Parasitic helminths of the pig: Factors influencing transmission and infection levels

International Journal for Parasitology

Volumn 29, Issue 6, 1999, Pages 877-891

  Nansen, Peter ^a   Roepstorff, Allan ^a  

^a UNIVERSITY OF COPENHAGEN   (Denmark)

Author keywords

Control; Epidemiology; Helminths; Pigs; Production system; Transmission

Indexed keywords

ANTHELMINTIC AGENT; FENBENDAZOLE; IVERMECTIN; LEVAMISOLE;

AGRICULTURAL INTENSIFICATION; AGRICULTURAL PRACTICE; INFECTIVITY; LITERATURE REVIEW; PARASITE TRANSMISSION; PIG;

ASCARIS SUUM; CONFERENCE PAPER; DISEASE TRANSMISSION; DRUG RESISTANCE; EGG; HELMINTHIASIS; IMMUNOGENICITY; INFECTION CONTROL; METASTRONGYLOIDEA; NEMATODIASIS; STRONGYLOIDEA; STRONGYLOIDES; SWINE; TRICHURIS; VERTICAL TRANSMISSION;

ANIMAL HUSBANDRY; ANIMALS; ANTHELMINTICS; DRUG RESISTANCE; HELMINTHIASIS, ANIMAL; HELMINTHS; SWINE; SWINE DISEASES;

SUS SCROFA; SUS SCROFA DOMESTICA; VERMES;

EID: 0032813102     PISSN: 00207519     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0020-7519(99)00048-X     Document Type: Conference Paper

References (124)

