Bacterial and viral co-infections in aquaculture under climate warming: co-evolutionary implications, diagnosis, and treatment.

Climate change and the associated environmental temperature fluctuations are contributing to increases in the frequency and severity of disease outbreaks in both wild and farmed aquatic species. This has a significant impact on biodiversity and also puts global food production systems, such as aquaculture, at risk. Most infections are the result of complex interactions between multiple pathogens, and understanding these interactions and their co-evolutionary mechanisms is crucial for developing effective diagnosis and control strategies. In this review, we discuss current knowledge on bacteria-bacteria, virus-virus, and bacterial and viral co-infections in aquaculture as well as their co-evolution in the context of global warming. We also propose a framework and different novel methods (e.g. advanced molecular tools such as digital PCR and next-generation sequencing) to (1) precisely identify overlooked co-infections, (2) gain an understanding of the co-infection dynamics and mechanisms by knowing species interactions, and (3) facilitate the development multi-pathogen preventive measures such as polyvalent vaccines. As aquaculture disease outbreaks are forecasted to increase both due to the intensification of practices to meet the protein demand of the increasing global population and as a result of global warming, understanding and treating co-infections in aquatic species has important implications for global food security and the economy.

Aquaculture at the crossroads of global warming and antimicrobial resistance.

In many developing countries, aquaculture is key to ensuring food security for millions of people. It is thus important to measure the full implications of environmental changes on the sustainability of aquaculture. We conduct a double meta-analysis (460 articles) to explore how global warming and antimicrobial resistance (AMR) impact aquaculture. We calculate a Multi-Antibiotic Resistance index (MAR) of aquaculture-related bacteria (11,274 isolates) for 40 countries, of which mostly low- and middle-income countries present high AMR levels. Here we show that aquaculture MAR indices correlate with MAR indices from human clinical bacteria, temperature and countries' climate vulnerability. We also find that infected aquatic animals present higher mortalities at warmer temperatures. Countries most vulnerable to climate change will probably face the highest AMR risks, impacting human health beyond the aquaculture sector, highlighting the need for urgent action. Sustainable solutions to minimise antibiotic use and increase system resilience are therefore needed.

The complete mitochondrial genomes of the yellowleg shrimp Farfantepenaeus californiensis and the blue shrimp Litopenaeus stylirostris (Crustacea: Decapoda).

Mitochondria play key roles in many cellular processes. Description of penaeid shrimp genes, including mitochondrial genomes are fairly recent and some are focusing on commercially important shrimp as the Pacific shrimp Litopenaeus vannamei that is being used for aquaculture not only in America, but also in Asia. Much less is known about other Pacific shrimp such as the yellowleg shrimp Farfantepenaeus californiensis and the blue shrimp Litopenaeus stylirostris. We report the complete mitogenomes from these last two Pacific shrimp species. Long DNA fragments were obtained by PCR and then used to get internal fragments for sequencing. The complete F. californiensis and L. stylirostris mtDNAs are 15,975 and 15,988 bp long, containing the 37 common sequences and a control region of 990 and 999 bp, respectively. The gene order is identical to that of the tiger shrimp Penaeus monodon. Secondary structures for the 22 tRNAs are proposed and phylogenetic relationships for selected complete crustacean mitogenomes are included. Phylogenomic relationships among five shrimp show strong statistical support for the monophyly of the genus across the analysis. Litopenaeus species define a clade, with close relationship to Farfantepenaeus, and both clade with the sister group of Penaeus and Fenneropenaeus.