Exam 1 Flashcards
What is symbiosis?
Neutral, antagoistis or synergistic relationship between 2 dissimular organisms (symbiotes/symbionts) living in close association with each other.
What is Mutualism?
Mutually beneficial relationship between two species.
What is commensalism?
Relationship between 2 species where one benefits and the other is not affected.
What is parasitism?
Relationship between 2 species where one benefits (parasite) from the other (host); usually detrimites the host but not always
Where is the highest amount of resident microbes?
The large intestine.
What/where is the resident flora of the skin?
Where=the epidermis
What=mostly staphylococcus
What/where is the resident flora of the oral cavity?
Where=cheeks, gum, teeth
What=streptococcus species
What/where is the resident flora of the stomach and intestine?
- gastric Helicobacter pylori
- L. intestine mostly anaerobic microbes
- microbes like E. coli and Lactobacillus
What is the resident flora of the upper respiratory tract?
- streptococcus and staphylococcus
- lower respiratory tract should be sterile
Whats is the resident flora of the genital tract?
- vaginal flora is influenced by hormones
- change in flora after puberty
- Lactobacillus
What is the resident flora of the urethra?
Many opportunitic microbes
What are the 4 roles of normal flora?
- Common source of infection
- Immune stimulation
- Keep out invadors
- Nutrition and metabolism
What are the 4 factors controlling the growth of microorganisms?
- Nutrient availability
- Environment
- Competition
- Host immune system
What is a fastidious organism?
An organism that has complex nutritional or cultural requirments, making isolation and culture more difficult.
What parameters are involved in the environment?
- Water activity (osmotic pressure)
- Oxygen requirements
- pH of the environment
- temperature
How is an infectious agent accquired?
- Enters the host
- Colonization
- Invasion
- Multiplication
What are some entries/exits?
- Ingestion
- Inhalation
- direct penetration
What does colonization mean?
Successful occupation of a new habitat by a species not normal found in that niche.
What does adherence mean?
Close association of bacterial cells and host cells generally characterized by receptors on target sites.
What is adhesin?
Structure or macromolecule located on the surface of a cell that facilitates adherence of a cell to a surface or to another cell.
What does invasion mean?
Entry and spread throughout cells and/or tissues of the host. (specific recognition of receptor sites on target cells enhances pathogenic advantage)
What are invasins (invasive factors)?
Structures or macromoles that facilitate invasion by a pathogenic microoganism.
What does multiplication mean?
The ability of a microorganism to reproduce during an infection; influenced by underlying disease, immunologic status, antibiotic treatment, nutrient availability
What is a vector?
A carrier; the animal that transfers an ifectious agent from one host to another, usually an arthropod.
What is a carrier?
A symptomless individual who is a host to a pathogenic microoganism with the potential to pass the pathogen to others.
What is a nosocomial infection?
An infection acquired in a hospital setting that was not present in the host prior to admission (generally occuring within 72 hrs).
What is pathogenicity?
Quality of producing disease or ability to produce pathologic changes or disease.
What is virulence?
Measure of pathogenicity; measurement of degree of disease-producing ability of a microorganism as indicated by severity of disease produced.
What does dosage mean?
Number of pathogenic organisms entering a host.
What is a true pathogen?
Any miccroorganism capable of cause a disease (infectious agent).
What is an opportunistic pathogen?
A usually harmless organism that becomes pathogenic under favorable conditions causing an opportunistic infection.
What does infection mean?
Colonization and/or invasion and multiplication of pathogenic microoganisms in a host with or without manifestation of disease.
What does disease mean?
Abnormal condition of bofy function(s) or structure that is considered harmful to the affected individual (host).
What does contagious mean?
Capable of being transmitted from one host to another.
What is an infectious dose?
Number of pathogenic organisms required to cause disease in a given host.
What does epidemic mean?
Disease occuring suddenly in numbers clearly in access of normal expectancy.
What does endemic mean?
A disease present or usually prevalent in a population or geographical area at all times.
What does pademic mean?
A widespread epidemic distributed or occuring widely throughout a region, country, contient, or globally.
What are Koch’s 4 postulates?
- pathogen must be present in all cases of disease
- pathogen can be isolated from the diseased host and grown in pure culture
- pathogen from pure culture must cause same disease when inoculated into a susceptible animal
- pathogen must be reisolated from new host and shown to be same as the originally inoculated
What is absent in bacteria that is present in fungi?
