Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.


Peter F Weller, MD, MACP
Karin Leder, MBBS, FRACP, PhD, MPH, DTMH
Section Editor
Edward T Ryan, MD, DTMH
Deputy Editor
Elinor L Baron, MD, DTMH


Trichinellosis (trichinosis) is a parasitic infection caused by nematodes (roundworms) of the genus Trichinella. Pigs are the most important source of human infection, although a number of other animals are also epidemiologically important hosts. Consumption of raw or undercooked meat is the principal mode of transmission.


Trichinellosis occurs worldwide (figure 1). The prevalence of Trichinella infection is unknown, and there is significant underreporting of cases. A thorough literature review from 1986 to 2009 revealed 65,818 cases of trichinellosis and 42 deaths reported from 41 countries [1]. Most cases were reported in Europe, especially Romania, the former Soviet Union and other parts of Central Europe [2,3]. Other countries with high prevalences of human infection are China, Thailand, Mexico, Argentina, and Bolivia.

There are 9 species and at least 12 genotypes of Trichinella; these are divided into those that encapsulate in host muscle tissue of mammals only and those that do not encapsulate and infect mammals, birds (one species), or reptiles (two species). All recognized species and genotypes can infect humans, but there are seven species of Trichinella that have been implicated in human disease [4,5]:

T. spiralis is found worldwide in a great variety of carnivorous and omnivorous animals.

T. nativa is found in arctic regions and infects bears, foxes, and walruses.

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Nov 03, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Murrell KD, Pozio E. Worldwide occurrence and impact of human trichinellosis, 1986-2009. Emerg Infect Dis 2011; 17:2194.
  2. Marincu I, Neghina AM, Calma CL, Neghina R. New foci of trichinellosis in western Romania, 2011. Acta Trop 2012; 121:47.
  3. Pozio E, Zarlenga DS. New pieces of the Trichinella puzzle. Int J Parasitol 2013; 43:983.
  4. Murrell KD, Bruschi F. Clinical trichinellosis. Prog Clin Parasitol 1994; 4:117.
  5. Murrell KD, Pozio E. Trichinellosis: the zoonosis that won't go quietly. Int J Parasitol 2000; 30:1339.
  6. Ranque S, Faugère B, Pozio E, et al. Trichinella pseudospiralis outbreak in France. Emerg Infect Dis 2000; 6:543.
  7. Jongwutiwes S, Chantachum N, Kraivichian P, et al. First outbreak of human trichinellosis caused by Trichinella pseudospiralis. Clin Infect Dis 1998; 26:111.
  8. Pozio E, La Rosa G. Trichinella murrelli n. sp: etiological agent of sylvatic trichinellosis in temperate areas of North America. J Parasitol 2000; 86:134.
  9. Pozio E, Owen IL, La Rosa G, et al. Trichinella papuae n.sp. (Nematoda), a new non-encapsulated species from domestic and sylvatic swine of Papua New Guinea. Int J Parasitol 1999; 29:1825.
  10. Khumjui C, Choomkasien P, Dekumyoy P, et al. Outbreak of trichinellosis caused by Trichinella papuae, Thailand, 2006. Emerg Infect Dis 2008; 14:1913.
  11. Kusolsuk T, Kamonrattanakun S, Wesanonthawech A, et al. The second outbreak of trichinellosis caused by Trichinella papuae in Thailand. Trans R Soc Trop Med Hyg 2010; 104:433.
  12. Lo YC, Hung CC, Lai CS, et al. Human trichinosis after consumption of soft-shelled turtles, Taiwan. Emerg Infect Dis 2009; 15:2056.
  13. Pozio E. Foodborne and waterborne parasites. Acta Microbiol Pol 2003; 52 Suppl:83.
  14. Krivokapich SJ, Pozio E, Gatti GM, et al. Trichinella patagoniensis n. sp. (Nematoda), a new encapsulated species infecting carnivorous mammals in South America. Int J Parasitol 2012; 42:903.
  15. International Trichinella Reference Center. http://www.iss.it/site/Trichinella/index.asp (Accessed on November 14, 2011).
  16. Ancelle T, Dupouy-Camet J, Desenclos JC, et al. A multifocal outbreak of trichinellosis linked to horse meat imported from North America to France in 1993. Am J Trop Med Hyg 1998; 59:615.
  17. Gottstein B, Pozio E, Nöckler K. Epidemiology, diagnosis, treatment, and control of trichinellosis. Clin Microbiol Rev 2009; 22:127.
  18. Wilson NO, Hall RL, Montgomery SP, Jones JL. Trichinellosis surveillance--United States, 2008-2012. MMWR Surveill Summ 2015; 64:1.
  19. Centers for Disease Control and Prevention (CDC). Trichinellosis associated with bear meat--New York and Tennessee, 2003. MMWR Morb Mortal Wkly Rep 2004; 53:606.
  20. Roy SL, Lopez AS, Schantz PM. Trichinellosis surveillance--United States, 1997-2001. MMWR Surveill Summ 2003; 52:1.
  21. Greene YG, Padovani T, Rudroff JA, et al. Trichinellosis caused by consumption of wild boar meat - Illinois, 2013. MMWR Morb Mortal Wkly Rep 2014; 63:451.
  22. Springer YP, Casillas S, Helfrich K, et al. Two Outbreaks of Trichinellosis Linked to Consumption of Walrus Meat - Alaska, 2016-2017. MMWR Morb Mortal Wkly Rep 2017; 66:692.
  23. Holzbauer SM, Agger WA, Hall RL, et al. Outbreak of Trichinella spiralis infections associated with a wild boar hunted at a game farm in Iowa. Clin Infect Dis 2014; 59:1750.
  24. Moorhead A, Grunenwald PE, Dietz VJ, Schantz PM. Trichinellosis in the United States, 1991-1996: declining but not gone. Am J Trop Med Hyg 1999; 60:66.
  25. Teunis PF, Koningstein M, Takumi K, van der Giessen JW. Human beings are highly susceptible to low doses of Trichinella spp. Epidemiol Infect 2012; 140:210.
  26. Kociecka W. Trichinellosis: human disease, diagnosis and treatment. Vet Parasitol 2000; 93:365.
  27. Vu Thi N, Trung DD, Litzroth A, et al. The hidden burden of trichinellosis in Vietnam: a postoutbreak epidemiological study. Biomed Res Int 2013; 2013:149890.
  28. Gould SE. Clinical manifestations. In: Trichinosis in Man and Animals, Gould SE (Ed), Charles C Thomas, Springfield, IL 1970. p.269.
  29. MacLean JD, Poirier L, Gyorkos TW, et al. Epidemiologic and serologic definition of primary and secondary trichinosis in the Arctic. J Infect Dis 1992; 165:908.
  30. Neghina R, Neghina AM. Reviews on trichinellosis (IV): hepatic involvement. Foodborne Pathog Dis 2011; 8:943.
