ABSTRACT
Using a real-time quantitative PCR (qPCR), we determined the number of DNA copies/mL of blood of a Babesia microti gene in infected patients. Thirty-six patients (whose median age was 62.5years and 75.0% were male) with at least 1 qPCR-positive blood sample were included in this analysis, including 16 with serial blood samples. Based on testing of serial blood samples, it could be demonstrated that the smear became negative while the qPCR remained positive. A moderate to strong correlation was found between the DNA copy number and the number of infected erythrocytes per milliliter of blood (Pearson's r=0.68, P<0.001). Based on limited data, the DNA copy number fell by a mean of 4.1-12.9% per day on active treatment and by 3.5-7.1% per day off therapy. qPCR methodology may permit systematic evaluations of the relative efficacy of various antiparasitic drug regimens and other therapeutic modalities, although a limitation of such testing is that DNA detection per se does not establish the presence of viable parasites.
Subject(s)
Babesia microti/isolation & purification , Babesiosis/diagnosis , Blood/parasitology , Microscopy/methods , Real-Time Polymerase Chain Reaction/methods , Adolescent , Adult , Aged , Aged, 80 and over , Babesia microti/cytology , Babesia microti/genetics , Child , Child, Preschool , Drug Monitoring/methods , Female , Humans , Infant , Male , Middle Aged , Sensitivity and Specificity , Young AdultABSTRACT
Babesia microti protozoa were detected by light and electron microscopy in the salivary glands of field-collected Ixodes ovatus ticks; 6 of 85 adult ticks were demonstrated to be positive for B. microti DNA by polymerase chain reaction assays. In the salivary glands of unfed ticks, B. microti existed in the sporoblast stage in the granular acinus cells, and developed into the sporozoite stage during feeding on the host for 2 days. The present results indicated for the first time that I. ovatus can indeed carry B. microti and is not infected mechanically with the parasites by blood-sucking. This frequent infection of I. ovatus with B. microti demonstrates the significance of such a vector-pathogen relationship in Japan, and strongly suggests that I. ovatus is involved in the maintenance of B. microti in the fauna of Japanese rodents.
Subject(s)
Arachnid Vectors/parasitology , Babesia microti/growth & development , Babesia microti/isolation & purification , Ixodes/parasitology , Animals , Babesia microti/cytology , Babesiosis/transmission , Babesiosis/veterinary , DNA, Protozoan/analysis , DNA, Protozoan/genetics , Japan , Microscopy , Microscopy, Electron , Polymerase Chain Reaction , Salivary Glands/parasitology , Salivary Glands/pathologyABSTRACT
The majority of babesia infections in Europe are life-threatening and caused by Babesia divergens and B. bovis. Although Babesia microti has been detected in ticks from Switzerland, few if any cases of babesiosis have been caused by B. microti. This first reported case, diagnosed by serology, DNA detection, and microscopy, is additionally interesting because there appears to be coinfection with the Lyme disease organism, Borrelia burgdorferi.