college of fisheries, Agartala

1. RHABDOVIRIDAE
PRESENTEDBY-
Ritesh chandravanshi
M.F.Sc. Iyr. I sem.
AQC02/17

2. INTRODUCTION
The name rhabdo means ‘rod’ and refers to the bullet shape
of the virus particle.
The best known rhabdovirus is rabies virus causing a serious
neurological disease in warm-blooded animals including
humans.
It is primarily a zoonosis of wild animals, mostly carnivores,
but domestic animals are also affected.
Vesicular stomatitis virus that causes disease in cattle, pigs,
horses and sometimes humans is another extensively studied
member of the Rhabdoviridae.

4. All the fish rhabdoviruses are now placed in two of
these genera:-
 Novirhabdovirus-
▫ IHNV (Infectious haematopoietic necrosis virus)
▫ VHSV (Viral haemorrhagic septicaemia virus)
▫ HIRRV (Hirame rhabdovirus disease)
▫ SHRV (Snakehead rhabdovirus).
Vesiculovirus -
▫ SVCV (Spring viraemia of carp)
▫ UDRV ( Ulcerative disease rhabdoviruses)
▫ PFRV (Pike fry rhabdovirus)

5. Infectious haematopoietic necrosis virus
(IHNV)
The disease was first described by Wolf (1988).
Natural outbreaks have been reported in wild populations of
rainbow trout including steelhead, sockeye, chinook, pink
salmon and brown trout (Wolf 1988).

6. Pathology
• Externally ;fish may have haemorrhage of fins, pale
gills, exophthalmia, swollen abdomen.
• Internally; the stomach and intestine are devoid of
food and contain a yellow to whitish fluid.
• liver, kidneys and spleen are pale and petechiation
may be present in several tissues including visceral
adipose tissue, swim bladder.

7. Histopathology
• The heart may show a necrotic
thrombus.
• The pancreas, adrenal cortex
and haematopoeitic tissue in
the kidney are similarly affected
as may be the liver.
• Histological examination shows
marked necrosis in the anterior
kidney.

8. Epizootiology
• As noted the virus has spread in North America, Europe, Asia
and Japan.
• Transmission of IHNV via the sex products and via eyed eggs has
been viewed as important to the global spread of IHNV.
Diagnosis
• Cell culture followed by identification of virus by polyclonal
antibody neutralisation and ELISA has been in long-term use.
• PCR methodology is now widely used to detect viral RNA (Barlic-
Maganja et al. (2002).

9. Control
• Various treatments are used to inactivate virus (e.g. ozone, UV
light, chlorination followed by dechlorination and iodination), all
with qualified success.
• Iodine as iodophor is used extensively for egg disinfection at
concentrations of 100 mg/l.

10. Viral haemorrhagic septicaemia (VHS)
• The disease was first described in rainbow trout by Schäperclaus
(1938).
Pathology
• Fry with darkened skin and a bloated appearance, the absence of
feed in the gut,exophthalmia, severe anaemia and a fluid-filled
abdomen.
• Internal haemorrhages are common over the mesentery, the
adipose tissue and through the musculature.
• The kidney is hyperaemic and often swollen reflecting necrosis
over the whole length.

11. Histopathology
• The kidney and liver are major target organs of the virus, in
addition to circulating leucocytes (Estepa & Coll 1991).
• In rainbow trout the liver also shows widespread focal necrosis,
degeneration of hepatocyte nuclei.
• This results in the typical petechial haemorrhaging within the
skeletal muscle.

14. Epizootiology
• It is now known VHS virus has a global distribution in the
Northen Hemisphere in fresh water and sea water across
North America,Northern Atlantic Ocean, coastal waters
around the United Kingdom, and coastal waters around Japan
(Skall et al. 2005).
Diagnosis
• immunfluorescent antibody test (IFAT) on fixed infected
smears or imprints,
• Direct ELISA on fish tissue homogenates.
• polymerase chain reaction (PCR) amplification of specific
VHSV RNA sequences in host tissue,
• monoclonal antibody

15. Control
Exposure to Time
50% ethylether <1 hour
50% chloroform <1 hour
50% glycerol 1–2 weeks
2% formalin <5 minutes
Virkon® Aquatic 0.1% <15 minutes
pH 2.5 10 minutes
70°C <1 minute

16. Spring viraemia of carp (SVC)
• The infection produces a generalised viraemia and
haemorrhages in viscera and muscles of young and adult
carp and several other cyprinids (Fijan et al. 1984).
Pathology
• External signs may include prominent abdominal
distension, exophthalmia, skin darkening and an
inflamed and oedematous vent.
• Internally ascites, catarrhal or haemorrhagic enteritis
and peritonitis are common.
• The viscera are oedematous and petechial haemorrhages
occurred in the heart, liver, kidney, intestine, internal
wall of the swim-bladder and skeletal muscle.

17. Histopathology
• Histological examination
has shown the swim
bladder tissues are
significantly affected.
• There is necrosis of liver
blood vessels and
hyperaemia and focal
necrosis of parenchyma.

18. Pike fry rhabdovirus (PFRV )