Seeing What Floats: Comparing Fecal Diagnostic Techniques for the Detection of Zoonotic Cestode Eggs

Sierra Felty, a student at Radford University, worked in the lab of Dr. Christopher Cleveland

Abstract Coyotes (Canis latrans) are an anthropogenically abundant and increasingly widespread species, Members of the genus Echinococcus are parasitic cestodes that pose a zoonotic threat to wildlife, livestock, domestic animals, and humans. They utilize wild canids, such as coyotes and foxes, as their definitive hosts. Two species of interest are E. multilocularis and E. granulosus given their impacts on native wildlife, agriculture, and human health. E. multilocularis uses rodents as intermediate hosts, and E. granulosus utilizes cervids as intermediate hosts. As the rate of urbanization continues to rise, humans and domestic animals are at greater risk of infection through more frequent interactions with wild canid hosts. Given the increased risk of infection, especially in non-endemic regions, it is important to have reliable detection methods in place. Our study sought to test the sensitivity and detection limits of three different fecal flotation methods (centrifugal, passive, and Mini-FLOTAC) in recovering Echinococcus spp. eggs. For each method, fecal samples were spiked with a known concentration of eggs (25, 40, and 60 eggs per gram of feces) and zinc sulfate was used as the flotation solution. Our findings indicated that the centrifugal flotation and Mini-FLOTAC were the most sensitive for detecting Echinococcus spp. eggs and the Mini-FLOTAC had the highest egg recovery. Therefore, the Mini-FLOTAC appears to be the most reliable fecal flotation method in detecting Echinococcus spp. eggs.