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42 Cards in this Set
- Front
- Back
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Where do endoparasites live?
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Inside a host's digestive system
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How do endoparasites feed?
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Oral and/or ventral sucker.
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What are Helminths?
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Parasitic worms including Platyhelminths (flatworms more specifically cestodes and trematodes) and Nematodes (roundworms)
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What is the two host life cycle?
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Intermediate host: larval stages
Definitive host: adult stages (mostly human) |
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Trematode Life Cycle
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Clonorchis Sinensis: Asian liver fluke. Definitive host - human. Resides in bile duct of liver. Ingested by raw fish. Prevented by cooking and good plumbing.
Paragonimus Westermani: Lung fluke. Definitive host human or sometimes cats. Ingested by eating crustaceans in metacercaria stage. |
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Cestode Life Cycle
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Taenia Saginata: Cow initial host
Taenia Solium: Pig initial host (sometimes def host) T. Solium: Lethal to humans. Neurocysticerosis (ingested from cow/pig meat) Echinococcus Granulosus: Lethal to humans if it goes to brain. Canines definitive host. |
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Enterobius Vermicularis
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Nematode. Pinworm.
One host transmitted through direct contact. Infants ingest eggs in soil. Lays eggs in human anus. |
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Ancylostoma Duodenale
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Hookworm. Nematode
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Necator Americanus
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Hookworm. Nematode. Larva penetrate skin. Live in small intestine as adults. In south eastern US because of humidity. Sense human temperatures and feed on blood.
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Trichinella Spiralis
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Whipworms. Infected by ingesting eggs in undercooked pork.
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Anisakines
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Sashimi worms. Human is not the regular host. In sushi. If fish are not properly refrigerated, larvae migrate to muscle.
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Clonorchis Sinensis
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3 host life cycle. Int. host - snail and fresh water fish. Def. host - human. Humans pass eggs in fecal matter. Hatch in water. Seeks snail host w/in 24 hours.
Free swimming cercariae encyst in skin of fish. Fish eaten by humans (only raw) |
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Parasitic vectors
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Vector transmits microorganism to next host. Act as the site or reproduction.
ex. lice fleas ticks mosquitos |
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Complex life cycle
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indefinite and definitive hosts. Dioecious or monoecious adults.
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Dioecious
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male or female reproductive organs in separate individuals.
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Monoecious
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male/female reproductive organs in each individual.
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Trematode body
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Oral and ventral suckers. Outer layer: cuticle. Monoecious.
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Cestode body
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3 regions: scolex (anterior head for attachment), neck (lead to the rest of the worm), and strobila (majority or worm)
Strobila made of proglottids. Mature as you move further from neck. Gravid: in state of reproduction and pores release eggs. |
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Nematode body
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Cylindrical shape. Dioecious and sexually dimorphic. Larger females.
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Characteristics of the virus
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Obligatory intracellular parasites (living host needed)
host range (only certain organisms can be infected) cell range (only certain cells can be infected) Can infect multiple species (varying from year to year) Submicroscopic (scanning electron needed to see) |
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Virion
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fully formed virus with all parts
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Viral structure
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Nucleic acid (genetic material)
Capsid (protein coat of capsomere units) Envelope (2nd layer made from host origin for attachment. not always there) |
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Are viruses DNA or RNA based?
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Both. HIV is RNA.
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Viral Morphology
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Helical (no envelope. filoviridae family)
Polyhedral (multi sided with no envelope) Enveloped (some with spikes. makes virus sticky) Complex (no envelope. sheath, pin, and baseplate for cell location and attachment and nucleic uptake) Oncovirus (cancer-causing. begins with infection. genetic material integrates to host DNA) |
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Lysogenic Cycle
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Host cell altered but remains alive. Phage attaches to host and injects DNA. DNA becomes circular and enters lysogenic cycle. Recombination of DNA (integration of viral and host). Bacterium reproduce normally. Prophage excises from DNA and initiates lytic cycle.
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Lytic Cycle
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Host dies and ruptures. Phage attaches to host. Penetrates host and injects DNA. Biosynthesis, DNA synthesizes viral components in host. Viral components assemble into virions. Host lyses and release virions into environment.
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What is burst size?
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Number of virions released at the end of the cycle, approx. 50-200 virions.
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Burst time?
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The amount of time between when a virus attaches and new virions are released. 20-40mins.
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Animal virus replication
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RNA based with envelope. Envelope and capsid are digested. Enzymes turn RNA into DNA within virus.
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Types of viral infections
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Acute (short time between exposure and replication. Ex. Flu.)
Persistent (replication gradually occurs and then spikes) Latent (virus hides after exposure, trigger causes replication. Ex. Leukemia) |
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Viroid
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Plant virus which infects crop plants.
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Prions
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Self replicating infectious proteins.
Infected by ingestion, transplant, or surgical instruments. Creutzfelot: Jakob Disease was first know. PrPsc: Scrapie protein. Forms plaque in brain. Lethal. |
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2009 Flu
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Global distribution.
5 viruses crossed barrier and combined. Human, avian, and swine viruses. Triple reassortment. H1N1 Pandemic. |
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What is sterilization?
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Destruction of all microbial life, including endospores. Steam under pressure.
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Disinfection?
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Destruction of vegetative pathogens. Use chemical and physical methods. UV, boiling water, steam.
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Antiseptics?
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Destruction of vegetative pathogens on living tissue. Chemical antimicrobials.
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What factors influence antimicrobials?
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Number of microbes and the level of contamination.
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How do microbial characteristics effect treatment?
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Environmental lifestyle effects what kinds of treatment should be used. pH too acidic then heat should be used. Lifestyle effects time of exposure and more.
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Killing mechanisms?
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Target plasma membrane to disrupt osmotic pressure.
Protein damage Nucleic acid damage |
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Physical methods of killing microbes.
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Heat: Autoclaving. Pasteurization (dairy product treatment). Dry heat (direct flaming and incineration).
Filtration Cold: Refrigeration, lyophilization (how bacteria is shipped), deep-freezing. High Pressure: (for fruit juices) Desiccation: (removes water) Osmotic Pressure (saline content) Radiation: Ionizing, nonionizing UV lamp, kills endospores and vegetative cells. |
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Chemical Methods of killing microbes.
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Phenol/phenolics: Used in healthcare
Halogens: Beta-iodine in surgery. Chloring Heavy Metals: Burn chemicals. Nitrates/nitrites: used in mean preservation. |
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Cidal vs Static
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Cidal - chemical reagent is lethal to microbe (ex. aldehydes)
Static - chemical reagent only inhibits growth. |
