Changes

The anatomic structure of the gills helps in its functions by providing a '''large and very thin surface'''. The gill filaments are divided into multiple finger-like projections, the primary lamellae, which in turn are divided into secondary lamellae.

Also known as: '''''Environmental Gill Disease — Bacterial Gill Disease

 

The most common response of the [[Gills|gill]] to damage is '''hyperplasia and hypertrophy of epithelial cells''', which results in '''shortening, rounding and fusion''' of the secondary lamellae. Sometimes even the primary lamellae are affected.

The most common reponse of the gill to damage is '''hyperplasia and hypertrophy of epithelial cells''', which results in '''shortening, rounding and fusion''' of the secondary lamellae. Sometimes even the primary lamellae are affected.

This severely affects the structure and function of the gills and reduces the surface area available for exchange. This also predisposes the gills to further bacterial colonisation and potential septicaemia.

This severely affects the structure and function of the gills and reduces the surface area available for exchange. This also predisposes the gills to further bacterial colonisation and potential septicaemia.

The most common causes are as follows:

The most common causes are as follows:

:'''Protozoa''': ''[[Trichodina spp.|Trichodina]]'', ''Chilodonella'', ''Ichtyobodo''

:'''Protozoa''': ''[[Trichodina spp.|Trichodina]]'', ''Chilodonella'', ''Ichtyobodo''

:'''Parasites''': ''[[Ichthyophthirius multifiliis|Ichthyophthirius]]'', ''Amlyoodinium''

:'''Parasites''': ''[[Ichthyophthirius multifiliis|Ichthyophthirius]]'', ''Amyloodinium''

:'''Bacteria'''

:'''Bacteria'''

:'''Environmental toxins''': ammonia, nitrite, heavy metals  

:'''Environmental toxins''': ammonia, [[Nitrite Toxicity|nitrite]], heavy metals  

:'''Poor water quality'''

:'''Poor water quality'''

:'''Pantothenic acid deficiency'''

:'''Pantothenic acid deficiency'''

==Diagnosis==

==Diagnosis==

'''Gill biopsies''' should be performed on dead fish to examing their gross and histological appearance.

'''Gill biopsies''' should be performed on dead fish to examine their gross and histological appearance.

'''Histology''' will reveal shortening, fusion and clubbing of the secondary lamellae.

'''Histology''' will reveal shortening, fusion and clubbing of the secondary lamellae.

Roberts, R. (2001) '''Fish Pathology''' ''Elsevier Health Sciences''

Roberts, R. (2001) '''Fish Pathology''' ''Elsevier Health Sciences''

[[Category:To Do - Helen]]

 

[[Category:To Do - Review]]

 

 

[[Category:Fish Diseases]]

[[Category:Expert Review - Exotics]]