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Paramoebiasis

Paramoebiasis is a disease caused by species of Paramoeba and Neoparamoeba, amoebas that parasitically target various biological systems of lobsters, sea urchins, crabs, salmon,and other marine life. In fish, it is caused by Neoparamoeba perurans, which targets the respiratory system, and is usually referred to as amoebic gill disease.

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Paramoebiasis is a disease caused by species of Paramoeba and Neoparamoeba, amoebas that parasitically target various biological systems of lobsters,1 sea urchins,2 crabs,3 salmon,4and other marine life.1 In fish, it is caused by Neoparamoeba perurans, which targets the respiratory system,5 and is usually referred to as amoebic gill disease.

Multiple outbreaks of the disease have been attributed to various species across the genera Paramoeba and Neoparamoeba, and species of both genera have been inconsistently taxonomized as a result of different approaches to classification.6

Epidemiology

Neoparamoeba species are largely free-living (both non-parasitic and non-endosymbiotic) in marine environments, but some species can become opportunistic parasites in certain conditions which are not well understood.1 Paramoebiasis can present in a variety of different ways, depending on the species of both the parasite and the host.

Respiratory

N. perurans causes paramoebiasis in marine farmed fish populations, particularly salmonids, and targets the gills. In advanced stages of the disease, white discoloration and heavy mucus are visible to the naked eye on the gills, and fish may show signs of hypoxia and difficulty breathing.7

Nervous

Among American lobster (Homarus americanus) populations, paramoebiasis has been linked to N. pemaquidensis8 and targets neurological pathways and circulatory systems, resulting in paresis and ultimately death.9

Paramoeba invadens targets the nerve rings of green sea urchins (Strongylocentrotus droebachiensis).1

Circulatory

In blue crabs (Callinectes sapidus), the species P. perniciosa is linked to "grey crab" disease in northeastern US fisheries. The disease primarily targets the hemolymph, but can also be observed in the endothelia, nervous systems and antennal gland connective tissue. In the later stages of the disease, affected crabs display lethargia, and heavily infected crabs may display muscular necrosis (possibly a result of hypoxia).10

Contributing factors

Temperature

Higher temperatures likely play an important role in the frequency and severity of paramoebiasis epidemics in marine species. In most locations the first appearance of amoebic gill disease in farmed marine fish populations was reported after above-average temperatures, suggesting that the heat tolerance of the fish species is an important factor in whether Neoparamoeba perurans is able to infect.11

Paramoeba invadens, the species responsible for frequent outbreaks of paramoebiasis in green sea urchins along the coasts of Nova Scotia,12 has been shown to thrive in warmer environments, which indicates that it is likely not indigenous to the Nova Scotia coastline, and is transported to the sea urchin population by high-energy storms like hurricanes.13 The frequency and severity of paramoebiasis-caused mass mortality events in sea urchin populations in Nova Scotia has increased since 1980, and can be correlated to warmer seawater temperatures due to climate change,14 as well as the increased frequency of hurricanes along the eastern coast of the United States.15

Salinity

The frequency of amoebic gill disease in salmonids is positively associated with high salinity sea water.16 Due to the low freshwater tolerance of Neoparamoeba perurans, a common treatment for farmed marine fish populations experiencing amoebic gill disease is the incorporation of routine freshwater baths.17

Overcrowding

More densely packed populations with poor water circulation, such as those often present in farmed marine fish populations, provide opportunities for quick growth and spread of Neoparamoeba species,18 likely as a result of increased proximity to infected fish and decreased avoidance response options.19

Notable incidents

In September 1995, in Nova Scotia, Canada, an outbreak of Neoparamoeba invadens within the green sea urchin population caused nearly full mortality of sea urchins along more than 130 kilometers of coastline, and smaller mass mortality events comprising another 40 km.2 Paramoebiasis caused by N. invadens has been associated with multiple events of recurrent mass mortality in sea urchin populations along the coasts of Nova Scotia,12 to the point that some researchers have suggested that the disease may have surpassed predation as a means of sea urchin population control in the area.20

In late 1999, the disease was responsible for an American lobster mass mortality event in Connecticut and New York, US (roughly 11 million dead, resulting in a 90-99% reduction in lobster harvests); as of 2018, the lobster fishery had not yet recovered from the die-off.1 A microscopic analysis of viscera and tissue from dead lobsters collected during the event revealed that a protozoan with the characteristics of Paramoeba (later identified as N. pemaquidensis8) had infiltrated the lobsters' circulatory and nervous systems.9

