Babesia microti: Difference between revisions
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Babesia microti
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==Background== |
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= Babesiosis (''Babesia microti'') = |
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*Causes '''babesiosis''' |
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== Microbiology == |
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===Microbiology=== |
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* Tickborne protozoa |
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* Different species of ''Babesia'' exist |
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* Seen as Maltese cross on blood smear |
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*Tickborne protozoa |
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== Epidemiology == |
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*Different species of ''Babesia'' exist |
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*Seen as Maltese cross on blood smear |
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===Epidemiology=== |
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* Tickborne by ''Ixodes scapularis'' |
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* Reservoir is white-footed mice |
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* Can be transmitted by blood transfusion and, rarely, transplacentally (5 cases) |
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* More common in the northeastern US, including Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin |
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** Highly endemic in Nantucket, Martha's Vineyard, the Elizabeth Islands, Block Island, Shelter Island, eastern Long Island, an Fire Island |
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*Tickborne by [[Vector::Ixodes scapularis]] |
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=== Other species === |
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*Reservoir is white-footed mice |
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*Can be transmitted by blood transfusion and, rarely, transplacentally (5 cases) |
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*More common in the northeastern US, including Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin |
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**Highly endemic in Nantucket, Martha's Vineyard, the Elizabeth Islands, Block Island, Shelter Island, eastern Long Island, an Fire Island |
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*Has been found in Canada as of 2013, with several case reports from Manitoba and on case report of [[Babesia duncani]] infection in souther Ontario[[CiteRef::yang2021ba]] |
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*Typically takes 36 hours or longer of tick attachment to be transmitted to human host |
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====Other Species==== |
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* ''B. duncani'' and ''B. duncani''-type organisms are present in the Pacific Coast |
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* ''B. divergens'' in Europe; rarely ''B. venatorum'' |
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*''B. duncani'' and ''B. duncani''-type organisms are present in the Pacific Coast |
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== Life Cycle == |
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*''B. divergens'' in Europe; rarely ''B. venatorum'' |
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==Clinical Manifestations== |
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[[File:Babesia_LifeCycle_1.gif|Babesia life cycle]] |
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*Incubation period [[Usual incubation period::1 to 6 weeks]] |
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== Clinical Presentation == |
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**Diagnosis can be delayed |
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**There are some cases of asymptomatic parasitemia |
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**May experience recrudescence after immunosuppression |
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*Symptoms include [[Causes::fatigue]], [[Causes::weakness]], and [[Causes::malaise]], followed by [[Causes::fever]] and chills, [[Causes::arthralgias]], or [[Causes::nausea]] |
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**Fever may be intermittent or persistent, and can be high |
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*Can also cause [[Causes::nuchal rigidity]], [[Causes::sore throat]], [[Causes::dyspnea]], [[Causes::weight loss]], [[Causes::vomiting]], [[Causes::diarrhea]], and dark urine |
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*Occasionally causes [[emotional lability]], [[depression]], [[hyperesthesia]], [[photophobia]], [[conjunctival injection]], [[abdominal pain]], [[petechiae]], and [[ecchymoses]] |
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*May have [[erythema chronicum migrans]] rash in cases of coinfection |
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*Bloodwork shows [[Causes::anemia]], [[Causes::jaundice]], and other evidence of [[Causes::hemolysis]], often with positive [[direct antiglobulin test]] |
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**Also [[Causes::thrombocytopenia]] and liver enzyme abnormalities |
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**If [[neutropenia]], suggests coinfection with anaplasmosis |
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=== Prognosis and Complications === |
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* Incubation period 1 to 6 weeks |
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* Can have delayed diagnosis |
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* Symptoms include fatigue, weakness, and malaise, followed by fever and chill, arthralgias, or nausea |
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* Fever may be intermittent or persistent, and can be high |
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* Can also cause nuchal rigidity, sore throat, dyspnea, weight loss, vomiting, diarrhea, and dark urine |
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* Occasionally causes emotional lability, depression, hyperesthesia, photophobia, conjunctival injection, abdominal pain, petechiae, and ecchymoses |
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* May have erythema chronicum migrans rash in cases of coinfection |
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* There are some cases of asympatomatic parasitemia |
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* May experience recrudescence after immunosuppression |
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* Bloodwork shows anemia, jaundice and other evidence of hemolysis, often with positive direct antiglobulin test |
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** Also thrombocytopenia and liver enzyme abnormalities |
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** If neutropenia, suggests coinfection with anaplasmosis |
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* 40% develop complications, including ARDS, DIC, CHF, coma, AKI, splenic rupture |
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*40% develop complications, including [[ARDS]], [[DIC]], [[CHF]], coma, [[AKI]], splenic rupture |
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=== Transplacentally-acquired neonatal infection === |
