Hemoflagellates, host-parasite relationships, and strategies against salmonid cryptobiosis
"To strive, to seek, to find, and not to yield" - Alfred Tennyson
Patrick TK Woo MSc, PhD [profile website]
University Professor Emeritus, Department of Integrative Biology
College of Biological Science, University of Guelph
Guelph, Ontario N1G 2W1, Canada

Email: pwoo@uoguelph.ca; Phone: 519-824-4120 ext. 53581
Office (Room 2443) & Laboratory (Room 2401), Science Complex

I. Parasites and Diseases:blood flagellates; mammalian trypanosomiasis; piscine cryptobiosis and spironucleosis

II. Publications: CABI books; special issue; reviews; refereed papers; gScholar citations; PubMed

III. Research: programs; collaborators; MSc & PhD students; consultancies; awards

IV. Presentations: lectures and seminars @ conferences/universities; contributed papers @ conferences

V. Editorial activities; WMC Advisory Board; Writing workshop; Research contributions; Abbreviated curriculum vitae

VI. The Roy C Anderson Memorial Lecture in Parasitology (2011 lecture); The Marcel N Ali Memorial Lecture in Aquatic Biology (2011 lecture)

I (a). Trypanosoma, Cryptobia and Spironucleus:

Patrick Woo has always focused his research on blood flagellates (Figs. 1 - 3 & 7) of vertebrates and they include parasites that are of medical (Fig. 2) and economic importance (Figs. 3 & 7). His early research was mainly on trypanosomes (Figs. 1 & 2), and mammalian trypanosomiasis which involved field studies in Africa (Figs. 4 - 6).

Fig. 1: Trypanosoma ranarum in frogs (Rana pipiens) Fig. 2: Trypanosoma b. rhodesiense in humans (Homo sapiens) Fig. 3: Spironucleus sp. in salmon (Oncorhynchus tschawytscha)

He also worked on mammalian Giardia spp. after his academic appointment at UoG (profile); his current program on Cryptobia (Fig. 7) and cryptobiosis (Figs. 8-10) which includes strategies, against the disease was initiated in 1974. The pathogen has been recorded from all species of Pacific salmon (Oncorhynchus spp.) on the west coast of North America, and it is transmitted by the freshwater leech (Piscicola salmositica) in streams and rivers.
Another of his program is on systemic spironucleosis; outbreaks of the disease have been reported in salmonids cultured in sea cages in Canada and Norway. Large numbers of Spironucleus (Fig. 3) are in the blood, internal organs, and ulcers on the body surface (Figs. 11-13) of infected fish. The pathogen is transmitted directly between fish.

I (b). Diseases: Trypanosomiasis, Cryptobiosis and Spironucleosis

Animal (includes human) Trypanosomiasis [Figs. 2 & 4 - 6; see #1 & #2 in 'selected contributions']

Fig. 4: Human trypanosomiasis (Trypanosoma brucei gambiense), EATRO, Uganda

Fig. 5: Haematocrit Centrifuge Technique, trypanosomiasis survey (human), SRI, Tanzania

Fig. 6: Bovine trypanosomiasis (Trypanosoma congolense), EATRO, Uganda

One of his early contributions on human trypanosomiasis in Africa was to use the Haematocrit Centrifuge Technique (HCT; Woo, 1969) in hospitals to detect trypanosomes in the blood and cerebral spinal fluid of patients with trypanosomiasis (Woo, 1970b). He adapted the HCT for use under field conditions (Woo, 1971) and used it in a survey on human trypanosomiasis (Onyango & Woo, 1971). "The . . . technique of Woo is the most suitable for rural hospitals" (Foulkes, 1981), and it " . . . is still in use in many HAT [Human African Trypanosomiasis] control programs" in Africa (Chappuis et al., 2005). It is also used to diagnose the disease in patients outside of Africa (Lejon et al., 2003), for the detection of congenital Chagas' disease caused by Trypanosoma cruzi in South America ( Moretti et al. 2005), and is ". . . recommended for the parasitological diagnosis of acute Chagas' disease and malaria" in rural areas (Fuente et al., 1985).
Since the HCT is a rapid and sensitive technique (Woo & Rogers, 1974) it is also " . . . widely used for the diagnosis of animal trypanosomiasis" (Schlater & Van Den Bossche, 2004).
It is sometimes called the "Woo test" (e.g. Chappuis et al., 2005) , or "Woo technique" (e.g. Quispe et al., 2003) , or "Woo method" (e.g. Uilenberg, 1998; Schlater & Van Den Bossche, 2004).

