Download Tuberculosis in fish

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Tuberculosis in fish
Mycobacteriosis in fish is a disease caused by certain bacterial species
within the genus (Mycobacterium.) There are many different species of
Mycobacterium that cause diseases in animals.Some of these cause
important diseases in humans.
those species that cause Mycobacteriosis in and do not cause major
disease in normal, healthy people.Non-tuberculous mycobacteria are
relatively common environmental bacteria. This means that they can live
in the aquatic environment and do norequire the presence of fish or fish
tissue to survive.They have been isolated from drinking watesupplies,
swimming pools, coastal waters, andaquaculturefacilities.
Mycobacteriosis is a disease of concern in fish for several reasons. First,
it causes a chronic wasting condition with continuous low, tomoderate,
level mortality within the affected population, and can result in
significant financialloss to fish culturists. Secondly, the disease
isconsidered non-treatable once established in the fish
host. Finally, Mycobacterium-infected fish do have the potential to
causedisease in humans.
Type of Mycobacteria in fish
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M. marinum
2- M.fortuitum
3- M. chelonae
4-M. fortuitum.
5-M. chelonae
Signs of Mycobacteriosis in Fish
1-emaciation
2- inflammation of the skin
3- exophthalmia “pop-eye” open lesions, or ulceration.
4- Fish may become sluggish and bloated,
5-refuse to eat, and develop fin and tail rot as well asscale loss,
6- gray-white granulomas
7-(nodules) develop in the liver, kidney, spleen, heart,and muscles.
8-in the organs, edema excess fluid accumulationmay develop,as well as
peritonitis, inflammation ofthe body cavity.
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9- deformities such as a bent spine may benoticed,
10- infected fish succumb and die.
11-. Granulomas (nodules) are readily visible onmultiple organs in
the abdominal cavity during necropsy.The disease in this fish was
very advanced.
Dignosis
1-the presence of typical granulomas,inliver, spleen, and kidney tissueas
part of a routine necropsy. Granulomas will be present on skin
ulcerations.
2-acid-fast stain should be performed immediately on suspect tissue. In
the laboratory,granulomatous material is smeared onto a slide,dried, heatfixed, and stained with Kinyoun orZiehl-Nielsen stain to confirm the
presence of acidfastbacteria. A positive acid-fast stain reveals redto pink
rod-shaped bacteria against alight greenbackground.
3-culture and identify the causative agent. Acidstainswill be performed on
fresh tissue as describedabove, in addition to acid-fast stains of
4-histopathological samples. Crushed granulomas arestreaked onto
Lowenstein-Jensen or Dorsetmedia, specialized growth media for
mycobacteria,where growth can take up to 28 days.
5-Confirmationof the diagnosis by culture of the organism isdesirable,
although no growth does not necessarilyrule out mycobacteria, especially
if acid-fast organisms are present.
Transmission
1-The most common method of transmission is tobeingestion of infected
material.This can occur if fishare fedfish products that have not been
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thoroughly cooked, or if an infected fish dies and is consumed by other
fish in the population
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2- Fish may also contract theinfection through open wounds in their skin
if thenumber of bacteria in the environment ishighenough or if the fish
has a poorly operating immune system.
3- It is suspected that vertical transmission(transmission from parent to
offspring) may occur through egg or sperm products. Ithis is the
case,maintenance ofmycobacteriainfectedbroodstockwould be totally
unacceptable for fish culturists.
Disease in Human
1-Mycobacterium spp. that cause disease in fish cause a skin infection in
human that isreferred to as “fish handler's disease" or "fish tank
granuloma.”,
2-The infection is characterized bypustules that resemble a rash and occur
on bodyparts exposed to contaminated water or fish,
generally the hands, arms, or legs. The pustules exude a thick white to
yellow fluid.
3- In healthyindividuals the disease is usually self-limiting and
often heals on its own, there are reportedcases of more severe localized
infections resulting from deep penetrating wounds in fishermen.
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