Intestinal/Tissue/Atrial Protozoa - Cal Flashcards by Johnny B

Long hair-like structures; characteristic of mastigophorans

Facilitates propelling of organism and in some cases procurement of food

Flagella

Organisms often describes by number/arrangement of flagellae

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Short hair-like structures; surrounds the organism, often in rows

Cilia

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Metabolic stage
Active, vegetative; feeding

Capable of movement:

Motility dependent on organelles

trophozoite

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Capable of reproduction: Mitotic division; mostly binary or transverse fission

Intracellular inclusions

trophozoite

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Dormant stages, produced by many of the protozoans

Capable of protection: During adverse environmental conditions

Cyst

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Cyst wall: Secreted?

scleroproteins

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The cyst stage in most parasitic species is entered just prior to passage from the host and all material, which has not been metabolized, is cast from the cell. This stage is associated with?

transmission to a new host

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Capable of invading tissue

Agent of amebic dysentery

Entamoeba histolytica

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Intestinal amebiasis

Non-dysenteric colitis or Amebic dysentery

Entamoeba histolytica

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Entamoeba histolytica rarely leaves the GI tract but… if it does… Extra-intestinal amebiasis… most frequent location?

Hepatic: Most frequent; right lobe of liver

Pulmonary
Brain: CNS

Other organs: Spleen, kidneys, etc.

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Ulceration: Penetration of the mucosal crypts; extension into submucosa forming flask-shaped lesions

Entamoeba histolytica

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flask-shaped lesions

Entamoeba histolytica

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Amebomas (amebic granulomas): Granulation tissues; tumors

Entamoeba histolytica

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Non-pathogenic forms of Entamoeba histolytica often will be named?

E. dispar

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Infective and diagnostic stage for Entamoeba histolytica?

Cysts/trophozoites passed in feces…

Mature cysts ingested

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Entamoeba histolytica Specimens of choice?

Feces and biopsies

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Special process for e. histolytica specimen processing?

Collect three specimens: One every other day
Avoid contact with water or urine
Liquid stools: Examine within 30 minutes
Perform direct examination in physiological saline and Lugol’s iodine
Perform concentration technique

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Charcot-Leyden crystals: Formed from the breakdown of eosinophilic blood cells; indication of bleeding or inflammation of the intestinal mucosa

Entamoeba histolytica

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Cyst form has four nuclei?

Entamoeba histolytica

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Entamoeba histolytica trophozoite description?

Occasional RBC inclusion

Centrally-located endosome

“bullseye”

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Worldwide distribution, but mostly in tropical areas with poor sanitation

Acquired through ingesting the quadrinucleate cyst on contaminated food or water.

Causes amoebic dysentery. 10% extraintestinal invasion to liver, lungs, brain.

Causes flask shaped ulcers
Trophozoites often contain ingested RBCs (diagnostic), but need molecular testing to be sure.

E. histolytica

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Often confused with Entamoeba histolytica

Nonpathogenic

Entamoeba coli

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The significance of recovering nonpathogenic intestinal protozoa is:

They are easily confused and misidentified as the pathogenic species

They indicate that there has been a breakdown in the hygienic and sanitary environment of the host.

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Karyosome: Small (larger than Entamoeba histolytica); usually eccentric?

Entamoeba coli

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Mature cysts of ____ characteristically have eight nuclei, rarely 16.

Entamoeba coli

Nonpathogenic commensal. Worldwide distribution Cysts will have 5 or more nuclei with eccentric endosome. An indicator of poor hygiene

Entamoeba coli

Disease: Giardiasis

Giardia lamblia

Giardia: Large numbers of parasites attached to the intestinal mucosa: Block absorption of?

Fat Fat soluble vitamins... primarily Vit. A

INfective and diagnostic stage of giardia?

Cysts

Habitat: Small intestine | Reservoir hosts: Beavers, small mammals, herbivores

Giardia lamblia

Mature quadrinucleated cyst? | Besides e. histolytica...

Giardia lamblia

Most common US pathogen?

Giardia lamblia

For giardia, Several stools may be necessary, cysts often passed on a cyclical basis You can also use what other test?

Enterotest capsule, helpful in recovering organisms from the duodenum

"wry little face“

Trophozoite form of Giardia lamblia

8 flagella?

Giardia lamblia

Worldwide distribution, common in daycare centers and institutionalized populations. Causes blunting of small intestinal villi and malabsorption, often of fats. Symptoms of persistent diarrhea, gas, greasy stools, can become chronic or carriers. Irregular patterns of cysts and trophs in stool samples, but are diagnostic. Molecular methods are available (PCR, antigen)

G. lamblia

Habitat: Genitourinary tract Mode of infection: Sexual contact

Trichomonas vaginalis

Trichomonas vaginalis in females? Males?

