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105 Cards in this Set
- Front
- Back
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reasons why the incidence of parasitic infections are low in the U.S
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1- quality of our water supply
2- sewage treatment |
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In Utah, list three reasons why the number of parasitic infections are increasing
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1- high number of returning missionaries
2- increase in international travel 3- increasing numbers of immigrants |
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List the general types of host damage that can be caused by a parasite.
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-Compete for nutrients and damage surface of host's intestines
- tissue parasites destroy cells in organs and tissues, cause sores on the skin, and damage blood vessels causing hemorraging - secondary bacterial infections often result from damage caused by the attachment of the parasite, and in some cases are due to the parasite wandering through the host's body looking for a place to mate and lay eggs |
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List and explain 7 factors influencing the prevalence of parasitic diseases
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1-Disease control- areas where treatment is not available, so people can live entire life not knowing what it's like to NOT be infected
2- Poor nutrition- nutrition affects immune system 3- Health education- making people aware of the life cycles of parasites 4- Regional and ethnic customs- common practice in some areas to spread human feces onto crops 5- Climatic conditions- tropics allow parasites to survive better outside of body 6- Opportunistic parasitism- as health and immune system decline number of parasites may increase in system 7- World travel- over last century travel has increased spread of parasites |
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In general, describe the symptoms of parasitic disease
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Mild- diarrhea, fever, chills, abdominal pain and cramping
Severe- anemia, vitamin deficiency, bowel obstruction, enlargement and impairment of major organs, skin lesions, and blindness |
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Give the percent increase in eosinophile count that would accompany a parasitic infection
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15-50%
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Define the term O & P
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Ova and Parasite
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Give the number of samples to be collected and over what number of days.
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3 samples collected over 10 day period
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List three fixatives used for the preservation of stool samples
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1- vial with 10% formalin used for making a wet prep iodine slide
2- vial with polyvinyl alcohol (PVA) for making a permanent slide (help glue material to slide) 3- vial with zinc sulfate based PVA or sodium-acetic acid-formalin (SAF) may be used for both the concentration and permanent smear |
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advantages and disadvantages of zinc sulfate based PVA or sodium acetic acid formalin
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eliminates problem of patient not returning both vials so the complete O and P can be performed, but morphology and staining quality is not as good as with the PVA media
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Explain the use of the wet prep. method and the which parasitic form is most likely to be seen.
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rapid screening used if stool is fresh, used to study trophozoite form
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What are the two concentration procedures
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1- formalin ethyl acetate technique
2- flotation method |
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Explain the most common concentration procedure
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Most common is formalin ethyl-acetate technique. concentrates parasites in the sediment at bottom. poor off upper layers and make two slides 1- iodine stain, 2- trichrome or iron hematoxylin stain
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Explain the older concentration procedure and some disadvantages
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- older procedure is flotation method.
- uses dense solution of zinc sulfate - not often done because not all eggs will float, and zinc sulfate will distort organism if not examined right away - operculated eggs will pop open when esposed to solution with high specific gravity and will fill with fluid and sink to the bottom |
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List the various layers that are formed after centrifugation of the formalin ethyl-acetate procedure
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Ethyl acetate
debris formalin sediment |
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List three stains (and specific examples of each) used for parasitology
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-Iodine
- permanent stains - acid-fast stains |
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Pros and cons of iodine stain
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used to stain in wet prep
- fine details of some parasites cannot be distinguished - good for rapid screening |
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List two common iodine stains
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Lugol's iodine
D'antoni iodine |
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Pros and cons of permanent stain
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most important way to recover and identify parasites
- usually trophozoites are only seen with this stain - better to see fine details in the nucleus and cytoplasm |
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List two common permanent stains
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Trichrome- AKA Gomori wheatly or Wheatly Trichrome
- Stains nucleus dark green - cytoplasm light green to blue - chromatin red Iron Hematoxylin - cytoplasm is light green - chromatin bar is black |
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Pros and cons of acid-fast stain
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- used if we suspect
- Cryptosporidium - Cyclospora - isospora |
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Describe the procedure for examining an iodine or permanent slide.
