Intro To Parsites Slide Deck Flashcards
What is symbiosis
Two organisms of different spp. Living together
What are the 3 types of symbiosis
Commensalism
Mutualism
Parasitism
What is commensalism
Symbiotic relationship in which one organism is benefited and the other is neither benefited nor harmed
What is mutualism
Symbiotic relationship in which both organisms are benefited
What is parasitism
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.
What are the 5 types of parasites
Facultative Obligate Incidental Endoparasite Ectoparasite
What is a facultative parasite
Facultative parasite: Normally free living organism, but may become an opportunistic parasite
What is an obligate parasite
Obligate parasite: Cannot survive in a free living state.
What is an incidental parasite
Incidental parasite: Establishes itself in a host in which it does not normally live (dog flea bites a human).
What is an endoparasite
Endoparasite: A parasite living inside the host
What is an ectoparasite
Ectoparasite: A parasite living on the external
surface of the host
What is a host
. Host: Any living organism, animal or plant that harbors or nourishes another organism
What are the 4 kinds of hosts
Definitive
Intermediate
Reservoir
Paratenic
What is a definitive host
Definitive host: The host that harbors the adult or sexually reproducing stages of a parasite
What is the intermediate host
Intermediate host: That host which harbors the immature, larval, or asexually reproducing forms of a
parasite
What is the reservoir host
Reservoir host: A host which replaces man in the life cycle of the parasite
What is the paratenic host
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
What is a life cycle
Life cycle- the process of a parasite’s growth, development and reproduction, which proceeds in one or more different host depending on the species of parasites.
What is the infective stage
Infective stage-a stage when a parasite can invade a human body and live in it.
What is the infective route
Infective route- the entrance which the parasite invades the human body.
What is the infective mode
Infective mode- how the parasite invades the human body.
What is a vector
A carrier, usually an arthropod, which transmits an infective form of the parasite from host to another
What is autoinfection
Autoinfection: A reinfection in which the host is its own source of infection from a source already present in the body
What are the 4 routes of infection
Ingestion (oral)
Active penetration
Injection
Congenital
What is Oral Ingestion route
Ingestion: Oral (nasopharyngeal) in food, water or aerosols, etc.
Remains in gastrointestinal tract
Internal migration to other host organs or systems
Migration through other host systems and return to gastrointestinal sites
What is active penetration route
Active penetration: Through host tissues, skin or mucous membranes
• Remains on or within the epidermis or subcutaneous tissues
• Penetrates to other host organs or tissues
What is injection route
Injection: Through host tissues by vector or agent
• Arthropod-borne: By mouth parts, salivary glands, or waste products
• Transfusion: Present in donor blood at time of transfusion
What is congenital route
Congenital: Transmission of parasites across the placental barrier from mother to fetus
What is epidemiology
Epidemiology is the study of the distribution and determinants of health- related states or events in specified populations, and the application of this study to the control of health problems
How do protozoan uptake food
Pinocytosis, phagocytosis of soluble or particulate, ingestion through cytostome, some use diffusion.
How do protozoan convert energy
Respiration in most parasitic protozoa is accomplished by facultatively anaerobic processes
How do protozoan survive ?
develop into a cyst form that is less metabolically active
Parasites that cannot form cysts must rely on direct transmission from host to host or require an arthropod vector to
complete their life cycle
protozoan have immunoevasive mechanisms that allow them to respond to attack by the host immune
system by continuously changing their surface antigens ensuring continued survival within the host
How do protozoan reproduce
Reproduction among the protozoa is generally by simple binary fission (merogony), although the life cycle of
some protozoa, such as the sporozoans, includes cycles of multiple fission (schizogony) alternating with a period of sexual reproduction (sporogony or gametogony).
How do helminths Take up food
Ingest host tissue/fluids, causing tissue destruction, or absorption of nutrients from the surrounding fluids
and intestinal contents
How do helminth convert energy
Respiration in helminths is primarily anaerobic, although the larval forms may require oxygen.
