Utilization of computer processed high definition video imaging for measuring motility of microscopic nematode stages on a quantitative scale: "The Worminator"

Bob Storey; Chris Marcellino; Melissa Miller; Mary Maclean; Eman Mostafa; Sue Howell; Judy Sakanari; Adrian Wolstenholme; Ray Kaplan

doi:10.1016/j.ijpddr.2014.08.003

Utilization of computer processed high definition video imaging for measuring motility of microscopic nematode stages on a quantitative scale: "The Worminator"

Int J Parasitol Drugs Drug Resist. 2014 Aug 28;4(3):233-43. doi: 10.1016/j.ijpddr.2014.08.003. eCollection 2014 Dec.

Authors

Bob Storey¹, Chris Marcellino², Melissa Miller¹, Mary Maclean¹, Eman Mostafa³, Sue Howell¹, Judy Sakanari⁴, Adrian Wolstenholme⁵, Ray Kaplan¹

Affiliations

¹ Department of Infectious Diseases, University of Georgia, Athens, GA, USA.
² Center for Discovery and Innovation in Parasitic Diseases, University of California San Francisco, San Francisco, CA, USA ; Case Western Reserve University School of Medicine, Cleveland, OH, USA.
³ Department of Infectious Diseases, University of Georgia, Athens, GA, USA ; Parasitology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
⁴ Center for Discovery and Innovation in Parasitic Diseases, University of California San Francisco, San Francisco, CA, USA.
⁵ Department of Infectious Diseases, University of Georgia, Athens, GA, USA ; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA.

Abstract

A major hindrance to evaluating nematode populations for anthelmintic resistance, as well as for screening existing drugs, new compounds, or bioactive plant extracts for anthelmintic properties, is the lack of an efficient, objective, and reproducible in vitro assay that is adaptable to multiple life stages and parasite genera. To address this need we have developed the "Worminator" system, which objectively and quantitatively measures the motility of microscopic stages of parasitic nematodes. The system is built around the computer application "WormAssay", developed at the Center for Discovery and Innovation in Parasitic Diseases at the University of California, San Francisco. WormAssay was designed to assess motility of macroscopic parasites for the purpose of high throughput screening of potential anthelmintic compounds, utilizing high definition video as an input to assess motion of adult stage (macroscopic) parasites (e.g. Brugia malayi). We adapted this assay for use with microscopic parasites by modifying the software to support a full frame analysis mode that applies the motion algorithm to the entire video frame. Thus, the motility of all parasites in a given well are recorded and measured simultaneously. Assays performed on third-stage larvae (L3) of the bovine intestinal nematode Cooperia spp., as well as microfilariae (mf) of the filarioid nematodes B. malayi and Dirofilaria immitis, yielded reproducible dose responses using the macrocyclic lactones ivermectin, doramectin, and moxidectin, as well as the nicotinic agonists, pyrantel, oxantel, morantel, and tribendimidine. This new computer based-assay is simple to use, requires minimal new investment in equipment, is robust across nematode genera and developmental stage, and does not require subjective scoring of motility by an observer. Thus, the "Worminator" provides a relatively low-cost platform for developing genera- and stage-specific assays with high efficiency and reproducibility, low labor input, and yields objective motility data that is not subject to scorer bias.

Keywords: Anthelmintic resistance; Brugia malayi; Dirofilaria immitis; Microfilaria; Motility measurement; Trichostrongyle.