PARASITOLOGY Flashcards
Motile, reproducing stage, feeding stage of Protozoa
Trophozoite
Amebae has chromatoid bodies in the cyst stage
Entamoeba
Amebiasis is cause by
E. histolytica
Organs of the body that is most often involved in extraintestinal amebiasis
Liver
Characteristic of true amebae
Peripheral chromatin on the nuclear body
Chromatin bodies in the cyst
Include pathogens and non pathogens
True ameba
E. hartmanni
Ameba that inhabits the gastrointestinal tract of man are non motile, nonfeeding and infective during what stage ?
Cyst
Mature cyst of E. polecki have how many nuclei
1
Cyst with chromatoid bodies that have two pointed ends or that can be round triangular or oval
E. coli
Small delicate nuclear chromatin
FIne, even, peripheral chromatin
Progressive motility with hyaline, finger like pseudopods
Trophozoites of E. histolytica
Trophozoite when acting as a pathogen is likely to ingest RBC of the host
E. histolytica
Point of differentiation between E. histolytica and E. hartmanni
size
The mature cyst of E. histolytica has how many nuclei
Four
Failure to find bacteria in purulent spinal fluid should alert one to find the possibility of an infection with
Amebae
Trophozoite is distinguished by the possession of achromatic granules surrounding its karyosomal chromatin
I. butschlii
Double walled, wrinkled cyst form
A. castellani
A cyst that possesses a single nucleus and a large glycogen vacuole that stains deeply with iodine belong to
I. butschlii
Some ameba have spiny, hyaline extensions called
Acanthopods
Best staining procedures for species of Naegleria and Acanthamoeba
Hematoxylin and eosin
Wright stain
Ameba inhabiting the CNS enter the body through
Nasal mucosa
Specimen are Acanthamoeba and Naegleria usually found
Cerebrospinal fluid
Found in the brain
Trophozoite can assume a limax form
Trophozoite can become an ameba flagellate
Naegleria
Trophozoite whose karyosomal chromatin appears as a rosette of 4-6 granules
N. fowleri
Often mistaken for cyst of amebae
Blastocystis hominis
Intestinal flagellates are usuallly which shape in the trophozoite stage
Pear shaped
Pathognomonic for G. lamblia and the stage it is found in
Ventral sucking disk- trophozoite
Protozoa that has an undulating membrane
Trichomonas
Trypanosoma
Symptoms in Infection with D. fragilis
Diarrhea
Abdominal discomfort without diarrhea
Asymptomatic
Common in D. fragilis and T. vaginalis
Neither has a cyst form
Flagellate that can be pathogen of small intestine
Giardia
Intestinal flagellate troph has a sucking disk, 2 nuclei, 8 flagella and a axostyle
G. lamblia
Red and white blood cells in stool specimens are characteristics of
Bacillary dysentery
A pear shaped flagellate with jerky motility that is found in a urine specimen
T. vaginalis
Eighty percent of the trophozoites of D. fragilis have
2 nuclei
Only bilaterally symmetrical protozoan
Giardia
Intracellular form of blood and tissue flagellates
Leishmanial
Cause of African sleeping sickness
Trypanosoma
Vector of African sleeping sickness
Tse tse fly (Glossina)
Species of Trypanosoma that cause Chaga’s disease
Cruzi
Characteristics of trypanosome form of T. cruzi
Prominent kinetoplast
C-shaped
Thick organism
Specimen would be suitable for a demonstration of the trypanosomes of sleeping sickness
Blood
Fluid from lymph node
CSF
The extracellular form of Trypanosoma is a slender organism characterized by an undulaitng membrane and a free flagellum that arises
Posteriorly from the kinetoplast
Found within the reticuloendothelial cells
L. donovani
H. capsulatum
T. gondii
Trypanosoma cruzi transmitted?
