Molecular Pathogens 2024, Vol.15, No.1, 17-29 http://microbescipublisher.com/index.php/mp 22 Kough et al. (2015) demonstrated the distribution and connectivity of coral reefs in islands and coastal areas through habitat mapping and pathogen transmission simulations in the Caribbean region. By comparing the two scenarios of waterborne and late larval transmission, it is clear that geographic spread and environmental interactions significantly influence pathogen transmission. This detailed approach not only contributes to understanding the dynamics of marine pathogens such as PaV1, but also highlights the critical role of spatial configuration in the management of marine diseases. These insights are essential for developing targeted conservation and intervention strategies to protect vulnerable marine ecosystems. 5.2 Epidemiological models Epidemiological models are essential tools for understanding and predicting the spread of marine infectious diseases. Various models, such as the stochastic, spatiotemporal hybrid simulation model DTU-DADS-Aqua, have been developed to simulate infection transmission and control strategies in marine aquaculture (Romero et al., 2021). These models incorporate compartmental and agent-based approaches to account for infection spread within and between net-pens, considering factors like seaway distance and farm-site hydroconnectivity (Romero et al., 2021). Metapopulation models, which consider patchily distributed hosts, have also been applied to coral reefs, highlighting the prolonged nature of epizootics and the slow recovery at regional scales (Sokolow et al., 2019). These models provide valuable insights into the long-term consequences of disease introduction and the effectiveness of various control measures. 5.3 Factors contributing to outbreaks Several factors contribute to the emergence and severity of marine pathogen outbreaks. Environmental conditions, such as climate change and pollution, can compromise host immunity and facilitate the introduction of new pathogens (Klinkenberg et al., 2017). For example, increased sea temperatures associated with El Niño events have been linked to higher incidences of coral bleaching and subsequent disease outbreaks. Anthropogenic activities, including aquaculture and global transport of species, also play significant roles in spreading pathogens to previously unexposed host populations (Thurber et al., 2020). Additionally, the presence of environmental reservoirs and the pathogen's ability to persist in these reservoirs can influence the likelihood and magnitude of outbreaks. 5.4 Case Studies of marine pathogen outbreaks Several case studies illustrate the dynamics and impacts of marine pathogen outbreaks. The spread of infectious salmon anaemia virus (ISAv) in farmed Atlantic salmon populations in New Brunswick, Canada, and Maine, USA, demonstrated the importance of disease detection, surveillance, and depopulation measures in controlling outbreaks (Romero et al., 2021). Another notable example is the white plague type II (WPII) outbreak among corals in the upper Florida Keys, where metapopulation models successfully predicted the spatial and temporal patterns of the disease over a decade (Sokolow et al., 2019). These case studies underscore the need for robust epidemiological models and effective management strategies to mitigate the impacts of marine pathogen outbreaks. 6 Detection and Monitoring 6.1 Molecular and microbiological techniques Molecular and microbiological techniques are fundamental in the detection and monitoring of marine pathogens. These methods include traditional culturing, polymerase chain reaction (PCR), and advanced next-generation sequencing (NGS) technologies. For instance, droplet digital PCR and Illumina MiSeq sequencing have been effectively used to detect fish pathogens such as Flavobacterium columnare and Flavobacterium psychrophilum in aquaculture settings, demonstrating high sensitivity and accuracy (Testerman et al., 2021). Additionally, environmental DNA (eDNA) and RNA (eRNA) approaches have emerged as powerful tools for monitoring pathogens in aquatic environments. These methods offer advantages such as lower cost, reduced labor, and the ability to detect non-culturable organisms, making them suitable for large-scale surveillance (Amarasiri et al.,
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