In females: Vaginitis, pruritus, strawberry cervix In males: Urethritis, prostatovesiculitis

strawberry cervix

Trichomonas vaginalis

Trichomonas vaginalis Specimen source?

Vaginal and urethral discharges, prostatic exudates

Pathogenicity: Considered nonpathogenic but often recovered from diarrheic stools Habitat: Colon Mode of infection: Ingestion, direct contact/sexual contact (prominent in homosexual communities)

Pentatrichomonas hominis

Pathogenicity: Considered to be nonpathogenic in the mouth (reported thoracic abscesses and respiratory infections) Habitat: Mouth Mode of infection: Direct contact

Trichomonas tenax

Specimen source: Gingival scrapings

Trichomonas tenax

Worldwide distribution, humans only T. vaginalis is pathogenic, the other two are easily confused commensals. Acquired through sexual intercourse or passed to infants during birth. T. vaginalis causes itching, petechial hemorrhaging, discharge (strawberry cervix) Often asymptomatic in men Increased risk of HIV passing or infection Diagnosis: No cyst, 4 anterior flagella with half body undulating membrane

Trichomonas

Only pathogenic ciliate

Balantidium coli

Causes balantidiasis, balantidial dysentery Diarrhea and secondary complications

Damage by mechanical action | Lytic action: Hyaluronidase

Balantidium coli

Balantidium coli geography?

Worldwide but more prominent in areas with swine

Habitat: Cecum Reservoir hosts: Swine, hogs Infective form: Cyst stage Mode of infection: Ingestion

Balantidium coli

Worldwide distribution, but endemic in Japan, South Africa, C & S America, New Guinea Acquired by eating contaminated food and water with feces from humans or animals. Causes ulcer in large intestine similar to E. histolytica, but very rarely travels to other organs. Diagnosis: ID ciliated trophozoite or cyst in stool sample.

Balantidium coli

Causes Primary Amebic Meningoencephalitis (PAM) Central nervous system involvement Rapid progression with high mortality

Naegleria fowleri

Naegleria fowleri distribution?

Australia, New Zealand, South America, Africa, southern Europe, and the southern United States.

Habitat: Along the meninges of the cerebrum, cerebellum and spinal cord Infective form: Amoebiod trophozoite Mode of infection: Active penetration through the nasal passages

Naegleria fowleri

Naegleria fowleri specimen source?

Specimen source: Cerebral spinal fluid NOTE: Finding the trophozoite in the spinal fluid is sufficient reason to initiate treatment.

Wide distribution, thermotolerant, found in hot springs, water above 37 degrees Celsius. Free living amoeba, but can infect humans through the nasal cavity. Causes primary amoebic encephalitis (PAM). Death can occur within 5 days, rapid diagnosis and treatment essential. Diagnosis: Amoeba isolated from CSF

Naegleria fowleri

Pathogenesis: Terramebiasis

Acanthamoeba species

Terramebiasis comes in two forms?

Meningoencephalitis: Subacute; chronic (prominent species are A. castellani and A. culbertsoni) Keratitis: Severe damage to eyes; blindness (prominent species are A. castellani and A. polyphaga),early on tied heavily to homemade contact lens solutions

Habitat: Usually free living; skin, central nervous system and corneal regions of the eye Reservoir hosts: A variety of mammals and invertebrates (oysters, grasshoppers and snails) Infective form: Amebic trophozoites or cysts Mode of infection: Uncertain

Acanthamoeba species Similar to `N. fowleri

Mode of infection: Active penetration through the nasal passages

N. fowleri

Infectiev stage of Acanthamoeba spp?

: Amebic trophozoites or cysts

Requires differentiation from N. fowleri ?

Acanthamoeba spp

Specimen source: Exudates, tissue sections, CSF?

Acanthamoeba spp

Three types of leishmaniasis?

visceral leishmaniasis cutaneous leishmaniasis mucocutaneous leishmaniasis

Three types of leishmaniasis?

visceral leishmaniasis cutaneous leishmaniasis mucocutaneous leishmaniasis

Common names: Kala-azar, Dum-Dum fever

Leishmania donovani

Visceral leishmaniasis?