Bite of reduviid bug
A chagoma is a lesion seen in infections with
T. cruzi
Organism cause of Kala-azar
L. donovani
In the lab diagnosis of L. donovani, which is the preferred specimen in which to fluid Leihman-Donovan bodies
Bone marrow
Only ciliate that is pathogenic in humans
B. coli
A very large cyst whose double wall encloses a ciliated organism with one visible nuclei would be
Acquired by accident by man, since it customarily infects swine
structures are used for motiliy of Balantidium coli
Cilia
Nucleus in the trophozoite of B. coli is the reproductive one
Micronucleus
Conjugation of trophozoites of B. coli never occurs between
Same size organisms
Definitive host (vector) to Plasmodium
Female Anopheles mosquito
Malarial organism presents as pale, very amoeboid ring trophozoites, infecting a large pale RBC with dots of hemoglobin
P. vivax
Malarial organisms preferentially invades retics
P. vivax
Malarial organism whose schizont resembles a “fruit pie” in which the merozoite form a rosette around the malarial pigment
P. malariae
Malarial organism characteristically has a band form trophozoite stretching across the RBC
P. malariae
Gametocyte of Plasmodium falciparum can be differentiated from the other malarial species by
Shape
Type of Malaria can Ziemann’s stippling can be found
Malariae
Type of Malaria can Maurer’s dot can be found
Falciparum
Malarial organism feaatures ring trophozoites that have double chromatin dots, applique forms and often have multiple parasites in the infected RBCs
P. falciparum
Malarial organism has large, coarse, red dots within a large, pale RBC with fimbriated edges
P. ovale
The sexual reproduction cycle in Plasmodium and Coccidia
Sporogony
Infective stage of the malarial parasite to the vector
Gametocyte
Infective stage of the malarial parasite to the humans
Sporozoites
Type of Malaria there’s synchronized rupture of the RBCs every 72 hours
Malariae
In falciparum malaria, there may be a sudden massive intravascular hemolysis producing hemoglobinuria. This is called
Blackwater fever
Hemoglobin is incompatible with malaria parasite survival
Hb-SS
Lab test that allows laboratory bred reduvid bugs to feed on patients suspected of having Chagas disease
Xenodiagnosis
Humans are infected with Babesia by
Bite of ticks
Blood transfusion
If immature oocysts of Isospora belli are found in stool specimens from infected humans, what should be done with the specimen for identification
Leave at room temperature
Stage of Isospora that is infective to humans
Oocyst
Isospora belli immature oocyst contain
Sporoblast
Infective oocyst of Isospora belli contain
Sporozoites
Laboratory request for the demonstration of retinochoroiditis and cerebral calcifications in a newborn
Titer of Toxoplasma antibodies
Both Definitive and Intermediate Host of Toxoplasma gondii
Cat
Appearance of Toxoplasma gondii in tissue fluids of man
Crescent
Constitutes a positive result in the Sabin Feldman dye test
Toxoplasma loses its affinity for methylene blue dye test
Test used for the detection of Cryptosporidium
Sheathers sugar flotation
Parasites poses a particular hazard for immunodeficient or immunosuppressed individuals
Cryptosporidium
Giardia
Strongyloides
Parasites associated with AIDS
Cryptosporidium
Operculated ovum contains a miracidium and can appear in sputum, often accompanied by blood and Charcoat-Layden crystals
Paragonimus westermani
Schistome eggs may be recovered in rectal biopsy
Schistosoma japonicum
Schistosoma mansoni
Scientific name of the head of a tapeworm
Scolex
Worms have an oral and ventral shaped sucker in the adult stage
Trematodes
Hermaphroditic
Flukes
Tapeworms
First intermediate host of the flukes
Snail
Common names for the schistosomes
Blood flukes
Common name for Clonorchis sinensis
Chinese liver fluke
What is schistosomule
Cercariae minus tail
Beef tapeworm is the common name for
T. saginata
Tapeworm proglottid makes its way across the fecal specimen by doubling movements and is seen under the microscope to have numerous regular uterine branches (more than 15) resembling those of a tree
T. saginata
Unarmed scolex
Beef tapeworm
Taenia has 7-12 uterine branches
T. solium
A hexacanth embryo enclosed in a radially striated shell belongs to the genus
Taenia
Tapeworm infection has to be treated with great care so that man does not acquire the larval infection
Taeniasis solium
A bile stained egg that is 75 microns at its greatest diameter and contains a hexacanth embryo that lacks polar knobs or filaments is that of
H. diminuta
Dwarf tapeworm
H. nana
Eggs of Echinococcus granulosus are found in the feces of
Dogs
Found in the intermediate host of Echinococcus granulosus
Hydatid cyst
Hydatid cyst infection of man is due to a larva of the tapeworm
