Trypanosoma cruzi: Difference between revisions

From IDWiki
Trypanosoma cruzi
(Imported from text file)
 
mNo edit summary
 
(6 intermediate revisions by the same user not shown)
Line 1: Line 1:
  +
== Background ==
= ''Trypanosoma cruzi'' (Chagas disease) =
 
   
  +
*Causes '''Chagas disease''' (South American trypanosomiasis)
== Microbiology ==
 
   
  +
===Microbiology===
* Protozoan parasite that causes Chagas disease (South American trypanosomiasis)
 
   
  +
*Protozoan parasite
== Life Cycle ==
 
   
  +
===Epidemiology===
[[File:Chagas_LifeCycle_19.jpg|T. cruzi Lifecycle]]
 
   
  +
*Endemic '''throughout the Americas''' from the southern half of the United States to Argentina
== Epidemiology ==
 
  +
**Particularly in rural, impoverished areas
  +
**A small number of autochthonous cases of Chagas disease in the US
  +
*Reservoirs include '''armadillos''', opossums, raccoons, woodrats, some other rodents, and domestic dogs
  +
*'''Triatomine''' vector species for trypanosomiasis belong to the genera ''Triatoma'', ''Rhodnius'', and ''Panstrongylus''
  +
**Bugs live in substandard dwellings (especially wood, mud, or stone houses)
  +
**Vector is present from southern US to southern Argentina
  +
**Transmission is via feces, either in direct contact with mucous membranes (especially conjunctivae), breaks in the skin, or contaminating the bite of the insect
  +
*Can also be transmitted via '''blood transfusion''' or '''vertically''' from mother to child or via '''ingestion''' of contaminated food and drink
   
  +
===Pathophysiology===
* Endemic '''throughout the Americas''' from the southern half of the United States to Argentina
 
** Particularly in rural, impoverished areas
 
** A small number of autochthonous cases of Chagas disease in the US
 
* Reservoirs include '''armadillos''', opossums, raccoons, woodrats, some other rodents, and domestic dogs
 
* '''Triatomine''' vector species for trypanosomiasis belong to the genera ''Triatoma'', ''Rhodnius'', and ''Panstrongylus''
 
** Bugs live in substandard dwellings (especially wood, mud, or stone houses)
 
** Vector is present from southern US to southern Argentina
 
** Transmission is via feces, either in direct contact with mucous membranes (especially conjunctivae), breaks in the skin, or contaminating the bite of the insect
 
* Can also be transmitted via '''blood transfusion''' or '''vertically''' from mother to child or via '''ingestion''' of contaminated food and drink
 
   
  +
*Infective metacyclic trypomastigotes from feces enter the skin or mucosa
== Pathophysiology ==
 
  +
*Multiply in host cells as amastigotes, developing into trypomastigotes intracellularly and rupturing the cell, releasing more trypomastigotes
  +
**Chagoma develops at site of inoculation
  +
**Intracellular amastigotes visible as characteristic pseudocysts on histopathology
  +
*Hematogenous spread to distant sites, especially muscles, with the cycle repeating
  +
**Especially tropic for myocardium, where it causes biventricular enlargement, thinning of ventricular walls, apical aneurysms, and mural thrombi
  +
*Parasitemia maintained for years
   
  +
==Clinical Manifestations==
* Infective metacyclic trypomastigotes from feces enter the skin or mucosa
 
* Multiply in host cells as amastigotes, developing into trypomastigotes intracellularly and rupturing the cell, releasing more trypomastigotes
 
** Chagoma develops at site of inoculation
 
** Intracellular amastigotes visible as characteristic pseudocysts on histopathology
 
* Hematogenous spread to distant sites, especially muscles, with the cycle repeating
 
** Especially tropic for myocardium, where it causes biventricular enlargement, thinning of ventricular walls, apical aneurysms, and mural thrombi
 
* Parasitemia maintained for years
 
   
  +
===Acute Disease===
== Clinical Presentation ==
 
   
  +
*Often asymptomatic
=== Acute disease ===
 
  +
*Incubation period of about [[Usual incubation period::1 week]]
  +
*Usually mild febrile illness, sometimes with hepatosplenomegaly, rash, edema, local inflammation
  +
**Incurs in 20% of infections
  +
**More common in children
  +
*Nodular lesions ("chagomas") may develop at site of inoculation
  +
**Romaña sign if periorbital, often with ipsilateral lymphadenopathy
  +
**Often 1-2 weeks after exposure
  +
*Acute myocarditis, pericardial effusion, and meningoencephalitis in 1-5%
   
