Overview of Protozoan Diseases and Their Impact

Cyst

Infective form that survives outside host.

Definitive Host

Host where mature parasites reproduce.

Transmission Methods

Ingestion, vector-borne, direct contact.

Trophozoite

Feeding and reproducing stage in hosts.

Excystment

Process where cysts develop into trophozoites.

Protozoan Diseases

Parasitic infections affecting humans worldwide.

Intermediate Host

Host where immature parasites develop.

Entamoeba histolytica

Pathogen causing amebiasis in humans.

Amebiasis Types

Luminal, invasive dysentery, extraintestinal amebiasis.

Luminal Amebiasis

Asymptomatic infection with minimal tissue damage.

Invasive Amebic Dysentery

Severe diarrhea and intestinal ulceration.

Extraintestinal Amebiasis

Severe infection spreading to other organs.

Diagnosis of E. histolytica

Identification of cysts or trophozoites in stool.

Treatment for E. histolytica

Paromomycin for asymptomatic, iodoquinol for symptomatic.

Acanthamoeba

Causes rare brain infections from contaminated water.

Naegleria

Causes amoebic meningoencephalitis from inhalation.

Acanthamoeba Keratitis

Eye infection from conjunctival inoculation.

Amoebic Encephalitis

Inflammation of brain leading to neurological deficits.

Flagellates

Protozoa with flagella causing zoonotic diseases.

Trypanosoma cruzi

Causes Chagas' disease, transmitted by kissing bugs.

Chagas' Disease Stages

Acute, generalized, asymptomatic, symptomatic stages.

Diagnosis of Chagas' Disease

Microscopic ID of trypomastigotes in blood.

Trypanosoma brucei

Causes African sleeping sickness via tsetse fly.

Tsetse Fly

Insect vector for Trypanosoma brucei transmission.

Preventive Measures for Chagas

Use concrete, insecticides, and bed nets.

Acanthamoeba Infections

Prevent by avoiding contaminated water sources.

T. brucei rhodesiense

Primarily found in eastern and southern Africa.

African sleeping sickness stages

Progresses through three stages if untreated.

Lesion at bite site

Contains dead tissue and rapidly dividing parasites.

CNS invasion symptoms

Includes headache, drowsiness, and coma.

Parasitemia waves

Cyclical waves occur every 7-10 days.

Surface antigen variation

Parasite changes surface antigens to evade immunity.

Diagnosis of T. brucei

Microscopic observation of trypomastigotes in fluids.

Treatment for early T. brucei

Pantamidine or suramin used in early stages.

Eflornithine

Effective against T. brucei gambiense infections.

Leishmania

Causes leishmaniasis, endemic in tropics and subtropics.

Leishmania hosts

Common in wild/domestic dogs and small rodents.

Leishmania life stages

Includes amastigotes and promastigotes.

Cutaneous leishmaniasis

Causes large painless skin ulcers.

Visceral leishmaniasis

Involves liver, spleen, and bone marrow infections.

Diagnosis of leishmaniasis

Microscopic ID of amastigotes in lesions.

Giardia intestinalis

Causative agent of giardiasis, common in the U.S.

Giardia life cycle

Cysts release trophozoites in the small intestine.

Symptoms of giardiasis

Includes severe diarrhea, abdominal pain, and nausea.

Apicomplexans

Parasites with complex life cycles and organelles.

Toxoplasma gondii

Causative agent of toxoplasmosis, widely distributed.

Toxoplasma transmission

Humans infected by undercooked meat or soil.

Symptoms of toxoplasmosis

Fever, headache, muscle pain, and lymph node swelling.

Severe toxoplasmosis populations

AIDS patients and fetuses are at higher risk.

Diagnosis of toxoplasmosis

Microscopic ID in tissue biopsies and serologic tests.

Treatment for symptomatic toxoplasmosis

Antimalarial drugs used for symptomatic patients.

Prevention of toxoplasmosis

Thorough cooking of meats and avoiding contaminated soil.