- Nuclear membrane
- mitochondria
- ER
- sterols in cytoplasmic membrane
- chitin, glucans, and mannans from cell wall
What does a sex pilus do?
mediates DNA transfer during conjugation
What does common pili or fimbriae do?
attachment to surface; protection against phagotrophic engilfment
What do capsules do?
- attachment to surfaces
- protection against phagotrophic engulfment
- reserve of nutrients or protection against dessication
What is the purpose of the cell wall?
Prevents osmotic lysis, confers rigidity and shape on cells.
What is the purpose of the plasma membrane?
- Permeable barrier
- transport of solutes
- energy generation
- location of many enzyme systems
What do ribosomes do?
Site of translation
What do inclusions do?
reserve nutrients
What is the purpose of the chromosome?
stores the genetic material
What does a plasmid contain?
extrachromosomal genetic material
Gram Positive Cell Walls
- the cell wall is a uniformly thick layer external to the plasma membrane
- mainly composed of peptidoglycan
Gram Negative Cell Wall
- appears thin and multilayered
- consists of a relatively thin layer of peptidoglycan between the plasma membrane and outer membrane
What are the characteristics of flagella?
- composed of the protein called flagellin
- not present in all bacteria
Cell walls of archaea never contain what substance?
Murein
What is the unique structure of Gram positive cell walls?
Teichoic Acid
What is the unique component of Gram Negative cell walls?
Lipopolysaccharide (LPS)
What is the toxic portion of LPS and what does is cause
- the lipo- part; lipid A
- causes fever, inflammation, hemorrhage, and shock
What is the function of the polysaccharide portion of LPS?
Responsible for antigenic properties of the bacterium, which influences how the animal’s immune system will respond.
Endospore Structure
Several layers:
- Cortex
- Core wall
- Spore coat, which contains Dipicolinic Acid (not found in vegetative cells)
- exosporium
Function of the Endospore
Resistance
Attributed to:
- layered structure
- dehydrated state
- negligible metabolism
- high content of dipicolinic acid
What do these images represent?
- Coccus
- diplococci
A=monotrichous flagellum
B=lophotrichous flagellum
C=amphitrichous flagellum
D=peritrichous flagellum
What do the images represent?
- (top) staphylococci
- (bottom) tetrad
What do the images represent?
- (left)streptococci
- (middle)sarcina
- (right)tetrad
What do the images represent?
- (left)coccobacillus
- (right)bacillus
What is this a picture of?
diplobacilli
What was the worst disaster of mankind?
spanish flu
What do viruses lack?
- the ablity to make their own energy and protein
- genetic capability to multiply by division
What is the capsid and what is it made up of?
- it is a protein shell that encases the viral nucleic acid(genome)
- it is made up of capsomeres
What is the nucleocapsid?
the capsid and the viral nucleic acid
What is the lipid envelope?
- covers the capsid
- a lipid bilayer derived from the host cell
- glycoproteins are present on the surface of the envelope and are called spikes
What is pleomorphism?
It is the ability of some viruses to alter their shape or size.
What are the steps to viral replication?
- Attachment
- Penetration
- Uncoating
- Synthesis of viral nucleic acid and proteins
- Assembly and maturation
- Release in large numbers
What is direct contact transmission?
Direct contact with infected/susceptible host.
What is indirect-contact transmission?
Contact with inanimate objects (fomites).
What is common-vehicle transmission?
Fecal contamination of water or food and virus contamination of meat.
What is vertical transmission?
Infection that is transferred from mother to embryo or fetus or newborn before, during or shortly after birth.
What are ways to diagnosis viruses?
- Clinical signs
- necropsy
- histopathology
- Cultivation/isolation
- electron microscopy
- serology
- fluorescent antibody staining
- immunohistichemical staining
- PCR
What are ways to treat viruses?
- Antiviral drugs
- Immune system stimulation (interferons)
- Synthesize antibodies or administration of natural antiserum
What are ways to prevent and control viruses?
- Vaccination
- Proper hygiene and sanitation
- Eliminating arthropod vectors
- Quarantine and culling
Why is parasitology important to veterinarians?
Because…
- we need to know which ones cause disease
- which ones are clinically relevant
- minimize impact on production
- which are zoonoses
- dianostic tools
What are the 3 main classes of parasites that can cause disease in humans?
