Theoretical work suggests that if environmental reservoirs (abiotic substrates or alternative biotic hosts that enable pathogen persistence) exist, diseases can have serious population-level effects on host species and even precipitate host extinction (29 ).
WS outbreaks have been shown to be dependent on multiple environmental factors as well as biotic factors like host density [e.g., 10], reflecting the role that interactions between coral hosts and pathogens play in disease causation [23].
In addition to reef fish, we found strong links between the spatial patterns of PorTrem and a further biotic predictor, namely host abundance.
The risk of exposure of humans to infected tick bites therefore depends on a wide range of environmental factors, both abiotic (climate and landscape features) and biotic (tick and host distributions and abundance), and on socio-economic factors affecting human behaviour.
The environmental gradient varies in abiotic characteristics (elevation, distance from the coast, temperature, and precipitation) and biotic interactions (with host plants) (Table 1).
Second, bacteriophages are viruses, and this study allows us to observe how a virus adapts to both abiotic (high temperature) and biotic factors (a host cell in heat shock).
Viruses belong to biology because they possess genes, replicate, evolve, and are adapted to particular hosts, biotic habitats, and ecological niches.
Biotic interactions between hosts are thought to be a pathogen transmission route between organisms (Merritt et al., 2010), with MU being integrated in the aquatic community from the environment thanks to filter feeder, herbivorous, and scavenger organisms and then transmitted across the community through predation (Marsollier et al., 2002, 2007a, 2007b; Mosi et al., 2008).
Biotic interactions between hosts in the community may play an important role on disease transmission, either promoting or diluting the overall prevalence of the pathogen (LoGiudice et al., 2003; Keesing et al., 2010; Johnson et al., 2013; Roche et al., 2013a).
Cyclical processes at Beringia resulted in alternating periods of biotic expansion, geographic colonization, host switching, intense isolation, and rapid speciation for assemblages of worm parasites in pinnipeds and among seabirds moving from Pacific to Atlantic and the reverse.
