Acanthamoeba troph motility wet mount Entamoeba histolytica troph iodine wet mount

1
Acanthamoeba troph - motility wet mount
Entamoeba histolytica troph - iodine wet mount
?
2
Diagnostic procedures continued

• 2. Concentrates same as 1. but concentrated
  material is easier to see. Problem is that
  debris is concentrated as well. Conduct like
  direct wet mount OR preserve with formalin for
  examination at a later time.
• a) flotation see page 1076
• b) sedimentation gravity or centrifugation,
  decant super
• 3. Permanent stained smears 1 for protozoan
  morphology/ID
• sample smeared on slide, chemically fixed,
  then stained
• a) Fe hematoxylin DNA PO4- groups tricky
  but good
• b) Trichrome - gt1 dye binds basic / () charged
  things with
• varying affinity 1 stains tissue, 1
  stains border, etc.
• easiest method gives good results for
  most protozoans
• c) modified acid fast - long C chain acids
  Crypto cysts
• d) Giemsa - DNA PO4- groups used for blood
  
• images?

3
Giardia lamblia cyst Iron hemtoxylin stain
Enatamoeba histolytica trophs
- trichrome stain
?
4
Plasmodium trophs in RBCs - Giemsa stain
Cryptosporidium cysts - modified acid fast
?
5
Diagnostic procedures continued

• miscellaneous - see 1078, 1079
• duodenal aspirates for Giardia Strongyloides
  larvae
• cellophane tape preparations for Enterobius
• tissue biopsies for Leishmania
• wet blood smear for hemoflagellate parasites
• vaginal swabs for Thichomonas vaginalis
  unstained direct wet mount performed within 30
  minutes and examined for pear-shape troph,
  undulating membrane and darting motility

6
Sample preservatives / fixatives

• Why to stabilize sample (maintains morphology
  and prevents further development of protozoan
  cysts certain juvenile trophs and helminth eggs
  larvae) if examination must be delayed beyond
  specified time limits due to need for sample
  transport, work load prevents immediate exam,
  etc.
• Each fixative has its particular intended uses
  its limitations
• Some commonly used products
  
• a)PVA polyvinyl alcohol Hg or non-Hg based
  ???
• Preferred product for preserving and fixing
  permanent smears of protozoan cysts trophs,
  especially when they are to be stained with
  trichrome or hematoxylin.
• Inferior for concentrates.
• ?

7
Sample preservatives/fixatives continued

• b)Formalin
• preserves all helminth forms protozoan cysts
  (only)
• is preferred for helminth eggs larvae
• preferred preservative for concentrates
• unsuitable for permanent smears
• pungent odor carcinogenic
• c)SAF sodium acetate/formalin
• vs PVA longer shelf life
• vs formalin suitable for concentrates
  permanent smears
• hematoxylin stain preferred to trichrome when
  SAF is used
• d)MIF?
• lab?

8
Host-parasite definitions see pg 1081
Intermediate host host in which some parasite
development may occur, but sexual maturity is NOT
reached. This host is often the reservoir and/or
the vector. Plasmodium is weird! Definitive
host hosts the parasite in the sexually mature
form, which is the pathogenic form in most cases.
This host may also be the reservoir and/or the
vector, or the only host. Reservoir (host)
organism in which the parasite normally resides
when not in, or in addition to the human host.
This organism may also be a host and or
vector. Vector organism that transmits the
parasite to the human host. This is often the
intermediate host, but not always. Consider the
examples on the table which (intermediate or
definitive) is the vector? see table?