Select Protozoal Infections

   
 
Table 4-16 Select Protozoal Infections
 Disease Organism/Vector Clinical Findings Treatement
 
Amebiasis
Entamoeba histolytica
Mainly GI symptoms (bloody diarrhea)

Rare skin findings: cysts, nodules, or ulcers with heaped-up borders and erythematous halo
Oral metronidazole
 
American Trypanosomiasis (Chagas Disease)
Trypanosoma cruzi (Central/South America)

Vector:reduviid bug (Triatoma spp.)
Erythema and edema at site of inoculation, regional lymphadenopathy

Romaña’s sign: eyelid edema and conjunctivitis

Chronic phase: cardiac and GI abnormalities (arrhythmia, heart block, megacolon, megaesophagus); infection mainly in children
Nifurtimox or benznidazole
 
African Trypanosomiasis (Sleeping Sickness)
T. brucei gambiense
T. brucei rhodesiense


Vector:tsetse fly
(Glossina spp.)
First stage: indurated chancre at site of inoculation → heals spontaneously; subsequent fever spikes correlating with annular erythematous patches

Winterbottom’s sign: posterior cervical lymphadenopathy

Second stage: daytime somnolence (neurologic phase)
Suramin or pentamidine
 
Toxoplasmosis
Toxoplasma gondii

Vector: contact with cat feces or ingestion of improperly cooked pork
Acute infection typically asymptomatic in competent hosts (± flu-like symptoms) Immunocompromised: CNS toxoplasmosis, pneumonitis, chorioretinitis
Sulfadiazine with pyrimethamine