Objective—To evaluate a portable real-time reverse
transcriptase-polymerase chain reaction (RT-PCR)
assay designed to detect all 7 viral serotypes of footand-
mouth disease virus (FMDV).
Design—Laboratory and animal studies.
Study Population—Viruses grown in tissue culture
and animals experimentally infected with FMDV.
Procedure—1 steer, pig, and sheep were infected
with serotype O FMDV. Twenty-four hours later, animals
were placed in separate rooms that contained 4
FMDV-free, healthy animals of the same species. Oral
and nasal swab specimens, oropharyngeal specimens
obtained with a probang, and blood samples were
obtained at frequent intervals, and animals were
observed for fever and clinical signs of foot-and-mouth
disease (FMD). Samples from animals and tissue cultures
were assayed for infectious virus and viral RNA.
Results—The assay detected viral RNA representing
all 7 FMDV serotypes grown in tissue culture but did
not amplify a panel of selected viruses that included
those that cause vesicular diseases similar to FMD;
thus, the assay had a specificity of 100%, depending
on the panel selected. The assay also met or exceeded
sensitivity of viral culture on samples from experimentally
infected animals. In many instances, the
assay detected viral RNA in the mouth and nose 24 to
96 hours before the onset of clinical disease.
Conclusions and Clinical Relevance—The assay
reagents are produced in a vitrified form, which permits
storage and transportation at ambient temperatures.
The test can be performed in 2 hours or less on
a portable instrument, thus providing a rapid, portable,
sensitive, and specific method for detection of FMDV.
(J Am Vet Med Assoc 2002;220:1636–1642)
PROCEDURES Each dog underwent 3 iohexol-injection protocols (700 mg of iodine/kg administered at a constant rate over 20 seconds, 700 mg of iodine/kg administered following an exponentially decelerated injection over 20 seconds, and 350 mg of iodine/kg at a constant rate over 10 seconds) during dynamic, whole renal-volume CT in randomized order with an interval of ≥ 7 days between experiments. Values of GFR determined from Patlak plots derived by use of 4 measurement techniques (standard transverse section, optimized transverse section, dorsal reconstruction, and volume calculation techniques) were compared.
RESULTS The measurement technique influenced the mean ± SD GFR results (standard transverse section technique, 2.49 ± 0.54 mL/kg/min; optimized transverse section technique, 2.72 ± 0.52 mL/kg/min; dorsal reconstruction technique, 3.00 ± 0.60 mL/kg/min, and volume calculation technique, 2.48 ± 0.51 mL/kg/min). The lower iodine dose resulted in a significantly higher GFR value (3.00 ± 0.65 mL/kg/min), compared with that achieved with either higher dose administration (constant rate injection, 2.54 ± 0.45 mL/kg/min and exponentially decelerated injection, 2.47 ± 0.48 mL/kg/min).
CONCLUSIONS AND CLINICAL RELEVANCE In healthy Beagles, the CT-derived GFR measurements obtained after injection of a full dose of contrast medium were reduced, compared with measurements obtained after injection of a half dose. This finding is important with regard to potential nephrotoxicosis in dogs with impaired renal function and for GFR measurement with CT-contrast medium protocols.