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Firas Abdul MalikM.Sc. Fish Biology

Spring Viremia of Carp

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Domain: VirusGroup: "RNA viruses"Order: MononegaviralesFamily: RhabdoviridaeGenus: VesiculovirusSpecies: spring viremia of carp virus

Classification of the Virus:

Source: (Zhang, et al., 2009).

This viral disease is caused by Rhabdovirus carpio, a bullet-shaped RNA virus (Sano, et al., 2011). Spring viremia of carp is systemic and acute and highly contagious viral disease of carp (Cyprinus carpio) and perhaps other cyprinids (Basic, et al., 2009). It usually occurs and causes high mortality at temperatures of (11-13C)-(Emmenegger & Kurath, 2008), typically as temperatures rise in spring (Carstens,2010). SVC is also called (Infectious Dropsy of Carp, Infectious Ascites, Hydrops, Red Contagious Disease, Rubella, Hemorrhagic Septicemia) (Sano, et al., 2011). The disease can cause up to 100% mortality and affects all ages of fish. It has resulted in significant economic losses to fisheries in all the World. ( Haghighi, et al., 2008).

Introduction:

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The disease was initially diagnosed in Yugoslavia (Fijan, et al., 1971). Since then, it has been identified in other European countries, Russia, Middle East, United States and United Kingdom. (Sano, et al., 2011). Mortality has reached 70% in yearling carp from European populations. Adult fish can also be affected but to a lesser degree.

History of the Virus:

Figure (1): SVC Virus (bullet like Shape)

CLINICAL SIGNS OF VIRUS:

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1. SKIN HEMORRHAGES

Photos: Garth Traxler (USGS, Seattle WA), Dr Jim Winton (USGS, Seattle WA), Dr Mohamed Faisal(MSU, Lansing MI) and Dr Paul Bowser (Cornell, Ithaca NY)

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Figure (2)

Figure (3)

Source: (Sano, et al., 2011).

Source: (Zhang, et al., 2009).

2. HEMORRHAGES OF INTERNAL ORGANS

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Figure (4) Figure (5)

Source: (Sano, et al., 2011). Source: (Dixon, 2008).

3. EXOPHTHALMIA 4. DISTENDED ABDOMEN (BULGING EYES) (BLOATED APPEARANCE)

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Figure (6) Figure (7)

Source: (Basic, et al., 2009).

Source: (Zhang, et al., 2009).

5. SKIN DARKENING 6. PALE GILLS

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Figure (9): Spring viremia of carp. Pale gills with hemorrhage in experimentally infected (a) carp compared with gills in control fish (b). Basic, et al., (2009).

Figure (8)

Source: (Zhang, et al., 2009).

7. HEMORRHAGES 8. HEMORRHAGES IN MUSCLE IN SWIM BLADDER

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Figure (10) Figure (11)

Source: (Sano, et al., 2011). Source: (Dixon, 2008).

10. HISTOPATHOLOGICAL SECTION OF GILL IN CARP

INFECTED WITH SVC

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9. SWOLLEN STOMACH

Figure (12) Figure (13)

Source: (Dixon, 2008).

Source: (Basic, et al., 2009).

11. FISH KILLS

Figure (14) : Salmon Hatchery, Washington – (Coho salmon killed by SVC virus).Source: (Dixon, 2008). 12

1.Appear lethargic.2.Slowed respiration.3.Loss of equilibrium. 4.Separate from the shoal.5.Tilting to one side.6.Lying on bottom of pond.7.Gather at the water inlet or sides

of a pond.

Fish behavior after infection:

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(Sano, et al., 2011); (Carstens, 2010); (Basic, et al., 2009); (Soliman , et al., 2008); (Emmenegger & Kurath, 2008).

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Video (1): Infected carp behavior.

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Fish types which affected by virus. 1.Common carp. 3.Grass carp. 5.Koi carp. 7.Bighead carp.9.Orfe.11.Salmon.

(Zhang,et al., 2009).

2.Silver carp. 4.Goldfish.6.Crucian carp. 8.Catfish. 10.Tench.

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Video (2): Lethargic carp.

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1.Direct transmission via water, 2.mechanical transmission via

parasites & birds

Transmission

Depends on:1.Age. 2.Water Temperature.3.Other Stress Factors.

Infection degree

Table (1): Virus transmission and Infection degree (Zhang,et al., 2009).

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Video (3): Infected carp gather at the water inlet or sides of a pond .

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1. Depopulation and disinfection. 2. Continuous rearing at 20-22°C.3. Hygienic measures. Beware of

potential carriers. Vaccination is at an experimental stage.