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examine on 10x or 40x then 100x for about 15 minutes or 300 fields
- slide should be covered methodically using a serpentine method |
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List 5 instances where immunological testing might be appropriate
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1- suspicion of an outbreak
2- specific organism is supected 3- certain organisms are prevalent in a certain area 4- travel history to endemic areas 5- immunocompromised status |
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List 4 general areas that need to be learned as you study the major groups of parasites
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1- Genus and species
2- Morphology of cyst and trophozoite stages or egg and adult if worm 3- life cycle and clinical manifestations which involves - mode of transmission - infectious stage - diagnostic stage 4- specimen source needed for ID |
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List the Kingdom, Subkingdom, Phylum, and Subphylum classifications for the 4 major groups of intestinal protozoa.
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Kingdom- Protista
Subkingdom- Protozoa Phylum Sarcomastigophora -subphylum sarcodina Mastigophora Phylum Ciliophora Phylum Apicomplexa |
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List the common names and mode of locomotion of Sarcodina
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Common name- Amoebas
Locomotion- pseudopods |
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List the common names and mode of locomotion of Mastigophora
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Common name- Flagellates
Locomotion- flagella |
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List the common names and mode of locomotion of Ciliphora
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Common name- ciliates
locomotion- cilia |
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List the common names and mode of locomotion of Apicomplexa
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common name- sporozoa
locomotion- none |
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Phylum or Subphylum designation of Entamoeba
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sub-phylum Sarcodina
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List the genus under sub phylum Sarcodina
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Intestinal protozoa
- Entamoeba - Iodamoeba - Endolimax - Blastocystis Non-intestinal protozoa - Naegleria - Acamthamoeba |
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List the genus under sub phylum Mastigophora
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Giardia
Trichomonas Chilomastix Dientamoeba |
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List the genus under phylum Ciliophora
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Balantidium
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List the genus under phylum Apicomplexa
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Cryptosporidium
Cyclospora |
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Define chromatin
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condensed DNA or RNA
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Define peripheral chromatin and give descriptive terms
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- Chromatin that lines the inside of nuclear membrane
- described as even or rough and blotchy |
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Define Karyosome and give descriptive terms
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-Small mass of chromatine located within the nucleus
- Described as central or eccentric |
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define fibrils
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-Lines of chromatin connecting karyosome to peripheral chromatin
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Define Chromatin bar and give descriptive terms
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condensed RNA found in cytoplasm
- described as cigar shaped with ends that are rounded or splintered -AKA chromatoid or chromatoidal bars |
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define Cytoplasm and give descriptive terms
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everything between cell wall and nucleus
-described as fine, granular, or coarse |
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Define cytoplasmic inclusions
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packets of vacoules
- may contain glycogen, ingested RBCs, or Bacteria |
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Define Cyst stage
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-infectious/ protective stage
- host ingest cysts from contaminated food and water |
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Define Trophozite stage
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-invasive stage
- invades host body system and replicates |
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Characteristics of cyst and trophozoite in Entamoeba histolytica
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Cyst- 1-4 nuclei
- central karyosome - even peripheral chromatin - cigar shaped chromatoidal bar with rounded ends - round in shape Trophozoite - progressive direcitonal motility - often contains RBC inclusions - peripheral chromatin and karysome same as cyst stage |
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Characteristics of cyst and trophozoite in Entamoeba coli
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Cyst
- 4 to 32 nuclei - Larger than E. histolytica - Eccentric karyosome - thick peripheral chromatin - chromotoidal bar somtimes with splintered ends Trophozoite - 1 nucleus - cytoplasmic inclusions- yeast, bacteria - peripheral chromatin and karyosome same as cyst stage |
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Cyst and trophozoite in Endolimax nana
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Cyst
- 1 to 4 nuclei - oval in shape - large "blotlike" karyosome - No peripheral chromatin Trophozoite - rarely seen - 1 nucleus - peripheral chromatin and karyosome same as cyst stage |
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Cyst and trophozoite stages in Iodamoeba butschlii
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Cyst
- 1 large nucleus - large irregularly shaped karyososme - LARGE GLYCOGEN VACOULE Trophozoite - Sluggish motility - large glycogen vacoule (often multiple) |
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Cyst, flagellate, and trophozoite stages in Naelgleria fowleri
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Cyst
- does not occur in humans Flagellate - two flagella extend form broad end - jerky or spinning motility - large karyosome - invasive form Trophozoite -slug like psuedopods - large karyosome - no peripheral chromatin |
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Pathogenicity and symptoms of Entamoeba histolytica
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Only intestinal amoeba that is pathogenic
Symptoms - abdominal pain with bloody diarrhea/pus and mucus - chronic weight loss - fatigue - may cause liver infection infects 10% of worlds population and can lead to death |
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Define flagella
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used for movement
