Date of Award

January 2016

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Marietta Vazquez

Abstract

Background: It is unknown if widespread use of Rotavirus (RV) vaccine will impact the primary causative agent of viral gastroenteritis (VGE).

Objective: To identify changes in epidemiology of VGE affected by vaccination, determine factors associated with higher severity of illness, and assess agreeability between two clinical severity-grading scales; Clark and Vesikari.

Methods: We analyzed fecal samples of children, 6 months-5 years of age, evaluated at YNHH for VGE. Fecal samples were tested using a real-time PCR assay. Primer and probe sequences targeted conserved regions of the genome for RV, Norovirus GI/GII, Adenovirus, Astrovirus, and Sapovirus. Data were analyzed using SPSS.

Results: Of the 268 fecal samples analyzed, 215 (80%) were positive for at least one viral pathogen. Of those, 133 (62%) had a single viral pathogen identified and 82 (38%) had multiple pathogens. The frequencies of pathogens were: RV in 132 (61%), Norovirus GI/GII in 93 (43%), Astrovirus in 32 (15%), Adenovirus in 24 (11%), and Sapovirus in 21 (10%). For subjects <12 months of age the frequency of viral pathogens were: RV 48 (41%), Norovirus GI/GII 41(35%), Astrovirus 12 (10%), Adenovirus 10 (9%), and Sapovirus 7 (6%). State of being infected by any pathogen, having educated caretakers, infection with RV, and not being vaccinated for RV were associated with greater severity of diarrheal illness. In contrast, difference in severity of illness seen with Hispanic ethnicity, Black race, and coinfection with multiple pathogens was not statistically significant. Lastly, Clark and Vesikari clinical severity grading scales were shown to have poor agreeability (k=0.309), which was not improved by modification.

Conclusions: We conclude that in the era of widespread use of RV vaccine, the epidemiology of VGE may be changing. We’ve identified several factors that may be associated with higher severity of illness, which may help guide clinicians in improving care and directing resources. Lastly, we confirm the poor agreeability between the Clark and Vesikari scales, which may guide future researchers to standardize use of clinical severity scales.

Comments

This is an Open Access Thesis.

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