SECTION 1 Flashcards
study of organisms that live on and obtain their nutrients from another organism
PARASITOLOGY
- a pathogen that simultaneously injures and derives sustenance from its host
Parasites
parasitic protozoa, parasitic helminths (worms), and the arthropods
Parasites
- concerned primarily with parasites of humans and their medical significance; Importance In human communities
MEDICAL PARASITOLOGY
the association of two living organisms, each of a different species
SYMBIOSIS
Ex. Clown fish w/ sea anemone – neutral; w/o benefit
SYMBIOSIS
association of two different species of organisms that are beneficial to one and neutral to the other
COMMENSALISM
Ex. Birds and trees
COMMENSALISM
association of two different species of organisms that are beneficial to both
MUTUALISM
association of two different species of organisms that are beneficial to one at the other’s expense
PARASITISM
a parasite that has demonstrated the ability to cause disease
PATHOGENIC
a parasite that cannot survive outside of a host
OBLIGATORY PARASITE
Ex. Tapeworm – once released, it will not survive outside the host; depends on the host to complete its life cycle; requires the infective stage
OBLIGATORY PARASITE
a parasite that is capable of existing Independently of a host
FACULTATIVE PARASITE
Ex. Acanthamoeba, w/c infects the eyes – free-living outside the host; can survive the outside environment
FACULTATIVE PARASITE
a parasite living inside the body of a host
ENDOPARASITE
Ex. Lice (infection)
ENDOPARASITE
a parasite living outside the body of a host
ECTOPARASITE
Ex. Fleas and ticks (infestation)
ECTOPARASITE
a parasite found in an organ that is not in its usual habitat
ERRATIC PARASITE
Ex. Ascaris lumbricoides, w/c lives in the GIT but (?) in the lungs
ERRATIC PARASITE
a parasite that.establishes itself in a host where it does not ordinarily live
ACCIDENTAL (INCIDENTAL) PARASITE
Ex. Dwarf tapeworm – only infects dogs and cats, only a cyst in humans
ACCIDENTAL (INCIDENTAL) PARASITE
a parasite that remains on or in the body of the host for its entire life
PERMANENT PARASITE
a parasite that lives on the host only for a short period of time
TEMPORARY PARASITE
a parasite that is a free-living organism that passes through the digestive tract without infecting the host
SPURIOUS PARASITE
Ex. Chicken w/ intestinal parasite releases dung → Dog eats dung and releases parasite as well
SPURIOUS PARASITE
Host other than the normal one that is harboring a parasite
ACCIDENTAL OR INCIDENTAL HOST
Host in which the adult sexual phase of parasite development occurs
DEFINITIVE (FINAL) HOST
Ex. Humans
DEFINITIVE (FINAL) HOST
Host in which the larval asexual phase of parasite development occurs
INTERMEDIATE HOST
Ex. Cattle, sheep, goat, pigs (Taenia), and snail (Schistosoma) with 2 IH
INTERMEDIATE HOST
Host harboring parasites that are parasitic for humans and from which humans may become infected
RESERVOIR HOST
Ex. Pigs (Balantidium coli), rats, cats
RESERVOIR HOST
Host responsible for transferring a parasite from one location to another
TRANSPORT HOST
Parasite-harboring host that is not exhibiting any clinical symptoms but can infect others
CARRIER
host in which the parasite does not develop further to later stages
PARATENIC HOST
Ex. Meat eaten by human – alive parasite in the host develops when passed
PARATENIC HOST
the process of inoculating an infective agent
EXPOSURE
connotes the establishment of the Infective agent in the host
INFECTION
the period between infection and evidence of symptoms
INCUBATION PERIOD
the period between infection or acquisition of the parasite and evidence of demonstration of infection
PRE-PATENT PERIOD
when an infected individual becomes his own. Direct source of Infection
AUTOINFECTION
Ex. Enterobius vermicularis (pinworm/social worm) – “hand-to-mouth infection”
AUTOINFECTION
happens when the already Inrected individual is further infected with the same species leading to massive infection with the parasite
SUPERINFECTION (HYPERINFECTION)
Ex. Trichuris trichiura – rectal prolapse
SUPERINFECTION (HYPERINFECTION)
Eggs of Ascaris lumbricoides, Trichiura, Strongyloides, Hookworn (Night soil
worm using human feces)
SOIL
Cyst of Amoeba and flagellates
WATER
Tapeworm and flukes (undercooked food)
FOOD
Mosquito, ticks, malaria, dengue
ARTHROPODS
contact w/ an infected person or
