Bacterial diseases, which affect the health, production efficiency, and economic sustainability of aquaculture, are becoming an increasing problem. Meanwhile, the widespread use and misuse of antimicrobial agents have also been responsible for the spread and emergence of antimicrobial-resistant bacteria, highlighting the need to find safer and more effective ways to manage diseases. Bacteriophages are viruses that target bacterial cells and are being studied more and more for biological approaches. There are many anti-phage defence mechanisms in bacteria, which can prevent phage adsorption, inhibit genome injection, degrade phage nucleic acids, and end infected cells before productive phage replication. In response, bacteriophages are constantly developing defenses such as production of depolymerase, nucleic acid modification and anti-CRISPR mechanisms, as well as diversification of receptors to which they bind. Bacteriophages, in turn, are constantly evolving defenses, such as the ability to produce depolymerases, to modify nucleic acids, and to provide anti-CRISPR mechanisms, while they are evolving the ability to bind to different receptors. This co-evolution is an ?arms race' that affects the dynamics of bacterial populations, the diversity of phages, and the success of phage therapy interventions. This article discusses the phases of the evolutionary arms race between bacteria and phages, their application to aquaculture disease management, and the potential of phages for sustainable management of aquatic animal diseases.

Leptospirosis is a bacterial infection that spreads through water contaminated by the urine of infected animals, especially rodents. In India, cases surge every monsoon season as heavy rains, flooding, and poor drainage create ideal conditions for the bacteria to survive and spread. This article explains how leptospirosis spreads, why it is closely linked to the monsoon, who is most at risk, and what can be done to prevent and control outbreaks.

Rapid urban growth is changing how humans interact with animals and the environment. Recent studies show that cities and their edges can concentrate pathogens that jump from animals to people, especially in soils, parks, and transition zones between wild and built areas. This article explains how urbanisation can increase zoonotic disease risk and how a One Health approach can help cities grow safely.