Viability of Pseudocapillaria tomentosa Eggs Exposed to Heat, Ultraviolet Light, Chlorine, Iodine, and Desiccation.

Abstract

Pseudocapillaria tomentosa is an important pathogen in zebrafish facilities. We investigated heat, ultraviolet (UV) light, chlorine, iodine, and dessciation for killing the parasite s eggs. Eggs released with feces larvate in about 5-10 days, and treatments were evaluated by exposing fresh eggs and subsequently comparing larvation to untreated eggs as an indication of survival. Collectively, untreated eggs in all trials showed high levels of survival. Eggs were exposed to elevated temperatures (40°C, 45°C and 50°C) for 1, 8, or 24\u2009h, which resulted in substantial reduction in viability of eggs. UV radiation was effective, with no larvation at 50-300\u2009mWs/cm2 and <2% at 20\u2009mWs/cm2. Three chlorine products (JT Baker, Clorox®, and Bi-Mart) were tested at 25, 50, 100, 500, and 3,000\u2009ppm (pH 7.0-7.3) with 10\u2009min exposure. All were effective at 500 or 1,000\u2009ppm. There was variability between three products and trials at lower concentrations, but overall chlorine was not very effective at 25-100\u2009ppm except for Bi-Mart brand at 100\u2009ppm. Povidone-iodine was not effective at 25 or 50\u2009ppm for 10\u2009min, but was effective at 200\u2009ppm for 1\u2009h. Desiccation was effective, and no eggs larvated after 2\u2009h drying.