- Helminths
- Ectoparasites
- Protozoa
Class Nematoda (from phylum nematheliminthes)-round worms
- free-living or parasitic
- elongated/cylindrical
- alimentary canal present
- sexes usually separate
- spaghetti shaped
Class Cestodes (from phylum platyhelminthes-flatworms)-tapeworms
- flat body
- NO alimentary canal
- scolex (holdfast organ)
- strobila (body) with proglottids
- each proglottid is hemaphroditic
- fettuccine shaped
Class Trematoda (from phylum platyhelminthes-flatworms)-flukes
- dorso-ventrally flattened
- leaf-like
- oral and ventral suckers
Class Insecta (from phylum arthropoda) included?
- flys
- fleas
- lice
Class Arachnida (from phylum arthropoda) includes?
- Ticks
- Mites
Subkingdom Protozoa are?
unicellular, eukaryotic animals
Protozoa move by way of?
- pseudopodia
- flagella
- gliding movements
- cilia
Insects are identified by what?
- adults: 3 pairs of legs
- head, thorax, abdomen
- antenna
Arachnids are identified by what?
- Nymphs and adults: 4 pairs of legs
- Larvae: 3 pairs of legs
- body: cephalo-thorax and abdomen
- NO antennae, but they do have palps
Infective dose and exposure of protozoa.
multiply in host
Infective dose and exposure in Helminths.
- Adult worms do not multiply in definitive-host. Worms die over time, unless the host is re-exposed.
(severity of disease is proportional to worm load introduced into the host)
Attachment occurs through?
- mechanical or biting mouthparts
- molecular interaction
Cell and tissue damage includes?
- mechanical damage
- immunopathologic reactions
- toxic products
Mechanical tissue damage occurs 3 different ways, which are?
- Blockage of intestinal organs
- pressure atrophy
- migration through tissues
Toxic parasite products include?
- destructive enzymes
- amoebic pore
- endotoxins
- catabolites
- toxic secretions
Immunopathology includes?
- anaphylactic
- cytotoxic
- immune complex
- cell mediated
Loss of nutrients includes?
- competition with host for nutrients
- interference with nutrient absorption
- nutrient loss-iron loss
What is premunition?
Resistance to reinfection dependent on retention of the infectious agent.
What is concomitant immunity?
The survival of some cells or organisms with the immune destruction of other cells or organisms of the same line.
What are the componets of cell walls that can cause toxic shock?
- Lipopolysaccharide (-)
- Teichoic acid (+)
What are the 2 ways that exotoxins are delivered to the host cell?
- secretion into the surrounding environment
- direct injection into the cell
What are the 4 functions of exotoxin?
- binding and delivery of toxin
- Proteolytic break down of host proteins
- membrane disrupting (pore formation)
- toxins against IgA and host cytoskeleton
What are the purposes of adhesins?
- expression of factors to allow bacteria to bind to host cells
- avoid removal via host mechanisms
What are the types of adhesions?
- polypeptide (protein)
- polysaccharide
What is the purpose of invasins?
to get into the host cell
What are the types of invasions?
- extracellular (use enzymes)
- intracellular (when whole organism enters into cell)
What examples of intracellular survival techniques?
- acidic phagolysosome
- phagosome with no fusion to a lysosome
What is virulence regulation?
rapid adaptation of bacteria to allow colonization and growth
What are the two mechanisms of virulence regulation?
- Sigma factors (control transcription)
- Two component systems (sensor proteins and response regulators)
How do novel pathogens evolve?
Horizontal gene transfer
What is primary viremia?
inital entry of virus into the blood
What is secondary viremia?
Virus has replicated/multiplied in major organs and once more entered the circulation.
What is a disseminated infection?
An infection that spreads beyond the primary site of infection.
What is a systemic infection?
An infection that affects a number of organs or tissues.
What is a neurotrophic virus?
A virus that can infect neural cells.
What is a neuroinvasive virus?
Viruses that enter the central nervous system after infection of a peripheal site.
What is a neurovirulent virus?
Viruses that cause disease of nervous tissue, manifested by neurological symptoms and often death.
What is tropism?
The specificity/affinity of a virus for a particular host tissue.
What is pantropic?
Virus can replicate in more than one
What are teratogenic viruses?
Viruses that cause developmental defects of embryo or fetus after in-utero infection.
