Answer:
bacterial
Step-by-step explanation:
A prokaryotic organism is an organism that does not possess a membrane-bound nucleus that houses its genetic material. Organisms grouped under this domain are bacteria, archaebacteia etc.
According to this question, Fernanda goes for a blood sample because she felt sick. The result of the blood sampling shows that the cells of Fernanda contain a pathogen that seems to be made of small cells with no nucleus. This property describes a prokaryotic pathogen. Hence, the infection is most likely to be that of a BACTERIAL INFECTION.
Note that, a fungus is eukaryotic while a virus is considered non-living because it can only replicate in a living host.