Three-Level Mixed-Effects Logistic Regression Analysis Reveals Complex Epidemiology of Swine Rotaviruses in Diagnostic Samples from North America

PLoS One. 2016 May 4;11(5):e0154734. doi: 10.1371/journal.pone.0154734. eCollection 2016.

Abstract

Rotaviruses (RV) are important causes of diarrhea in animals, especially in domestic animals. Of the 9 RV species, rotavirus A, B, and C (RVA, RVB, and RVC, respectively) had been established as important causes of diarrhea in pigs. The Minnesota Veterinary Diagnostic Laboratory receives swine stool samples from North America to determine the etiologic agents of disease. Between November 2009 and October 2011, 7,508 samples from pigs with diarrhea were submitted to determine if enteric pathogens, including RV, were present in the samples. All samples were tested for RVA, RVB, and RVC by real time RT-PCR. The majority of the samples (82%) were positive for RVA, RVB, and/or RVC. To better understand the risk factors associated with RV infections in swine diagnostic samples, three-level mixed-effects logistic regression models (3L-MLMs) were used to estimate associations among RV species, age, and geographical variability within the major swine production regions in North America. The conditional odds ratios (cORs) for RVA and RVB detection were lower for 1-3 day old pigs when compared to any other age group. However, the cOR of RVC detection in 1-3 day old pigs was significantly higher (p < 0.001) than pigs in the 4-20 days old and >55 day old age groups. Furthermore, pigs in the 21-55 day old age group had statistically higher cORs of RV co-detection compared to 1-3 day old pigs (p < 0.001). The 3L-MLMs indicated that RV status was more similar within states than among states or within each region. Our results indicated that 3L-MLMs are a powerful and adaptable tool to handle and analyze large-hierarchical datasets. In addition, our results indicated that, overall, swine RV epidemiology is complex, and RV species are associated with different age groups and vary by regions in North America.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diarrhea / virology
  • Logistic Models
  • North America / epidemiology
  • Rotavirus / pathogenicity*
  • Rotavirus Infections / epidemiology*
  • Swine / virology*
  • Swine Diseases / epidemiology*
  • Swine Diseases / virology*

Associated data

  • Dryad/10.5061/dryad.cg17c

Grants and funding

The authors thank the Ministry of Science and Technology of the Royal Thai Government and in part by Skoll Global Threats Fund for funding PhD training of NH. The study was funded by the MNVLD. The funder provided support in the form of salaries for authors (NH, AD, SR, MC, and DM), but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the author contributions section.