Salmonid Cryptobiosis [Figs. 7 - 10; see #3, #4, #5 & #6 in 'selected contributions']

Fig. 7: Cryptobia (T.) salmositica with a red cell from an anemic fish Fig. 8: Bilateral exophthalmia in salmonid cryptobiosis (acute phase)
Fig. 9: Splenomegaly (6 - 8 times by volume) Fig. 10: General edema and abdominal distension with ascites
Salmonid cryptobiosis is caused by the hemoflagellate, Cryptobia salmositica (Figs. 7-10; Woo, 2003). The parasite is transmitted by leeches (Piscicola salmositica) in streams and rivers on the Pacific coast of North America; however, direct transmission can also occur when infected and uninfected fish are held for prolonged periods in the same tank or under certain hatchery conditions. Clinical signs include anorexia, exophthalmia (Fig. 8), splenomegaly (Fig. 9), hepatomegaly, general edema and abdominal distention with ascites (Fig. 10), a microcytic and hypochromic anemia, and red cells are antiglobulin positive. Infected salmonids are susceptible to hypoxia, and their metabolism and swimming performance are reduced. Also, the lytic activities of complement in sera of infected fish are reduced, and the ability of infected fish to mount a protective response against a secondary pathogen and/or antigen is depressed. The anemia and anorexia in infected fish contribute to the immunodepression. The pathogen has at least two proteases - the cysteine protease is a metabolic enzyme while metalloprotease (a histolytic enzyme) is the main virulent factor.

The program on cryptobiosis is a multidisciplinary study. It is on the biology of the pathogen, diagnosis of infection, pathobiology in cryptobiosis including elucidation of the disease mechanism, host immune responses, and the development of strategies against the parasite and disease (Woo, 2003). Preventive strategies include exploiting innate and adaptive immunity, chemotherapy and immunochemotherapy (Woo, 2010).

Salmonid Spironucleosis [Figs. 3 & 11-13]
Systemic spironucleosis is caused by Spironucleus (Fig. 3) - the parasite is in the blood and internal organs of salmonids. The parasite causes morbidity and mortality in fishes and there have been outbreaks of the disease in salmon cultured in sea cages - in chinook salmon on the west coast of Canada and in Atlantic salmon in Norway. Fish mortality was high and some infected chinook salmon had abdominal distensions and were anemic while infected Atlantic salmon were significantly smaller than healthy fish and they behaved 'abnormally' prior to death. Little is known about the biology of the pathogen nor factors that precipitated the outbreaks, and there are at present no preventive nor control strategies against the parasite and the disease. (Woo, 2006. Chapter 3. In: Fish Diseases and Disorders, Vol. 1: Protozoan and Metazoan Infections, 2nd edition, pages 46-114).

