Fish Disease: MArine White Spot Disease

Fish Diseases in Taiwan

p r o t o z o a

C r y p t o c a r y o n i r r i t a n s
Marine White Spot Disease

Cryptocarryon irritans, the notoriouscausative agent of 'white spot disease' in marine fish, is one of the major enemy to aquculture in southern Taiwan. This disease affects grouper, snook, snapper and almost all saltwater speceis. In grouper culture, it causes great loss every year.
This disease always happen when seasons change. March and October are their party times. We usually have about 5-10 C. irritans infection cases per day during that period every year.

C. irritans was rarely seen in Taiwan before 1987. But after 1988, this parasite caused high mortality in mariculture every year, sometimes the mortality might be 100% in severe cases. This disease reaches its height between October and March in the next year.
In early stage of infection only some grouper swim in upper layer of water at night (grouper is a bottom-dwelling species). Gradually the fish lose their appetite and swim around constantly, day and night. At this stage, fish increase the mucus production in gills and skin, eyes getting cloudy and some white spots appear on their skin. Sometimes you can see fish rubbing themselves against hard surfaces, trying to get rid of the parasite. Finally fish die of oxygen deprivation due to hyperplasia of gill epithelium.
Treatment we are using now is 40 ppm formalin, doing it every other day. There are some problems about this treatment. In some ponds it was not possible to get formalin concentration to 40 ppm. Bacteria in the pond somehow metabolized the formalin. In this case, extensive water change before treatment can sometimes be helpful.

Figure 1
Infected grouper.
Numerous white spots can be seen grossly on body surface.

Figure 2
Closer view of body surface

Figure 3
Microscopic examination of gill clipping reveals the presence of trophonts under the gill epithelium.

Figure 4
Closer view of a trophont.

Figure 5
Tomonts that just left the host. Later they will encyst and undergo mitosis and replicate.

Figure 6
Tomont undergoing mitosis.

Figure 7
Hundreds of these cell mass inside a cyst. They will become theront, the infective stage later.

Figure 8
Theront. They are fast swimming and able to penetrate into fish epithelum.

Figure 9
Scanning electron micrograph of a theront, reveals beautiful delicate ciliation.

Figure 10
Sometimes they can encyst on host gills, although the size is much smaller.

Chao, C. -B. and H. -Y. Chung. 1994. Study on Cryptocaryon irritans infection on captive grouper (Epinephelus sp.) life cycle and pathgenicity. Fish Disease Research 14: 31-40.
Bryant, M. S., R. P. Lee, R. J. G. Lester and R. J. Whittington. 1999. Anti-immunoglobulin antisera used in an ELISA to detect antibodies in barramundi Lates calcarider to Cryptocaryon irritans. Diseases of Aquatic Organisms 36: 21-28.
Bunkley-Williams, L. and E. H. Williams, Jr. 1994. Diseases caused by Trichodina spheroidesi and Cryptocaryon irritans (Ciliophora) in wild coral reef fishes. Journal of Aquatic Animal Health 6: 360-361.
Burgess, P. J. and R. A. Matthews. 1995. Cryptocaryon irritans (Ciliophora): acquired protective immunity in the thick-lipped mullet, Chelon labrosus. Fish and Shellfish Immunology 5: 459-468.
Burgess, P. J. and R. A. Mathews. 1995. Fish host range of seven isolates of Cryptocaryon irritans (Ciliophora). Journal of Fish Biology 46: 727-729.
Burgess, P. J. and R. A. Mathews. 1994. Crptocaryon irritans (Ciliophora): photoperiod and transmission in marine fish. Journal of Marine Biology Association U.K. 74: 535-542.
Burgess, P. J. and R. A. Mathews. 1994. A standardized method for the in vivo maintenance of Cryptocaryon irritans (Ciliophora) using the grey mullet Chelon labrosus as an experimental host. Journal of Parasitology 80: 288-292.
Cheung, P. F., R. F. Nigrelli and G. D. Ruggieri. 1981. Scanning electron microscope on Cryptocaryon irritans Brown 1951, a parasitic ciliate in marine fishes. Journal of Aquaculture 2: 70-72.
Colorni, A. 1987. Biology of Cryptocaryon irritans and strategies for its control. Aquaculture 67: 236-237.
Diggle, B. K. and R. D. Adlard. 1997. Intraspecifi variation in Cryptocaryon irritans. Journal of Eukaryotic Microbiology 44: 25-32.
Diggles, B. K. 1997. Some information on the morphology of Cryptocaryon irritans from south-east Queensland, Australia. European Journal of Protistology 33: 200-210.
Diggles, B. K., R. J. Lester. 1996. Infections of Cryptocaryon irritans on wild fish from southeast Queensland, Australia. Diseases of Aquatic Organisms 25: 159-167.
Diggles, B. K. and R. D. Adlard. 1995. Taxonomic affinities of Cryptocaryon irritans and Ichthyophthirius multifiliis inferred from ribosomal RNA sequence data. Diseases of Aquatic Organisms 22: 39-43.
Diggles, B. K. and R. J. G. Lester. 1996. Influence of temperature and host species on the development of Cryptocaryon irritans. Journal of Parasitology 82: 45-51.
Diggles, B. K. and R. J. G. Lester. 1996. Variation in the development of two isolates of Cryptocaryon irritans. Journal of Parasitology 82: 384-388.
Hirazawa, N., S. Oshima, T. Hara., T. Mitsuboshi and K. Hata. 2001. Antiparasitic effect of medium-chain fatty acids against the ciliate Cryptocaryon irritans infestation in the red sea bream Pagrus major. Aquaculture 198: 219-228.
Jee, B. -Y., K. H. Kim, S. -I. Park and Y. -C. Kim. 2000. A new strain of Cryptocaryon irritans from the cultured olive flounder Paralichthys olivaceus. Diseases of Aquatic Organisms 43: 211-215.
Kakuta, I and H. Kurokura. Defensive effect of orally administered bovine lactoferrin against Cryptocaryon irritans infection on red sea bream. Fish Pathology 30: 289-290.
Mathews, R. A. and P. J. Burgess. 1995. Cryptocaryon irritans (Ciliophora): primary infection in thick-lipped mullet, Chelon labrosus (Risso). Journal of Fish Diseases 18: 329-335.
Yoshinaga, T. and H. W. Dickerson. 1994. Laboratory propagation of Cryptocaryon irritans on a slt-water-adapted Poecilia hybrid, the Black Molly. Journal of Aquatic Animal Health 6: 197-201.