E. granulosus
First intermediate host of D. latum
copepod
Second intermediate host of D. latum
Freshwater fish
Infective stage of the broad fish tapeworm to humans
Plerocercoid
Eggs of this tapeworm are developed and have an operculum at one and a small abopercular knob at the other end
D. latum
Worm that can cause Megaloblastic anemia
D. latum
Worms have separate sexes
Blood flukes
Male roundworm is differentiated from the female roundworm by its
Dorsally curved posterior
Best way to demonstrate a pinworm infection is by what technique
Cellophane tape preparation
The gravid female of E. vermicularis deposits her embryonated eggs
On the perianal skin
Eggs that average 60 microns in length, are oval with one flattened side and contain a motile larva
E. vermicularis
Eggs that are bile stained and have clear polar plugs
Whipworm
nematodes does NOT have a free living stage
E. vermicularis
Stage of Trichuris trichiura infective to humans
Embryonated egg
Where does the larva of Ascaris lumbricoides go after it hatches in the small intestine
Migrates through the blood, liver, lungs, pharynx and then back to the small intestine
If an Ascaris egg lacks its bile stained mammilliated coat, we refer to the egg as
Decorticated
T. trichiura, hookworm and ___ form the “unholy three” of roundworms
A. lumbricoides
First stage larva of intestinal nematodes
Rhabditiform larva
Organisms cause infections where the larvae migrate into the lymphatics and blood, lung, alveoli, bronchiolus, pharynx and then to small intestines
N. americanus
A. duodenale
S. stercoralis
An embryo in the two to eight cell stage of cleavage
Oval, thin shell
Clear space between shell and embryo
eggs of Hookworms
Helminth that induces a hypochromic microcytic anemia in its hosts
Hookworm
The rhabditiform larva of the hookworm has a
Long buccal cavity equal to the width of the body
Larval worms enters the hosts by penetration of the skin
S. stercoralis
A. duodenale
N. americanus
A roundworm that inhabits the SI and usually is demonstrated as rhabditiform larvae in the fecal specimen
Threadworm
Muscle biopsy is a diagnostic technique employed to detect
Trichinosis
Roundworms that gave birth to her young
Wuchereria
Mansonella
Brugia
A viviparous female nematode
Produces living larvae
One of the differential characteristics of the microfilariae is the presence or absence of
A sheath
Adults of filarial worms live in
Lymphatics and subcutaneous tissue
One of the pathological findings in infestations of Wuchereria
Elephantiasis
Intermediate host of guinea worm
Copepod
Dirofilaria immitis is the
Dog heartworm
Dracunculus infections cause ulcers that
On contact with water, release larvae
Microfilaria does NOT have sheath
Mansonella
Eye worm
Loa loa
Cutaneous larva migrans or creeping eruption is caused by
Filariform larvae of Dog hookworm
Causes a chronic cough, pulmonary and artery obstruction but no invasion of the heart in humans
Dirofialria immitis
Caused by the ingestion of snails by humans
Rat lungworm
Cercarial dermatitidis commonly known as swimmer’s itch is caused by
Cercariae of schistosomes
Scientific name of the body of a tapeworm
Strobila
The gravid segments of a tapeworm are filled with
Eggs
A six hooked embryo
Hexacanth
“Ground itch” occurs in infections of hookworms at the
Site of larval penetration of the skin
Direct examination of stool specimens stained with iodine make the trophozoite of the Protozoa stain what color
Trophozoites are destroyed by iodine
What color does the cytoplasm of protozoan cysts stain in an iodine wet stool preparation
Yellow-brown
What color do chromatoid bodies of protozoan cyst stain in an iodine wet stool preparation
Do not stain
Advantages of the sedimentation mtd of concentrating stool specimen
All eggs will sediment
Recovers operculated eggs
Fecal debris and soluble material can be removed
Trophozoite structures of protozoans when stained with trichrome stain appear
Glycogen- colorless
Nucleus-red purple
Charcoat leyden crystals- bright red
When stained in trichrome stain, chromatoid bodies appear what color
Bright to red
The preservative to be employed with the trichrome stain is
Polyvinyl alcohol
The ideal temperature at which hold a fecal specimen for more than 1 hour is
refrigerator temperature
Preferred Sp. Gr. of zinc sulfate solution for the flotation mtd
1.18
type of blood specimen is preferred for preparing blood smears for protozoa
Finger puncture
What will happen if blood from a finger stick mixes with the alcohol used to clean the area
“Fixes” red blood cells
Venipuncture blood is not recommended for
Malaria, Babesia, Hemoflagellates
To detect stippling, prepare blood films venipuncture within
30 minutes to 1 hour after being drawn
