Fish diseases and parasites

This gizzard shad has VHS, a deadly infectious disease which causes bleeding. It affects over 50 species of freshwater and marine fish in the northern hemisphere.^[1]

This flatfish Limanda limanda has an outgrowth called a xenoma. It is caused by a microsporidian fungal parasite in its intestines.^[2]

Like humans and other animals, fish suffer from diseases and parasites. Fish defences against disease are specific and non-specific. Non-specific defences include skin and scales, as well as the mucus layer secreted by the epidermis that traps microorganisms and inhibits their growth. If pathogens breach these defences, fish can develop inflammatory responses that increase the flow of blood to infected areas and deliver white blood cells that attempt to destroy the pathogens.

Specific defences are specialised responses to particular pathogens recognised by the fish's body, that is adaptative immune responses.^[3] In recent years, vaccines have become widely used in aquaculture and ornamental fish, for example vaccines for commercial food fishes like Aeromonas salmonicida, furunculosis in salmon and Lactococcosis\Streptococcosis ^[4] in farmed grey mullet, Tilapia and koi herpes virus in koi.^[5]^[6]

Some commercially important fish diseases are VHS, ICH, and whirling disease.

^ Disease Factsheets: Viral Hemorrhagic Septicemia Iowa State University, The Center for Food Security & Public Health. Last updated 17 May 2007. Retrieved on 2007-07-12.
^ Lom J, Dyková I (2005). "Microsporidian xenomas in fish seen in wider perspective". Folia Parasitologica. 52 (1–2): 69–81. doi:10.14411/fp.2005.010. PMID 16004366.
^ Helfman G., Collette B., & Facey D.: The Diversity of Fishes, Blackwell Publishing, pp 95-96, 1997, ISBN 0-86542-256-7
^ Rao, S, Byadgi, O, Pulpipat, T, Wang, P-C, Chen, S-C. Efficacy of a formalin-inactivated Lactococcus garvieae vaccine in farmed grey mullet (Mugil cephalus). J Fish Dis. 2020; 43: 1579– 1589. https://doi.org/10.1111/jfd.13260
^ Cipriano RC (2001) "Furunculosis And Other Diseases Caused By Aeromonas salmonicida" Archived 2009-05-07 at the Wayback Machine Fish Disease Leaflet 66, US Department of the Interior.
^ Hartman KH et al. (2004) "Koi Herpes Virus (KHV) Disease". Fact Sheet VM-149. University of Florida Institute of Food and Agricultural Sciences.

[iastate-1] Disease Factsheets: Viral Hemorrhagic Septicemia Iowa State University, The Center for Food Security & Public Health. Last updated 17 May 2007. Retrieved on 2007-07-12.

[Lom2005-2] Lom J, Dyková I (2005). "Microsporidian xenomas in fish seen in wider perspective". Folia Parasitologica. 52 (1–2): 69–81. doi:10.14411/fp.2005.010. PMID 16004366.

[3] Helfman G., Collette B., & Facey D.: The Diversity of Fishes, Blackwell Publishing, pp 95-96, 1997, ISBN 0-86542-256-7

[4] Rao, S, Byadgi, O, Pulpipat, T, Wang, P-C, Chen, S-C. Efficacy of a formalin-inactivated Lactococcus garvieae vaccine in farmed grey mullet (Mugil cephalus). J Fish Dis. 2020; 43: 1579– 1589. https://doi.org/10.1111/jfd.13260

[5] Cipriano RC (2001) "Furunculosis And Other Diseases Caused By Aeromonas salmonicida" Archived 2009-05-07 at the Wayback Machine Fish Disease Leaflet 66, US Department of the Interior.

[6] Hartman KH et al. (2004) "Koi Herpes Virus (KHV) Disease". Fact Sheet VM-149. University of Florida Institute of Food and Agricultural Sciences.

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