Non-linear effects of non-host diversity on the removal of free-living infective stages of parasites.

Among the ecological functions and services of biodiversity is the potential buffering of diseases through dilution effects where increased biodiversity results in a reduction in disease risk for humans and wildlife hosts. Whether such effects are a universal phenomenon is still under intense debate and diversity effects are little studied in cases when non-host organisms remove free-living parasite stages during their transmission from one host to the next by consumption or physical obstruction. Here, we investigated non-host diversity effects on the removal of cercarial stages of trematodes, ubiquitous parasites in aquatic ecosystems.

Marine virus predation by non-host organisms.

Viruses are the most abundant biological entities in marine environments, however, despite its potential ecological implications, little is known about virus removal by ambient non-host organisms. Here, we examined the effects of a variety of non-host organisms on the removal of viruses. The marine algal virus PgV-07T (infective to Phaeocystis globosa) can be discriminated from bacteriophages using flow cytometry, facilitating its use as a representative model system.

Consumer and host body size effects on the removal of trematode cercariae by ambient communities.

Parasite transmission can be altered via the removal of parasites by the ambient communities in which parasite-host interactions take place. However, the mechanisms driving parasite removal remain poorly understood. Using marine trematode cercariae as a model system, we investigated the effects of consumer and host body size on parasite removal rates.

Effect of dose and frequency of exposure to infectious stages on trematode infection intensity and success in mussels.

Marine parasites such as trematodes often compromise the fitness of their hosts. Such effects are generally considered to be density-dependent, i.e.

Parasites as prey: the effect of cercarial density and alternative prey on consumption of cercariae by four non-host species.

In parasites with complex life cycles the transmission of free-living infective stages can be influenced by ambient community diversity, in particular via predation. Here, we experimentally investigated whether parasite density and the presence of alternative prey can alter predation rates on free-living cercarial stages of a marine trematode by several non-host predators. All four predator species consumed increasing numbers of cercariae with an increase in cercarial density, indicating that the removal of cercariae by predators is effective over a range of natural densities as well as in the presence of alternative prey for a number of predators typical of marine ecosystems.

The Use of Filter-feeders to Manage Disease in a Changing World.

Rapid environmental change is linked to increases in aquatic disease heightening the need to develop strategies to manage disease. Filter-feeding species are effective biofilters and can naturally mitigate disease risk to humans and wildlife. We review the role of filter-feeders, with an emphasis on bivalves, in altering disease outcomes via augmentation and reduction.

Pathological and physiological effects of nicking on brown crab (Cancer pagurus) in the Irish crustacean fishery.

Nicking is used in fisheries to immobilize claws of brown crab (Cancer pagurus) in order to prevent cannibalism and fighting during storage. Nicking fractures the apodemes creating an open wound and damage to the internal claw tissues, which is the most valuable product of brown crab. In turn, this results in a reduction of quality of product and possibly compromises the host's defence mechanisms to other physiological challenges experienced throughout the post-harvest process.