1. Smith H.M., Davidson W.R., Neetles V.F., Gerrish R.R. Parasitisms among wild swine in southeastern United States. J Am Vet Med Assoc. 181:1982;1281-1285.
2. Barutzki D., Schoierer R., Gothe R. Helmintheninfektionen von Wildschweinen bei Gatterhaltung in Süddeutschland: Artenspektrum und Befallshäufigkeit. Tierärztl Prax. 18:1990;529-534.
3. Roberts F.H.S. The incidence, prevalence and distribution of the helminths infesting the lungs and alimentary tract of the pig in Queensland. Aust Vet J. 16:1940;259-266.
4. Ajayi J.A., Arabs W.L., Adeleye G.A. Helminths and protozoa of pigs on the Jos Plateau, Nigeria: occurrence, age incidence and seasonal distribution. Bull Anim Hlth Prod Afr. 36:1988;47-54.
5. Murrell K.D. Epidemiology, pathogenesis and control of major swine helminth parasites. Vet Clin N Am: Food Anim Pract. 2:1986;439-454.
6. Hale O.M., Stewart T.B. Feed and maintenance costs of internal parasites in growing-finishing swine. AgriPract. 8:1987;33-35.
7. Roepstorff A, Nansen P. The epidemiology, diagnosis and control of helminth parasites of swine. An FAO handbook. FAO, Rome, Italy, 1998, in press.
8. Roepstorff A., Nansen P. Epidemiology and control of helminth infections in pigs under intensive and non-intensive production systems. Vet Parasitol. 54:1994;69-85.
9. Boes J., Medley G.F., Eriksen L., Roepstorff A., Nansen P. Distribution of Ascaris suum in experimentally and naturally infected pigs and comparison with Ascaris lumbricoides infections in humans. Parasitology. 117:1998;589-596.
10. Eriksen L., Nansen P., Roepstorff A., Lind P., Nilsson O. Response to repeated inoculations with Ascaris suum eggs in pigs during the fattening period. I. Studies on worm population kinetics. Parasitol Res. 78:1992;241-246.
11. Roepstorff A., Murrell K.D. Transmission dynamics of helminth parasites of pigs on continuous pasture: Ascaris suum and Trichuris suis. Int J Parasitol. 27:1997;563-572.
12. Roepstorff A., Eriksen L., Slotved H.-C., Nansen P. Experimental Ascaris suum infection in the pig: worm population kinetics following single inoculations with three doses of infective eggs. Parasitology. 115:1997;443-452.
13. Roepstorff A. Natural Ascaris suum infections in swine diagnosed by coprological and serological (ELISA) methods. Parasitol Res. 84:1998;537-543.
14. Olson L.S., Kelley G.W., Sen H.G. Longevity and egg production of Ascaris suum. Trans Am Microbiol Soc. 77:1958;380-383.
15. Nilsson O. Ascariasis in the pig. An epizootiological and clinical study. Acta Vet Scand 1982, Suppl 79:1-108.
16. Bindseil E. Observations on the relationship between Ascaris suum burdens in pigs and faecal egg counts. Acta Pathol Microbiol Scand B. 82:1974;879-884.
17. Boes J., Nansen P., Stephenson L.S. False-positive Ascaris suum egg counts in pigs. Int J Parasitol. 27:1997;833-838.
18. Müller G. Untersuchungen über die Lebensdauer von Ascarideneiern in Gartenerde. Zblt Bakteriol Parasitenkd Infektionskrankh Hyg, 1952/53;159:377-379.
19. Roepstorff A. Helminth surveillance as a prerequisite for anthelmintic treatment in intensive sow herds. Vet Parasitol. 73:1997;139-151.
20. Seamster A.P. Developmental studies concerning the eggs of Ascaris lumbricoides var. suum. Am Midland Naturalist. 43:1950;450-468.
21. Connan R.M. Ascariasis: the development of eggs of Ascaris suum under the conditions prevailing in a pig house. Vet Rec. 100:1977;421-422.
22. Stevenson P. The influence of environmental temperature on the rate of development of Ascaris suum eggs in Great Britain. Res Vet Sci. 27:1979;193-196.
23. Goodall E.A., McLoughlin E.M., Menzies F.D., McIlroy S.G. Time series analysis of the prevalence of Ascaris suum infections in pigs using abattoir condemnation data. Anim Prod. 53:1991;367-372.
24. Taffs L.F. Immunological studies on experimental infection of pigs with Ascaris suum Goeze, 1782. III. The antibody response and acquired immunity. J Helminthol. 38:1964;129-150.
25. Eriksen L. Experimentally induced resistance to Ascaris suum in pigs. Nord Vet Med. 34:1982;177-187.
26. Urban J.F., Tromba F.G. An ultraviolet-attenuated egg vaccine for swine ascariasis: parameters affecting the development of protective immunity. Am J Vet Res. 45:1984;2104-2108.