Fig. 11: Unilateral exophthalmia Fig. 12: Ulceration on body surface Fig. 13: Globulated and enlarged spleen

Spironucleus barkhanus has a blood and a tissue phase in experimentally infected Atlantic salmon. It first appears in the blood about a week after infection in some fish and the parasitaemia peaks at about 6 weeks. The parasite is not detectable in the blood at about 8 weeks after infection but it occurs in high numbers in the spleen, liver, eye socket, and muscles. Thirty eight out of 40 infected fish died in one experiment, and mortality was equally high (29 out of 30 infected fish) in another experiment with Atlantic salmon from 3 families of fish. Clinical signs of spironucleosis include unilateral exophthalmia (Fig. 11), skin blisters and ulcerations (Fig. 12), enlarged and globulated spleens (Fig. 13), livers with whitish to yellowish nodules, and haemorrhaging in organs. The parasite can be experimentally transmitted by inoculation of infected blood or through co-habition of infected and uninfected fish ( Guo & Woo, 2004).

II (a). Books (1995-present):

Diseases and Disorders of Finfish in Cage Culture (2002) Fish Diseases and Disorders, Vol. 1, 2nd edition (2006) Fish Diseases and Disorders, Vol. 2, 2nd edition (2010) Fish Diseases and Disorders, Vol. 3, 2nd edition (2011) Fish Parasites: Pathobiology and Protection (2012)

Woo P.T.K. & Buchmann K. (eds.), 2012. Fish Parasites: Pathobiology and Protection, CABI, U.K., 400 pages.

Woo P.T.K. & Bruno D.W. (eds.) 2011. Fish Diseases and Disorders, Volume 3: Viral, Bacterial and Fungal Infections, 2nd edition, CABI, U.K., 940 pages.

Leatherland J.F. & Woo P.T.K. (eds.) 2010. Fish Diseases and Disorders, Volume 2: Non-infectious Disorders, 2nd edition, CABI, U.K., 416 pages.

Woo P.T.K. (ed.) 2006. Fish Diseases and Disorders, Volume 1: Protozoan and Metazoan Infections, 2nd edition, CABI, U.K., 800 pages.

Woo P.T.K., Bruno D.W. & Lim L.H.S. (eds.) 2002. Diseases and Disorders of Finfish in Cage Culture, CABI, U.K., 384 pages.

Woo P.T.K. & Bruno D.W. (eds.) 1999. Fish Diseases and Disorders, Volume 3: Viral, Bacterial and Fungal Infections, CABI, U.K., 874 pages.

Leatherland J.F. & Woo P.T.K. (eds.) 1998. Fish Diseases and Disorders, Volume 2: Non-infectious Disorders, CABI, U.K., 386 pages.

Woo P.T.K. (ed.) 1995. Fish Diseases and Disorders, Volume 1: Protozoan and Metazoan Infections, CABI, U.K., 808 pages.

II (b). Book Chapters and Refereed Conference Proceedings (2001-present):
[complete lists - (i) book chapters and (ii) conference proceedings]

Jung, S.J. & Woo, P.T.K. 2012. Miamiensis avidus. In: Fish Parasites: Pathobiology and Protection, (eds. P.T.K. Woo & K. Buchmann), CABI, Oxfordshire, U.K. pp. 73-91.

Woo, P.T.K. 2012. Cryptobia (Trypanoplasma) salmositica. In: Fish Parasites: Pathobiology and Protection, (eds. P.T.K. Woo & K. Buchmann), CABI, Oxfordshire, U.K. pp. 30-54.

Guo, F.C. & Woo, P.T.K. 2009. Selected parasitosis in cultured and wild fish. In: 22nd World Association for the Advancement of Veterinary Parasitology, Calgary, Canada (conference held in 2009); Vet. Parasitol. 163: 207-216.

Woo, P.T.K. 2007. Protective immunity in fish against protozoan diseases. In: 7th International Symposium on Fish Parasites, Viterbo, Italy (conference held in 2007); Parassitologia 49: 185-191.

Woo, P.T.K. 2006. Strategies against piscine parasitosis: the 'Cryptobia model'. In: Innovations and Technologies in Oceanography for Sustainable Development (eds. S.M. Phang, Siti Aisyah, V.C. Chong, M. George, Siti Aisyah & S.C. Ho), Kuala Lumpur, Malaysia (conference held in 2005); Maritime Research Centre, University of Malaya, Kuala Lumpur, Malaysia, pp. 17-28 .

