Preventing Transfusion-Transmitted Babesiosis.

Evan M Bloch,Laura Tonnetti,Peter J Krause

doi:10.3390/pathogens10091176

Evan M Bloch, Laura Tonnetti + Show 1 more

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https://doi.org/10.3390/pathogens10091176

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Abstract

Babesia are tick-borne intra-erythrocytic parasites and the causative agents of babesiosis. Babesia, which are readily transfusion transmissible, gained recognition as a major risk to the blood supply, particularly in the United States (US), where Babesia microti is endemic. Many of those infected with Babesia remain asymptomatic and parasitemia may persist for months or even years following infection, such that seemingly healthy blood donors are unaware of their infection. By contrast, transfusion recipients are at high risk of severe babesiosis, accounting for the high morbidity and mortality (~19%) observed in transfusion-transmitted babesiosis (TTB). An increase in cases of tick-borne babesiosis and TTB prompted over a decade-long investment in blood donor surveillance, research, and assay development to quantify and contend with TTB. This culminated in the adoption of regional blood donor testing in the US. We describe the evolution of the response to TTB in the US and offer some insight into the risk of TTB in other countries. Not only has this response advanced blood safety, it has accelerated the development of novel serological and molecular assays that may be applied broadly, affording insight into the global epidemiology and immunopathogenesis of human babesiosis.

Highlights

Babesia are tick-borne apicomplexan parasites and the causative pathogens of the clinical illness, babesiosis
Over 100 species of Babesia infect a wide array of vertebrates, yet only six species have been implicated in human infections, of which Babesia microti is overwhelmingly predominant [1]
Findings from Babesia surveillance and clinical case reporting suggest a significant increase in B. microti incidence in the United States (US) over the past two decades [3]

Summary

Introduction

Babesia are tick-borne apicomplexan parasites and the causative pathogens of the clinical illness, babesiosis. While B. microti has been reported frequently from the northeastern and northern midwestern United States (US), cases of babesiosis have been described globally [2]. Findings from Babesia surveillance and clinical case reporting suggest a significant increase in B. microti incidence in the United States (US) over the past two decades [3]. Factors that have been postulated for the emergence of Babesia include an increase in the deer population that amplifies the number of ticks, an increase in the human population, and building homes in tick infested areas [3,4,5]. Babesia was historically under-investigated, whereby greater attention (i.e., awareness) following its becoming a notifiable disease in many US states in 2011 likely contributed to the observed increase in cases

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