  +
===Indeterminate Phase===
* Often asymptomatic
 
* Incubation period of about 1 week
 
* Usually mild febrile illness, sometimes with hepatosplenomegaly, rash, edema, local inflammation
 
** Incurs in 20% of infections
 
** More common in children
 
* Nodular lesions ("chagomas") may develop at site of inoculation
 
** Romaña sign if periorbital, often with ipsilateral lymphadenopathy
 
** Often 1-2 weeks after exposure
 
* Acute myocarditis, pericardial effusion, and meningoencephalitis in 1-5%
 
   
  +
*Following acute infection, may enter a latent phase
=== Indeterminate phase ===
 
   
  +
===Chronic Disease===
* Following acute infection, may enter a latent phase
 
   
  +
*Following acute infection can remain asymptomatic (indeterminate form)
=== Chronic disease ===
 
  +
*Cardiac complications in 25-30% (1.5-5% per year)
  +
**Non-ischemic dilated biventricular (right more than left) cardiomyopathy with heart failure
  +
**Apical aneurysms and mural thrombi
  +
**Conduction defects, with heart blocks, bundle branch blocks, sinus node dysfunction, bradycardia, and ventricular arrhythmias
  +
**Can cause sudden cardiac death
  +
*GI involvement in 10-15%
  +
**Megaesophagus, with dysphagia, odynophagia, chest pain, cough, and regurgitation
  +
***May result in aspiration and recurrent pneumonias
  +
**Megacolon, with constipation and abdominal pain
  +
*Meningoencephalitis
  +
*Other: polyneuropathy, stroke syndrome
   
  +
===Immunocompromised Patients===
* Following acute infection can remain asymptomatic (indeterminate form)
 
* Cardiac complications in 25-30% (1.5-5% per year)
 
** Non-ischemic dilated biventricular (right more than left) cardiomyopathy with heart failure
 
** Apical aneurysms and mural thrombi
 
** Conduction defects, with heart blocks, bundle branch blocks, sinus node dysfunction, bradycardia, and ventricular arrhythmias
 
** Can cause sudden cardiac death
 
* GI involvement in 10-15%
 
** Megaesophagus, with dysphagia, odynophagia, chest pain, cough, and regurgitation
 
*** May result in aspiration and recurrent pneumonias
 
** Megacolon, with constipation and abdominal pain
 
* Meningoencephalitis
 
* Other: polyneuropathy, stroke syndrome
 
   
  +
*May have reactivation following immune suppression or HIV
=== Immunocompromised patients ===
 
  +
*Severe acute infection; may have skin lesions and cerebral masses/abscesses
  +
*Meningoencephalitis
   
  +
==Diagnosis==
* May have reactivation following immune suppression or HIV
 
* Severe acute infection; may have skin lesions and cerebral masses/abscesses
 
* Meningoencephalitis
 
   
== Diagnosis ==
+
===Acute Disease===
   
  +
*'''Direct microscopy''' blood film or tissue biopsy (e.g. lymph node, bone marrow, pericardial fluid, CSF)
=== Acute disease ===
 
  +
**In immunocompromised, these other samples are even more important
  +
*Hemoculture is only 50% sensitive and takes several weeks
  +
*Serology for IgM is useless
  +
*'''PCR''' is sensitive and specific
  +
*Xenodiagnosis
   
  +
===Indeterminate and Chronic Disease===
* '''Direct microscopy''' blood film or tissue biopsy (e.g. lymph node, bone marrow, pericardial fluid, CSF)
 
** In immunocompromised, these other samples are even more important
 
* Hemoculture is only 50% sensitive and takes several weeks
 
* Serology for IgM is useless
 
* '''PCR''' is sensitive and specific
 
* Xenodiagnosis
 
   
  +
*No gold standard
=== Indeterminate and chronic disease ===
 
  +
*Serology for IgG is most useful
  +
**Detectable after 6 to 9 months following infection
  +
**Many assays (ELISA, indirect hemagglutination, chemiluminescence, and IFA)
  +
*PCR (of blood) less sensitive
   
