Intestinal/Tissue/Atrial Protozoa - Cal Flashcards
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
Short hair-like structures; surrounds the organism, often in rows
Cilia
Metabolic stage
Active, vegetative; feeding
Capable of movement:
Motility dependent on organelles
trophozoite
Capable of reproduction: Mitotic division; mostly binary or transverse fission
Intracellular inclusions
trophozoite
Dormant stages, produced by many of the protozoans
Capable of protection: During adverse environmental conditions
Cyst
Cyst wall: Secreted?
scleroproteins
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
Capable of invading tissue
Agent of amebic dysentery
Entamoeba histolytica
Intestinal amebiasis
Non-dysenteric colitis or Amebic dysentery
Entamoeba histolytica
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.
Ulceration: Penetration of the mucosal crypts; extension into submucosa forming flask-shaped lesions
Entamoeba histolytica
flask-shaped lesions
Entamoeba histolytica
Amebomas (amebic granulomas): Granulation tissues; tumors
Entamoeba histolytica
Non-pathogenic forms of Entamoeba histolytica often will be named?
E. dispar
Infective and diagnostic stage for Entamoeba histolytica?
Cysts/trophozoites passed in feces…
Mature cysts ingested
Entamoeba histolytica Specimens of choice?
Feces and biopsies
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
Charcot-Leyden crystals: Formed from the breakdown of eosinophilic blood cells; indication of bleeding or inflammation of the intestinal mucosa
Entamoeba histolytica
Cyst form has four nuclei?
Entamoeba histolytica
Entamoeba histolytica trophozoite description?
Occasional RBC inclusion
Centrally-located endosome
“bullseye”
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
Often confused with Entamoeba histolytica
Nonpathogenic
Entamoeba coli
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.
Karyosome: Small (larger than Entamoeba histolytica); usually eccentric?
Entamoeba coli
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
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
- 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