1. Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas;
2. Department of Epidemiology and Biostatistics, Texas A&M Health Science Center, College Station, Texas;
3. Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania;
4. Department of Entomology, Texas A&M University, College Station, Texas