Biography

Dr. Deon van der Merwe is a veterinary toxicologist with over 25 years of experience spanning clinical practice, research, academia, and consultancy. He holds a PhD in Comparative Biomedical Sciences from North Carolina State University and has served in academic roles at Kansas State University and Oklahoma State University, where he currently teaches toxicology. Since 2019, he has been a toxicologist at Royal GD, where his work supports animal health and food safety through research, diagnostics, and risk assessment. Dr. van der Merwe is a European Registered Toxicologist, a Fellow of the American Academy of Veterinary and Comparative Toxicology, and a member of the Royal College of Veterinary Surgeons. He has authored numerous peer-reviewed publications and book chapters on toxicology, environmental health, and veterinary medicine. His expertise includes toxic plants, trace elements, harmful algal blooms, and remote sensing applications in environmental and agricultural contexts.

Publications

Peer reviewed articles

• Van der Merwe D, Jacobs Y, Van der Drift S, Koopmans A 2023. Reference intervals for trace minerals and heavy metals in livers of cattle in wilderness areas in the Netherlands. Journal of Veterinary Diagnostic Investigation, https://doi.org/10.1177/10406387251325864
• Furr M, Van der Merwe D, Raczkoski B 2023. The influence of mode of instruction (recorded versus in-person lecture) on student achievement on written examinations in a veterinary clinical toxicology course. Journal of Veterinary Medical Education, https://doi.org/10.3138/jvme-2023-0056.
• Van der Merwe D, Van den Wollenberg L, Van Hees-Valkenberg J, Van der Drift S 2023. Reference intervals for trace mineral and heavy metal concentrations in horse livers in the Netherlands. Journal of Veterinary Diagnostic Investigation, 34(6), https://doi.org/10.1177/10406387231193328. 
• Gadhwal, Manoj and Sangha, Harman Singh and Sharda, Ajay and Merwe, Deon van der, 2023. Spatial Corn Canopy Temperature Extraction: How Focal Length and sUAS Flying Altitude Influence Thermal Infrared Sensing Accuracy. Computers and Electronics in Agriculture, 209:1-11, https://doi.org/10.1016/j.compag.2023.107812 (previously published online under SSRN).
• Daniel J, Brugger D, van der Drift S, van der Merwe D, Kendall N, Windisch W, Doelman J, Martin-Tereso J 2023. Zinc, copper, and manganese homeostasis and potential trace metal accumulation in dairy cows: longitudinal study from late lactation to subsequent mid-lactation. The Journal of Nutrition, 153(4):1008-1018, https://doi.org/10.1016/j.tjnut.2023.02.022.
• Van der Merwe D, Van den Wollenberg L, Van Hees-Valkenberg J, Van der Drift S, Vandendriessche V 2022. Evaluation of hair analysis for determination of trace mineral status and exposure to heavy metals in horses in the Netherlands. Journal of Veterinary Diagnostic Investigation, 34(6), https://doi.org/10.1177/10406387221116069.
• Hatton N, Schapaugh W, Sharda A, van der Merwe D 2020. Remote thermal infrared imaging for rapid screening of sudden death syndrome in soybean. Computers and Electronics in Agriculture, 178:105738, https://doi.org/10.1016/j.compag.2020.105738.
• Van der Merwe D, Baldwin CE, Boyer W 2020. An efficient method for estimating dormant season grass biomass in tallgrass prairie from ultra-high spatial resolution aerial imaging produced with small unmanned aircraft systems. International Journal of Wildland Fire, 29(8):696-701.
• Hatton N, Menke E, Sharda A, van der Merwe D, Schapaugh W 2019. Assessment of sudden death syndrome in soybean through multispectral broadband remote sensing aboard small unmanned aerial systems. Computers and Electronics in Agriculture, 167:105094.
• Counotte GH, Holzhauer H, Carp-van Dijken S, Muskens J, van der Merwe D 2019. Levels of trace elements and potential toxic elements in bovine livers: a trend analysis from 2007 to 2018. PLoS ONE, 14(4):1-11.
• Hong M, Bremer D, van der Merwe D 2019. Early Drought Stress Detection in Turfgrass Utilizing Thermal Imaging and Small Unmanned Aircraft Systems. Agrosystems, Geosciences & Environment, 2(1):1-9.
• Hong M, Bremer D, van der Merwe D 2019. Utilizing small unmanned aircraft systems for early detection of drought stress in turfgrass. Crop Science, 59:1-16. doi:10.2135/cropsci2019.04.0212.
• Bartle SJ, van der Merwe D, Reinhardt CD, Schwandt EF, Thomson DU 2018. Case study: Mitigation of heat stress in feedlot cattle by applying reflective pigments to the dorsal surface. The Professional Animal Scientist, 34(3)299-305.
