Source : Webster's Revised Unabridged Dictionary (1913)

Haematozoon \H[ae]m`a*to*zo"["o]n\, n.; pl. {H[ae]matozoa}.
   [NL., fr. Gr. ?, blood + ? animal.] (Zo["o]l.)
   A parasite inhabiting the blood; esp.:
   (a) Certain species of nematodes of the genus {Filaria},
       sometimes found in the blood of man, the horse, the dog,
       etc.
   (b) The trematode, {Bilharzia h[ae]matobia}, which infests
       the inhabitants of Egypt and other parts of Africa, often
       causing death.

Source : WordNet®

haematozoa
     See {haematozoon}