  +
==Management==
* No gold standard
 
* Serology for IgG is most useful
 
** Detectable after 6 to 9 months following infection
 
** Many assays (ELISA, indirect hemagglutination, chemiluminescence, and IFA)
 
* PCR (of blood) less sensitive
 
   
== Management ==
+
===Acute===
   
  +
*Treatment is most useful in acute disease, congenital Chagas, and children with chronic infection up to 18 years
=== Acute ===
 
  +
**It can decrease illness severity and mortality
  +
**Start ASAP before infection can become established
  +
**However, treatment may not result in parasitologic cure
  +
*Treatment options
  +
**Nifurtimox: 90-120 day treatment course; AEs include anorexia, weight loss, neurologic symptoms
  +
**Benznidazole: 60 day treatment course; AEs include hypersensitivity, GI upset, rare polyneuropathy and agranulocytosis
  +
*Adverse events are common during treatment
   
  +
===Chronic===
* Treatment is most useful in acute disease, congenital Chagas, and children with chronic infection up to 18 years
 
** It can decrease illness severity and mortality
 
** Start ASAP before infection can become established
 
** However, treatment may not result in parasitologic cure
 
* Treatment options
 
** Nifurtimox: 90-120 day treatment course; AEs include anorexia, weightloss, neurologic symptoms
 
** Benznidazole: 60 day treatment course; AEs include hypersensitivity, GI upset, rare polyneuropathy and agranulocytosis
 
* Adverse events are common during treatment
 
   
  +
*Less clear benefit to antiparasitic treatment
=== Chronic ===
 
  +
*Cardiac disease
  +
**May benefit from pacemaker in patients with conduction disease
  +
***Monitor with ECG q6mo
  +
**May need heart transplantation, though this can become complicated by ongoing chronic infection or recrudescence
  +
*Megaesophagus: balloon dilatation or surgical management
  +
*Megacolon may need surgical management
   
  +
==Prevention==
* Less clear benefit to antiparasitic treatment
 
* Cardiac disease
 
** May benefit from pacemaker in patients with conduction disease
 
*** Monitor with ECG q6mo
 
** May need heart transplantation, though this can become complicated by ongoing chronic infection or recrudescence
 
* Megaesophagus: balloon dilatation or surgical management
 
* Megacolon may need surgical management
 
   
  +
*Screening immigrants and then following up with regular cardiac screening, if positive
== Prevention ==
 
  +
*Avoid sleeping in dilapidated dwellings in endemic countries, use insect repellent and bed nets
  +
*Improve housing in endemic areas
   
  +
===Canadian Blood Services===
* Screening immigrants and then following up with regular cardiac screening, if positive
 
* Avoid sleeping in dilapidated dwellings in endemic countries, use insect repellent and bed nets
 
* Improve housing in endemic areas
 
   
  +
*Samples are only tested for antibodies when increased risk is present, determined by the donor screening questions
=== Canadian Blood Services ===
 
  +
*No reported cases since screening began in 2010
   
  +
{{DISPLAYTITLE:''Trypanosoma cruzi''}}
* Samples are only tested for antibodies when increased risk is present, determined by the donor screening questions
 
  +
[[Category:Protozoa]]
* No reported cases since screening began in 2010
 

Latest revision as of 11:43, 6 March 2023

Background

  • Causes Chagas disease (South American trypanosomiasis)

Microbiology

  • Protozoan parasite

Epidemiology

  • Endemic throughout the Americas from the southern half of the United States to Argentina
    • Particularly in rural, impoverished areas
    • A small number of autochthonous cases of Chagas disease in the US
  • Reservoirs include armadillos, opossums, raccoons, woodrats, some other rodents, and domestic dogs
  • Triatomine vector species for trypanosomiasis belong to the genera Triatoma, Rhodnius, and Panstrongylus
    • Bugs live in substandard dwellings (especially wood, mud, or stone houses)
    • Vector is present from southern US to southern Argentina
    • Transmission is via feces, either in direct contact with mucous membranes (especially conjunctivae), breaks in the skin, or contaminating the bite of the insect
  • Can also be transmitted via blood transfusion or vertically from mother to child or via ingestion of contaminated food and drink