• Bartle SJ, Thomson DU, Gehring R, van der Merwe D 2017. The effects of titanium dioxide coatings on light-derived heating and transdermal heat transfer in bovine skin. International Journal of Biometeorology, 61(11)1913-1917.
• Hijaz F, Manthey J, van der Merwe D, Killiny N 2016. Nucleotides, micro- and macro-nutrients, limonoids, flavonoids, and hydroxycinnamates composition in the phloem sap of sweet orange. Plant Signaling & Behavior, 11(6).
• Van der Merwe D, Price KP 2015. Harmful algal bloom characterization at ultra-high spatial and temporal resolution using small unmanned aircraft systems. Toxins, 7(4):1065-1078.
• Trevino-Garrison I, DeMent J, Ahmed F, Haines-Lieber P, Langer T, Menager H Neff J, van der Merwe D, Carney E 2015. Human illness and animal deaths associated with freshwater harmful algal blooms – Kansas. Toxins. 7(2).
• Wang C, Price KP, van der Merwe D, An N, Burchfield D, Bryant J. 2014. Modelling tallgrass prairie above-ground biomass in the central Great Plains using ultra-high spatial resolution multispectral imagery. Photogrammetric Engineering & Remote Sensing. 80(12):1151-1159.
• Wang H, Rush B, Wilkerson MJ, van der Merwe D 2014. Exploring the Use of Tablet PC in Veterinary Medical Education: Opportunities or Obstacles. Journal of Veterinary Medical Education, 41(2):122-131.
• Kenne G, van der Merwe D 2013. Classification of toxic cyanobacterial blooms by Faurier-Transform infrared technology (FTIR). Advances in Microbiology, 3(6)1-8.
• Mahdi AJ, van der Merwe D 2013 Dog and Cat Exposures to Hazardous Substances Reported to the Kansas State Veterinary Diagnostic Laboratory: 2009–2012. Journal of Medical Toxicology, 9(2):207-211.
• Botha CJ, Coetser H,Schultz A, Labuschagne L, van der Merwe D 2013 Spatial variation of epoxyscillirosidine concentrations in yellow tulp (Moraea pallida) in South Africa. Onderstepoort Journal of Veterinary Research, 80(1):543-549.
• Sebbag L, Schmid D, van der Merwe D 2013 Liver failure in a dog following suspected ingestion of blue-green algae (Microcystis spp.): A case report and review of the toxin. Journal of the American Animal Hospital Association, 49(5):342-346.
• Van der Merwe D, Sebbag L, Nietfeld JC, Aubel MT, Foss A, Carney E 2012 Investigation of a Microcystis aeruginosa cyanobacterial freshwater harmful algal bloom associated with acute microcystin toxicosis in a dog. Journal of Veterinary Diagnostic Investigation, 24(4):679-687.
• Al-Bataneih MM, van der Merwe D, Schultz BD, Gehring R. Molecular and Functional Identification of Organic Anion Transporter Isoforms In Cultured Bovine Mammary Epithelial Cells (BME-UV). Journal of veterinary Pharmacology and Therapeutics 35(3):209-215.
• Raghavan R, Brenner K, Higgins J, van der Merwe D, Harkin KR 2011 Evaluations of land cover risk factors for canine leptospirosis: 94 cases (2002-2009). Preventive Veterinary Medicine 101:241-249.
• Van der Merwe D, Carpenter JW, Nietfeld JC, Miesner JF 2011 Adverse health effects in Canada geese (Branta canadensis) associated with waste from zinc and lead mines in the Tri-State Mining District (Kansas, Oklahoma, and Missouri, USA). Journal of Wildlife Diseases 47(3):650-660.
• Al-Bataneih MM, van der Merwe D, Schultz BD, Gehring R 2010 Tumor necrosis factor alpha increases p-glycoprotein expression in a BME-UV in vitro model of mammary epithelial cells. Journal of Veterinary Pharmacology and Therapeutics 31(8-9):506-515.
• Hanzlicek A, van der Merwe D 2010 Dibucaine toxicosis in a dog. Journal of Medical Toxicology 6:44-49.
• Schumm P, Scoglio CM, van der Merwe D 2009 A network model of successive partitioning-limited solute diffusion through the stratum corneum. Journal of Theoretical Biology 262:471-477.
