UV radiation at 222, 254, and 282 nm inhibits sporulation and suppresses infectivity of <i>Eimeria acervulina</i> oocysts

<i>Eimeria acervulina</i> is one of several apicomplexan parasites that can cause the economically important disease avian coccidiosis, which is transmitted <i>via</i> the fecal-oral route. It is also a valuable model for exploring interventions capable of reducing the public health risks posed by the related foodborne parasite <i>Cyclospora cayetanensis</i>. Unsporulated (noninfectious) oocysts are shed in the feces and sporulate in the environment to become infectious. In this study, the effect of UV radiation (UVR) on <i>E. acervulina</i> sporulation efficiency was evaluated. Nonstandard wavelengths including 222 and 282 nm have been established as alternatives to standard 254 nm UVR for sterilization. To address the disinfection capability of these nonstandard wavelengths, <i>E. acervulina</i> sporulation was scored following treatment under three wavelengths: 222, 254, or 282 nm. Each wavelength significantly (<i>P</i> < 0.05) reduced the sporulation rate relative to untreated controls, supporting the utility of nonstandard UVR treatments for coccidian inactivation. Furthermore, infectivity assays showed that chickens administered <i>E. acervulina</i> treated at each wavelength shed significantly fewer oocysts (<i>P</i> < 0.05) than those that received untreated oocysts, demonstrating a near 3-log reduction and verifying that these alternative wavelengths successfully break the transmission cycle. Owing to its biological similarity with the emerging enteric parasite <i>Cyclospora cayetanensis</i>, it is proposed that disinfection with 222 or 282 nm UVR will likewise be efficacious against <i>Cyclospora</i>.IMPORTANCECoccidian parasites cause enteric disease in animals and people. For example, <i>Eimeria acervulina</i> imposes major economic burdens on the poultry industry and provides a surrogate for investigating means to mitigate the foodborne risk that <i>Cyclospora cayetanensis</i> poses to human health. Previous work established that UV radiation at 254 nm can inactivate the oocysts of <i>E. acervulina,</i> but radiation at this wavelength harms human skin and eyes. Since nonstandard UVR at wavelengths of 222 and 282 nm shows promise against pathogens like <i>Giardia</i> and <i>Cryptosporidium,</i> the present work sought to determine whether such exposures could arrest <i>E. acervulina</i> development and reduce their infectivity. These nonstandard wavelengths proved capable of disrupting transmission. Epidemiological evidence suggests <i>Cyclospora</i> transmission through the food chain; the use of nonstandard UV wavelengths represents a promising method to inactivate coccidian oocysts, thereby protecting produce supply chains while, specifically in the case of 222 nm, incurring less risk to occupational health.