can be located posterior or anterior |
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define undulating membrane
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finlike extension of the cell membrane
aids in movement with wave like pattern |
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define Costa
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connect base of undulating membrane to body
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define cytostome
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rudimentary mouth
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define Axostyle
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rod-like support structure found in some flagellates
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Cyst and trophozoite stages in Giardia lamblia
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Cyst
- up to 4 nuclei - peanut shaped - axostyle - median bodies (parabasal) Trophozoite - motility resembles falling leaf - 2 nuclei - sucking discs |
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Giardia lamblia pathology
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new designation= Giardia intestinalis
-infection from ingestion of water containing cysts, or fecal/oral route - causes a form of diarrhea called Giardiasis AKA beaver fever |
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Giardia symptoms
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asymptomatic/carrier state
self limiting diarrhea, malaise, cramps, and nausea MALABSORPTION SYNDROME in severe cases, severe diarrhea, weight loss, fatigue, and anorexia |
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for giardia ist the methods of diagnosis
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ID cysts or trophozoites in stools
-immunofluorescence - antigen/antibody tests - color pak -prospect P - Enterotest - done if no parasite can be found in stool sample AKA string test |
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Treatment for giardia
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Metronidazole
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two species of trichomonas
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T. hominis (non-pathogenic)
T. vaginalis (pathogenic) |
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Trichomonas vaginalis pathology and stuff
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- Common STD causing
- Vaginitis with frothy vaginal exudate - urethritis - males usually asymptomatic carriers Active jerky motility - only pathogen seen in fresh (within 20 min) urine microscope preps Specimen sources - Vag discharge - urethral discharge - spun urine - prostate secretions |
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T. vaginalis treatment
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Metronidazole
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Cyst and trophozoite stages in Chilomastix mesnili
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Cyst
- lemon shape - clear hyaline knob - prominent nucleus and cytostome Trophozoite - pointed posterior end - prominent nucleus and cytosotme - shepard's crook - spiral groove sometimes seen |
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Trophozoite stage of Dientamoeba fragilis
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-has 2 nuclei
- each nuclei has 4-8 centrally located chromatin granules - no peripheral chromatin |
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Balantidium coli characteristics
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Phylum- Ciliphora
- pigs are natural resevoirs - humans acquire from contaminated food and water - disease in human is uncommon -causes conditions similar to E. histolytica leading to erosion of lrg intestine -LARGEST PROTOZOA INFECTING HUMANS |
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Cyst and Troph stages of Balantidium coli
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Cyst
-Cilia on inside - macro and micronucleus - cytostome Troph - Cilia on outside - macro and micronucleus - cytostome |
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List the common names of the three classes of helminths along with the phylum and class designations of each
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Phylum- Nemathelminthes
Class- Nematoda common name- roundworm Phylum- Platyhelminthes Class- Cestoda common name- tapeworms Class- Tremotoda common name- flukes or flatworms |
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Explain what the term helminth means.
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worms
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Define helminth egg
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female sex cell
-AKA oocyte or ovum (ova=plural) fertilized egg=embryonated egg |
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define larvae
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juvenile stage of worm
Larva=singular |
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define adult worm
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Tube within a tube body plan
- body wall with underlying muscles - digestive tract |
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intermediate host for helminth
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Where the larval stage grows and develops
- asexual phase |
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Definitive host for helminth
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where the adult worms live, mature, and produce eggs
-sexual phase |
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accidental host for helminth
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occurs in humans because of close association with the definitive host
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Name the three most common helminth infections in the U.S
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#1- Enterobius vermicularis
#2- Ascaris lumbricoides #3- Trichuris trichiuria |
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For Ascaris lumbricoides, give the common name and symptoms
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round worm
- Most infections are asymptomatic, but can cause abdominal pain, nausea, vomiting, and intestinal obstruction. -May also cause LOEFFLERS SYNDROME, which can occur during larval migration - often have secondary bacterial infection as a result of worm boring out of intestines |
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For Ascaris lumbricoides
mode of infection and life cycle |
Life cycle
1- humans ingest mature ova in food or drink 2- ova hatch in duodenum 3- penetrate intestinal wall and get into blood stream where first stop is liver, and second stop is capillaries in lungs 4- bore through capillaries into alveoli, migrate into bronchioles cause acute pneumonitis and pneumonia 5- worm is coughed up into pharynx, some swallowed, some come out of nose or mouth 6- swallowed worms mature in small intestines where female can lay 200,000 eggs/day for years |
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For Ascaris lumbricoides treatment and specimen source
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Treat with mebendazole
-specimen source is stool |
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Define corticated
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deposits of coarse mammillated albuminous material.
