Exam 4 - Parasitology Flashcards
Definition of Eukaryotes?
(a) Nuclear membrane separates nucleus from cytoplasm
(b) DNA composed of paired, linear chromosomes
(c) Reproduction by binary fission and mitosis
(d) Energy produced in mitochondria
(a) Nuclear membrane separates nucleus from cytoplasm
(b) DNA composed of paired, linear chromosomes
(c) Reproduction by binary fission and mitosis
(d) Energy produced in mitochondria
Definition of Eukaryotes
Parasites of humans are classified in six major divisions.
Protozoa; the Nematoda, or roundworms; the Platyhelminthes or flatworms, that contains Cestoda (tapeworms) and Trematoda (flukes); the Pentastomids, or tongue worms; the Acanthocephala, or thorny-headed worms; and the Arthropoda .
NAAPPP
N-ematoda A-canthocephala A-rthropoda P-rotozoa P-latyhelminthes P-entastomids
unicellular eukaryotic organisms, having true nuclei and membrane bound organelles. Includes amebas, flagellates, and sporozoans.
Kingdom Protista
The Father of parasitology
Francesco Redi in 1684
Within subkingdom Eukaryota; contains most pathogenic protozoa
Phylum Sarcomastigophora
(a) Class Zoomastigophora: The flagellates (b) Class Lobosea: The amoebas
Within subkingdom Eukaryota; contains malaria and coccidians
Phylum Apicomplexa
Within subkingdom Eukaryota; contains the microsporidia
Phylum Microspora
Within subkingdom Eukaryota; contains the ciliates
Phylum Ciliophora
Kingdom Animalia:
Multicellular higher animals
I. Phylum Platyhelminthes: Flatworm
(a) Class Trematoda: The flukes (b) Class Cestoda: The tapeworms
II. Phylum Aschelminthes: Roundworms/Nematodes
Two organisms of different species living together = ?
2 Examples?
Symbiosis
a. commensalism
b. mutualism
Symbiotic relationship in which one organism is benefited and the other is neither benefited nor harmed
Commensalism
Symbiotic relationship in which both organisms are benefited
Mutualism
Symbiotic relationship in which one organism, the parasite, is metabolically dependent on the other organism (host) and gains all the benefit. The host is adversely affected.
5 examples?
Parasitism
(1) Facultative parasite: Normally free living organism, but may become an opportunistic parasite
(2) Obligate parasite: Cannot survive in a free living state.
(3) Incidental parasite: Establishes itself in a host in which it does not normally live.
(4) Endoparasite: A parasite living inside the host
(5) Ectoparasite: A parasite living on the external surface of the host
Normally free living organism, but may become an opportunistic parasite
Facultative parasite
Cannot survive in a free living state.
Obligate parasite
Establishes itself in a host in which it does not normally live.
Incidental parasite
A parasite living inside the host
Endoparasite
A parasite living on the external surface of the host
Ectoparasite:
Any living organism, animal or plant that harbors or nourishes another organism
4 types listed?
Host:
(a) Definitive host: The host that harbors the adult or sexually reproducing stages of a parasite
(b) Intermediate host: That host which harbors the immature, larval, or asexually reproducing forms of a parasite
(c) Reservoir host: A host which replaces man in the life cycle of the parasite
(d) Paratenic host: A host that serves as a transport host in which the parasitic forms undergo no development, but passes on to the final host
The host that harbors the adult or sexually reproducing stages of a parasite
Definitive host
That host which harbors the immature, larval, or asexually reproducing forms of a parasite
Intermediate host
A host which replaces man in the life cycle of the parasite
Reservoir host
A host that serves as a transport host in which the parasitic forms undergo no development, but passes on to the final host
Paratenic host
the process of a parasite’s growth, development and reproduction, which proceeds in one or more different host depending on the species of parasites.
Life Cycle
a stage when a parasite can invade a human body and live in it.
Infective stage
the entrance which the parasite invades the human body.
Infective route
how the parasite invades the human body.
Infective mode
A carrier, usually an arthropod, which transmits an infective form of the parasite from host to another
Vector
A reinfection in which the host is its own source of infection from a source already present in the body
Autoinfection
Routes of Infection
Ingestion
Active Penetration
Injection
Congenital
Ingestion: Oral (nasopharyngeal) in food, water or aerosols, etc.
