Parasitology part 1: Protist Diseases

Protists

• unicellular eukaryotic organisms that are neither plants nor animals nor fungi

• part of Protozoans kingdom

Protists causes dz where? (3)

1. skin

2. digestive system

3. genitourinary tract

Protists: Dinoflagellates facts (3)

• protists that cause dz

• unicellular

• prod. red & green pigments

What dz does dinoflagellates cause? (2) What toxic blooms cause these?

Diseases

1. Red tides

2. Shellfish poisoning

Toxic blooms:

1. Gonyaulax sp.

2. Gymnodinium sp.

3. Alexandrium sp.

What is the biggest issue that can result from shellfish poisoning?

resp. collapse bc of phytoplankton toxins

Leishmania forms

1. cutaneous leishmania-ulcers + sores

2. visceral leishmania- affects internal organs

Leishmania (cause + transm)

• Caused by:

  • L. major -cutaneous form

  • L. donovani- visceral form

• transmitted: sandfly bite

What cells are affected by leishmania?

1. macrophages

2. monocytes

What is the latent form of Leishmania?

Post-kala-azar dermal leishmaniasis (PKDL)

• result of visceral leish.

• nodules + maculopapular rash

Life cycle of Leishmania

• Infective stage: Promastigote

  • sandfly injects the Infective stage, promastigotes, during blood meals

  • Promastigotes that reach the puncture wound are phagocytized by macrophages in human

• Diagnostic Stage: Amastigotes

  • Promastigotes → amastigotes

  • Amastigotes multiply in infected cells and affect different tissues, depending in part on the Leishmania species

Giardiasis (cause + transm)

• caused by": Giardia Intestinalis

• transmission: food/water cont/ w/ sewage containing cysts

Life cycle of Giardia

• Infective stage: cysts

  • ingestion of cysts

  • gets into intestinal tract

• Diagnostic stage: Trophozoite

  • trophozoite emerges from cyst and starts feeding

  • replicates in IT

  • cysts+ tropho. found in feces

Cyclosporiasis

• caused by: Cyclospora cayetanensis

• transmission: cont. fresh produce+ water

Cryptosporidiosis

• caused by:

  • Cryptosporidium parvum

  • C. hominis

• Transmission: fecal-oral route; cont. water

Cryptospirdiosis and Cyclosporiasisis are especially lethal to?

HIV patients

Protists: Amoebas

free-living single cells

What are the 2 stages of Amoebas?

1. Infective Stage: Cyst= dormant

2. Diagnostic stage: Trophozoite= Active; does damage

Amebiasis

• caused by: Entamoeba histol

• transmission: fecal-oral route; direct contact w/ feces

• second leading cause of dz by parasite

Common symptom of Amoebiasis

amoebic dysentery may include violent diarrhea

Amoebiasis can cause?

Amebic encephalitis

• amoebas can pass thru bloodstream and infect other organs like the brain

Trichomoniasis

• casued by: Trichomonas vaginalis

• transmission: sexual intercourse w/ infected ind.

• only parasite that cause STD

Symptom of Trichomoniasis?

Strawberry cervix aka colpitis macualris

Protists: Ciliates

• have 2 types of nuclei

• reservoir: animals; especially swine

• only know ciliate to cause dz in humans: Balantidium coli

Malaria

• caused by: Plasmodium species

• transmission: bite of infected female mosquito

Malaria is the____ in human history?

biggest killer

What type of cells does malaria infect?

• liver cells

• RBCs

Malaria Life Cycle'

• Infective stage: Sporozoites

  • mosquito bites human

  • sporozoite migrates thru blood to liver

  • sporozoite→merozoite

• Diagnostic Stage: Merozoite

  • merozoite released from liver into blood

  • infects RBCs and creates rings

  • develop into male+ female gametocytes

  • new mosq. bites human + ingests gametocytes

  • gametocytes→ sporozoites in salivary gland of mosq. ( can now infect new host)

Malaria symptoms

• flu-like symptoms

• enlarges liver+ spleen

Paroxysm and malaria

a sudden recurrence or attack of a disease; a sudden worsening of symptoms

• tertian malaria: Fever attacks occur every 48 hrs; fever spike are when rbc’s are breaking up

• quartan malaria: Fever spikes every 3 days

Worst species of malaria to get? What does it cause?

Plasmodium falciparum

• black water urine fever

• RBC’s breaking up bc of fever; every time fever spikes black urine is produced

Babesia

• caused by: Babesia microti

• transmission: transmitted by ticks

  • Parasites invade RBCs

• malaria-like dz

Toxoplasmosis

• caused by: Toxoplasma gondii

• transmission: cats; cont meat

Symptoms of Toxoplasmosis

• hydrocephalus in fetus- fluid buildup in brain

• attacks brain AIDs patients

African sleeping sickness

• caused by: T. brucei 

  • T brucei gambiense: chronic

  • T brucei rhodesiense: acute

• transmission: bite of infected Tsetse fly

Symptoms of African sleeping sickness

• chancre at bite site

• parasites invade blood+ CNS

African Sleeping Sickness Life Cycle

• infective stage: metacyclic trypomastigote

• vector: tsetse fly

• diagnostic stage: trypomastigotes found in rbcs

Chagas Dz (American trypanosomiasis)

• caused by: T. cruzi

• transmission: bite of reduvid bug

What is the acute phase

• Romana’s sign

  • Develops feces; junk on skin and causes immune reaction

  • inflammation of eye

Life cycle of Chagas Dz

• Infective stage: metacylclic trypomastigotes

• Diagnostic stage: amastigotes (biopsy) or tryptomastigote (blood)

primary amebic meningoencephalitis (PAM)

• caused by: Naegleria fowleri:

• brain eating dz

• Major inflammation of brain by free living parasite found in lakes/fresh water; water gets into nasal passages and parasite climbs thru it and goes straight to brain