Experimental transfusion-induced Babesia microti infection: Dynamics of parasitemia and immune responses in a rhesus macaque model
Published Date:Feb 19 2016
Source:Transfusion. 56(6 Pt 2):1508-1519.
Pubmed Central ID:PMC4905818
Funding:CC999999/Intramural CDC HHS/United States
P30 AI050409/AI/NIAID NIH HHS/United States
P51 OD011132/OD/NIH HHS/United States
Babesiosis is an emerging tick-borne infection in humans. The increasing numbers of reported cases of transfusion-associated babesiosis (TAB), primarily caused by Babesia microti, represents a concern for the safety of the U.S. blood supply.
STUDY DESIGN AND METHODS
This study investigated kinetics of parasitemia, innate immune responses and dynamics of antibody responses during B. microti infection in rhesus macaques using blood smears, quantitative PCR (qPCR), flow cytometry, and indirect fluorescent antibody testing. A total of 6 monkeys were transfused with either hamster or monkey-passaged B. microti infected erythrocytes (2 and 4 monkeys, respectively) simulating TAB.
The prepatent period in monkeys inoculated with hamster-passaged B. microti was 35 days compared with 4 days in monkeys transfused with monkey-passaged B. microti; the latter monkeys also had markedly higher parasitemia levels. The duration of the window period from the first detected parasitemia by qPCR analysis to the first detected antibody response ranged from 10–17 days. Antibody responses fluctuated during the course of the infection. Innate responses assessed by the frequencies of monocytes and activated B cells correlated with the kinetics and magnitude of parasitemia. On day 14, additional activation peaks were noted for CD14+CD16+ and CD14−CD16+ monocytes and for CD11c+ myeloid dendritic cells, but only in animals transfused with monkey-passaged B. microti. Parasitemia persisted in these immunocompetent animals, similar to human infection.
The results suggest that transfusion-associated transmission of B. microti leads to rapid onset of parasitemia (day 4) in rhesus macaques, detectable antibody response 14 days later and persistent parasitemia.
Supporting Files:No Additional Files
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