How do helminths survive
The major protective barrier for most helminths is the tough external layer (cuticle or tegument).
Worms may also secrete enzymes that destroy host cells and neutralize immunologic and cellular defense
mechanisms.
Some evade the host immune response by incorporating host antigens into their external cuticular layer.
The worm can in some diseases (e.g., schistosomiasis) survive within the host for decades.
How do Helminths reproduce
Most lay eggs but some bear live young.
What are the 6 factors associated with parasite pathogenicity
Infective dose and exposure
Penetration of anatomic barriers
Attachment
Replication
Cell and tissue damage
Disruption, evasion, and inactivation of host defenses
What are the 5 parasite ports of entry
Ingestion, direct penetration, arthropod bite, trans placental penetration,
Organism directed penetration
How do parasites disrupt, evade, or inactive the host defenses
parasites elicit humoral and cell-mediated immune responses
parasites are particularly adept at interfering with or avoiding these defense mechanisms
What medications can interfere with examination of a specimen
Antacids
Antidiarrheal compounds
Mineral oil
Antibiotics
What will barium sulfate do for examination for patients in radiographs
Make the stool specimens difficult to examine for 1-2 weeks.
Crystals interfere with detection
What will water do in specimen recovery of trophozoites
Destroy them
What is one of the most importation factors affecting the diagnosis of infections
Age of a stool specimen
When should liquid and diarrhetic specimens be observed
Should be examined within 30 minutes from time of passage (type of specimen where trophozoites may be found)
What should soft specimens be observed
Examined within one hour of passage
When should formed specimens be observed
Can be delayed for several hours. If longer they should be preserved.
What is the most common fecal preservative
10% formalin
no stain, yes EIA
What temperature should fecal specimens be preserved at
Fecal specimens may be stored at 4*C, but not frozen
What should be noted on macroscopic examination of stool
Note consistency, presence of blood, mucus, worms, and proglottids
IN stool examination, what is detected under saline and iodine direct wet mount (fresh stools)
Detect motile trophozoites, larvae (Strongyloides), helminth eggs, protozoan cysts, and host cells such as leukocytes and red blood cells
What does 10 % formalin do
Separates protozoan cysts and helminth eggs from the bulk of fecal material and thus enhance the ability to detect small numbers of organisms usually missed by the use of only a direct smear.
What is essential for stool sample definitive diagnosis
The cytologic detail seen in permanently stained slides is essential for definitive diagnosis
What method gives best recovery of Pinworm eggs if used before defecation, bathing or dressing in the morning
Scotch tape prep
What test is used to detect parasites, protozoa and helminths, in the upper part if the small intestin
Entero test- string test
How long should the pt fast before the Estero- string test
12 hours
How is the enterotest- string test performed
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
What type of test would you use for plasmodium spp.
A blood test
What test is useful to detect parasites in the lungs
Sputum test
What test will detect parasites in the urogenital tract
Urine sediment test
When would you use a Urethral and Vaginal exudates test
To detect parasites of the urogenital tract
What is the best method of controlling the parasitic life cycle
Proper disposal of human and animal waste
- application of latrines
- avoid raw feces on soil
What chemicals are used to purify drinking water
Chlorine or Iodine
What temperature should food be at to interrupt the parasitic life cycle
Cooking/ heating for 1 hour at 55 *C
Or
Freezing for 20 days at -10 * C
What kind of drug is choloquine phosphate
Antimalarial
Aka Aralen
What kind of drug is praziquantel
Antihemlminthic
Aka Biltricide
What kind of drug is metronidazole
Anti protozoal
Aka flagyl
What is eosinophilia
When eosinophils are elevated during a parasitic infection
- does not reveal the specific parasite
- can be caused by other inflammatory conditions like cancer
What kind of nucleus does a eosinophil have
Bilobed nucleus
Eosinophils account for what percent of peripheral blood
1-3%
How do eosinophils attack foreign parasites
Chemotaxis to site
Recognize target (Fc receptors)
Phagocytosis
Induce Chemical Attack (granules)
