Figure 1. Examples of relation between enterovirus RNA in blood and in the concomitant stool samples.

A. The tested blood, and the concomitant stool were both positive. B. The tested blood was positive, while the concomitant stool was negative. C. The tested blood was negative, while the concomitant stool was positive. D. The tested blood, and the concomitant stool were both negative. The four possible combinations of positivity and negativity of stool and blood are shown, each exemplified by ten individuals. Typical situations are shown. Concomitant is a stool sample taken within the interval 30 days before to 15 days after the tested blood. The graphs show the life lines of the infants during their first year of life. Each line denotes one child. The children are aligned by birth (asterisk), the horizontal axis shows age (yrs). The triangles are blood samples: full black, positive already in the first PCR round; dark grey, positive in the second round of PCR; empty, negative. The circles correspond to the stool samples: full circles, stool with more than 10 000 enterovirus copies per µl RNA; lower half-circles, stool positive up to 10 000 copies per µl RNA; empty circles, stool negative or with a trace of enterovirus up to 10 copies per µl.