Ranavirus sp. Factsheet
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Scientific Name: Ranavirus sp.
Common Name: largemouth bass virus (LMBV)
Taxonomy: Family Iridoviridae; details available through ITIS
Identification: The largemouth bass virus is an icosahedral-shaped particle without an envelope. It occurs in the cytoplasm of host fish cells. When it passes out of the plasma membrane of the host fish cell, it acquires an envelope (Plumb et al. 1996).
In largemouth bass (Micropterus salmoides), signs of the disease may include increased blood flow and darkened skin, distended abdomen, bloated swim bladder, lesions in the membrane lining the body cavity, necrosis (burst cells resulting in inflammation) of gastrointestinal mucosa, pale liver, red spleen, red intestinal caeca, infected gills, lethargic swimming, decreased responsiveness, swimming at the surface and/or in circles, and difficulty remaining upright. Sores or lesions on the outside of the body are secondary and not caused by the actual viral infection (Zilberg et al. 2000; Goldberg 2002; Brunner 2003; Grizzle and Whelan 2004; Beck et al. 2006).
Size: LMBV particles are ~130 nm from side to side and 145 nm from corner to corner when they are in the cytoplasm of the host cells. After acquiring an envelope they measure ~175 nm in maximum dimension (Plumb et al. 1996).
Native Range: Unknown. However, this virus is very similar to two fish viruses from southeast Asia (Mao et al. 1999; Plumb et al. 1999).
Nonindegenous Occurences: LMBV has been recorded from many areas of the Great Lakes watershed, particularly in Michigan. Occurrences include Lake George (Lake Michigan watershed) in 2000; Devils Lake (Lake Erie watershed) in 2002; Lake St. Clair in 2003; and Sanford Lake (Lake Huron watershed) in 2003 (Grizzle and Brunner 2003; Whelan 2004).
Means of Introduction: Transport of LMBV in North America probably occurs in live wells of fishing boats when infected fish or water are dumped into new habitat or put in contact with uninfected fish, which are then released. Stocking of infected fish could also be a vector.
Status: Established.
Ecology: LMBC is stable in lab conditions at pH of 3-9. It remains viable in water for at least 3-4 hours, is 10% infective after 2 days, and is still detectable after 7 days (Piaskoski et al. 1999; Scott and Aron 2002; Grizzle and Brunner 2003). LMBV grows best and is most virulent at 30°C, but is able to kill cells in a broad range of temperatures (Grant et al. 2003; Grizzle and Brunner 2003; McClenahen et al. 2005).
LMBV can be passed from one infected fish to another so any practices that keep infected and uninfected fishes that are in close contact or at high densities can increase transmissions (Grant et al. 2005; Inendino et al. 2005). LMBV can be transmitted through the water and also orally via ingestion of infected animals (Woodland et al. 2002). Transmission from adult to offspring probably does not occur or is very rare (Grizzle and Brunner 2003).
This virus was first known only from wild fish and was not reported from hatcheries until 1999 in the southeastern USA. LMBV can affect largemouth bass lethally or subclinically (without symptoms), and is particularly prone to infect bass over 30 cm long. The virus is experimentally pathogenic in striped bass (Morone saxatilis) but has never caused fish kills in this species in the wild. LMBV can also subclinically and non-lethally infect smallmouth bass (Micropterus dolomieui), bluegill (Lepomis macrochirus), crappie (Pomoxis spp.), and chain pickerel (Esox niger). Once exposed to LMBV, a population of largemouth bass produces antibodies such that subsequent exposures result in less extreme manifestations of the disease. Fish kills can be slow and last for several weeks (Goldberg 2002; Woodland et al. 2002; Grizzle and Brunner 2003; Grizzle et al. 2003; Whelan 2004).
Impact of Introduction:
A) Realised: A major largemouth bass die-off occurred in Lake George in 2000. Die-offs involving 100-500 fish deaths (a ~10% mortality rate) have typically occurred in affected areas throughout Michigan (Grizzle and Brunner 2003; Whelan 2004).
B) Potential: Major die-offs likely attributable to LBMV have occurred outside the Great Lakes basin. In a reservoir in South Carolina, a die-off involving ~1000 fish occurred in 1995 (Plumb et al. 1996). In a reservoir in the northern Mississippi drainage in 1998, 3000 largemouth bass were killed (Hanson et al 2001). In some infected populations, there have been unpublished but noticeable population declines in fish over 2.3 kg, possibly due to LMBV or some other coincidental factor (Grizzle and Brunner 2003).
Remarks: It is possible that LMBV was first introduced to largemouth bass populations in Florida in 1991 through contact with imported tropical guppies (Poecilia reticulata) or doctor fish (Labroides dimidatus). These two species can harbor nearly identical viruses, known as Guppy virus (GV6), and doctor fish virus (DFV), respectively. Given that the technology existed much earlier than the 1990s to detect such a virus and that it was being used to detect other fish diseases, it is unlikely that LMBV was present for many years before 1991. Spread of LMBV has occurred from Florida through adjacent states, and has only recently reached the Great Lakes drainage. This pattern of spread from Florida could either be due to increased detection efforts in states adjacent to places where recent outbreaks occurred, or to an actual radial spread of the disease.
There are a few different strains of this virus present in North America, which suggests either multiple introductions to the continent or that LMBV is not exotic to the continent. More studies need to be carried out to clarify where the virus originated (Mao et al. 1999; Plumb et al. 1999; Goldberg 2002; Grizzle et al. 2002; Goldberg et al. 2003; Grizzle and Brunner 2003).