(a) Remains in gastrointestinal tract
(b) Internal migration to other host organs or systems
(c) Migration through other host systems and return to gastrointestinal sites
Active penetration: Through host tissues, skin or mucous membranes
(a) Remains on or within the epidermis or subcutaneous tissues
(b) Penetrates to other host organs or tissues
Through host tissues by vector or agent
Injection
two examples of injection?
(a) Arthropod-borne: By mouth parts, salivary glands, or waste products
(b) Transfusion: Present in donor blood at time of transfusion
Transmission of parasites across the placental barrier from mother to fetus
congenital
Make note of all:
Life cycles
Autoinfection
NOTED!
By mouth parts, salivary glands, or waste products
Arthropod-borne Injection
Forms of Parasites Studied:
- Adult
- Larva
- Egg/Ova
- Trophozoite
- Cysts
Specimen Recovery
General Considerations
1. Proper collection and handling of specimens: Essential to ensure parasites will be recovered
- Old, inadequate or poorly preserved specimens: Of limited value and may lead to inaccurate results
- Ingestion of medicinal substances prior to collection may interfere with examination of specimen
(a) Antacids
(b) Antidiarrheal compounds
(c) Mineral oil
(d) Antibiotics - Administration of barium sulfate to patients undergoing radiological exams will make stool specimens difficult to examine for 1-2 weeks
(a) Crystals interfere with detection of organisms - All specimens should be properly labeled
(a) According to local SOP
(b) It may be useful to note any special information, clinical symptoms, prior infections, antibiotic therapy or travel history
Cool beans nerd
Specimen Recovery
Stool for O and P (Ova and Parasites) Occult blood Pinworm prep- Scotch tape prep Enterotest-string test NAT (Nucleic acid testing)
Collection of Fecal Specimens
- Collected in clean, wide mouthed containers
(a) Disposable cardboard containers with wax coating and tight-fitting lid: Container of choice
i. Prevents leakage
ii. Prevents loss of moisture
(b) Plastic containers with Snap-On or screw-on lids: Do not retain moisture as well as cardboard
(c) Glass containers: More expensive and breakable
(d) Collection of feces directly into the container: The preferred collection method; avoid contamination by water, urine or other material
i. Water will destroy trophozoites
ii. Water may contain free-living organisms that can complicate diagnosis
iii. Urine may have an adverse effect on the motility of trophozoites - Several stool examinations are necessary before parasitic infection can be ruled out
(a) Though most helminth eggs are passed continuously, many protozoa are passed intermittently
(b) Protozoan detection: Best accomplished by examination of at least three specimens collected at intervals with in 6-10 days
(c) Report of “no parasites seen” based on the examination of a single specimen should be accepted with caution
too much for one slide ya yahoo
Collection of Fecal Specimens
(a) Though most helminth eggs are passed continuously, many protozoa are passed intermittently (b) Protozoan detection: Best accomplished by examination of at least three specimens collected at intervals with in 6-10 days (c) Report of "no parasites seen" based on the examination of a single specimen should be accepted with caution
3 specimens over 6-10 days for protozoan detection
Collection of Fecal Specimens
(a) Though most helminth eggs are passed continuously, many protozoa are passed intermittently (b) Protozoan detection: Best accomplished by examination of at least three specimens collected at intervals with in 6-10 days (c) Report of "no parasites seen" based on the examination of a single specimen should be accepted with caution
3 specimens over 6-10 days for protozoan detection
- Time factor in examination of specimens
(a) Age of a stool specimen: One of the most important factors affecting the diagnosis of infections(b) Liquid and diarrheic specimens: Should be examined within 30 minutes from time of passage (type of specimen where trophozoites may be found)
(c) Soft specimens: Examined within one hour of passage
(d) Formed specimens: Can be delayed for several hours or longer, but should be examined on the same day of submission
Sorry it’s boring and long, but you gotta know dis
most common fecal preservatives
10 % Formalin
No stain, yes EIA
Polyvinyl Alcohol (PVA) No EIA, yes stain
Fecal specimens may be stored at 4⁰C, but not frozen
Pinworm prep-scotch tape prep best for?
Pinworm eggs (Enterobius vermicularis) are deposited around the perianal region
Pinworm prep-scotch tape prep best for?