Woo, P.T.K. 2006. Diplomonadida (Phylum Parabasalia) and Kinetoplastea (Phylum Euglenozoa). In: Fish Diseases and Disorders, Volume 1: Protozoan and Metazoan Infections, 2nd edition (ed. P.T.K. Woo), CABI, Oxfordshire, U.K. pp. 46-114.

Ardelli, B.F. & Woo, P.T.K. 2006. Immunocompetent cells and their mediators in finfish. In: Fish Diseases and Disorders, Volume 1: Protozoan and Metazoan Infections, 2nd edition (ed. P.T.K. Woo), CABI, Oxfordshire, U.K. pp. 699-721.

Woo, P.T.K. 2005. Salmonid cryptobiosis and strategies against the disease. In: 19th International Congress of Zoology, Beijing, China (conference held in 2004); Acta Zool. Sinica 51: 546-549.

Woo, P.T.K. 2004. The pathophysiology of salmonid cryptobiosis and Glossina-transmitted mammalian trypanosomiasis in livestock. In: Host-Parasite Interactions (eds. G.F. Wiegerties & G. Flik), BIOS Scientific Publishers, New York, U.S.A. pp. 91-105.

Bruno, D.W. & Woo, P.T.K. 2002. Sporadic, emerging diseases and disorders. In: Diseases and Disorders of Finfish in Cage Culture (eds. P.T.K. Woo, D.W. Bruno & S.L.H. Lim), CABI, Oxfordshire, U.K., pp. 305-343.

Woo, P.T.K. 2001. Cryptobiosis and its control in North American fishes. In: 3rd. Internet Conference on Salivarian Trypanosomes. (conference held in 2000); Internat'l. J. Parasitol. 31: 565-573 .

II (c). Selected Refereed Papers in Journals (2001-present):
[complete list]

Jung, S.J., Im, E.Y., Struder-Kypke, M.C., Kitamura, S.I. & Woo, P.T.K. 2011. Small submit ribosomal RNA and mitochondrial cytochrome C oxidase subunit 1 gene sequences of 21 strains of parasitic Scuticociliate Miamiensis avidus (Ciliophora, Scuticociliatida). Parasitol. Res. 108: 1153-1161 [Epub. 2010 Nov 27. PMID: 21113725]. .

Woo, P.T.K. 2010. Immunological and therapeutic strategies against salmonid cryptobiosis (Special issue: Immunology and Cell Biology of Parasitic Diseases), J. Biomed. Biotechnol. Article ID341783, 9 pages [doi:10.1155/2010/341783]. .

Guo, F.C. & Woo, P.T.K. 2009. Selected parasitosis in cultured and wild fish. Vet. Parasitol. 163: 207-216.

Nourollahi-Fard, S.R. & Woo P.T.K. 2008. Contribution of food deprivation to the immune response in rainbow trout (Oncorhynchus mykiss) vaccinated against Cryptobia salmositica and Aeromonas salmonicida. Acta Vet. Hung. 56: 197-206.

Tan, C.W., Jesudhasan, R.R.R. & Woo, P.T.K. 2008. Towards a metalloprotease-DNA vaccine against piscine cryptobiosis caused by Cryptobia salmositica. Parasitol. Res. 102: 265-275.

Currie, J.L.M. & Woo, P.T.K. 2007. Susceptibility of sexually mature rainbow trout, Oncorhynchus mykiss to experimental cryptobiosis caused by Cryptobia salmositica. Parasitol. Res. 101: 1057-1067.

Jesudhasan, P.R.R., Tan, C.W. & Woo, P.T.K. 2007. A metalloproteinase gene from the pathogenic piscine hemoflagellate, Cryptobia salmositica. Parasitol. Res. 100: 899-904.
[Jesudhasan, P.R.R. & P.T.K. Woo (2004) Major surface glycoprotein metalloproteinase gene - key gene involved in pathogensis. GENBANK No. AY632692.]