27. Stewart T.B., Southern L.L., Gibson R.B., Simmons L.A. Immunization of pigs against Ascaris suum by sequential experimental infections terminated with fenbendazole during larval migration. Vet Parasitol. 17:1985;319-326.
28. Eriksen L., Lind P., Nansen P., Roepstorff A., Urban J. Resistance to Ascaris suum in parasite naïve and natural exposed growers, finishers and sows. Vet Parasitol. 41:1992;137-149.
29. Urban J.F., Alizadeh H., Romanowski R.D. Ascaris suum: development of intestinal immunity to infective second-stage larvae in swine. Exp Parasitol. 66:1988;66-67.
30. Andersen S., Jørgensen R.J., Nansen P., Nielsen K. Experimental Ascaris suum infection in piglets. Inverse relationship between the numbers of inoculated eggs and the numbers of worms established in the intestine. Acta Pathol Microbiol Scand B. 81:1973;650-656.
31. Jørgensen R.J., Nansen P., Nielsen K., Eriksen L., Andersen S. Experimental Ascaris suum infection in the pig. Population kinetics following low and high levels of primary infection in piglets. Vet Parasitol. 1:1975;151-157.
32. Eriksen L., Andersen S., Nielsen K., Pedersen A., Nielsen J. Experimental Ascaris suum infection in pigs. Serological response, eosinophilia in peripheral blood, occurrence of white spots in the liver and worm recovery from the intestine. Nord Vet Med. 32:1980;233-242.
33. Eriksen L. Epidemiologiske undersøgelser af Ascaris suum infektioner hos slagtesvin. Dansk Vet Tidsskr. 66:1983;830-833.
34. Bernardo T.M., Dohoo I.R., Ogilvie T. A critical assessment of abattoir surveillance as a screening test for swine ascariasis. Can J Vet Res. 54:1990;274-277.
35. Bøgh H.O., Eriksen L., Lawson L.G., Lind P. Evaluation of an enzyme-linked immunosorbent assay and a histamine release test system for the detection of pigs naturally infected with Ascaris suum. Prev Vet Med. 21:1994;201-214.
36. Poelvoorde J. Oesophagostomosis in sows. Zblt Vet Med. 25:1978;835-840.
37. Stewart T.B., Gasbarre L.C. The veterinary importance of nodular worms (Oesophagostomum spp.). Parasitol Today. 5:1989;209-213.
38. Pattison H.D., Smith W.C., Thomas R.J. The effect of sub-clinical nematode parasitism on reproductive performance in the sow. Anim Prod. 29:1979;321-326.
39. Pattison H.D., Thomas R.J., Smith W.C. The effect of subclinical nematode parasitism on digestion and performance in growing pigs. Anim Prod. 30:1980;285-294.
40. Christensen C.M., Barnes E.H., Nansen P. Experimental Oesophagostomum dentatum infections in the pig: worm populations at regular intervals during trickle infections with three dose levels of larvae. Parasitology. 115:1997;545-552.
41. Rose J.H., Small A.J. Transmission of Oesophagostomum spp. among sows at pasture. Vet Rec. 107:1980;223-225.
42. Christensen C.M., Barnes E.H., Nansen P., Roepstorff A., Slotved H.-C. Experimental Oesophagostomum dentatum infection in the pig: worm populations resulting from single infections with three doses of larvae. Int J Parasitol. 25:1995;1491-1498.
43. Roepstorff A., Bjørn H., Nansen P., Barnes E.H., Christensen C.M. Experimental Oesophagostomum dentatum infections in the pig: worm populations resulting from trickle infections with three dose levels of larvae. Int J Parasitol. 26:1996;399-408.
44. Roepstorff A., Murrell K.D. Transmission dynamics of helminth parasites of pigs on continuous pasture: Oesophagostomum dentatum and Hyostrongylus rubidus. Int J Parasitol. 27:1997;553-562.
45. Roepstorff A. Transmission of intestinal parasites in Danish sow herds. Vet Parasitol. 39:1991;149-160.
46. Petkevičius S., Knudsen K.E.B., Nansen P., Roepstorff A., Skjøth F., Jensen K. The impact of diets varying in carbohydrates resistant to endogenous enzymes and lignin on populations of Ascaris suum and Oesophagostomum dentatum in pigs. Parasitol. 114:1997;555-568.
47. Petkevičius S, Nansen P, Knudsen KEB, Skjøth F. The effect of increasing levels of insoluble dietary fibre on the establishment and persistence of Ascaris suum and Oesophagostomum dentatum. Parasite (in press).
48. Rose J.H., Small A.J. Observations on the development and survival of the free-living stages of Oesophagostomum dentatum both in their natural environments out-of-doors and under controlled conditions in the laboratory. Parasitology. 81:1980;507-517.