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For Enterobius vermicularis, give the common name, describe the symptoms,
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common name= pinworm
symptoms- intense rectal itching, restlessness, insomnia |
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For Enterobius vermicularis,
mode of infection, life cycle |
Gravid (pregnant) females oviposit in perianal area
- embryonated eggs become infective in 4-6 hours - infective eggs distributed in environment - infective eggs eaten by human - larvae hatch in small intestine - larvae migrate to cecum, appendix, and colon |
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treatment For Enterobius vermicularis and Explain why stool exam is of no value in identifying the parasite
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Treatment= mebendazole
-worms are not found in stool, they stay in colon, to diagnose use cellophane tape on perianal area to identify microcopic eggs |
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For Trichuris trichiura, give the common name and describe the symptoms
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Common name= whip worm
symptoms- chronic dysentery, severe anemia, possibly growth retardation, ulcerative colitis (with heavy worm load) |
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common name for Necator americanus and Ancylostoma duodenale
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hook worm
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Necator americanus and Ancylostoma duodenale life cycle
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adults in intestine
ova in feces soil rhabiditiform larvae (non-infectious form) filariform larvae (infectious form non-feeding) bores into skin of feet causes GROUND ITCH blood stream lungs coughed up and swallowed intestines adult |
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how much blood loss a human host will loose to various amounts of worm load of Necator and Ancylostoma
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one worm consumes 0.25 ml of blood per day
- 500 worms results in loss of 1/4 pint per day |
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Necator americanus and Ancylostoma duodenale symptoms
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primary clinical manifestation is anemia
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Where is Necator ameicanus usually found
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New world- prevalent in southeastern U.S.
Ancylostoma is in old world |
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define ground itch
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itching, rash and inflammation that can persist from weeks, which occurs at the sire of skin penetration by Necator americanus and Ancylostoma duodenale larvae
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For Strongyloides stercoralis, give common name and describe the symptoms of infection
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common name= threadworm
Causes both cutaneous and pulmonary diseases |
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How do you differentiate between Strongyloides and Necator americanus/Ancylostoma duodenale.
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rhabditiform larvae
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define hexacanth embryo
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The infective stage in a cestode egg after fertilization takes place
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define intermediate host
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host in which immature forms of the parasite are present and undergoing various stages of maturation
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define definitive host
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host in which mature and sometimes sexual forms of the parasite are present and usually reproducing
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Define cysticercus
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larvae stage of tapeworms
-bladder-like cyst filled with water - larvae consist of a scolex Plural is cysticerci |
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define onchosphere
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the larva of the tapeworm armed with six hooks
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Cysticercosis
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infection of muscle tissue by larvae in human/animal
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Scolex
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head of the worm- structured for attachment
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Stroblia
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chain of segments
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Proglottids
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individual segments
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gravid proglottids
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fertilized and producing eggs
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tegument
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absorbs nutrients and excretes waste how a tapeworm obtains its nutrients without an esophagus.
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List and arrange the 5 tapeworms covered in this unit in terms of the size of adult worm
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- Taenia saginata 25-50 ft
- Diphyllobothrium 30 ft - Taenia solium 8-10 ft - Hymenolepis spp. 1 inch |
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For the genus Taenia, list two species, their common names, and intermediate hosts
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Taenia saginata
- beef tapeworm Taenia solium - pork tapeworm |
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explain life cycle of taenia
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Intermediate host (cow or pig)----->ingests hexacanth embryo (from feces)----->develops into cycticerus----->condition known as cysticercosis----->humans ingest cycticerci from meat----->adult worm develops in intestines
If human ingests hexacanth embryo directly----->becomes accidental intermediate host----->develops cysticercosis |