In 2019 Paramoeba sp. was identified for the first time in Pacific white shrimp in a hatchery in North America,21 and in 2022, Janickina feisti n. sp. was identified in samples of edible crab in the UK after reports of increased post-capture mortality in 2019.22

See also

See also

References

References

  1. Nowak, Barbara F.; Archibald, John M. (May 2018). "Opportunistic but Lethal: The Mystery of Paramoebae". Trends in Parasitology. 34 (5): 404–419. doi:10.1016/j.pt.2018.01.004. ISSN 1471-4922. PMID 29422444.
  2. Feehan, C.; Scheibling, R.E.; Lauzon-Guay, J.-S. (February 2012). "An outbreak of sea urchin disease associated with a recent hurricane: Support for the "killer storm hypothesis" on a local scale". Journal of Experimental Marine Biology and Ecology. 413: 159–168. Bibcode:2012JEMBE.413..159F. doi:10.1016/j.jembe.2011.12.003.
  3. Johnson, Phyllis T. (January 1977). "Paramoebiasis in the Blue Crab, Callinectes sapidus". Journal of Invertebrate Pathology. 29 (3): 308–320. Bibcode:1977JInvP..29..308J. doi:10.1016/S0022-2011(77)80036-0.
  4. Kent, Ml; Sawyer, Tk; Hedrick, Rp (1988). "Paramoeba pemaquidensis (Sarcomastigophora: Paramoebidae) infestation of the gills of coho salmon Oncorhynchus kisutch reared in sea water" (PDF). Diseases of Aquatic Organisms. 5: 163–169. doi:10.3354/dao005163. ISSN 0177-5103.
  5. Crosbie, P.B.B.; Bridle, A.R.; Cadoret, K.; Nowak, B.F. (2012). "In vitro cultured Neoparamoeba perurans causes amoebic gill disease in Atlantic salmon and fulfils Koch's postulates". International Journal for Parasitology. 42 (5): 511–515. doi:10.1016/j.ijpara.2012.04.002.
  6. Laboratory of Cellular and Molecular Protistology, Zoological Institute of the Russian Academy of Sciences; Kudryavtsev, Alexander; Volkova, Ekaterina; Laboratory of Cellular and Molecular Protistology, Zoological Institute of the Russian Academy of Sciences; Voytinsky, Fyodor; Laboratory of Cellular and Molecular Protistology, Zoological Institute of the Russian Academy of Sciences (2021). "A checklist of Amoebozoa species from marine and brackish-water biotopes with notes on taxonomy, species concept and distribution patterns" (PDF). Protistology (4). doi:10.21685/1680-0826-2021-15-4-3.
  7. Mitchell, S O; Rodger, H D (2011). "A review of infectious gill disease in marine salmonid fish: Infectious gill disease in salmonids". Journal of Fish Diseases. 34 (6): 411–432. doi:10.1111/j.1365-2761.2011.01251.x.
  8. "Nuclear Small-Subunit Ribosomal RNA Gene-Based Characterization, Molecular Phylogeny and PCR Detection of the Neoparamoeba from Western Long Island Sound Lobster". Journal of Shellfish Research. 24 (3): 719–731. October 2005. doi:10.2983/0730-8000(2005)24[719:NSRRGC]2.0.CO;2. ISSN 0730-8000.
  9. Mullen, Thomas E.; Russell, Spencer; Tucker, Meghan T.; Maratea, Jennifer L.; Koerting, Claudia; Hinckley, Lynn; De Guise, Sylvain; Frasca, Salvatore; French, Richard A.; Burrage, Thomas G.; Perkins, Christopher (2004-03-01). "Paramoebiasis Associated with Mass Mortality of American Lobster Homarus americanus in Long Island Sound, USA". Journal of Aquatic Animal Health. 16 (1): 29–38. Bibcode:2004JAqAH..16...29M. doi:10.1577/H02-045.1. ISSN 0899-7659.
  10. Kennedy, Victor S.; Cronin, L. Eugene, eds. (2007). The Blue crab: Callinectes sapidus. College Park, Md: Maryland Sea Grant College, University of Maryland. pp. 271–276. ISBN 978-0-943676-67-8.