49. Haupt W. Ein Beitrag zur Überwinterungsfähigkeit der dritten invasionsfähigen Oesophagostomum-larven des Schweines auf der Weide. Arch Exp Veterinärmed. 23:1969;1211-1215.
50. Smith H.J. Transmission of Oesophagostomum species in swine on pasture in the maritime provinces. Can Vet J. 20:1979;184-185.
51. Soulsby EJL. Helminths, arthropods and protozoa of domesticated animals. Philadelphia: Lea and Febiger, 7th edn, 1982.
52. Urquhart GM, Armour J, Duncan JL, Dunn AM, Jennings FW. Veterinary parasitology. Oxford: Blackwell Science Ltd, 2nd edn, 1996.
53. Stewart M., Holmes C.W., Smith W.C., Charleston W.A.G. The energy and nitrogen metobolism and performance of pigs infected with Oesophagostomum dentatum. Anim Prod. 36:1983;137-142.
54. Bjørn H., Roepstorff A., Waller P.J., Nansen P. Resistance to levamisole and cross resistance between pyrantel and levamisole in Oesophagostomum quadrispinulatum and Oesophagostomum dentatum of pigs. Vet Parasitol. 37:1990;21-30.
55. Talvik H., Christensen C.M., Joachim A., Roepstorff A., Bjørn H., Nansen P. Prepatent periods of different Oesophagostomum spp. isolates in experimentally infected pigs. Parasitol Res. 83:1997;563-568.
56. Hill H.C. The survival of swine whipworm eggs in hog lots. J Parasitol. 43:1957;104.
57. Burden D.J., Hammet N.C., Brookes P.A. Field observations on the longevity of Trichuris suis ova. Vet Rec. 121:1987;43.
58. Powers K.G., Todd A.C., Goldsby M.S. Swine whipworm in Wisconsin. Vet Med. 54:1959;397-398.
59. Burden D.J., Hammet N.C. The development and survival of Trichuris suis ova on pasture plots in the south of England. Res Vet Sci. 26:1979;66-70.
60. Jacobs D.E., Dunn A.M. Helminths of Scottish pigs: occurrence, age incidences and seasonal variations. J Helminthol. 43:1969;327-340.
61. Pattison H.D., Thomas R.J., Smith W.C. A survey of gastrointestinal parasitism in pigs. Vet Rec. 107:1980;415-418.
62. Jensen T.K., Svensmark B. Trichuriasis hos udendørs slagtesvin. Vet Information. 2:1996;3-7.
63. Mansfield L.S., Urban J.F. The pathogenesis of necrotic proliferative colitis in swine is linked to whipworm induced suppression of mucosal immunity to resident bacteria. Vet Immunol Immunopathol. 50:1996;1-17.
64. Boes J., Johansen M.V., Eriksen L., Bøgh H.O., Nansen P., Stephenson L.S. False-positive Trichuris suis egg counts in pigs in relation to coprophagia. Parasite. 5:1998;91-93.
65. Rose J.H., Small A.J. Observations on the development and survival of the free-living stages of Hyostrongylus rubidus both in their natural environments out-of-doors and under controlled conditions in the laboratory. Parasitology. 85:1982;33-43.
66. Fossing E.C., Knudsen T.S.B., Bjørn H., Nansen P. Development of the free-living stages of Hyostongylus rubidus and Oesophagostomum spp. at different temperatures and humidities. J Helminthol. 69:1995;7-11.
67. Kendall S.B., Harding J.D.J. The biology of Hyostrongylus rubidus. II. Repeated infection in young pigs. J Comp Pathol. 80:1970;145-149.
68. Davidson JB, Murray, Sutherland IH. Observations on the clinical pathology of natural strongyle infestations in the pig, and their control, with special reference to Hyostrongylus rubidus. Vet Med Rev 1968;9-23.
69. Burden D.J., Kendall S.B. The biology of Hyostrongylus rubidus. VI. The peri-parturient faecal egg output in pigs. J Comp Pathol. 83:1973;71-81.
70. Poelvoorde J., Berghen P. De diagnostische betekenis van koprokulturen bij varkens, besmet met Hyostrongylus rubidus en Oesophagostomum spp. Vlaams Diergeneeskd Tidjschr. 49:1980;360-364.
71. Murrell K.D. Induction of protective immunity to Strongyloides ransomi in pigs. Am J Vet Res. 42:1981;1915-1919.
72. Gadomska K. The qualitative and quantitative structure of the helminthocoenosis of wild boar (Sus scrofa L.) living in natural (Kampinos National Park) and breeding conditions. Acta Parasitol Polonica 1981;28:12-24, 151-170.
73. Hobmaier A., Hobmaier M. Die Entwicklung der Larve des Lungenwurmes Metastrongylus elongatus (Strongylus paradoxus) des Schweines und ihr Invasionsweg, sowie vorläufige Mitteilung über die Entwicklung von Choerostrongylus brevivaginatus. Münch Tierärztl Wochenschr. 80:1929;365-369.
