Nanochitosan-Based Fish Disease Prevention and Control

Globally, diverse infections and diseases abound that have engendered morbidity and mortality in humans and not excluding other biota members. Predominant microorganisms of bacteria, fungi, parasites and viruses are responsible for these maladies with the significant focus on remedies and preventions since the birth of man. Generally, antimicrobials are applied in diverse sectors including homes, health care, marine amongst others hence the crucial focus for improvement. Despite copious approaches including vaccination, diverse challenges have been validated encapsulating infectious disease dynamics and emerging antimicrobial-resistant microorganisms. Hence, the call for a more robust process of drug delivery and efficacy scheme through the incorporation of nanoparticles, from nanotechnology, that possess differential merits for revamping the bioavailability, solvability and retention time of biologically active compounds with significance in economic, social and ecological sectors. These nanoconstituents protect the compounds from degradation caused by photolysis and hydrolysis. Chitosan and chitosan oligosaccharides are recognised biological control agents due to their non-toxic, biodegradable and biocompatible unique features. Reports have situated that chitosan possess broad-spectrum antimicrobial activity against microbial agents such as Escherichia coli, Aspergillus fumigatus, Rhizopus stolonifer, Alternaria sp., amongst others. The route of activation involves incorporating medicaments into the chitosan-composed nanoparticles recognising that chitosan functions concertedly with other nanocrystals. This mechanism for both antibacterial and antifungal activities is hinged on the immense degree of decetylation and pH values. Chitosan-based antibacterials comprised of both inorganic and organic components of which metal oxides from the inorganics portray stability under adverse conditions and are safe for animal and human treatments. Antifungals formulated with chitosan-based compounds mediate through the inhibition of SAGA complex component expression followed by the subsequent alteration/disruption of cell integrity and maturation. Other mechanisms include the precipitation of energy-dependent permeabilisation of sensitive fungal and bacterial plasma membranes with reports of its potential to suppress biofilm production. Susceptibility to chitosan in aquatic pathogens involves various target components. For the remedial of viral infections, chitosan-based components facilitate the uptake of antigens by mucosal lymphatic tissue to obtain more efficacious mucosal and systemic immune response required for treatment. Thus, the advancement in nanotechnology using chitosan-based composites have generated concerted efforts/results in the mitigation of infections and diseases engendered by a broad range of microbes from the aerial, terrestrial and aquatic habitats.