Chronic Babesia, Negative Tests, Re-treatment, Etc. 

"In many cases, parasitemia may be very low and infected patients may have negative smears.  This is especially likely in chronic infections in non-splenectomized patients.

Source-  Maryland Department of Health and Mental Hygiene- Page 2 right side- 2nd paragraph.


***

Johns Hopkins ABX Guide

Babesia Species-  John G. Bartlett, M.D. 
09-24-2008 

MICROBIOLOGY

For persistent/recurrent parasitemia: treat with one of the above regiments for > 6 weeks and > 2 weeks after the parasitemia has resolved.

Comments: Comparison of 14 case patients also had substantial morbidity with persistent Babesia microti infection despite treatment were compared to 46 controls who had this parasitic infection and responded to treatment. The case patients were all immunosuppressed, most had B cell lymphomas and were asplenic or received rituximab. Case patients had persistence with 2-10 courses of treatment and 3 died. The recommendation is to treat these patients for > 6 weeks and > 2 weeks after the parasitemia has resolved. 

The Ixodid ticks ingest Babesia during feeding from the host, multiply the protozoa in their gut wall,and concentrate it in their salivary glands. The tick inoculates a new host when feeding again. The parasite then infects red blood cells (RBCs) and differentiated and undifferentiated trophozoites are produced. The former produce 2-4 merozoites that disrupt the RBC and go on to invade other RBCs.

Babesiosis exists as a spectrum of disease in 3 distinct groups: (1) asymptomatic infection, (2) a mild/moderate viral-like syndrome, and (3) severe disease with a fulminant course resulting in death orpersistent relapsing course.1    


***

Babesiosis

Author: Tarlan Hedayati, MD, Assistant Professor of Emergency Medicine, Rush Medical College, John H Stroger Hospital of Cook County
Coauthor(s): Cameron Nima Nourani, MD, Resident Physician, Department of Emergency Medicine, John H Stroger Hospital of Cook County
Contributor Information and Disclosures

Updated: Jun 4, 2010

  • Immunofluorescence antibody test (IFA) is considered the criterion standard for serologic detection of B microti infection.
  • This test is used to confirm the diagnosis when the peripheral blood smear result is negative.
  • A titer of greater than 1:64 is considered positive.
  • Enzyme-linked immunosorbent assay (ELISA) immunoglobulin M (IgM) Lyme test is used because of the high percentage (25%) of patients co-infected with Lyme disease.
  • Co-infection increases the severity of disease; therefore, diagnosing and treating both infections is important.
  • http://emedicine.medscape.com/article/780914-overview
***

Babesiosis

Author: Tarlan Hedayati, MD, Assistant Professor of Emergency Medicine, Rush Medical College, John H Stroger Hospital of Cook County
Coauthor(s): Cameron Nima Nourani, MD, Resident Physician, Department of Emergency Medicine, John H Stroger Hospital of Cook County
Contributor Information and Disclosures

Updated: Jun 4, 2010


Immediately start elderly, immunocompromised, or asplenic patients on a combination treatment regimen of intravenous clindamycin and oral quinine or intravenous atovaquone and intravenous azithromycin to avoid acute renal failure.

Parasitemia may persist despite treatment with either of the described drug regimens.

Additionally, patients initially treated may require re-treatment if repeat smears or PCR are positive more than 3 months after initial therapy.


***

Babesiosis

Author: Tarlan Hedayati, MD, Assistant Professor of Emergency Medicine, Rush Medical College, John H Stroger Hospital of Cook County
Coauthor(s): Cameron Nima Nourani, MD, Resident Physician, Department of Emergency Medicine, John H Stroger Hospital of Cook County
Contributor Information and Disclosures

Updated: Jun 4, 2010


Antibiotics

Therapy should cover all likely pathogens in the context of this clinical setting.




***

Johns Hopkins Microbiology

In one study, 54% of patients with babesiosis had antibodies to Borrelia burgdorferi.  [Benach J, Coleman J, Habicht G, et al. Serologic evidence for simultaneous occurrences of Lyme disease and babesiosis. Journal of Infectious Diseases 1985: 152:473-477.]

Persistent subclinical infection may occur and presents a risk to blood supplies in endemic regions.