74. Spindler L.A. Persistence of swine lungworm larvae in earthworms. Proc Helminthol Soc Wash. 5:1938;63-68.
75. Spindler LA, Andrews JS. The swine kidney worm, Stephanurus dentatus. Proc 58th Annual Meeting of the US Livestock Sanitary Association 1955;296-302.
76. Kapel C.M.O., Webster P., Lind P.et al. Trichinella spiralis, T. britovi, and T. nativa: infectivity, larval distribution in muscle, and antibody response after experimental infection of pigs. Parasitol Res. 84:1998;264-271.
77. Kapel C.M.O. Trichinella in arctic, subarctic and temperate regions: Greenland, the Scandinavian countries and the Baltic states. Southeast Asian J Trop Med Publ Hlth. 28(Suppl.1):1997;14-19.
78. Persson L., Lindqvist J.-O. Studier av parasitägg och larver in svinträck och gödsel vid slaktsvinuppfödning. Svensk Vet Tidn. 27:1975;997-1002.
79. Knudsen T.S.B., Fossing E.C., Bjørn H., Nansen P. Transmission of Hyostrongylus rubidus in housed pigs. Bull Scand Soc Parasitol. 4:1994;117-122.
80. Jacobs D.E., Andreassen J. Gastro-intestinal helminthiasis and the adult pig in Denmark. II. The geographical distribution of Hyostrongylus rubidus and Oesophagostomum spp. Nord Vet Med. 19:1967;462-465.
81. Connan R.M. The prevalence of Hyostrongylus rubidus. Vet Rec. 100:1977;242-243.
82. Hörchner F., Grelck H., Unterholzner J., Heydorn K.P., Tunger G. Helminthosen im Schweinebetrieb. Berl Münch Tierärztl Wochenschr. 93:1980;370-373.
83. Alfredsen S.A. Miljøets innflytelse på gastrointestinale parasitter hos purke. Norsk Vet Tidsskr. 95:1983;481-487.
84. Möller K. Endoparasitenbefall bei Sauen unter dem Ein-fluss der sich wandelnden Haltungsformen in rheinland-pfälzischen Ferkelerzeugerbetrieben. Tierärtzl Umschau. 38:1983;163-166.
85. Biehl L.G. Internal parasitism of feeder pigs in Southern Illinois. AgriPract. 5:1984;20-26.
86. Morris R.G., Jordan H.E., Luce W.G., Coburn T.C., Maxwell C.V. Prevalence of gastrointestinal parasitism in Oklahoma swine. Am J Vet Res. 45:1984;2421-2423.
87. Kennedy T.J., Bruer D.J., Marchiondo A.A., Williams J.A. Prevalence of swine parasites in major hog producing areas of the United States. AgriPract. 9:1988;25-32.
88. Mercy A.R., de Chaneet G., Emms Y. Survey of internal parasites in Western Australian pig herds. 2. Relationship to anthelmintic usage and parasite control practices. Aust Vet J. 66:1989;6-9.
89. Roepstorff A., Jorsal S.E. Relationship of the prevalence of swine helminths to management practices and anthelmintic treatment in Danish sow herds. Vet Parasitol. 36:1990;245-257.
90. Dangolla A., Willeberg P., Bjørn H., Roepstorff A. Associations of Ascaris suum and Oesophagostomum spp. infections of sows with management factors in 83 Danish sow herds. Prev Vet Med. 27:1996;197-209.
91. Raynaud J.-P., Sennelier J., Irisarri E. Contamination parasitaire des porcelets apres leur naissance au contact de meres infestees. Etude sur 20 truies et 164 porcelets dont 42 sacrifies au sevrage. Folia Vet Latina. 5:1975;412-429.
92. Fiedler H. Zur Verbreitung des Wurmbefalles bei Schweinen im westfälischen Raum unter besonderer Berücksichtigung der Magen-Darmstrongyliden. Berl Münch Tierärztl Wochenschr. 20:1970;398-401.
93. Roepstorff A., Nilsson O., Oksanen A.et al. Intestinal parasites in swine in the Nordic countries: prevalences and geographical distribution. Vet Parasitol. 76:1998;305-319.
94. Alfredsen S.A. Forekomst av gastrointestinale parasitter hos purke. Norsk Vet Tidsskr. 93:1981;603-609.
95. Roepstorff A, Jørgensen RJ, Nansen P, Henriksen SA, Skovgaard Pedersen J, Andreasen M. Parasitter hos økologiske svin. Rapport over projekt finansieret af Jordbrugsdirektoratet under Landbrugsministeriet. Landsudvalget for svin, Danske Slagterier, 1992;36.
96. Kelley G.W., Nayak D.P. Passive immunity to Ascaris suum tranferred in colostrum from sows to their offspring. Am J Vet Res. 26:1965;948-950.
97. van der Wall G. Zur Frage des pränatalen Spulwurmbefalls beim Schwein. Tierärztl Umschau. 13:1958;48-50.
98. Olson L.D., Gaafar S.M. Absence of prenatal infection with Ascaris lumbricoides in swine. J Am Vet Med Assoc. 143:1963;1217-1218.