animal, directly from the source
to the susceptible host without
involving an intermediate object
Direct
involves an intermediate object
Indirect
Droplet spread
Direct
Sexual intercourse – pingpong disease (Trichomanas vaginalis)
Direct
Kissing – Amoeba (gingivalis)
Direct
Holding hands – Enterobius vermicularis
Direct
Transplacental / Vertical - mother to fetus
Direct
Malaria
Toxoplasma gondii
Trypanosoma cruzi
Transplacental / Vertical - mother to fetus
Ingestion of contaminated food & drink
Indirect
Contact w/ contaminated soil
Indirect
Bite of an infected arthropod (vector)
Indirect
Through fomites
Indirect
LIFE CYCLE
- Mode of transmission
- Morphologic form
2 Morphologic form
Infective stage
diagnostic stage
: capable of invading the host
Infective stage
: seen in the sample
diagnostic stage
2 PHASES OF LIFE CYCLE
- Route a parasite follows independ on to the human
- Route a parasite follows independently of the human body
Major body areas associated with parasitic disease:
- GIT/UGT
- Blood and Tissue
- Liver, Lung, and other major organs
- Miscellaneous location: CSF, eye, skin, extremities (up to only 2 parasite can infect)
Symptoms Associated with Parasitic Disease Processes
Diarrhea
Fever
Chills
Abdominal pain
Abdominal cramping
Elephantiasis - most common symptom; enlargement of arms, breast, legs,a nd sex organs
Anemia
Vitamin deficiency
Bowel obstruction
Edema
Enlargement of major organs
Skin lesions
Blindness
PREVENTION AND CONTROL
Development and Implementation of
Use of insecticides and
Use of protective
Use of protective netting
Proper
Good
Proper
Proper handling, cooking, and
Avoidance of unprotected
parasite awareness (education programs
other chemicals
clothing
netting
water treatment
personal hygiene
sanitation practices
protection of food
sexual relations
3 FACTORS INFLUENCING PARASITIC INFECTION
- Source of Infection (causative agent)
- Mode of Transmission (ingestion, percutaneous, inhalation)
- Presence of Susceptible host
- for intestinal protozoans, nematodes and helminthes
Stool
- for the recovery of Trichomonas vaginalis and Schistosoma haematobium
Urine
Urine Collection:
mid- stream catch
- Paragonimus westermani, larvae of nematodes
Sputum
Sputum
• Must be digested using
4-5% sodium hydroxide (acts as a fixative)
- for malarial parasites, filarial worms, Leishmania and Trypanosoma (mosquito, ticks, flies)
Blood
- Acanthamoeba species (present in stagnant water;enters from from the nose to the brain)
Cerebrospinal fluid
Cerebrospinal fluid Collection:
lumbar tap
Liver aspirate
hydatid cyst and liver amoebic abscess
Duodenal aspirate
-Giardiasis and Strongyloidiasis infection
• Duodenal aspirate Collection:
endoscopy
: duodenal contents collected for Giardia and Strongylodes
• Duodenal drainage or “String test”
: Schistosomiasis, Amoebiasis, Balantidiasis and Shigellosis (Large intestines)
• Sigmoidoscopy
Broncho-alveolar lavage–
Paragonimus westermani
- with gelatin capsule to easily ingest the string
Duodenal drainage or “String test”
: Schistosomiasis, Amoebiasis. Balantidiasis and Shigellosis (Large intestines)
*Sigmoidoscopy
2 Orifice swab
Vaginal swab
Perianal swab
Vaginal swab-
Trichomonas vaginalis
Perianal swab -
Enterobius vermicularis and Taenia
Tissue Biopsy
Muscle
Rectal
Muscle-
Trichinella spiralis
Rectal - granulomas secondary to
Schistosomiasis
(only present in muscle)
Trichinella spiralis
– for diagnosis of Trypanosomes and microfilaria
(motile stage)
Fresh water smears
– for the study of the morphology of the parasites and the blood cells
Thin Dry smears
edge of blood tube must be at least 1 cm; 1 drop of blood to the slide
Thin Dry smears
For species identification
Thin Dry smears
specify
Thin Dry smears
gold standard for malarial diagnosis (species
identification)
Thin Dry smears
– used for malaria survey among patients with chronic infections or who are undergoing anti- malaria therapy
Thick Dry smears
edge of blood tube must be at least 1 cm; 1 drop of blood to the slide
Thick Dry smears
to check for the presence of parasite
Thick Dry smears
identify
Thick Dry smears
for rapid diagnosis for malarial infection
Thick Dry smears
- Thick film
a. Obtain a (?)
b. Add a drop of (?) (to dehemoglobinize)
c. Puddle to (?) (to avoid peeling from the slide when dried)
large drop
water
defibrinize