  31. Akar S, Gurler O, Pozio E, et al. Frequency and severity of musculoskeletal symptoms in humans during an outbreak of trichinellosis caused by Trichinella britovi. J Parasitol 2007; 93:341.
  32. Pozio E. New patterns of Trichinella infection. Vet Parasitol 2001; 98:133.
  33. Andrews JR, Ainsworth R, Abernethy D. Trichinella pseudospiralis in humans: description of a case and its treatment. Trans R Soc Trop Med Hyg 1994; 88:200.
  34. Lazarević AM, Nesković AN, Goronja M, et al. Low incidence of cardiac abnormalities in treated trichinosis: a prospective study of 62 patients from a single-source outbreak. Am J Med 1999; 107:18.
  35. Compton SJ, Celum CL, Lee C, et al. Trichinosis with ventilatory failure and persistent myocarditis. Clin Infect Dis 1993; 16:500.
  36. Neghina R, Neghina AM, Marincu I. Reviews on trichinellosis (III): cardiovascular involvement. Foodborne Pathog Dis 2011; 8:853.
  37. Fourestie V, Douceron H, Brugieres P, et al. Neurotrichinosis. A cerebrovascular disease associated with myocardial injury and hypereosinophilia. Brain 1993; 116 ( Pt 3):603.
  38. Puljiz I, Beus A, Kuzman I, Seiwerth S. Electrocardiographic changes and myocarditis in trichinellosis: a retrospective study of 154 patients. Ann Trop Med Parasitol 2005; 99:403.
  39. Dalcin D, Zarlenga DS, Larter NC, et al. Trichinella Nativa Outbreak With Rare Thrombotic Complications Associated With Meat From a Black Bear Hunted in Northern Ontario. Clin Infect Dis 2017; 64:1367.
  40. Mawhorter SD, Kazura JW. Trichinosis of the central nervous system. Semin Neurol 1993; 13:148.
  41. Gelal F, Kumral E, Vidinli BD, et al. Diffusion-weighted and conventional MR imaging in neurotrichinosis. Acta Radiol 2005; 46:196.
  42. Neghina R, Neghina AM, Marincu I, Iacobiciu I. Reviews on trichinellosis (II): neurological involvement. Foodborne Pathog Dis 2011; 8:579.
  43. Januszkiewicz J. Participation of the respiratory system in trichinosis. Epidemiol Rev 1967; 21:169.
  44. ROBIN ED, CRUMP CH, WAGMAN RJ. Low sedimentation rate, hypofibrinogenemia and restrictive pseudo-obstructive pulmonary disease associated with trichinosis. N Engl J Med 1960; 262:758.
  45. Neghina R, Neghina AM, Marincu I, Iacobiciu I. Reviews on trichinellosis (I): renal involvement. Foodborne Pathog Dis 2011; 8:179.
  46. Murrell KD, Bruschi F. Clinical trichinellosis. In: Progress in clinical parasitology, Sun T (Ed), CRC Press, Boca Raton 1994. p.117.
  47. Moskwa B, Bien J, Cabaj W, et al. The comparison of different ELISA procedures in detecting anti-Trichinella IgG in human infections. Vet Parasitol 2009; 159:312.
  48. Ivanoska D, Cuperlović K, Gamble HR, Murrell KD. Comparative efficacy of antigen and antibody detection tests for human trichinellosis. J Parasitol 1989; 75:38.
  49. Bruschi F, Murrell KD. New aspects of human trichinellosis: the impact of new Trichinella species. Postgrad Med J 2002; 78:15.
  50. Rombout YB, Bosch S, Van Der Giessen JW. Detection and identification of eight Trichinella genotypes by reverse line blot hybridization. J Clin Microbiol 2001; 39:642.
  51. Zarlenga DS, Chute MB, Martin A, Kapel CM. A single, multiplex PCR for differentiating all species of Trichinella. Parasite 2001; 8:S24.
  52. Drugs for Parasitic Infections, 3rd ed, The Medical Letter, New Rochelle, NY 2013.
  53. Watt G, Saisorn S, Jongsakul K, et al. Blinded, placebo-controlled trial of antiparasitic drugs for trichinosis myositis. J Infect Dis 2000; 182:371.
  54. Pozio E, Sacchini D, Sacchi L, et al. Failure of mebendazole in the treatment of humans with Trichinella spiralis infection at the stage of encapsulating larvae. Clin Infect Dis 2001; 32:638.
  55. Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clin Infect Dis 2017; 65:e45.
  56. Nuñez GG, Costantino SN, Gentile T, Venturiello SM. Immunoparasitological evaluation of Trichinella spiralis infection during human pregnancy: a small case series. Trans R Soc Trop Med Hyg 2008; 102:662.
  57. Dubinský P, Böör A, Kinceková J, et al. Congenital trichinellosis? Case report. Parasite 2001; 8:S180.
  58. Nuñez GG, Gentile T, Calcagno ML, Venturiello SM. Increased parasiticide activity against Trichinella spiralis newborn larvae during pregnancy. Parasitol Res 2002; 88:661.
  59. Dupouy-Camet J, Kociecka W, Bruschi F, et al. Opinion on the diagnosis and treatment of human trichinellosis. Expert Opin Pharmacother 2002; 3:1117.
  60. Gyorkos TW, Larocque R, Casapia M, Gotuzzo E. Lack of risk of adverse birth outcomes after deworming in pregnant women. Pediatr Infect Dis J 2006; 25:791.
  61. Faber M, Schink S, Mayer-Scholl A, et al. Outbreak of trichinellosis due to wild boar meat and evaluation of the effectiveness of post exposure prophylaxis, Germany, 2013. Clin Infect Dis 2015; 60:e98.