Establishment of a continuous in vitro culture of Babesia duncani in human erythrocytes reveals unusually high tolerance to recommended therapies

Abstract

by guest on July 10, 2020 http://www.jbc.org/ Downloaded from Figure 1. Continuous in vitro culture of B. duncani in hamster RBCs and transfer to human RBCs. A, parasitemia expressed as the percentage of hamster RBCs infected by the parasite at 1, 2, and 3 days post-inoculation (DPI) in a representative experiment. Columns represent mean Ϯ S.E. (error bars) of six biological replicates. B, micrograph of the intracellular development of cultured B. duncani in hamster RBCs in a Giemsa-stained smear prepared at 3 days post-inoculation. The parasitemia was 15% in this sample. C, transfer of B. duncani to human RBCs. B. duncani-infected hamster RBCs (haRBCs) were freshly harvested and maintained in culture in the presence of human RBCs (hRBCs). Left, free merozoites and infected haRBCs. Right, successful development of B. duncani in hRBCs. Human RBCs are distinguishable from haRBCs by their larger size and darker staining. ACCELERATED COMMUNICATION: In vitro culture of B. duncani

Detection and Transstadial Passage of Babesia Species and Borrelia burgdorferi Sensu Lato in Ticks Collected from Avian and Mammalian Hosts in Canada

“…Once established in the human body, this babesial piroplasm is refractory, and recalcitrant to treat with standard antimicrobials. When human babesiosis is advanced, this zoonosis is commonly recrudescent, and often associated with the presence of severe anemia and persistent parasitemia [99,[109][110][111].…”

In vitro cultivation of Babesia duncani (Apicomplexa: Babesiidae), a zoonotic hemoprotozoan, using infected blood from Syrian hamsters (Mesocricetus auratus)

“…The enriched formulation of HL-1with additional supplementation seems to have provided the required nutrients to allow the establishment of continuous B. duncani cultures in this study. Another more likely theory is that the high parasitemia collected from infected hamsters led to a slower initial growth rate as observed by Abraham et al (2018). The growth curve did become more consistent and increase PPE over time (Figs.…”

“…Many extracellular parasites were seen upon examination of the daily RBC smears. A few rare (0-4 iRBC/500 RBC) early ring forms as observed in Abraham et al (2018) were seen each day until day 14. An average of 2 infected blood cells out of 1000 were seen on day 16 postinoculation.…”

“…Free-floating parasites were visible the day after inoculation. Intracellular parasites became visible as early ring forms (Abraham et al 2018) on stained smears relative to the passage level at which they were cryopreserved. Early ring forms began to be seen in the P12 revival at day 8 post-inoculation, P7 revival had a few at day 10, and P5 revival showed visible early ring forms at day 16.…”

Transient Transfection of the Zoonotic Parasite Babesia microti

“…Compared to another human Babesia parasite B. duncani [27], a lack of an in vitro culture system for B. microti has severely impacted studies on the parasite, including the search for suitable diagnostic and blood screening markers. Especially for genetic manipulation study, the common drug selection systems used for Babesia parasites, such as human dihydrofolate reductase (hDHFR)/WR99210 and blasticidin-S deaminase (BSD)/bsd selection systems, cannot be used for B. microti [28].…”