99. Connan R.M. Observations on the epidemiology of parasitic gastro-enteritis due to Oesophagostomum spp. and Hyostrongylus rubidus in the pig. Vet Rec. 80:1967;424-429.
100. Jacobs D.E., Dunn A.M. The epidemiology of porcine oesophagostomiasis. Nord Vet Med. 20:1968;258-266.
101. Marti O.G., Hale O.M. Parasite transmission in confined hogs. Vet Parasitol. 19:1986;301-314.
102. Moncol D.J., Batte E.G. Transcolostral infection of newborn pigs with Strongyloides ransomi. Vet Med Small Anim Clin. 61:1966;583-586.
103. Willingham AL III, Johansen MV, Bøgh HO, et al. Congenital transmission of Schistosoma japonicum. Am J Trop Med Hyg (in press).
104. Roepstorff A., Jorsal S.E. Prevalence of helminth infections in swine in Denmark. Vet Parasitol. 33:1989;231-239.
105. Dangolla A., Bjørn H., Willeberg P., Roepstorff A., Nansen P. A questionnaire investigation on factors of importance for the development of anthelmintic resistance of nematodes in sow herds in Denmark. Vet Parasitol. 63:1996;257-271.
106. Nansen P. Current and future prospects for control of ostertagiasis in Northern Europe - examples from Denmark. Vet Parasitol. 46:1993;3-21.
107. Rose J.H., Small A.J. Observations on the effect of anthelmintic treatment on the transmission of Hyostrongylus rubidus and Oesophagostomum spp. among sows at pasture. J Helminthol. 57:1983;1-8.
108. Myer R.O., Walker W.R., Brasher C.L., Hewitt T.D. Effects of management system, season and deworming on performance of growing-finishing swine: follow-up three-year study. Anim Swine Field Day. 35:1990;44-59.
109. Thomas R.J., Smith W.C. Anthelmintic treatment of sows with thiabendazole. Vet Rec. 83:1968;489-491.
110. Stewart T.B., Hale O.M., Andrews J.S. Eradication of the swine kidney worm, Stephanurus dentatus, from experimental pastures by herd management. Am J Vet Res. 25:1964;1141-1150.
111. Wagner B., Polley L. Anthelmintic use on Saskatchewan pig farms: results from a postal survey. Vet Parasitol. 73:1997;299-307.
112. Behlow RF, Batte EG. North Carolina swine parasite control program. North Carolina Agricultural Extension Service 1974; Extension folder 259.
113. Levine ND. Nematode parasites of domestic animals and of man. Minneapolis: Burgess Publishing Company 1980.
114. Roepstorff A., Bjørn H., Nansen P. Resistance of Oesophagostomum spp. in pigs to pyrantel citrate. Vet Parasitol. 24:1987;229-239.
115. Bjørn H., Roepstorff A., Nansen P., Waller P.J. A dose response investigation on the level of resistance to pyrantel-citrate in nodular worms of pigs. Vet Parasitol. 31:1989;259-267.
116. McKenna P.B. The efficacy of levamisole and ivermectin against a morantel-resistant strain of Trichostrongylus colubriformis. N Z Vet J. 33:1985;198-199.
117. Waller P.J., Dobson R.J., Obendorf D.L., Gillham R.-J. Resistance of Trichostrongylus colubriformis to levamisole and morantel: differences in relation to selection history. Vet Parasitol. 21:1986;255-263.
118. Jackson F. Anthelmintic resistance - the state of play. Brit Vet J. 149:1993;123-138.
119. Roepstorff A., Nansen P. Kontrol med orm i svinebesætninger. Vet Information. 2:1991;6-8.
120. Grønvold J., Wolstrup J., Nansen P., Henriksen S.A. Nematode-trapping fungi against parasitic cattle nematodes. Parasitol Today. 9:1993;137-140.
121. Larsen M., Nansen P., Wolstrup J., Grønvold J., Henriksen S.A., Zorn A. Biological control of trichostrongyles in calves by the fungus Duddingtonia flagrans fed to animals under natural grazing conditions. Vet Parasitol. 60:1995;321-330.
122. Nansen P., Larsen M., Grønvold J., Wolstrup J., Zorn A., Henriksen S.A. Prevention of clinical trichostrongylidosis in calves by strategic feeding with the predacious fungus Duddingtonia flagrans. Parasitol Res. 81:1995;371-374.
123. Larsen M., Nansen P., Grøndahl C.et al. The capacity of the fungus Duddingtonia flagrans to prevent strongyle infections in foals on pasture. Parasitology. 113:1996;1-6.
124. Nansen P., Larsen M., Roepstorff A., Grønvold J., Wolstrup J., Henriksen S.A. Control of Oesophagostomum dentatum and Hyostrongylus rubidus in outdoor-reared pigs through daily feeding with the microfungus Duddingtonia flagrans. Parasitol Res. 82:1996;580-584.