Epizootic Ulcerative Syndrome (EUS) is spreading

D

dynamicthings

New member
jake ek het die inligting gekry


WHAT IS EPIZOOTIC ULCERATIVE SYNDROME?
Epizootic ulcerative syndrome (EUS) or 'red-spot' as it is known colloquially, is an ulcerative syndrome
of fish which affects a range of native species in the Northern Territory. The disease also occurs in New
South Wales, Queensland and in Western Australia, as well as in many Asian countries. It begins as a
small area of reddening over a single scale, which subsequently spreads to involve a number of
adjacent scales; this is the characteristic 'red spot'. As the condition progresses, the 'red-spot' expands
and deepens, giving a deep ulcer, which sometimes extends into the abdominal cavity. Some fish,
especially barramundi (Lates calcarifer) develop unilateral or bilateral cloudiness of the cornea; these
changes in the eye may or may not be accompanied by lesions in the skin. Some cases of EUS heal
spontaneously, but many affected fish, especially juveniles, die.
CAUSE
A pathogenic fungus, Aphanomyces invadans causes EUS. Infection occurs when motile spores in the
water are attracted to the skin of fish. The spores penetrate the skin and germinate, forming fungal
filaments or hyphae. The hyphae invade widely into the surrounding skin and deeply into underlying
muscle tissues, resulting in extensive ulceration and destruction of tissues (Figures 1, 3, 4 and 5). In the
Northern Territory the factors that initiate infection are not clear. Low water temperatures depress the
immune system of fish, which may partially explain the apparent dry season occurrence of EUS. There
appears to be no definite relationship between dissolved oxygen levels and EUS; affected fish have
been seen in water with dissolved oxygen levels of between 2 to 8 ppm.

TREATMENT AND CONTROL
There are no specific control measures in fish for EUS in natural environments. Fish from infected
waterways, especially those with lesions of EUS, should not be relocated to other waterways.
In captive fish, early 'red-spot' lesions may respond to topical treatment with an antiseptic iodophore
solution. Increasing salinity of holding waters may prevent outbreaks of EUS in aquaculture ponds.
IMPLICATIONS FOR WILD FISH STOCKS AND AQUACULTURE
The overall impact of EUS on wild stocks of fish is uncertain, although high losses in juvenile stocks are
known to occur. Currently, restrictions are placed in areas where EUS occurs on translocation of live
fish from river basins and estuaries to prevent further spread of the disease in NT waters. If EUS
invades aquaculture farms it may cause unsightly injuries in fish, market rejection and fish mortality.
PUBLIC HEALTH
The EUS fungus is not known to cause disease in humans. However, advanced lesions in fish
sometimes contain bacteria which potentially cause disease in humans. Therefore, people should not
eat EUS-affected fish.
 
J

Jake1

Senior Member
dynamicthings wrote:
jake ek het die inligting gekry


WHAT IS EPIZOOTIC ULCERATIVE SYNDROME?
Epizootic ulcerative syndrome (EUS) or 'red-spot' as it is known colloquially, is an ulcerative syndrome
of fish which affects a range of native species in the Northern Territory. The disease also occurs in New
South Wales, Queensland and in Western Australia, as well as in many Asian countries. It begins as a
small area of reddening over a single scale, which subsequently spreads to involve a number of
adjacent scales; this is the characteristic 'red spot'. As the condition progresses, the 'red-spot' expands
and deepens, giving a deep ulcer, which sometimes extends into the abdominal cavity. Some fish,
especially barramundi (Lates calcarifer) develop unilateral or bilateral cloudiness of the cornea; these
changes in the eye may or may not be accompanied by lesions in the skin. Some cases of EUS heal
spontaneously, but many affected fish, especially juveniles, die.
CAUSE
A pathogenic fungus, Aphanomyces invadans causes EUS. Infection occurs when motile spores in the
water are attracted to the skin of fish. The spores penetrate the skin and germinate, forming fungal
filaments or hyphae. The hyphae invade widely into the surrounding skin and deeply into underlying
muscle tissues, resulting in extensive ulceration and destruction of tissues (Figures 1, 3, 4 and 5). In the
Northern Territory the factors that initiate infection are not clear. Low water temperatures depress the
immune system of fish, which may partially explain the apparent dry season occurrence of EUS. There
appears to be no definite relationship between dissolved oxygen levels and EUS; affected fish have
been seen in water with dissolved oxygen levels of between 2 to 8 ppm.

TREATMENT AND CONTROL
There are no specific control measures in fish for EUS in natural environments. Fish from infected
waterways, especially those with lesions of EUS, should not be relocated to other waterways.
In captive fish, early 'red-spot' lesions may respond to topical treatment with an antiseptic iodophore
solution. Increasing salinity of holding waters may prevent outbreaks of EUS in aquaculture ponds.
IMPLICATIONS FOR WILD FISH STOCKS AND AQUACULTURE
The overall impact of EUS on wild stocks of fish is uncertain, although high losses in juvenile stocks are
known to occur. Currently, restrictions are placed in areas where EUS occurs on translocation of live
fish from river basins and estuaries to prevent further spread of the disease in NT waters. If EUS
invades aquaculture farms it may cause unsightly injuries in fish, market rejection and fish mortality.
PUBLIC HEALTH
The EUS fungus is not known to cause disease in humans. However, advanced lesions in fish
sometimes contain bacteria which potentially cause disease in humans. Therefore, people should not
eat EUS-affected fish.
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Thanks dyna, nou weet ek ook presies wat is eus
 
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