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

Toxoplasmosis in immunocompetent hosts

Michael Tolentino, MD
Eskild Petersen, MD, DMSc, DTM&H
Section Editor
Peter F Weller, MD, MACP
Deputy Editor
Jennifer Mitty, MD, MPH


Toxoplasmosis, an infection with a worldwide distribution, is caused by the intracellular protozoan parasite, Toxoplasma gondii. Immunocompetent persons with primary infection are usually asymptomatic. However, in some immunocompetent hosts, T. gondii infection can present as an acute systemic infection or as ocular disease (eg, posterior uveitis).

After initial infection (even if asymptomatic), latent infection can persist for the life of the host. Immunocompromised individuals (eg, those with HIV/AIDS) can have reactivation of latent infection; such patients typically present with multiple central nervous system abscess-like, round processes with ring enhancement.

Toxoplasmosis in immunocompetent persons will be reviewed here. Toxoplasmosis in HIV-infected individuals, pregnant women, and neonates is discussed separately. (See "Toxoplasmosis and pregnancy" and "Congenital toxoplasmosis: Clinical features and diagnosis" and "Toxoplasmosis in HIV-infected patients".)


Genotypes — There are three main T. gondii genotypes (types I, II, and III), which are prevalent in different geographic areas, and can impact the clinical presentation of T. gondii infection [1]. As an example, in Europe, where genotype II is present, 80 to 90 percent of individuals who become infected are asymptomatic. This is in contrast to South and Central America, where other genotypes are present, and infection is associated with a higher rate and increased severity of disease, such as retinochoroiditis in immunocompetent adults and children with congenital disease [2-4]. A mix of genotype I and II are the most prevalent in North America.

Prevalence — The seroprevalence of T. gondii infection ranges widely depending upon the geographic area. Seroepidemiologic surveys in the United States report that 11 percent of persons aged 6 to 49 are seropositive for T. gondii [5], whereas the seroprevalence is as high as 78 percent in some areas of Brazil [6].

