MLS 2213 Exam 3

Units 11, 11-1b, 11-2b

List two reasons why the incidences of parasitic infections are low in the U.S.

• Quality of water supply

• Sewage treatment

List the reasons why the number of parasitic infections are increasing in Utah.

• High number of return missionaries

• increase in international travel

• Increase in immigration

List the general types of host damage that can be caused by a parasite.

• Intestinal parasites compete for host nutrients and damage intestines

• Tissue parasites destroy cells in organs and tissues

• can cause secondary bacterial infections

In general, describe the symptoms of parasitic disease.

• Can be asymptomatic for months to years

• Diarrhea, fever, chills, abdominal pain, anemia, bowel obstructions, organ failure, skin lesions, blindness

Give the percent increase in eosinophile count that would accompany a parasitic infection.

15 to 50%

List 7 factors influencing the prevalence of parasitic diseases

• Disease control

• poor nutrition

• heath education

• regional and ethnic customs

• climatic conditions

• opportunistic parasitism

• world travel

Define symbiosis

A relationship of 2 organisms of different species living together

Define parasite

A symbiotic relationship where one organism is physically dependent on another organism

define mutualism

2 organisms, each physically depended on each other

define commensalism

Parasite benefits without damage to the host, neither species is dependent on each other

define definitive host

The organism that supports the adult or sexually reproductive form of a parasite, often harboring the mature stage of the parasite's lifecycle.

define intermediate host

A host organism that harbors the immature or non-reproductive forms of a parasite, facilitating its development before it reaches the definitive host.

What is an O&P and what does it consist of

• Ova and parasite exam

  • Direct wet smear, concentration procedure, iodine stained slide and permanent stained slide.

For an O&P exam how many samples should be collected over how many days?

• 3 samples

• 10 day period a few days apart

What are the additive in the preservation for stool samples

• Vial one typically has 10% formalin

• Vial two has PVA and mercuric acid

• A single vial system has zinc sulfate based PVA or sodium-acetic acid formalin

What is a direct wet prep and what parasite form is most likely to be seen?

• A small portion of fresh stool is mixed with saline and examined on 10x

• Trophozoites

What are the two concentration methods used?

• Formalin ethyl acetate

  • concentrates the parasites in a sediment after centrifugation

• Flotation method

  • uses zinc sulfate, not done commonly because not all eggs will float and can cause distortion of the eggs or parasites

List the various layers that are formed after centrifugation of the formalin ethylacetate procedure

• Ethyl acetate

• debris

• formalin

• sediment

What stains are used for iodine slides?

• Lugol’s iodine

• D’antoni iodine

What is the procedure for examining iodine or permanent stained slides

Examine on 10x or 40x and then an oil immersion for 15 minutes or 300 fields if no parasites are found before then.

What stains are used in permanent staining?

• Trichrome or Gomori Wheatley or Wheatley trichrome

• Iron hematoxylin

How does trichrome stain?

• Stain nucleus dark green

• Cytoplasm light green or blue

• Chromatin red

How does Iron hematoxylin stain

• Cytoplasm is light green

• chromatin bar is black

What types of parasites should be stained with an acid fast stain

• Cryptosporidium

• Cyclospora

• Isospora

List the instances where immunological testing might be appropriate.

• Suspicion of an outbreak

• A specific organism is suspected

• Certain organisms are prevalent in a certain area

• travel history to endemic areas

• immunocompromised status

List the general areas that need to be learned as you study the major groups of parasites.

• Genus and species

• Morphology of the parasite and forms

• life cycle and clinical manifestation

• Specimen needed for lab ID

What is the kingdom and subkingdom for intestinal protozoa

• Kingdom: Protista

• Subkingdom: Protozoa

What are the 4 subphylums of the major groups of intestinal protozoans

• Sarcodina

• Mastigophora

• Ciliophora

• Apicomplexa

What is the phylum of the major groups of intestinal protozoa

Sarcomastigophora

What is the common name of Sarcodina

Amoebas

What is the common name of Mastigophora

Flagellates

What is the common name of Ciliophora

Ciliates

What is the common name for apicomplexa

Sporozoa

What is sarcodinas mode of motility

pseudopods

What is mastigophoras mode of motility

flagella

What is ciliophora mode of motility

cilia

What is apicomplexa mode of motility

none, imoible

Define chromatin

Condensed DNA or RNA

Define peripheral chromatin and its descriptive terms

• Chromatin that lines the inside of the nuclear membrane

• Even, rough, blotchy

Define Karyosome

Small mass of chromatin located with the nucleus

Define chromatin bar

condensed RNA found within the cytoplasm, typically cigar shaped

Define cytoplasm

Semi liquid gelatinous material between cell wall and nucleus

Define cytoplasmic inclusions

pockets or vacules, may contain glycogen, RBCs, or bacteria

What genus are intestinal amoebas

• Entamoeba

• Iodamoeba

• Endolimax

• Blastocystis

What genus are non-intestinal amoebas

• Naegleria

• Acamthamoeba

What genus are Flagellates

• Giardia

• Trichomonas

• Chilomastix

• Dientamoeba

What genus are Ciliates

• Balantidium

What genus are Apicomplexa

• Cryptosporidium

• Cyclospora

What is the cyst stage?

