Transmission dynamics of ectoparasitic gyrodactylids (Platyhelminthes, Monogenea): An integrative review

Abstract

Parasite transmission is the ability of pathogens to move between hosts. As a key component of the interaction between hosts and parasites, it has crucial implications for the fitness of both. Here, we review the transmission dynamics of Gyrodactylus species, which are monogenean ectoparasites of teleost fishes and a prominent model for studies of parasite transmission. Particularly, we focus on the most studied host–parasite system within this genus: guppies, Poecilia reticulata, and G. turnbulli/G. bullatarudis. Through an integrative literature examination, we identify the main variables affecting Gyrodactylus spread between hosts, and the potential factors that enhance their transmission. Previous research indicates that Gyrodactylids spread when their current conditions are unsuitable. Transmission depends on abiotic factors like temperature, and biotic variables such as gyrodactylid biology, host heterogeneity, and their interaction. Variation in the degree of social contact between hosts and sexes might also result in distinct dynamics. Our review highlights a lack of mathematical models that could help predict the dynamics of gyrodactylids, and there is also a bias to study only a few species. Future research may usefully focus on how gyrodactylid reproductive traits and host heterogeneity promote transmission and should incorporate the feedbacks between host behaviour and parasite transmission.

Season, size, and sex: factors influencing monogenean prevalence and intensity on Gambusia affinis in New Zealand

“…Instead, parents give birth to crawling, sexually mature young, that attach onto the same host as their parent (Bakke et al 2007 ). Transfer from one host to another is usually not undertaken by the parasites as it is a risky maneuver that can result in high mortality (Bakke et al 2007 ; Tepox-Vivar et al 2022 ). However, transmission by Gyrodactlyus may be achieved in a number of other ways.…”

“…Unlike other platyhelminth parasites, such as those in the Digenea, monogeneans have a single-host life cycle and any single monogenean species typically infests only a single host species (Poulin 1992 ). With the exception of the viviparous members of the Gyrodactylidae family, which produce fully grown young able to transmit directly to new hosts via brief contact between fish (Tepox-Vivar et al 2022 ), monogeneans release eggs directly into the water column that hatch into ciliated larval oncomiracidia. These oncomiracidia then swim to find and attach to a prospective host where they mature into adult parasites (Chubb 1977 ; Whittington and Chisholm 2008 ).…”

Evolutionary Dynamics of Lineage-Specific Class-A GPCR Subsets Reveal Widespread Chemosensory Roles and Adaptations in Lophotrochozoa

“…For instance, Schistosoma mansoni, a well-known parasite causing schistosomiasis, encodes approximately 99 Class-A GPCRs (61). Platyhelminthes, with distinct parasitic modes-Monogenea being ectoparasitic and Cestoda/Trematoda being endoparasitic-have evolved various adaptations (58,62), including tegument formation, specialized attachment structures, body elongation, complex life cycles, and reductions in sensory and locomotor structures compared to free-living ancestors (63,64). At the genomic level, adaptations to parasitism also marked a substantial reduction in homeodomaincontaining genes, piwi, vasa, Wnt, NEK kinases, fatty acid biosynthesis, and opsin genes (39,65,66).…”