Prevention

&

ControlRaise of water Temperature to above 20 °C.

Treatment

Table (2): Control and treatment of disease (Carstens, 2010).

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Video (4): Carp loss of equilibrium.

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Table (3): Degree of infection according to the fish age (Adel, et al., 2008).

% Mortality % Infection Fish stage

>60% >80% Fry

40-55% 55-70% Fingerlings

30-40% 40-50% Juvenile

<25% <30% Adult

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Video (5): Carp death.

Incubation period:The incubation period of SVC depends on:

1.Water temperature,

2.Species,

3.Age,

4.Condition of the fish,

5.Quantity of virus, and on

6.Certain environmental conditions.

(Sano, et al., 2011); (Adel, et al., 2008); (Basic, et al., 2009);

Table (4): Effect of temperature fluctuation on mortality rate (Sano, et al., 2011).

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Period (days) % Mortality Temp.

2-4 90% 10-12°C

4-7 75% 12-16°C

7-15 60% 16-17°C

15-21 30% 17-26°C

Figure (15): Influence of water temperature on SVCV (spring viremia of carp virus)-infection of carp Cyprinus carpio leading to virus multiplication (10-12°C) or to production of antibodies (20-22°C). SPF carp (25-30g) were intra peritoneally infected with SVCV. Infected fish kept at 10-12°C and 20-22°C were analyzed for values of virus, antibodies and death . Source: (Dixon, 2008).

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1. Disease outbreaks in carp generally occur between 11-17°C.

2. Disease rarely occur below 10°C.3. Small fish more affected than older fish.4. Fish mortalities decline as the temperature exceeds

22°C.5. In carp, the disease is often observed in springtime

(hence the common name for the disease).6. Rare in countries having cold winters. 7. It is believed that the poor condition of the over-

wintered fish may be a contributory factor in disease occurrence.

8. The disease can occur in fish in quarantine following the stress of transportation, even though there has been no evidence of virus in the fish prior to transportation.

Conclusion:

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References:Adel, H. K.; Moigan, B.; Zarrin, S. & Bahram, K. (2008). The First Report of

Spring Viraemia of Carp in Some Rainbow Trout Propagation and Breeding by Pathology and Molecular Techniques in Iran. 2013 Science Alert. All Rights Reserved. Asian Journal of Veternary Advances.3 (4): 263-268. Islamic Azad University of Iran,Tehran.

Basic, A.; Schachner, O.; Bilic, I. & Hess, M. (2009). Phylogenetic analysis of spring viraemia of carp virus isolates from Austria indicates the existence of at least two subgroups within genogroup Id. Dis. aquat. Org., 85, 31–40.

Carstens, E.B. (2010). Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2009). Arch. Virol., 155, 133–146.

Dixon, P.F. (2008). Virus diseases of cyprinids. In: Fish Diseases, Vol. 1. Eiras J.C., Segner H., Wahli, T. & Kapoor, B.G. eds. Science Publishers, Enfield, New Hampshire, USA, 87–184.

Emmenegger, E.J. & Kurath, G. (2008). DNA vaccine protects ornamental koi (Cyprinus carpio koi) against North American spring viremia of carp virus. Vaccine, 26, 6415–6421.

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References:Fijan, N.; Petrinec, Z.; Sulimanovic, D.; Zwillenberg, L. (1971). Isolation of the

viral causative agent from the acute form of infectious dropsy of carp, Veterinarski Arhiv 41:125-138.

Haghighi Khiabanian Asl A., Azizzadeh M., Bandehpour M., Sharifnia Z. & Kazemi B. (2008). The first report of SVC from Indian carp species by PCR and histopathologic methods in Iran. Pakistan J. Biol. Sci., 11, 2675–2678.

Sano, M., Naki, T. and Fijan, N. (2011) Viral Diseases and Agents of Warm water Fish. In: Fish Diseases and Disorders, Volume 3: Viral, Bacterial and Fungal Infections, 2nd edition (eds. Woo, P.T.K. and Bruno, D.W.), CABI, Wallingford, UK. Pp. 166-244.

Soliman M.K., Aboeisa M.M., Mohamed S.G. & Saleh W.D. (2008). First record of isolation and identification of spring viraemia of carp virus from Oreochromis niloticus in Egypt. 8th International Symposium on Tilapia in Aquaculture 2008, 1287–1306.

Zhang, N.Z.; Zhang, L.F.; Jiang, V.N.; Zhang, T. & Xia, C. (2009). Molecular analysis of spring viraemia of carp virus in China: A fatal aquatic viral disease that might spread in East Asian. PLoS ONE, 4, pp 1–9.

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