• Al-Bataneih MM, van der Merwe D, Schultz BD, Gehring R 2009 Cultured mammary epithelial monolayers (BME-UV) express functional organic anion and cation transporters. Journal of Veterinary Pharmacology and Therapeutics 32(5):422-428
• Van der Merwe D, Tawde S, Pickrell JA, Erickson LE 2009 Nanocrystalline titanium dioxide and magnesium oxide in vitro dermal absorption in human skin. Cutaneous and Ocular Toxicology 28(2):78-82
• Van der Merwe D, Tawde S 2009 Antacids in the initial management of metallic zinc ingestion in dogs. Journal of Veterinary Pharmacology and Therapeutics 32:203-206
• Oliver C M, Skinner J D, van der Merwe D 2007 Territorial behaviour in southern impala rams (Aepyceros melampus Lichtenstein). African Journal of Ecology  45(2):142-148 
• Spickett A M, van Der Merwe D, Matthee O 2007 The effect of orally administered Aloe marlothii leaves on Boophilus decoloratus tick burdens on cattle. Experimental and Applied Acarology 41(1-2):139-46.
• McGaw LJ, van der Merwe D, Eloff JN 2007 In vitro anthelmintic, antibacterial and cytotoxic effects of extracts from plants used in South African ethnoveterinary medicine.Veterinary Journal 173(2):366-72.
• Van der Merwe D, Du Plessis L 2006 Microscopic morphology of Dichapetalum cymosum (Hook.) Engl. as an aid in the identification of leaf fragments in the digestive tract of poisoned animals. Journal of the South African Veterinary Association 77(4):197-201.
• Van der Merwe D, Riviere J E 2006 Cluster analysis of the dermal permeability and stratum corneum/solvent partitioning of ten chemicals in twenty-four chemical mixtures in porcine skin. Skin Pharmacology and Physiology 19(4):198-206.
• Luseba D, van der Merwe D 2006 Ethnoveterinary medicine practices among Tsonga speaking people of South Africa. Onderstepoort Journal of Veterinary Research 73(2):115-122
• Van der Merwe D, Brooks JD, Gehring R, Baynes RE, Monteiro-Riviere NA, Riviere JE 2006 A physiologically based pharmacokinetic model of organophosphate dermal absorption. Toxicological Sciences 89(1):188-204. 
• Van der Merwe D, Riviere J E 2005 Effect of vehicles and sodium lauryl sulphate on xenobiotic permeability and stratum corneum partitioning in porcine skin. Toxicology 206:325-335.
• Van der Merwe D, Riviere J E 2005 Comparative studies on the effects of water, ethanol and water/ethanol mixtures on chemical partitioning into porcine stratum corneum and silastic membrane. Toxicology In Vitro 19(1):69-77.
• Gehring R, van der Merwe D, Pierce AN, Baynes RE, Craigmill AL, Riviere JE 2005 Multivariate meta-analysis of pharmacokinetic studies of ampicillin trihydrate in cattle. American Journal of Veterinary Research 66(1):108-112.
• Botha C J, Shakespeare A S, Gehring R, van der Merwe D 2001 Evaluation of a commercially available molybdate formulation and zinc oxide boluses in preventing hepatic copper accumulation and thus enzootic icterus in sheep. Journal of the South African Veterinary Association 72(4): 183-188.
• Van der Merwe D, Swan G E, Botha C J 2001 Use of ethnoveterinary medicinal plants in cattle by Setswana-speaking people in the Madikwe area of the North West province of South Africa. Journal of the South African Veterinary Association 72(4): 189-196.

Book chapters

• Van der Merwe D 2022. Harmful Algal Blooms (Chapter 42). In: Kirk and Bonagura’s Current Veterinary Therapy XVI.
• Van der Merwe D, Burchfield DR, Witt TD, Price KP, Sharda A 2020. Drones in Agriculture. In: Advances in Agronomy: AGRON Volume 162, DL Sparks (ed.), Elsevier/Academic Press, New York, pp. 1-28. 
• Van der Merwe D, Jordaan A, van den Berg M 2019. Case report: Fipronil contamination of chickens in the Netherlands and surrounding countries. In: Food Safety Assurance and Veterinary Public Health: Chemical Hazards in Foods of Animal Origin, FJM Smulders (ed.), Wageningen Academic Publishers, Wageningen, pp. 567-584.
• Fink-Gremmels J, van der Merwe D 2019. Mycotoxins. In: Food Safety Assurance and Veterinary Public Health: Chemical Hazards in Foods of Animal Origin, FJM Smulders (ed.), Wageningen Academic Publishers, Wageningen, pp. 241-261.
• Van der Merwe D 2013 Freshwater cyanotoxins. . In Gupta R C, (ed.) Biomarkers in Toxicology. Elsevier/Academic Press, New York, pp. 539-548.
• Gehring R, van der Merwe D 2013 Toxicokinetic-Toxicodynamic modeling. In Gupta R C, (ed.) Biomarkers in Toxicology. Elsevier/Academic Press, New York, pp. 149-156.
• Van der Merwe D, Buur JL, Gehring R 2012 Toxicokinetics. In: Gupta R C, (ed.) Veterinary Toxicology: Basic & Clinical Principles 2nd edition. Elsevier/Academic Press, New York, pp. 37-47. 