Leishmania donovani

Darkening of the skin (Kala-azar, black poison) Destruction of reticuloendothelial cells and histiocytes throughout the body

Leishmania donovani Visceral leishmaniasis

Hepatosplenomegaly Frequently fatal (95% for untreated cases) Immunity: Gamma globulins; only after recovery from initial infection

Leishmania donovani Visceral leishmaniasis

South and Central America, Mediterranean regions, Central Africa, Asia (India)

Leishmania donovani Visceral leishmaniasis

Common name: Oriental sore

Leishmania tropica

Initial lesion: Shallow, dry scaly ulcerated lesion Ulceration: Crater-like with thickened edges Secondary bacterial infections common

Cutaneous leishmaniasis Leishmania tropica/major

Ulcers leave disfiguration Seldom fatal Immunity: Self-healing process confers immunity

Cutaneous leishmaniasis Leishmania tropica/major

Mediterranean regions, Latin America, Near East and Central Africa, Middle East

Cutaneous leishmaniasis Leishmania tropica

Common name: “Baghdad boil”

Leishmania major Cutaneous leishmaniasis (like tropica)

Middle East, Northern Africa, China, and India

Leishmania major

Common names: Espundia, uta, chiclero ulcer

Leishmania braziliensis/L. panamensis

Ulcers with moist centers Secondary lesions: Destruction of the nasal septum; masses of necrotic tissue Marked deformities Frequently fatal

Leishmania braziliensis/L. panamensis

Central and South America

Leishmania braziliensis/L. panamensis

Habitat: Phagocytic macrophages of the reticuloendothelial system

Leishmania

Sandflies of the genus Phlebotomus

Leishmania

Reservoir hosts: Cats, dogs, other mammals

Leishmania

Infective stage: Promastigote

Leishmania

Mode of infection: Injection by the bite of the vector

Leishmania

Looking for what when looking a potential leishmania specimen?

amastigotes

Nearly worldwide distribution Causes 3 different diseases based on species Visceral, cutaneous, mucocutaneous Acquired through the bite of an infected sandfly. Promastigotes injected into the skin which become amastigotes once phagocytized.

Leishmania

Visceral LM

L. donovani

Cutaneous LM

L. tropica | L. major

Mucocutaneous

L. braziliensis | L. panamensis

Sandflies from phlebotomus

Leishmania

Sleeping Sickness

Trypanosoma

1. Common name: African sleeping sickness

Trypanosoma brucei

T. brucei gambiense

West African sleeping sickness

Affects humans more (reservoir host), spread by riverine TseTse fly

T. brucei gambiense: West African sleeping sickness

East African sleeping sickness

T. brucei rhodesiense

Affects game animals more (reservoir host), savanna-woodland TseTse fly

T. brucei rhodesiense: East African sleeping sickness

Pathogenesis: Often fatal in untreated cases Invasion of lymph nodes: Winterbottom’s sign (posterior cervical lymph nodes involved)

Trypanosoma brucei

Localized inflammatory reaction near entry site | Invasion of lymph nodes: Winterbottom’s sign (posterior cervical lymph nodes involved)

Trypanosoma brucei

Invasion of central nervous system (CNS)

Trypanosoma brucei

Disinclination to exertion and lack of interest Reflexes retarded: Difficulty in articulation, incoherent speech, loss of coordination Lapses of diurnal sleep Coma: Usually terminal Evades immune system by varying surface antigens (1000 VSGs)

Trypanosoma brucei

Chronic may last for several years

T. brucei gambiense

Easily cured during circulatory invasion; fatal in 12 to 18 months, Acute

T. brucei rhodesiense

Trypanosoma Infective stage:

Metacyclic trypomastigote

Trypanosoma Specimen source:

Blood or CSF, thick and thin blood smears

Common name: Chagas disease

Trypanosoma cruzi

Romaña’s sign

Trypanosoma cruzi

Localized severe inflammation: Chagoma; periorbital swelling, Romaña’s sign

Trypanosoma cruzi

Invasion of host cells: Cardiomyopathy OR mega-disease: enlargement of visceral organs

Trypanosoma cruzi

Trypanosoma cruzi Geographical distribution

Western Hemisphere Human cases in Latin America and South America

Habitat: Circulatory and reticuloendothelial systems; HEART MUSCLE; bone marrow, etc

Trypanosoma cruzi

T. cruzi intermediate host?

Intermediate hosts (vectors): Reduviid bugs (kissing bugs)

Mode of infection: Contamination of infected bug feces in the bite wound; also transfusion and organ transplants

Trypanosoma cruzi

Chronic and in the lymph versus Acute and in the blood? Protoza

T. brucei gambiense West African Sleeping Sickness - found in LYMPH aka CHRONIC - found more in HUMANS (reservoir host) - spread by RIVERINE Tse Tse fly T. brucei rhodesiense: East African SLeeping SIckness - found in BLOOD aka ACUTE - found more in GAME ANIMALS (reservoir host) - spread by Savannah wood land Tse Tse fly THEY CLOG THE ARTERIES AND BRAIN EVADES IMMUNE SYSTEM BY VARYING SURFACE ANTIGENS AKA WITH VARIABLE SURFACE GLYCOPROTEINS

Intestinal/Tissue/Atrial Protozoa - Cal Flashcards

(112 cards)