Voucher Specimens:
References:
Beck, B. H., R. S. Bakal, C. J. Brunner, and J. M. Grizzle. 2006. Virus distribution and signs of disease after immersion exposure to largemouth bass virus. Journal of Aquatic Animal Health 18(3):176-183.
Goldberg, T. L. 2002. Largemouth bass virus: an emerging problem for warmwater fisheries? Pp. 411 – 416 in D. P. Philipp, ed. Black bass: ecology, conservation, and management. Proceedings of the American Fisheries Society Symposium 31, St. Louis, Missouri, USA, August 21 – 24, 2000. 724 pp.
Goldberg, T. L., D. A. Coleman, E. C. Grant, K. R. Inendino, and D. P. Philipp. 2003. Strain variation in an emerging iridovirus of warm-water fishes. Journal of Virology 77:812-8818.
Grant, E. C., D. P. Philipp, K. R. Indendino, and T. L. Goldberg. 2003. Effects of temperature on the susceptibility of largemouth bass to largemouth bass virus. Journal of Aquatic Animal Health 15(3):215-220.
Grant, E. C., K. R. Inendino, W. J. Love, D. P. Philipp, and T. L. Goldberg. 2005. Effects of practices related to catch-and-release angling on mortality and viral transmission in juvenile largemouth bass infected with largemouth bass virus. Journal of Aquatic Animal Health 17(4):315-322.
Grizzle, J. M. and C. J. Brunner. 2003. Review of largemouth bass virus. Fisheries (Bethesda) 28(11):10-14.
Grizzle, J. M., I. Altinok, and A. D. Noyes. 2003. PCR method for detection for largemouth bass virus. Diseases of Aquatic Organisms 54(1):29-33.
Grizzle, J. M., I. Altinok, W. A. Fraser, and R. Francis-Floyd. 2002. Diseases of Aquatic Organisms 50(3):233-235.
Hanson, L. A., L. Petrie-Hanson, K. O. Meals, V. G. Chinchar, and M. Rudis. 2001. Persistence of largemouth bass virus infection in a northern Mississippi reservoir after a die-off. Journal of Aquatic Animal Health 13:27-34.
Inendino, K. R., -E. C .Grant, D. P. Philipp, and T. L. Goldberg. 2005. Effects of factors related to water quality and population density on the sensitivity of juvenile largemouth bass to mortality induced by viral infection. Journal of Aquatic Animal Health 17(4):304-314.
Mao, J., J. Wang, G. D. Chinchar, and V. G. Chinchar. 1999. Molecular characterization of a ranavirus isolated from largemouth bass Micropterus salmoides. Diseases of Aquatic Organisms 37(2):107-114.
McClenahen, S. D., B. H. Beck, and J. M. Grizzle. 2005. Evaluation of cell culture methods for detection of largemouth bass virus. Journal of Aquatic Animal Health 17(4):365-372.
Piaskoski, T. O., J. A. Plumb, and S. R. Roberts. 1999. Characterization of the largemouth bass virus in cell culture. Journal of Aquatic Animal Health 11(1):45-51.
Plumb, J. A., A. D. Noyes, S. Graziano, J. Wang, J. Mao, and V. G. Chinchar. 1999. Isolation and identification of viruses from adult largemouth bass during a 1997 – 1998 survey in the southeastern United States. Journal of Aquatic Animal Health 11(4):391-399.
Plumb, J. A., J. M. Grizzle, H. E. Young, A. Noyes, and S. Lamprecht. 1996. An iridovirus isolated from wild largemouth bass. Journal of Aquatic Animal Health 8(4):265-270.
Scott, B. A. and G. M. Aron. 2002. Effect of chemical and physical agents on the infectivity of largemouth bass virus. Abstracts of the General Meeting of the American Society for Microbiology 102:421.
Whelan, G. 2004. Largemouth bass virus continues to spread in Michigan waters. Michigan Department of Natural Resources Press Release.
Woodland, J. E., A. D. Noyes, and J. M. Grizzle. 2002. A survey to detect largemouth bass virus among fish from hatcheries in the southeastern USA. Transactions of the American Fisheries Society 131(2):308-311.
Woodland, J. E., C. J. Brunner, A. D. Noyes, and J. M. Grizzle. 2002. Experimental oral transmission of largemouth bass virus. Journal of Fish Diseases 25(11):669-672.
Zilberg, D., J. M. Grizzle, and J. A. Plumb. 2000. Preliminary description of lesions in juvenile largemouth bass injected with largemouth bass virus. Diseases of Aquatic Organisms 39(2):143-146.
Other Resources
Authors: Rebekah M. Kipp
Revision Date: June 12, 2007
Citation for this Information: Rebekah M. Kipp. 2007. GLANSIS.
Group: Category not available - virus
Lake(s): Lake St. Clair, Lake Erie drainage, Lake Michigan drainage, Lake Huron drainage
Genus: Ranavirus (Family Iridoviridae)
Species: unknown
Common Name: largemouth bass virus (LMBV)
Status: Established
Freshwater/Marine: Freshwater
Pathway: Category not available (probably trasnported in live wells of fishing boats from lake to lake as uninfected fish came into contact with infected water or other infected fish)
Exotic/Transplant: Unknown
For the current distribution map and collection information, please use the database at: http://www.glerl.noaa.gov/res/Programs/ncrais/nas_database.html