoplasma bovis |
fee schedule |
Culture broth (preferred) or plate |
3 |
7 |
Culture may be done in WADDL Bacteriology lab.
Speciation of bacterial isolate by PCR. |
|
Myxobolus cerebralis (Whirling Disease) |
fee schedule |
|
3 |
7 |
|
| Neospora caninum |
fee schedule |
Fixed tissue block (brain or affected organ) |
4 |
7 |
|
| Renibacterium salmoninarum (BKD) |
fee schedule |
Tissue pool (processed at WADDL) |
4 |
7 |
WADDL Aquaculture Section preprocessed samples for PCR.
Samples which test negative may be further tested by nested
PCR as required by OIE or Blue Book standards for
pre-shipment, at extra charge. |
|
Rhodococcus equi |
fee schedule |
Tracheal wash |
1 |
5 |
|
| Toxoplasma gondii |
fee schedule |
Fixed tissue block (brain or affected organ) |
4 |
7 |
|
| West Nile virus |
fee schedule |
Whole bird. Brainstem from horse. Brain, tissue pool
from others. Mosquito pool (25 or less in 2.0 ml microfuge
tube) |
3 |
8 |
|
| Yersinia postis(Plague) |
fee schedule |
Culture isolate |
2 |
7 |
Zoonotic Disease Surveillance Program Contact Lab |
| Yersinia ruckeri |
fee schedule |
Slant of plate with isolate. Tissue. |
3 |
7 |
PCR done on isolated colonies. |
| Direct PCR / Sequencing |
fee schedule |
Fresh or fixed tissue. Isolate (fungi, bacteria,
mycobacteria) on slant |
7 |
20 |
|
| Cloning / Sequencing |
fee schedule |
|
15 |
40 |
|