In pets and people, the time it takes to diagnose an infection may mean life or death, and identifying ways to diagnose pet infections in approximately a third of the current diagnosis time could be used eventually for humans.

Veterinarians at the University of Missouri (Columbia, MO, USA) tested several biomarkers for infection in dogs. They found that found that measuring the amount of the blood biomarker N-terminal portion of pro C-type natriuretic peptide (NT-pCNP) is a good indication of infection, and the same could be applied in humans. In one study, the NT-pCNP assay was performed by a sandwich enzyme-linked immunoassay (ELISA), (Biomedica Medizinprodukte GmbH & Co KG, Vienna, Austria). This ELISA utilizes a highly purified polyclonal sheep antibody directed against amino acids 1-19 and 30-50 of human NT-pCNP that is 96% homologous with canine pCNP.

In a separate study plasma samples obtained from both septic and normal control groups were used for determination of the nitric oxide end products nitrate (NO3–) and nitrite (NO2–) using a commercially available kit , the Parameter Total Nitric Oxide and Nitrite/Nitrate Assay; (R&D Systems, Minneapolis, MN, USA). This two-step assay utilizes nitrate reductase to convert nitrate to nitrite and then detects total nitrite using the Greiss reaction to produce an azo dye compound. The range of detection of this assay is 3.12-200 µmol/L.

Plasma total nitrate/nitrite was significantly greater in the sepsis group compared with the control group and a systemic inflammatory response syndrome (SIRS) group. Serum NT-pCNP concentration was significantly greater in the sepsis group (median, 11 pmol/L) compared with the noninfectious forms of SIRS (5.2 pmol/L); and healthy control groups (6.4 pmol/L). Amy DeClue, DVM, assistant professor of veterinary internal medicine, said, "My group has been evaluating different blood biomarkers that could give a quick and accurate indication of infection, and we believe we've found a biomarker that will only require a simple blood test. The systems in dogs and people are very applicable to each other, so whatever biomarkers we find in dogs could also benefit people."

The scientists hope to develop a portable bedside test that veterinarians could use to quickly test patients for infection and ultimately target a better cure. The NT-pCNP biomarker study was published in the May/June 2011 issue of Journal of Veterinary Internal Medicine and the plasma nitrate/nitrite study was published online on September 9, 2011, in the journal Veterinary Record.

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University of Missouri
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