• Pickrell JA, van der Merwe D 2012 Respiratory toxicosis. In: Gupta R C, (ed.) Veterinary Toxicology: Basic & Clinical Principles 2nd edition. Elsevier/Academic Press, New York, pp. 223-234.
• Van der Merwe D, Pickrell JA 2012 Nanomaterials toxicity. In: Gupta R C, (ed.) Veterinary Toxicology: Basic & Clinical Principles 2nd edition. Elsevier/Academic Press, New York, pp. 383-390.
• Pickrell JA, van der Merwe D, Erickson LE, Dhakal K, Dhakal M, Klabunde KJ, Sorensen C 2010 Comparative pulmonary toxicity of metal oxide nanoparticles. In: Nanoscale materials in chemistry. Larry E. Erickson, Ranjit T. Koodali, Ryan M. Richards (eds), ACS Books, Washington, D.C., ACS Symposium Series Volume 1045, pp. 225-233.
• Van der Merwe D 2009 Chapter 145: Poisons of plant origin. In: General and Applied Toxcology (3rd ed), Bryan Ballantyne, Timothy C. Marrs, Tore Syversen (eds.), Wiley, Hoboken, NJ, Volume 6, pp. 3449-3466.
• Gehring R, van der Merwe D 2008 Drug interactions. In: Haskell SSR (ed.) Five Minute Veterinary Consult, Rruminant. Wiley-Blackwell Publishing, Aimes, Iowa, 310-311.
• Gehring R, van der Merwe D 2008 Drug hypersensitivity. In: Haskell SSR (ed.) Five Minute Veterinary Consult, Rruminant, Supplementary Material. Wiley-Blackwell Publishing, Aimes, Iowa, 176.
• Gehring R, van der Merwe D 2008 Prudent use of antimicrobials. In: Haskell SSR (ed.) Five Minute Veterinary Consult, Rruminant, Supplementary Material. Wiley-Blackwell Publishing, Aimes, Iowa, 327-328.
• Van der Merwe D, Buur J L, Riviere J E 2007 Physiologically Based Pharmacokinetic Modeling. In: Gupta R C, (ed.) Veterinary Toxicology: Basic & Clinical Principles. Elsevier/Academic Press, New York, 42-50.
• A.T.M. van Knegsel, S.G.A. van der Drift, M. Horneman, A.P.W. de Roos, B. Kemp, and E.A.M. Graat. 2010. Short communication: Ketone body concentration in milk determined by Fourier transform infrared spectroscopy: value for the detection of hyperketonemia in dairy cows. J. Dairy Sci. 93:3065-3069.
• M. Houweling, S.G.A. van der Drift, R. Jorritsma, and A.G.M. Tielens. 2012. Technical note: Quantification of plasma 1- and 3-methylhistidine in dairy cows by high-performance liquid chromatography-tandem mass spectrometry. J. Dairy Sci. 95:3125-3130.
• S.G.A. van der Drift, M. Houweling, J.T. Schonewille, A.G.M. Tielens, and R. Jorritsma. 2012. Protein and fat mobilization and associations with serum beta-hydroxybutyrate concentrations in dairy cows. J. Dairy Sci. 95:4911-4920.
• S.G.A. van der Drift, R. Jorritsma, J.T. Schonewille, H.M. Knijn, and J.A. Stegeman. 2012. Routine detection of hyperketonemia in dairy cows using Fourier transform infrared spectroscopy analysis of beta-hydroxybutyrate and acetone in milk in combination with test day information. J. Dairy Sci. 95:4886-4898.
• S.G.A. van der Drift, K.J.E. van Hulzen, T.G. Teweldemedhn, R. Jorritsma, M. Nielen, and H.C.M. Heuven. 2012. Genetic and nongenetic variation in plasma and milk betahydroxybutyrate and milk acetone concentrations of early-lactation dairy cows. J. Dairy Sci. 95:6781-6787.
• S.G.A. van der Drift, R.R. Everts, M. Houweling, L.A.M.G. van Leengoed, J.A. Stegeman, A.G.M. Tielens, and R. Jorritsma. 2013. Effects of β-hydroxybutyrate and isoproterenol on lipolysis in isolated adipocytes from periparturient dairy cows and cows with clinical ketosis. Res. Vet. Sci. 94(3):433-439.
• A.T. van Knegsel, S.G. van der Drift, J. Cermáková, B. Kemp. 2013. Effects of shortening the dry period of dairy cows on milk production, energy balance, health, and fertility: a systematic review. Vet J. 198(3), 707-713.
• S.G. van der Drift, M. Houweling, M. Bouman, A.P. Koets, A.G. Tielens, M. Nielen, R. Jorritsma. Effects of a single glucocorticoid injection on propylene glycol-treated cows with clinical ketosis. Vet J. 204(2):144-149.