Chin, A. & Woo, P.T.K. 2005. Innate cell-mediated immune response and peripheral leukocyte populations in Atlantic salmon, Salmo salar L., to a live Cryptobia salmositica vaccine. Parasitol. Res. 95: 299-304.

Woo, P.T.K. 2005. Salmonid cryptobiosis and strategies against the disease. Acta Zool. Sinica 51: 546-549.

Guo, F.C. & Woo, P.T.K. 2004. Experimental infections of Atlantic salmon, Salmo salar L. (Salmonidae) with Spironucleus barkhanus (Diplomonidida: Hexamitidae). Dis. Aquat. Org. 61: 59-66.

Chin, A., Guo, F.C., Bernier, N. & Woo, P.T.K. 2004. Cryptobia salmositica-induced anorexia and its effects on gastric evacuation, feeding hierarchy, and immune response against a live vaccine in juvenile rainbow trout, Oncorhynchus mykis. Dis. Aquat. Org. 58: 17-26.

Torgerson, D.G., Lampo, M., Velazquez, Y. & Woo, P.T.K. 2003. Genetic relationships among some species groups within the genus Lutzomyia (Diptera: Psychodidae). Amer. J. Trop. Med. & Hyg. 69: 484-493.

Woo, P.T.K. 2003. Cryptobia (Trypanoplasma) salmositica and salmonid cryptobiosis. J. Fish Dis. 26: 627-646.

Ardelli, B.F. & Woo, P.T.K. 2002. Experimental Cryptobia salmositica (Kinetoplastida) infections in Atlantic salmon (Salmo salar): Cell-mediated and humoral response against the pathogenic and vaccine strains of the parasite. J. Fish Dis. 25: 265-274.

Mehta, M. & Woo, P.T.K. 2002. Acquired cell-mediated protection in rainbow trout, Oncorhynchus mykiss, against the haemoflagellate, Cryptobia salmositica. Parasitol. Res. 88: 956-962.

Bahmanrokh, M. & Woo, P.T.K. 2001. Relationships between histopathology and parasitaemias in Oncorhynchus mykiss infected with Cryptobia salmositica, a pathogenic haemoflagellate. Dis. Aquat. Org. 46: 41-45

Feng, S. & Woo, P.T.K. 2001. Cell membrane glycoconjugates on virulent and avirulent strains of the pathogenic haemoflagellate Cryptobia salmositica Katz. J. Fish Dis. 24: 23-32.

IV. Invited Presentations @ Conferences and Universities (2001-present):
[complete list of invited lectures/papers @ conferences;
& partial list of invited lectures/seminars @ universities/Institutes]

2011. Plenary Lecture, 3rd World Congress in Biotechnology, Hyderabad, India (invitation declined).

2012. "Aquculture and parasitosis: protozoan infections in finfish" (Public Lecture), Institute of Bioscience, Universiti Putra Malaysia, Serdang, Malaysia.

2012. "Strategies against parasitic diseases: the cryptobiosis model" (Plenary Lecture), 3rd Vaccines and Therapeutic Seminar and Workshop: Fish Diseases, Serdang, Malaysia.

2011. Plenary Lecture, 3rd International Symposium on Cage Aquaculture in Asia, Kuala Lumpur, Malaysia (invitation declined).

2011. "Miaminensis avidus, pathobiology and protection" (Public Lecture), Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, Kuala Terengganu, Malaysia.

2010. "Strategies against parasitic diseases in fish:The Cryptobia model" (Public Lecture), Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur, Malaysia.

2009. "Relacion entre parasitos protozoarios patogenos y estrategias de defensa del sistema immune: perspectiva para el desarrollo de una vacuna" (Plenary Lecture), Seminario Internacional de Parasitologia Applicada a la Acuicultura, Puerto Montt, Chile.