• Infectious stage

• The host injects cysts from contaminated food and water

What is the trophozoite stage?

• Invasive and reproductive stage

• Invades host body systems and replicates

What is excystation

The process by which a cyst breaks open to release the trophozoite stage, allowing it to invade the host.

What is encystation

The process by which trophozoites form cysts when environmental conditions become unfavorable, enabling survival outside the host.

Would you expect to see cysts or trophozoites in formed stool?

Cysts

Would you expect to see cysts or trophozoites in liquid stool?

Trophozoites

What is the only pathogenic intestinal amoeba

Entamoeba histolytica

What are the symptoms of Entamoeba histolytica

• Abdominal pain with blood diahrea/pus

• chronic weight loss

• fatigue

• liver infection

What causes amoebic dysentery

Entamoeba histolytica

What is the life cycle of Entamoeba histolytica

• Cysts are ingested from contaminated food and water

• In the intestines they undergo excystation

• The trophozoites replicate and feed on host cells

  • Enzymes made lyse host cells which causes bloody diarrhea

• Forms back into cysts and passes in stool

• If gets into blood stream from intestinal damage can go to liver and cause infection

What is the treatment for Entamoeba histolytica

Metronidazole

What are the characteristics of Entamoeba histolytica in cyst form?

• 1-4 Nuclei

• Central karyosome

• Even peripheral chromatin

• Cigar shaped chromatoidal bar

What are the characteristics of Entamoeba histolytica trophozoite

• Progressive directional motility

• Often contains RBCs inclusions which is diagnostic of Entamoeba histolytica

• Even peripheral chromatin and central karyosome

Entamoeba histolytica

Entamoeba histolytica

Entamoeba histolytica

Entamoeba histolytica

What can cause amebic pneumonitis?

Entamoeba histolytica if it spreads to the lungs

What are the differences between Entamoeba histolytica and Entamoeba hartmannii

• Smaller

• non pathogenic

How do you differentiate between Entamoeba histolytica and Entamoeba dispar?

A Entamoeba histolytica trophozoite with a RBC inclusion

What two parasites is it not uncommon to have at the same time/

Entamoeba histolytica and Entamoeba coli

What are the characteristics of Entamoeba coli cysts

• 1-32 nuclei

• Larger than Entamoeba histolytica

• Eccentric karyosome

• Thick peripheral chromatin

• Chromatin bar with splintered ends

What are the characteristics of Entamoeba coli trophozoites

• 1 nucleus

• Cytoplasmic inclusions - yeast, bacteria

• Eccentric karyosome

• thick peripheral chromatin
  
  

Entamoeba coli

Entamoeba coli

Entamoeba coli

Entamoeba coli

Entamoeba coli

Entamoeba coli

What are some characteristics of Endolimax nana cysts

• 1-4 nuclei

• oval shape

• Large blot like karyosome

• No peripheral chromatin, hard to see nucleus

What are some characteristics of Endolimax nana trophozoites

• Rarely seen

• 1 nuclei

• large blot like karyosome

• no peripheral chromatin

Endolimax nana

Endolimax nana

Endolimax nana

Endolimax nana

What are the characteristics of Iodamoeba butschlii cysts

• One large nucleus

• Large irregular karyosome

• large glycogen vacuole

What are the characteristics of Iodamoeba butschlii trophozoites

• Sluggish motility

• multiple large glycogen vacuoles

   

Entamoeba histolytica

Iodamoeba butschlii

What is the only amoeba with 3 forms?

Naegleria fowleri

What are the three stages of Naegleria fowleri

• Trophozoite

• Flagellate

• Cysts - does not occur in humans

What are some characteristics of Naegleria fowleri trophozoites

• Slug like pseudopods

• Large karyosome

• No peripheral chromatin

What are some characteristics of Naegleria fowleri flagellate

• Two flagella extend from broad end of organism

• Jerky or spinning motility

• Large karyosome

• Invasive form

What are some characteristics of Naegleria fowleri cysts

• Does Not occur in humans

What does Naegleria fowleri cause?

Primary amoebic meningoencephalitis

How do humans get Naegleria fowleri

• Contaminated water gets into the nasal cavity

Define Flagella

Used for movement and propellment

Define undulating membrane

• Fin like extension of cell membrane

• Aids in movement

• Wavelike pattern

Define axostyle

Rod like support, like a back bone

Define cytostome

rudimentary mouth

What are some characteristics of Giardia lamblia cysts

• Up to 4 nuceli

• Small oval

• Axostyles

• Median bodies