Post by craftycarper on Oct 20, 2008 21:37:26 GMT
INTRODUCTION
Koi Herpesvirus Disease is a viral disease of common carp
Cyprinus carpio, including all its ornamental varieties such
as koi, ghost koi etc. The virus is highly contagious and may
cause up to 100% mortality. KHV has already caused severe
fish losses to ornamental wholesalers, retailers and carp
fishery owners and continues to pose a significant threat to
anyone dealing with or keeping common carp.
Etiological agent: Koi Herpesvirus of the family Herpesviridae.
GEOGRAPHICAL DISTRIBUTION
KHV Disease was first recorded in Israel in 1998 following
large-scale mortalities in farmed fish. Further losses
attributed to the virus were later found in Europe and the
USA and have subsequently been reported throughout the
world. In the UK, the virus has caused increasing numbers of
mortalities in angling waters as well as in ornamental dealers
and hobbyists fish stocks.
KHV Disease appears to be widespread in ornamental carp
and it is possible that the disease is present in many more
countries than have reported its presence to date.
SUSCEPTIBLE SPECIES
Currently, KHV infections have only been recorded in common
carp Cyprinus carpio and its different varieties (mirror,
leather, koi, ghost koi, etc).
EPIZOOTIOLOGY AND CLINICAL SIGNS
The disease occurs at water temperatures between 15°C
and 28°C. Within this temperature range acute mortalities
are often observed. Mortalities are often highest at the
mid-temperature range. There are a variety of clinical signs
associated with KHV disease: infected fish may be lethargic
and move away from the shoal. They may display erratic
behaviour, often gathering at water inlets or points of
oxygenation, show loss of balance, loss of mucus resulting
in dry, rough patches, sloughing of mucus, and sunken
eyes. The gills are frequently affected displaying necrotic
patches of dead tissue. In addition to the clinical signs of the
disease the effects of secondary infections by bacteria and
fungi, the result of immunosuppressed infected fish, further
complicate diagnosis.
The disease is transmitted by fish to fish contact and it is
also possible that the disease can spread through contaminated
water, nets and other equipment. Transmission of the
virus through ova cannot be ruled out. The virus is thought to
be shed through faeces, and urine, and also possibly via gills
and skin. KHV may have the capacity to remain latent in its
host for long periods of time before becoming active, stress
is often the ‘trigger’ before an outbreak of the disease.
It is in the interests of owners and keepers of fish to ensure
that the animals in their care are kept according to good
husbandry practices.
Please note: The Animal Welfare Act 2006 makes owners
and keepers responsible for ensuring that the welfare needs
of their animals, including fish, are met. This includes protecting
them from disease.
Koi Herpesvirus Disease is a viral disease of common carp
Cyprinus carpio, including all its ornamental varieties such
as koi, ghost koi etc. The virus is highly contagious and may
cause up to 100% mortality. KHV has already caused severe
fish losses to ornamental wholesalers, retailers and carp
fishery owners and continues to pose a significant threat to
anyone dealing with or keeping common carp.
Etiological agent: Koi Herpesvirus of the family Herpesviridae.
GEOGRAPHICAL DISTRIBUTION
KHV Disease was first recorded in Israel in 1998 following
large-scale mortalities in farmed fish. Further losses
attributed to the virus were later found in Europe and the
USA and have subsequently been reported throughout the
world. In the UK, the virus has caused increasing numbers of
mortalities in angling waters as well as in ornamental dealers
and hobbyists fish stocks.
KHV Disease appears to be widespread in ornamental carp
and it is possible that the disease is present in many more
countries than have reported its presence to date.
SUSCEPTIBLE SPECIES
Currently, KHV infections have only been recorded in common
carp Cyprinus carpio and its different varieties (mirror,
leather, koi, ghost koi, etc).
EPIZOOTIOLOGY AND CLINICAL SIGNS
The disease occurs at water temperatures between 15°C
and 28°C. Within this temperature range acute mortalities
are often observed. Mortalities are often highest at the
mid-temperature range. There are a variety of clinical signs
associated with KHV disease: infected fish may be lethargic
and move away from the shoal. They may display erratic
behaviour, often gathering at water inlets or points of
oxygenation, show loss of balance, loss of mucus resulting
in dry, rough patches, sloughing of mucus, and sunken
eyes. The gills are frequently affected displaying necrotic
patches of dead tissue. In addition to the clinical signs of the
disease the effects of secondary infections by bacteria and
fungi, the result of immunosuppressed infected fish, further
complicate diagnosis.
The disease is transmitted by fish to fish contact and it is
also possible that the disease can spread through contaminated
water, nets and other equipment. Transmission of the
virus through ova cannot be ruled out. The virus is thought to
be shed through faeces, and urine, and also possibly via gills
and skin. KHV may have the capacity to remain latent in its
host for long periods of time before becoming active, stress
is often the ‘trigger’ before an outbreak of the disease.
It is in the interests of owners and keepers of fish to ensure
that the animals in their care are kept according to good
husbandry practices.
Please note: The Animal Welfare Act 2006 makes owners
and keepers responsible for ensuring that the welfare needs
of their animals, including fish, are met. This includes protecting
them from disease.
Did you also know that neither DEFRA or the EA have the powers to close these infected waters. On Tight Lines last Friday evening the owner of White Acres openly admitted that they had only lost 5% of the stock, believe that if you want. These commercial fisheries are all still open and are letting this desease continue to spread. 