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: Mar 17, 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. Dardé ML. Toxoplasma gondii, "new" genotypes and virulence. Parasite 2008; 15:366.
  2. Ferreira IM, Vidal JE, de Mattos Cde C, et al. Toxoplasma gondii isolates: multilocus RFLP-PCR genotyping from human patients in Sao Paulo State, Brazil identified distinct genotypes. Exp Parasitol 2011; 129:190.
  3. Silveira C, Muccioli C, Holland GN, et al. Ocular Involvement Following an Epidemic of Toxoplasma gondii Infection in Santa Isabel do Ivaí, Brazil. Am J Ophthalmol 2015; 159:1013.
  4. Lindsay DS, Dubey JP. Toxoplasma gondii: the changing paradigm of congenital toxoplasmosis. Parasitology 2011; 138:1829.
  5. Jones JL, Kruszon-Moran D, Sanders-Lewis K, Wilson M. Toxoplasma gondii infection in the United States, 1999 2004, decline from the prior decade. Am J Trop Med Hyg 2007; 77:405.
  6. Pappas G, Roussos N, Falagas ME. Toxoplasmosis snapshots: global status of Toxoplasma gondii seroprevalence and implications for pregnancy and congenital toxoplasmosis. Int J Parasitol 2009; 39:1385.
  7. Tenter AM, Heckeroth AR, Weiss LM. Toxoplasma gondii: from animals to humans. Int J Parasitol 2000; 30:1217.
  8. Baril L, Ancelle T, Goulet V, et al. Risk factors for Toxoplasma infection in pregnancy: a case-control study in France. Scand J Infect Dis 1999; 31:305.
  9. Rai SK, Matsumura T, Ono K, et al. High Toxoplasma seroprevalence associated with meat eating habits of locals in Nepal. Asia Pac J Public Health 1999; 11:89.
  10. Cook AJ, Gilbert RE, Buffolano W, et al. Sources of toxoplasma infection in pregnant women: European multicentre case-control study. European Research Network on Congenital Toxoplasmosis. BMJ 2000; 321:142.
  11. Jones JL, Dargelas V, Roberts J, et al. Risk factors for Toxoplasma gondii infection in the United States. Clin Infect Dis 2009; 49:878.
  12. O'Connell S, Guy EC, Dawson SJ, et al. Chronic active toxoplasmosis in an immunocompetent patient. J Infect 1993; 27:305.
  13. McCabe RE, Brooks RG, Dorfman RF, Remington JS. Clinical spectrum in 107 cases of toxoplasmic lymphadenopathy. Rev Infect Dis 1987; 9:754.
  14. Leal FE, Cavazzana CL, de Andrade HF Jr, et al. Toxoplasma gondii pneumonia in immunocompetent subjects: case report and review. Clin Infect Dis 2007; 44:e62.
  15. Montoya JG, Jordan R, Lingamneni S, et al. Toxoplasmic myocarditis and polymyositis in patients with acute acquired toxoplasmosis diagnosed during life. Clin Infect Dis 1997; 24:676.
  16. Chandenier J, Jarry G, Nassif D, et al. Congestive heart failure and myocarditis after seroconversion for toxoplasmosis in two immunocompetent patients. Eur J Clin Microbiol Infect Dis 2000; 19:375.
  17. Franco-Paredes C, Rouphael N, Méndez J, et al. Cardiac manifestations of parasitic infections. Part 2: Parasitic myocardial disease. Clin Cardiol 2007; 30:218.
  18. Cunningham T. Pancarditis in acute toxoplasmosis. Am J Clin Pathol 1982; 78:403.
  19. Behan WM, Behan PO, Draper IT, Williams H. Does Toxoplasma cause polymyositis? Report of a case of polymyositis associated with toxoplasmosis and a critical review of the literature. Acta Neuropathol 1983; 61:246.
  20. Calore EE, Minkovski R, Khoury Z, et al. Skeletal muscle pathology in 2 siblings infected with Toxoplasma gondii. J Rheumatol 2000; 27:1556.
  21. Dorfman RF, Remington JS. Value of lymph-node biopsy in the diagnosis of acute acquired toxoplasmosis. N Engl J Med 1973; 289:878.
  22. Zaharopoulos P. Demonstration of parasites in toxoplasma lymphadenitis by fine-needle aspiration cytology: report of two cases. Diagn Cytopathol 2000; 22:11.
  23. Weiss LM, Chen YY, Berry GJ, et al. Infrequent detection of Toxoplasma gondii genome in toxoplasmic lymphadenitis: a polymerase chain reaction study. Hum Pathol 1992; 23:154.
  24. Angel SO, Matrajt M, Margarit J, et al. Screening for active toxoplasmosis in patients by DNA hybridization with the ABGTg7 probe in blood samples. J Clin Microbiol 1997; 35:591.
  25. REMINGTON JS, BARNETT CG, MEIKEL M, LUNDE MN. Toxoplasmosis and infectious mononucleosis. Arch Intern Med 1962; 110:744.
  26. Georgiev VS. Management of toxoplasmosis. Drugs 1994; 48:179.
