ABSTRACT
Hybridization of the parasite deoxyribonucleic acid (DNA) with a species-specific repetitive sequences probe distinguishes Plasmodium falciparum from other Plasmodiumspecies with a sensitivity of 10 pg of purified P. falciparum DNA, which is equivalent to 100 parasites. This dot blot test, requiring minimal equipment and sample handling, was shown to detect approximately 40 parasites per microliter of blood. Spot assays detecting 5 parasites per microliter in a 10-µ1 sample of blood have also been reported. However, nonspecific cross-reactivities were observed. Primers targeted to a 206-bp P. falciparum DNA sequence can detect as little as 0.01 pg of DNA, equivalent to one-half of a parasite, in blood without prior extraction. Babesiosis is a tick-transmitted infection caused by malaria-like parasites of the genus Babesia, which invade and destroy erythrocytes. The infrequent infections in humans are caused mostly by B. microti, although B. bovis and B. divergens also have been reported in humans.