Pinworm eggs (Enterobius vermicularis) are deposited around the perianal region
Used to detect parasites, protozoa and helminths, in the upper part of the small intestine
Do not eat 12 hours prior to testing
The end of the string is taped to your cheek or neck
A capsule containing the remainder of the string is swallowed
The capsule will dissolve and move into your stomach were the string will unravel
Usually the patient relaxes for about four hours
The string gathers materials from the stomach and upper intestines
After the allotted time, the string will be pulled back up through the throat, placed in a container and sent to the lab
Remove mucous from string and examine by wet mount technique
Enterotest-String Test
Nucleic Acid Testing for?
Enteric Parasite panels
For Giardia, Cryptosporidium, and Entamoeba
High sensitivity and specificity
BD Max 3 and Luminex 200
If a stool is liquid and thus is more likely to contain trophozoites, it should reach the laboratory for examination by?
Should be examined within 30 minutes from time of passage (type of specimen where trophozoites may be found)
Blood- For which species?
Plasmodium sp. (Thick and thin smears)
Monitoring of incidence, prevalence, distribution and severity of disease
Surveillance:
Interruption of parasitic life cycle
(a) Proper disposal of human and animal waste
(b) Purification of drinking water
(c) Processing and treatment of food supply
(d) Improvement of housing quality
(e) Elimination of intermediate host(s) or vectors
Control of Parasitic Infections
Protection ex’s
(a) Prophylaxis when entering into highly endemic areas
(b) Immunization against parasite infective forms
Best method of controlling parasitic life cycle?
Proper disposal of human and animal waste
Control of Parasitic Infections
Therapeutic measures
(a) Protection from infected persons: Isolation (b) Curative therapy: Antiparasitic drugs
Antimalarial?
Antihelminthic?
Antiprotozoal?
i. Antimalarial: Chloroquine phosphate (Aralen)
ii. Antihelminthic: Praziquantel (Biltricide)
iii. Antiprotozoal: Metronidazole (Flagyl)
which natural innate immune system factor fights parasites?
eosinophils!
Administration of ____ to patients undergoing radiological exams will make stool specimens difficult to examine for 1-2 weeks
(a) Crystals interfere with detection of organisms
barium sulfate
(a) Crystals interfere with detection of organisms (stool specimens)
barium sulfate
Ingestion of medicinal substances prior to collection may interfere with examination of specimen (4)?
(a) Antacids
(b) Antidiarrheal compounds
(c) Mineral oil
(d) Antibiotics
Protozoan detection: Best accomplished by examination of at least…?
three specimens collected at intervals with in 6-10 days
Collection of feces directly into the container: The preferred collection method; avoid contamination by water, urine or other material… why?
i. Water will destroy trophozoites
ii. Water may contain free-living organisms that can complicate diagnosis
iii. Urine may have an adverse effect on the motility of trophozoites
Collection of Fecal Specimens
Ideal container?
- Collected in clean, wide mouthed containers
(a) Disposable cardboard containers with wax coating and tight-fitting lid: Container of choice
i. Prevents leakage
ii. Prevents loss of moisture
Time factor in examination of specimens
One of the most important factors affecting the diagnosis of infections
(a) Age of a stool specimen
Time factor in examination of specimens
(b) Liquid and diarrheic specimens: Should be examined within…
30 minutes from time of passage (type of specimen where trophozoites may be found)
Time factor in examination of specimens
(c) Soft specimens: Examined within…?
one hour of passage
Time factor in examination of specimens
(d) Formed specimens: Can be delayed for several ___, but… ?
hours or longer, but should be examined on the same day of submission
Fecal specimens may be stored at 4⁰C, but not frozen
T or F?
TRUE….
Fecal specimens may be stored at 4⁰C, but not frozen
Fecal preservatives?
10 % Formalin
– No stain, yes EIA (Most common)
• Polyvinyl Alcohol (PVA)
– No EIA, yes stain (most common)
• Merthiolate-Iodine-Formalin
(MIF)
– Stains and EIA vary
• Sodium Acetate Formalin (SAF)
– Stains and EIA vary
- Used to detect parasites, protozoa and helminths, in the upper part if the small intestine
- Do not eat 12 hours prior to testing
- The end of the string is taped to your cheek or neck
- A capsule containing the remainder of the string is swallowed
• The capsule will dissolve and move into your
stomach were the string will unravel
Enterotest-String Test