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*More severe illness in patients with [[asplenia]], [[X-linked agammaglobulinemia]], [[malignancy]], [[HIV]] with low CD4 count, [[TNF-α inhibitors]], and immunosuppression for transplantation, [[B-cell lymphoma]], or autoimmune disorders |
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===Congenital Infection=== |
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* Five cases |
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* Symptom onset around 3 to 6 weeks |
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* Parasitemia 2-15% on diagnosis |
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*Five cases |
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=== Other ''Babesia'' species === |
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*Symptom onset around 3 to 6 weeks |
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*Parasitemia 2-15% on diagnosis |
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===Other ''Babesia'' species=== |
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* ''B. divergens'' usually in aplenic patients, causing fulminant disease |
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*''B. divergens'' usually in [[Asplenia and hyposplenia|asplenic patients]], causing fulminant disease |
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== Diagnosis == |
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==Diagnosis== |
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* Parasites visualized on blood film, with parasitemia from 1 to 20% but as high as 85% in splenectomized patients |
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*Parasites visualized on blood film, with parasitemia from 1 to 20% but as high as 85% in splenectomized patients |
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== Management == |
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==Management== |
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* Asymptomatic parasitemia: no treatment necessary unless immunocompromised or persists for longer than 3 months |
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* Mild: atovaquone plus azithromycin |
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*Asymptomatic parasitemia: no treatment necessary unless immunocompromised or persists for longer than 3 months |
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* Severe: clindamycine plus quinine, ± RBC exchange transfusion |
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*'''Mild''': [[Is treated by::atovaquone]] 750 mg PO q12h plus [[Is treated by::azithromycin]] 500-1000 mg PO once followed by 250-500 mg PO daily for 7 to 10 days |
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* ''B. divergens'': RBC exchange transfusion plus clinda plus quinine |
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*'''Severe''': [[Is treated by::clindamycin]] 300-600 mg IV q6h or 600 mg PO q8h plus [[Is treated by::quinine]] 650 mg PO q6-8h |
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* Duration |
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**± RBC exchange transfusion if parasitemia ≥10%, severe hemolysis, or pulmonary, renal, or hepatic failure |
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** 7 to 10 days for most |
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*'''''B. divergens''''': RBC exchange transfusion plus [[clindamycin]] plus [[quinine]] |
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** Can relapse when immunocompromised, so these patients need 6+ weeks including 2+ weeks without parasitemia |
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*Duration |
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**7 to 10 days for most |
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**Can relapse when immunocompromised, so these patients need 6+ weeks including 2+ weeks without parasitemia |
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{{DISPLAYTITLE:''Babesia microti''}} |
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[[Category:Vector-borne infections]] |
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[[Category:Haemosporida]] |
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Latest revision as of 15:53, 2 May 2024
Background
- Causes babesiosis
Microbiology
- Tickborne protozoa
- Different species of Babesia exist
- Seen as Maltese cross on blood smear
Epidemiology
- Tickborne by Ixodes scapularis
- Reservoir is white-footed mice
- Can be transmitted by blood transfusion and, rarely, transplacentally (5 cases)
- More common in the northeastern US, including Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin
- Highly endemic in Nantucket, Martha's Vineyard, the Elizabeth Islands, Block Island, Shelter Island, eastern Long Island, an Fire Island
- Has been found in Canada as of 2013, with several case reports from Manitoba and on case report of Babesia duncani infection in souther Ontario1
- Typically takes 36 hours or longer of tick attachment to be transmitted to human host
Other Species
- B. duncani and B. duncani-type organisms are present in the Pacific Coast
- B. divergens in Europe; rarely B. venatorum
Clinical Manifestations
- Incubation period 1 to 6 weeks
- Diagnosis can be delayed
- There are some cases of asymptomatic parasitemia
- May experience recrudescence after immunosuppression
- Symptoms include fatigue, weakness, and malaise, followed by fever and chills, arthralgias, or nausea
- Fever may be intermittent or persistent, and can be high
- Can also cause nuchal rigidity, sore throat, dyspnea, weight loss, vomiting, diarrhea, and dark urine
- Occasionally causes emotional lability, depression, hyperesthesia, photophobia, conjunctival injection, abdominal pain, petechiae, and ecchymoses
- May have erythema chronicum migrans rash in cases of coinfection
- Bloodwork shows anemia, jaundice, and other evidence of hemolysis, often with positive direct antiglobulin test
- Also thrombocytopenia and liver enzyme abnormalities
- If neutropenia, suggests coinfection with anaplasmosis
Prognosis and Complications
- 40% develop complications, including ARDS, DIC, CHF, coma, AKI, splenic rupture
- More severe illness in patients with asplenia, X-linked agammaglobulinemia, malignancy, HIV with low CD4 count, TNF-α inhibitors, and immunosuppression for transplantation, B-cell lymphoma, or autoimmune disorders
Congenital Infection
- Five cases
- Symptom onset around 3 to 6 weeks
- Parasitemia 2-15% on diagnosis
Other Babesia species
- B. divergens usually in asplenic patients, causing fulminant disease
Diagnosis
- Parasites visualized on blood film, with parasitemia from 1 to 20% but as high as 85% in splenectomized patients
Management
- Asymptomatic parasitemia: no treatment necessary unless immunocompromised or persists for longer than 3 months
- Mild: atovaquone 750 mg PO q12h plus azithromycin 500-1000 mg PO once followed by 250-500 mg PO daily for 7 to 10 days
- Severe: clindamycin 300-600 mg IV q6h or 600 mg PO q8h plus quinine 650 mg PO q6-8h
- ± RBC exchange transfusion if parasitemia ≥10%, severe hemolysis, or pulmonary, renal, or hepatic failure
- B. divergens: RBC exchange transfusion plus clindamycin plus quinine
- Duration
- 7 to 10 days for most
- Can relapse when immunocompromised, so these patients need 6+ weeks including 2+ weeks without parasitemia
References
- ^ Jiayu Yang, Catherine Smith, Anthony Battad. Babesia microti acquired in Canada. Canadian Medical Association Journal. 2021;193(31):E1213-E1217. doi:10.1503/cmaj.201983.
