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Journal of Fish Diseases Nov 2019Samples from multiple animals may be pooled and tested to reduce costs of surveillance for infectious agents in aquatic animal populations. The primary advantage of...
Samples from multiple animals may be pooled and tested to reduce costs of surveillance for infectious agents in aquatic animal populations. The primary advantage of pooling is increased population-level coverage when prevalence is low (<10%) and the number of tests is fixed, because of increased likelihood of including target analyte from at least one infected animal in a tested pool. Important questions and a priori design considerations need to be addressed. Unfortunately, pooling recommendations in disease-specific chapters of the 2018 OIE Aquatic Manual are incomplete and, except for amphibian chytrid fungus, are not supported by peer-reviewed research. A systematic review identified only 12 peer-reviewed aquatic diagnostic accuracy and surveillance studies using pooled samples. No clear patterns for pooling methods and characteristics were evident across reviewed studies, although most authors agreed there is a negative effect on detection. Therefore, our purpose was to review pooling procedures used in published aquatic infectious disease research, present evidence-based guidelines, and provide simulated data examples for white spot syndrome virus in shrimp. A decision tree of pooling guidelines was developed for use by peer-reviewed journals and research institutions for the design, statistical analysis and reporting of comparative accuracy studies of individual and pooled tests for surveillance purposes.
Topics: Animals; Communicable Diseases; Crustacea; Diagnostic Tests, Routine; Epidemiological Monitoring; Fish Diseases; Guidelines as Topic; Population Surveillance; Prevalence; White spot syndrome virus 1
PubMed: 31637760
DOI: 10.1111/jfd.13083 -
Environmental Microbiology Reports Jun 2024The pathogenic fungus Batrachochytrium dendrobatidis has caused declines of amphibians worldwide. Yet our understanding of how water quality influences fungal...
The pathogenic fungus Batrachochytrium dendrobatidis has caused declines of amphibians worldwide. Yet our understanding of how water quality influences fungal pathogenicity is limited. Here, we reviewed experimental studies on the effect of water quality on this pathogen to determine which parameters impacted disease dynamics consistently. The strongest evidence for protective effects is salinity which shows strong antifungal properties in hosts at natural levels. Although many fungicides had detrimental effects on the fungal pathogen in vitro, their impact on the host is variable and they can worsen infection outcomes. However, one fungicide, epoxiconazole, reduced disease effects experimentally and likely in the field. While heavy metals are frequently studied, there is weak evidence that they influence infection outcomes. Nitrogen and phosphorous do not appear to impact pathogen growth or infection in the amphibian host. The effects of other chemicals, like pesticides and disinfectants on infection were mostly unclear with mixed results or lacking an in vivo component. Our study shows that water chemistry does impact disease dynamics, but the effects of specific parameters require more investigation. Improving our understanding of how water chemistry influences disease dynamics will help predict the impact of chytridiomycosis, especially in amphibian populations affected by land use changes.
Topics: Animals; Batrachochytrium; Amphibians; Water Quality; Mycoses; Salinity; Fungicides, Industrial; Chytridiomycota; Pesticides; Disinfectants; Antifungal Agents
PubMed: 38775382
DOI: 10.1111/1758-2229.13274