Protozoans

E. histolytica

Transmission

• Fecal-oral

Morphology

• Oocyst 
• Troph: bullseye shaped nucleus; RBC in cytoplasm

Clinical Findings

• Asymptomatic carrier
• Bloody diarrhea
• Liver abscess

Diagnosis

• Fecal smear
• Serology
• CT Scan

G. lamblia

Transmission

• Fecal-oral

Morphology

• Oocyst 
• Flagellated trophozoite

Clinical Findings

• Foul smelling,greasy diarrhea

Diagnosis

• Fecal smear
• Immunoassay

Isospora spp.

Transmission

• Fecal-oral

Morphology

• Oocyst

Clinical Findings

• Severe diarrhea and malabsorption in AIDS patient

Diagnosis

• Fecal exam
• Biopsy
• Eosinophilia

C. cayetanensis

Transmission

• Oocyst from stool

Morphology

• Oocyst

Clinical Findings

• Watery diarrhea
• Nausea
• vomiting

Diagnosis

• Oocyst fluoresce under UV light

Cryptosporidium

Transmission

• Fecal-oral

Morphology

• Oocyst

Clinical Findings

• Watery diarrhea
• Abdominal pain & vomiting

Diagnosis

• Fecal exam Biopsy in small intestine

T. vaginalis

Transmission

• Sexually transmitted

Morphology

• Trophozoite ONLY

Clinical Findings

• Vaginal itching
• Burning on urination
• Yellow green, frothy vaginal discharge

Diagnosis

• Urinalysis
• Vaginal discharge examination

N. fowleri

Transmission

• Lives in freshwater lake

Morphology

• Amoeba

Clinical Findings

• Acute meningitis

Diagnosis

• CSF examination

Acanthamoeba spp.

Transmission

• Lives in freshwater lake
• Eye infection from dirty contact lenses

Morphology

• Amoeba and cyst stage in brain

Clinical Findings

• Chronic granulomatous brain abscess
• Corneal infection

Diagnosis

• CSF; brain tissue; corneal scrapping exam

T. gondii

Transmission

• Ingestion of oocyst in raw pork
• Inhalation of oocyst
• Congenital

Morphology

• Oocyst(infectious)
• Trophozoite

Clinical Findings

• Congenital
• Dissemination infection

Diagnosis

• Serology
• CT Scan

Leishmania spp.

Transmission

• Sandfly bite
• Blood transfusion
• Zoonotic

Morphology

• Promastigote 
• Amastigote

Clinical Findings

• Cutaneous leishmaniasis
• Kala-azar

Diagnosis

• Blood smear
• Biopsy of skin, spleen or liver

African Trypanosomes 

• T. rhodesiense 
• T. gambiense

Transmission

• Tsetse fly
• Blood transfusion

Morphology

• Motile trypomastigote 
• Epimastigote

Clinical Findings

• African sleeping sickness

Diagnosis

• Trypomastigote in blood, spinal fluid and lymph fluid
• Serology

T. cruzi

Transmission

• Kissing Bug
• Blood transfusion

Morphology

• Trypomastigote 
• Amastigote 
• Epimastigote

Clinical Findings

• Chagas Disease

Diagnosis

• Trypomastigote in blood
• Xenodiagnosis