Date of Graduation

5-2015

Document Type

Thesis

Degree Name

Master of Science in Cell & Molecular Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

Kristen E. Gibson

Committee Member

Burton H. Bluhm

Second Committee Member

Byung-Whi Kong

Third Committee Member

Mary C. Savin

Keywords

Biological sciences

Abstract

Among all known causes of acute gastroenteritis, human noroviruses (HuNoV) are the primary cause (68%) of outbreaks and are associated with 78% of illnesses, 46% of hospitalizations, and 86% of deaths. The main obstacle to studying the pathogenesis of HuNoV is the lack of cell culture system and small animal model. Murine norovirus (MNV) and feline calicivirus (FCV) have been utilized as model surrogate viruses to study HuNoV. In this research, a more recent surrogate virus, Tulane virus (TV), was evaluated for physicochemical stability and environmental persistence. The primary goal was to determine the suitability of TV as a surrogate for HuNoV by comparing its environmental persistence and physicochemical stability to previously published results for MNV and FCV. Physicochemical profiles suggest that TV is more stable at 56, 63 and 72°C. When exposed to 60 and 70% ethanol concentrations at room temperature (RT), TV is more tolerant, but at 90% ethanol, TV is less tolerant. Tulane virus is also stable at acidic (2 and 3), neutral (7) and basic (9 and 10) pH levels though after 90 min there was a 2.25-log reduction in TV at pH 10. Last, TV is stable on a solid surface when exposed to 200 and 1000ppm chlorine for 10 min resulting in 0.63- and 2.22-log10 reduction, respectively. For environmental persistence, TV can survive in surface water for 28 d with less than 0.3-log10 reduction at RT under diurnal variations. Conversely, TV is not persistence in groundwater in the dark at 4°C with a complete loss of infectivity after day 14. Tulane virus is also stable at RT on non-porous fomite surfaces (acrylic based solid surface and stainless steel surface) with only a 1-log10 reduction at day 14. Comparing these observations and data published on TV elsewhere to previously published studies on MNV and FCV, it can be concluded that TV is likely a more conservative surrogate to study HuNoV though experimental differences make direct comparisons difficult.

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