  27. Holland GN, Muccioli C, Silveira C, et al. Intraocular inflammatory reactions without focal necrotizing retinochoroiditis in patients with acquired systemic toxoplasmosis. Am J Ophthalmol 1999; 128:413.
  28. Alavi SM, Alavi L. Treatment of toxoplasmic lymphadenitis with co-trimoxazole: double-blind, randomized clinical trial. Int J Infect Dis 2010; 14 Suppl 3:e67.
  29. Silveira C, Muccioli C, Nussenblatt R, Belfort R Jr. The Effect of Long-term Intermittent Trimethoprim/Sulfamethoxazole Treatment on Recurrences of Toxoplasmic Retinochoroiditis: 10 Years of Follow-up. Ocul Immunol Inflamm 2015; 23:246.
  30. Holland GN. Ocular toxoplasmosis: a global reassessment. Part I: epidemiology and course of disease. Am J Ophthalmol 2003; 136:973.
  31. Kodjikian L, Wallon M, Fleury J, et al. Ocular manifestations in congenital toxoplasmosis. Graefes Arch Clin Exp Ophthalmol 2006; 244:14.
  32. Montoya JG, Remington JS. Toxoplasmic chorioretinitis in the setting of acute acquired toxoplasmosis. Clin Infect Dis 1996; 23:277.
  33. Holland GN, Crespi CM, ten Dam-van Loon N, et al. Analysis of recurrence patterns associated with toxoplasmic retinochoroiditis. Am J Ophthalmol 2008; 145:1007.
  34. Rothova A, de Boer JH, Ten Dam-van Loon NH, et al. Usefulness of aqueous humor analysis for the diagnosis of posterior uveitis. Ophthalmology 2008; 115:306.
  35. http://www.cdc.gov/parasites/toxoplasmosis/health_professionals/index.html#tx.
  36. Maenz M, Schlüter D, Liesenfeld O, et al. Ocular toxoplasmosis past, present and new aspects of an old disease. Prog Retin Eye Res 2014; 39:77.
  37. Ozgonul C, Besirli CG. Recent Developments in the Diagnosis and Treatment of Ocular Toxoplasmosis. Ophthalmic Res 2017; 57:1.
  38. Rothova A, Meenken C, Buitenhuis HJ, et al. Therapy for ocular toxoplasmosis. Am J Ophthalmol 1993; 115:517.
  39. Opremcak EM, Scales DK, Sharpe MR. Trimethoprim-sulfamethoxazole therapy for ocular toxoplasmosis. Ophthalmology 1992; 99:920.
  40. Pradhan E, Bhandari S, Gilbert RE, Stanford M. Antibiotics versus no treatment for toxoplasma retinochoroiditis. Cochrane Database Syst Rev 2016; :CD002218.
  41. Soheilian M, Sadoughi MM, Ghajarnia M, et al. Prospective randomized trial of trimethoprim/sulfamethoxazole versus pyrimethamine and sulfadiazine in the treatment of ocular toxoplasmosis. Ophthalmology 2005; 112:1876.
  42. Felix JP, Lira RP, Zacchia RS, et al. Trimethoprim-sulfamethoxazole versus placebo to reduce the risk of recurrences of Toxoplasma gondii retinochoroiditis: randomized controlled clinical trial. Am J Ophthalmol 2014; 157:762.
  43. Pearson PA, Piracha AR, Sen HA, Jaffe GJ. Atovaquone for the treatment of toxoplasma retinochoroiditis in immunocompetent patients. Ophthalmology 1999; 106:148.
  44. Balaskas K, Vaudaux J, Boillat-Blanco N, Guex-Crosier Y. Azithromycin versus Sulfadiazine and Pyrimethamine for non-vision-threatening toxoplasmic retinochoroiditis: a pilot study. Med Sci Monit 2012; 18:CR296.
  45. Martínez Castillo S, Gallego-Pinazo R, Francés-Muñoz E, et al. [Macular toxoplasmosis and intravitreal clindamycin: an alternative to oral treatment]. Arch Soc Esp Oftalmol 2012; 87:93.
  46. Aytemir MD, Calis U. Anticonvulsant and neurotoxicity evaluation of some novel kojic acids and allomaltol derivatives. Arch Pharm (Weinheim) 2010; 343:173.
  47. Soheilian M, Ramezani A, Azimzadeh A, et al. Randomized trial of intravitreal clindamycin and dexamethasone versus pyrimethamine, sulfadiazine, and prednisolone in treatment of ocular toxoplasmosis. Ophthalmology 2011; 118:134.
  48. Jasper S, Vedula SS, John SS, et al. Corticosteroids as adjuvant therapy for ocular toxoplasmosis. Cochrane Database Syst Rev 2013; :CD007417.
  49. Bosch-Driessen LH, Verbraak FD, Suttorp-Schulten MS, et al. A prospective, randomized trial of pyrimethamine and azithromycin vs pyrimethamine and sulfadiazine for the treatment of ocular toxoplasmosis. Am J Ophthalmol 2002; 134:34.
  50. Panel on Opportunistic Infections in HIV-Infected Adults and Adolescents. Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: Recommendations from the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. http://aidsinfo.nih.gov/contentfiles/lvguideline s/adult_oi.pdf (Accessed on March 04, 2016).