Toxoplasma gondii: Difference between revisions

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Toxoplasma gondii
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== Pathophysiology ==
 
== Pathophysiology ==
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* Following ingestion, bradyzoites and sporozoites invade the small intestinal mucosa and develop into tachyzoites within the gut epithelium
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* There, they insert themselves into monocytes and other nucleated cells
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* Infection triggers a Th-1 response
   
 
== Clinical Presentation ==
 
== Clinical Presentation ==

Revision as of 05:28, 17 September 2019

  • Protozoan parasite associated with cats and raw beef mostly known for causing opportunistic infections and congenital infections

Microbiology

  • Protozoan parasite
  • Organized into twelve haplotypes

Epidemiology

  • Zoonotic disease with worldwide distribution
  • Modes of transmission
    • Ingesting tissue cysts in meat, or oocytes in food or water
    • Solid-organ transplantation, especially heart
    • Vertical or transplacental transmission
    • Case reports of lab-acquired needlestick transmission
    • Theoretical risk with blood transfusion
  • Seroprevalence around 10-18% in Canada 12
    • As high as 60% in Nunavut, however 3
  • There are large parts of South and Central America, as well as Pacific Islands, that have very high seroprevalence 4

Life Cycle

  • The only definitive hosts are in the Felidae family, essentially housecats and their relatives
  • Intermediate hosts are many, and include birds and rodents
  • An infected cat sheds oocytes into the environment (for 1 to 3 weeks), where they spend 1 to 5 days sporulating
  • Intermediate hosts ingest the sporulated oocyte, where they mature into tachyzoites
  • Tachyzoites migrate to brain and muscle, where they encyst and become bradyzoites
  • Bradyzoites are ingested by a cat, completing the life cycle

Pathophysiology

  • Following ingestion, bradyzoites and sporozoites invade the small intestinal mucosa and develop into tachyzoites within the gut epithelium
  • There, they insert themselves into monocytes and other nucleated cells
  • Infection triggers a Th-1 response

Clinical Presentation

Immunocompetent

Immunocompetent

Pregnancy

Congenital

Diagnosis

Management

Further Reading

  • Epidemiology of and Diagnostic Strategies for Toxoplasmosis. Clin Microbiol Rev. 2012;25(2):264. doi: [10.1128/CMR.05013-11]

References

  1. ^  Samar Shuhaiber, Gideon Koren, Rada Boskovic, Thomas R Einarson, Offie Porat Soldin, Adrienne Einarson. Seroprevalence of Toxoplasma gondiiinfection among veterinary staff in Ontario, Canada (2002): Implications for teratogenic risk. BMC Infectious Diseases. 2003;3(1). doi:10.1186/1471-2334-3-8.
  2. ^  EL Ford-Jones, I Kitai, M Corey, R Notenboom, N Hollander, E Kelly, H Akoury, G Ryan, I Kyle, R Gold. Seroprevalence of Toxoplasma Antibody in a Toronto Population. Canadian Journal of Infectious Diseases. 1996;7(5):326-328. doi:10.1155/1996/172651.
  3. ^  V. Messier, B. Lévesque, J.-F. Proulx, L. Rochette, M. D. Libman, B. J. Ward, B. Serhir, M. Couillard, N. H. Ogden, É. Dewailly, B. Hubert, S. Déry, C. Barthe, D. Murphy, B. Dixon. Seroprevalence of Toxoplasma gondii Among Nunavik Inuit (Canada). Zoonoses and Public Health. 2009;56(4):188-197. doi:10.1111/j.1863-2378.2008.01177.x.
  4. ^  Georgios Pappas, Nikos Roussos, Matthew E. Falagas. Toxoplasmosis snapshots: Global status of Toxoplasma gondii seroprevalence and implications for pregnancy and congenital toxoplasmosis. International Journal for Parasitology. 2009;39(12):1385-1394. doi:10.1016/j.ijpara.2009.04.003.