Pathophysiology

  • Infective metacyclic trypomastigotes from feces enter the skin or mucosa
  • Multiply in host cells as amastigotes, developing into trypomastigotes intracellularly and rupturing the cell, releasing more trypomastigotes
    • Chagoma develops at site of inoculation
    • Intracellular amastigotes visible as characteristic pseudocysts on histopathology
  • Hematogenous spread to distant sites, especially muscles, with the cycle repeating
    • Especially tropic for myocardium, where it causes biventricular enlargement, thinning of ventricular walls, apical aneurysms, and mural thrombi
  • Parasitemia maintained for years

Clinical Manifestations

Acute Disease

  • Often asymptomatic
  • Incubation period of about 1 week
  • Usually mild febrile illness, sometimes with hepatosplenomegaly, rash, edema, local inflammation
    • Incurs in 20% of infections
    • More common in children
  • Nodular lesions ("chagomas") may develop at site of inoculation
    • Romaña sign if periorbital, often with ipsilateral lymphadenopathy
    • Often 1-2 weeks after exposure
  • Acute myocarditis, pericardial effusion, and meningoencephalitis in 1-5%

Indeterminate Phase

  • Following acute infection, may enter a latent phase

Chronic Disease

  • Following acute infection can remain asymptomatic (indeterminate form)
  • Cardiac complications in 25-30% (1.5-5% per year)
    • Non-ischemic dilated biventricular (right more than left) cardiomyopathy with heart failure
    • Apical aneurysms and mural thrombi
    • Conduction defects, with heart blocks, bundle branch blocks, sinus node dysfunction, bradycardia, and ventricular arrhythmias
    • Can cause sudden cardiac death
  • GI involvement in 10-15%
    • Megaesophagus, with dysphagia, odynophagia, chest pain, cough, and regurgitation
      • May result in aspiration and recurrent pneumonias
    • Megacolon, with constipation and abdominal pain
  • Meningoencephalitis
  • Other: polyneuropathy, stroke syndrome

Immunocompromised Patients

  • May have reactivation following immune suppression or HIV
  • Severe acute infection; may have skin lesions and cerebral masses/abscesses
  • Meningoencephalitis

Diagnosis

Acute Disease

  • Direct microscopy blood film or tissue biopsy (e.g. lymph node, bone marrow, pericardial fluid, CSF)
    • In immunocompromised, these other samples are even more important
  • Hemoculture is only 50% sensitive and takes several weeks
  • Serology for IgM is useless
  • PCR is sensitive and specific
  • Xenodiagnosis

Indeterminate and Chronic Disease

  • No gold standard
  • Serology for IgG is most useful
    • Detectable after 6 to 9 months following infection
    • Many assays (ELISA, indirect hemagglutination, chemiluminescence, and IFA)
  • PCR (of blood) less sensitive

Management

Acute

  • Treatment is most useful in acute disease, congenital Chagas, and children with chronic infection up to 18 years
    • It can decrease illness severity and mortality
    • Start ASAP before infection can become established
    • However, treatment may not result in parasitologic cure
  • Treatment options
    • Nifurtimox: 90-120 day treatment course; AEs include anorexia, weight loss, neurologic symptoms
    • Benznidazole: 60 day treatment course; AEs include hypersensitivity, GI upset, rare polyneuropathy and agranulocytosis
  • Adverse events are common during treatment

Chronic

  • Less clear benefit to antiparasitic treatment
  • Cardiac disease
    • May benefit from pacemaker in patients with conduction disease
      • Monitor with ECG q6mo
    • May need heart transplantation, though this can become complicated by ongoing chronic infection or recrudescence
  • Megaesophagus: balloon dilatation or surgical management
  • Megacolon may need surgical management

Prevention

  • Screening immigrants and then following up with regular cardiac screening, if positive
  • Avoid sleeping in dilapidated dwellings in endemic countries, use insect repellent and bed nets
  • Improve housing in endemic areas

Canadian Blood Services

  • Samples are only tested for antibodies when increased risk is present, determined by the donor screening questions
  • No reported cases since screening began in 2010