Meeting Abstract
The emerging integrative field of One Health science departs from traditional focus on disease as malady and conceptualizes infection as natural organismal and ecological process. Our research over 3 decades has utilized electron, light and confocal microscopy to examine reproduction and development of parasitic worms that constitute strategies for dispersal in the environment between hosts and optimize targeted colonization of specific sites within hosts. Studying cestodes and trematodes from basal to highly derived taxa, we have demonstrated wide variation in structural and developmental strategies that facilitate dispersal and colonization. These range from specialized embryonic and larval structures to highly plastic morphogenesis of both reproductive and somatic systems. Our newest results analyzed in this synthetic review include: embryonic structures of Gyrocotyle urna (from European marine fish); embryonic and larval structures of 4 microphalloid digenean species (from Eurasian frogs); uterine and extrauterine structures of Thysanotaenia congolensis (from African rodents); serial multistage larval structures of Ornithodiplostomum ptychocheilus (from North American freshwater fish); aberrant neoplastic structures of Hymenolepis nana (juveniles/adults from humans) and Mesocestoides and Spirometra (juveniles from mammals, birds, reptiles and amphibians on 6 continents). The latter are examples of malignant transformation (cancer) in invertebrates, which becomes highly pathogenic and ultimately deadly to the host as the parasite becomes uncontrollably invasive. Taken together, these examples demonstrate remarkable evolutionary and developmental plasticity among flatworms that have undertaken infection of vertebrate hosts as a life strategy.