  11. Oldham, Tina; Rodger, Hamish; Nowak, Barbara F. (2016-04-20). "Incidence and distribution of amoebic gill disease (AGD) — An epidemiological review". Aquaculture. 457: 35–42. Bibcode:2016Aquac.457...35O. doi:10.1016/j.aquaculture.2016.02.013. ISSN 0044-8486.
  12. Feehan, Cj; Johnson-Mackinnon, J; Scheibling, Re; Lauzon-Guay, Js; Simpson, Agb (April 11, 2013). "Validating the identity of Paramoeba invadens, the causative agent of recurrent mass mortality of sea urchins in Nova Scotia, Canada". Diseases of Aquatic Organisms. 103 (3): 209–227. Bibcode:2013DisAO.103..209F. doi:10.3354/dao02577. ISSN 0177-5103. PMID 23574707.
  13. Jellett, Joanne F.; Scheibling, Robert E. (July 1988). "Effect of Temperature and Prey Availability on Growth of Paramoeba invadens in Monoxenic Culture". Applied and Environmental Microbiology. 54 (7): 1848–1854. Bibcode:1988ApEnM..54.1848J. doi:10.1128/aem.54.7.1848-1854.1988. PMC 202756. PMID 16347695.
  14. Scheibling, Re; Hennigar, Aw (1997). "Recurrent outbreaks of disease in sea urchins Strongylocentrotus droebachiensis in Nova Scotia:evidence for a link with large-scale meteorologic and oceanographic events". Marine Ecology Progress Series. 152: 155–165. Bibcode:1997MEPS..152..155S. doi:10.3354/meps152155. ISSN 0171-8630.
  15. Scheibling, Robert E.; Lauzon-Guay, Jean-Sébastien (November 2010). "Killer storms: North Atlantic hurricanes and disease outbreaks in sea urchins". Limnology and Oceanography. 55 (6): 2331–2338. Bibcode:2010LimOc..55.2331S. doi:10.4319/lo.2010.55.6.2331. ISSN 0024-3590.
  16. Munday, B L; Zilberg, D; Findlay, V (2001). "Gill disease of marine fish caused by infection with Neoparamoeba pemaquidensis". Journal of Fish Diseases. 24 (9): 497–507. Bibcode:2001JFDis..24..497M. doi:10.1046/j.1365-2761.2001.00329.x. ISSN 0140-7775.
  17. Douglas-Helders, G.M.; Weir, I.J.; O'Brien, D.P.; Carson, J.; Nowak, B.F. (November 2004). "Effects of husbandry on prevalence of amoebic gill disease and performance of reared Atlantic salmon (Salmo salar L.)". Aquaculture. 241 (1–4): 21–30. Bibcode:2004Aquac.241...21D. doi:10.1016/j.aquaculture.2004.07.026.
  18. Munday, B.L.; Foster, C.K.; Roubal, F.R.; Lester, R.J.G. (1990), "PARAMOEBIC GILL INFECTION AND ASSOCIATED PATHOLOGY OF ATLANTIC SALMON, SALMO SALAR, AND RAINBOW TROUT, SALMO GAIRDNERI, IN TASMANIA", Pathology in Marine Science, Elsevier, pp. 215–222, doi:10.1016/b978-0-12-550755-4.50026-4, ISBN 978-0-12-550755-4, retrieved 2026-07-04{{citation}}: CS1 maint: work parameter with ISBN (link)
  19. Nowak, Barbara F. (2007). "Parasitic diseases in marine cage culture – An example of experimental evolution of parasites?". International Journal for Parasitology. 37 (6): 581–588. doi:10.1016/j.ijpara.2007.01.003. PMID 17316650.
  20. Feehan, Cj; Scheibling, Re (March 17, 2014). "Disease as a control of sea urchin populations in Nova Scotian kelp beds". Marine Ecology Progress Series. 500: 149–158. Bibcode:2014MEPS..500..149F. doi:10.3354/meps10700. ISSN 0171-8630.
  21. Han, Jee Eun (2019-05-30). "Detection of the amoebic parasite (order Dactylopodida) in cultured Pacific white shrimp (Litopenaeus vannamei)". Aquaculture. 507: 246–250. Bibcode:2019Aquac.507..246H. doi:10.1016/j.aquaculture.2019.04.036. ISSN 0044-8486.
  22. Bateman, Ks; Stentiford, Gd; Kerr, R; Hooper, C; White, P; Edwards, M; Ross, S; Hazelgrove, R; Daumich, C; Green, Mj; Ivory, D; Evans, C; Bass, D (2022-07-07). "Amoebic crab disease (ACD) in edible crab Cancer pagurus from the English Channel, UK". Diseases of Aquatic Organisms. 150: 1–16. doi:10.3354/dao03668. ISSN 0177-5103. PMID 35796507.