Description of Anophryoides haemophila n. sp. (Scuticociliatida:Orchitophryidae), a pathogen of American lobsters Homarus americanus

Thirteen wild sea bass from the Oslo fjord in south-eastern Norway were examined for parasites. Nineteen species were found, comprising 5 protozoans, 1 monogenean, 8 digeneans, 1 cestode, 2 nematodes and 2 crustaceans. Based on the similarity to the parasitic fauna of Mediterranean sea bass, it is predicted that sea bass farmers in Northern Europe will experience the same parasite problems as sea bass farmers in warmer regions. KEY WORDS: Aquaculture · Fish farming · Parasitic diseases Resale or republication not permitted without written consent of the publisherDis Aquat Org 48: [209][210][211][212] 2002 RESULTSA total of 19 parasite species were found in the 13 examined sea bass (Table 1). The 5 protozoans found in fresh mucosal smears from the skin and gills of the fish were not identified to species level. Preservation was considered impractical, due to the low numbers of each organism (exemplified by the finding of a single trichodinid ciliate).The most common parasites were diplectanid monogeneans, occurring at 100% prevalence. On the basis of morphological characters of the squamodisc and the penis, all were designated Diplectanum aequans. They were commonly aggregated in small clusters of 2 to 4 individuals on the gill filaments. The attachment sites were commonly whitish, thickened and apparently necrotic when observed by light microscopy. Scanning electron microscopy showed loss of lamellae in such filaments (Figs. 1 to 3).The trematodes were the dominating parasite group with 8 (possibly 9) species present. One unidentified species was present as metacercariae in the skin and fins, and the rest were present as adults in the gastrointestinal tract. With few exceptions, all species were present in low numbers and no signs of a pathological effect of the infections were seen.The 2 nematode species and the cestode were all found as larval or immature stages. The 2 crustaceans were found on fish caught in June. DISCUSSIONAquaculture conditions, concentrating many hosts within a limited space, favour parasites with direct life cycles. In marine fish this has been shown to apply to Ichthyobodo necator (Urawa et al. 1998), trichodinid ciliates (Moksness et al. 1989, Moksness 1990, Lom 1995, Nilsen 1995 and scuticociliates (Cheung et al. 1980, Dragesco et al. 1995, Cawthorn et al. 1996, Messick & Small 1996, Munday et al. 1997, Sterud et al. 2000. Although protozoans were found at very low intensities in the present study, their potential as serious skin and gill parasites in farmed sea bass should thus not be underestimated.Two diplectanid monogeneans are commonly found on sea bass in the Mediterranean: Diplectanum aequans and D. laubieri (González-Lanza et al. 1991 Table 1 comprised 2 morphs based on differences in size and number of eggs in the uterus. B. baeri and B. labracis, which are both parasites of sea bass, are not distinguished by these features but primarily by their site specificity (Maillard 1976). Unfortunately the digeneans were sampled without paying sufficient attention to thei...

Section: Discussioncontrasting

confidence: 38%

Parasites of wild sea bass Dicentrarchus labrax from Norway

Sterud¹

2002

“…The ciliates were observed in various tissues throughout the crayfish and were often associated with extensive necrosis in several organs, particularly the hepatopancreas. Haemocytopenia has been reported to be characteristic of most systemic infections by scuticociliates in crustaceans (Bang et al 1972, Sparks et al 1982, Cawthorn et al 1996 although lesions in other tissues have been described (Armstrong et al 1981, Sparks et al 1982. The ciliate infections in the crayfish were not considered to be long-standing (chronic or latent) as the hepatopancrea of the crayfish with only minor concomitant infections were not depleted of lipid reserves and there were no indications of organ atrophy.…”

Section: Discussionmentioning

confidence: 94%

“…Several species of Mesanophrys (synonyms Mugardia, Paranophrys and Anophrys) have been described from crabs (Bang et al 1972, Groliere & Leglise 1977, Sparks et al 1982, Morado & Small 1994, one Anophryoides sp. from lobster (Cawthorn et al 1996) and one Parauronema sp. from prawns (Couch 1978).…”

Section: Introductionmentioning

confidence: 99%

Systemic infection of freshwater crayfish Cherax quadricarinatus by hymenostome ciliates of the Tetrahymena pyriformis complex

Edgerton¹,

O’Donoghue²,

Wingfield³

et al. 1996

ABSTRACT-A survey of cultured freshwater crayfish Cherax g~~adricarinatus in north Queensland revealed systemic infections by hymenostome clliates in moribund crayfish from one location. The ciliates were identified following protargol impregnation as belonging to the Tetrahymena pyriformis species complex on the basis of their somatic and oral ciliature and morphometric characteristics. Live ciliates were observed in the haemal sinuses of the gills browsing on tissue fragments. H~stological examination revealed the ciliates to have invaded most organs and tissues, causlng extensive necrosis particularly in the hepatopancreas and antenna1 gland. Lipid reserves were not depleted in the hepatopancreas, suggesting the rapid de\telopment of acute disease. This is the flrst record of systeinlc ciliate infections in freshwater decapods.

“…Scuticociliates have also been associated with cllnical disease in crabs, lobsters and prawns (Morado & Small 1995, Cawthorn et al 1996 and clam Venecrupis sp. larvae (G. Maguire pers, comm.)…”

Section: R Ventralmentioning

confidence: 99%

Fatal encephalitis due to the scuticociliate Uronema nigricans in sea-caged, southern bluefin tuna Thunnus maccoyii

Munday¹,

O'Donoghue²,

Watts³

et al. 1997

109

A syndrome characterized by atypical swimming behaviour followed by rapid death was first reported in captive southern bluefin tuna Thunnus maccoyii (Castelnau) in the winter of 1993. The cause of this behaviour was found to be a parasitic encephalitis due to the scuticociliate Uronema nigricans (Mueller) Based on parasitological and histological findings, it is proposed that the parasites initially colonise the olfactory rosettes and then ascend the olfactory nerves to eventually invade the brain. Possible epidemiological factors ~nvolved in the pathogenesis of the disease include water temperature (<18"C) and the immune status of the fish.