Colorni, A. 1985. Aspects of the biology of Cryptocaryon irritans , and hyposalinity as a control measure in cultured gilt-head sea bream Sparus aurata. Diseases of Aquatic Organisms 1:19-22.
Diamant, A., G. Issar, A. Colorni and I. Paperna. 1991. A pathogenic Cryptocaryon-like ciliate from the Mediterranean Sea. Bulletin of the European Association of Fish Pathologists 11: 122-124.
Huff, J. A. and C. D. Burns. 1981. Hypersalinity and chemical control of Cryptocaryon irritans in red snapper, Lutjanus campechanus monoculture. Aquaculture 22: 181-184.
Kaige, N. and T. Miyazaki. 1985. A histological study of white spot disease in Japanese flounder. Fish Pathology 20: 61-64.
Nigrelli, R. F. and G. D. Ruggieri. 1966. Enzootics in New York Aquarium caused by Cryptocaryon irritans Brown, 1951 (= Ichthyophthirius marinus Sikama, 1961), a histophagous ciliate in the skin, eyes and gills of marine fishes. Zoologica 51: 97-102.
Colorni, A. and A. Diamant. 1993. Ultrasstructural features of Cryptocaryon irritans, a ciliate parasite of marine fish. European Journal of Protistology 29: 425-434.
Mathews, B. F., R. A. Mathews and P. J. Burgess. 1993. Cryptocaryon irritans Brown, 1951 (Ichthyophthiriidae): the ultrastructure of the somatic cortex throughout the life cycle. Journal of Fish Diseases 16: 339-349.
Wilkie, D. W. and H. Gordin. 1969. Outbreak of cryptocaryoniasis in marine aquaria at Scripps Institute of Oceanography. California Fish Game 55: 227-236.

Last Update: 30 October 2001

	Figure 1 Infected grouper. Numerous white spots can be seen grossly on body surface.
	Figure 2 Closer view of body surface
	Figure 3 Microscopic examination of gill clipping reveals the presence of trophonts under the gill epithelium.
	Figure 4 Closer view of a trophont.
	Figure 5 Tomonts that just left the host. Later they will encyst and undergo mitosis and replicate.
	Figure 6 Tomont undergoing mitosis.
	Figure 7 Hundreds of these cell mass inside a cyst. They will become theront, the infective stage later.
	Figure 8 Theront. They are fast swimming and able to penetrate into fish epithelum.
	Figure 9 Scanning electron micrograph of a theront, reveals beautiful delicate ciliation.
	Figure 10 Sometimes they can encyst on host gills, although the size is much smaller.