Figure 49-31 Left, Giardia iambiia trophozoite. Right, G. lamblia cysts.
stains (Figure 49-39). These infections are seen more frequently in compromised patients, such as those with AIDS.
Of the coccidia, C. parvum is the most important; this organism has been reported in numerous waterborne outbreaks, some of which have involved thousands of people.2,3,31 Outbreaks have been reported worldwide; these infections tend to be self-limiting in the immunocompetent host but can be life-threatening in the immunocompromised host. Of 15 named species of Cryptosporidium infectious for nonhuman vertebrate hosts C. baileyi, C. amis, C.felis, C. hominis, C. meleagridis, C. muris, and C. parvum have been reported to also infect humans. Humans are the primary hosts for C. hominis, and except for C. parvum, which is widespread among nonhuman hosts and is the most frequently reported zoonotic spedes, the remaining species have been reported primarily in immunocompromised humans. The
Figure 49-33 Left, Chilomastix mesniii trophozoite, silver stain. Right, C. mesniii cyst.
Figure 49-34 Trophozoites of Dientamoeba fragilis.
Figure 49-32 A to C, Trophozoites of Chilomastix mesniii (A, silver stain). D and E, Cysts of C. mesniii.
Was this article helpful?