2009. "Selected parasitosis in cultured and wild fish' (Plenary Lecture; presenter - F.C. Guo), 22nd World Association for the Advancement of Veterinary Parasitology, Calgary, Canada.

2008. "Aquaculture and parasitosis: strategies against protozoan diseases in finfish" (Public Lecture), College of Fisheries and Ocean Sciences, Chonnam National University, Republic of Korea.

2007. "Protective immunity in fish against protozoan diseases" (Plenary Lecture), 7th International Symposium on Fish Parasites, Viterbo, Italy.

2006. "Development of an integrated strategy against parasitic diseases in finfish under aquaculture conditions" (Public Lecture), College of Fisheries and Ocean Sciences, Chonnam National University, Republic of Korea.

2005. "Strategies against piscine parasitosis: the Cryptobia model" (Symposium Paper – Marine Biotechnology: New Uses of Marine Resources), International Conference on Innovations and Technologies in Oceanography for Sustainable Development, Kuala Lumpur, Malaysia

2005. "Strategies against piscine parasitosis: the Cryptobia model" (Public Lecture),

(a) University of Malaya, Kuala Lumpur, Malaysia

(b) Burapha University, Bangsaen, Thailand

2004 Symposium Paper, World and Ehrlich Conference on Magic Bullets, Numberg, Germany (invitation declined; prior commitments).

2004. "Salmonid cryptobiosis and strategies against the disease" (Symposium Paper - Parasitic Diseases of Finfish and Their Control), 19th International Congress of Zoology, Beijing, China.

2004. "Control measures against Cryptobia and cryptobiosis" (Public Lecture), Kolej Universiti Sains dan Technologi Malaysia, Kuala Terengganu, Malaysia.

2003. "Strategies against salmonid diseases" (Plenary Lecture), Sustainable Control of Fish Diseases in Aquaculture, Danish Network for Fisheries and Aquaculture Research, Copenhagen, Denmark.

2003. "Cryptobia and cryptobiosis: some recent studies" (Public Lecture), The Royal Veterinary and Agriculture University, Copenhagen, Denmark.

2003. "Current and future trends in Biological Sciences" (Public Lecture), Kolej Universiti Sains dan Technologi Malaysia, Kuala Terengganu, Malaysia.

2002. "Salmonid cryptobiosis and its control" (Workshop Paper - Haemoflagellate Diseases), Wageningen University, Wageningen, The Netherlands.

2002. "The pathophysiology in piscine and mammalian haemoflagellate diseases" (Symposium Paper- Host Parasite Interactions: A Comparative Approach), American Physiological Society, San Diego, U.S.A.

2002. "Towards an integrated strategy against salmonid cryptobiosis" (Public Lecture), The Royal Veterinary and Agricultural University, Copenhagen, Denmark.

2002. "Cryptobia and cryptobiosis in economically important fishes" (Plenary Lecture - Impact and Control of Diseases in Fish), Danish Network for Fisheries and Aquaculture Research, Denmark.

2002. "Immunological response in Atlantic salmon, and the identification of molecular markers associated with an efficient immune system", (Symposium Paper - Animal Production Theme), AquaNet Annual Meeting, Moncton, Canada.

2001. "Fish as an important animal protein and the development of an integrated strategy against piscine parasitosis" (Plenary Lecture), International Congress of Parasitology and Tropical Medicine, Kuala Lumpur, Malaysia.

2001. "The pathobiology in salmonid cryptobiosis" (Symposium Paper - Infectious Organisms in the Aquatic System: From Molecules to Organisms), International Congress of Parasitology and Tropical Medicine, Kuala Lumpur, Malaysia.

9th International Congress of Parasitology, Chiba
Fish Parasitologists with the Official ICOPA Flag
(Photograph: Courtesy of the late Shunya Kamegai
 Meguro Parasitology Museum, Tokyo, Japan)


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