Test 1 Flashcards
What is Virology?
the study of viruses and virus-like agents
What is a virus?
- from the latin virus meaning toxin or poison
- microscopic infectious agent that is an obligate intracellular pathogens
What can Viruses infect?
all types of organisms from animals and plants to bacteria
How do you classify Viruses?
- host range
- enveloped or non enveloped
- type of nucleic acid in the virion
- shape
- dimensions of the virion and capsid
What does each virus contain?
- nucleic acid
- capsid
- protein
- enzymes
- sometimes has a capsid
How are Viruses seen?
- under electron microscope
- negative staining with heavy metal
- thin sectioning with positive staining
What is a Capsomere?
capsid composed of protein subunits
What are the functions of the Capsomere?
- protective
- recognitive / attachment to host cell
- introduction of nucleic acid into host cell
What are Envelopes?
- Composed of lipids from host cell membrane
- proteins
- glycoproteins
What are the functions of Envelopes?
- camoflage
- recognition/attachment to host cell
- helps introduce nucleic acids into host cell
- protects nucleic acids
What is an example of a Helical Shape?
rabies
What is an example of a Complex Shape?
bacteriophage
What ways can viruses be transmitted?
- aerosols
- break in skin
- fluids (blood, saliva, sexual contact)
How do viruses attach/penetrate?
- bind to specific surface receptors
- fuse with or engulfed by the plasma membrane
How do viruses get released?
- lyse cells
- bud through plasma membrane
What is the life cycle of the Viruse?
- Entry into host cell
- Uncoating
- Replication of nucleic acids and production of proteins
- Maturation/assembly
- Release of Virus
What ways can a virus enter the host cell?
- endocytosis (engulfment)
- fusion of cell membrane with viral envelope via spikes
What is Uncoating?
nucleic acid is released from nucleocapsid
What happens during the Multiplication Cycle?
- DNA enters nucleus
- DNA is transcribed
- RNA is exported to cytoplasm and translated
- DNA is replicated in nucleus
- Viral DNA inserted into host genome
What happens during Maturation/Assembly?
new nucleocapsids self assemble
How is a virus released?
exocytosis
What is an Acute Infection?
- has short duration
- often not fatal
- dissappears when disease process ends
What is a Latent Infection?
- remain in equilibrium with the host
- don’t produce disease for a long period
What are Persistent/Chronic Infections?
- often fatal
- occurs gradually over a long period of time
What are the methods of diagnsosis for Viral Diseases?
- Serology
- Cytology
What is a 4 fold?
-greater rise in titer between 2 serum specimens provide a positive diagnosi
What is a Paired Sera?
- first taken as early as possible in the iillness
- second 10-14 days after the onset of symproms
-
What are Inclusion Bodies?
-nuclear or cytomplasmic aggregates of stainable substances, usually proteins
What are Negir Bodies?
type of cytoplasmic inclusion, body
When was Bacteria first observed?
- 1676
- by Leeuwenhock
- with single lens microscope
What is Bacteria?
- single celled microorganisms with a variet of shapes
- aka prokaryotes
- genetic material contained in a single circular chromosome in the cytoplasm of cell nucleoid
What are the characteristics of Prokaryotes?
- fewer organelles
- smaller than eukakryote
- cell wall
- +/- capsule
- cell/plasma membrane
- nucleoid
- cytoplasm
- ribosomes
- +/- pil
- endospores
What are characteristics of Eukaryotes?
- cell/plasma membrane
- nucleus
- nucleolus
- cytoplasm
- mitochondria
- golgi apparatus
- endoplasmic reticulum
- ribosomes
- vacuoles
- lysosomes
What is the most common disease caused by Bacteria?
respiratory disease
What are the shapes Bacteria can be?
- Spherical (cocci/coccus)
- Rod (bacilli/bacillus)
- Single cells, pairs, chains, clusters
- Elongated to form filaments
What is the Cell Membrane?
- barrier to hold nutrients, proteins and other components of cytoplasm inside cell
- no membrane bound organelles
- no nucleus, mitochondria, chloroplasts, golgi apparatus, or E.R
What is Genetic Material?
- single circular chromosome
- in nucleoid of cytoplasm
How do you treat Bacterial Infections?
antibiotics
What are Industrial Processes of Bacteria?
- waste treatment
- cheese and yogurt production
- manufacture antibiotics and other chemicals
What is the Cell Wall?
- surrounds cell membrane
- essential to survival
What is Gram Staining?
- divides bacterial kingdom into 2 main categories
- created by Hans Christian Gram
- stain illustrates composition of cell wall
What color is Gram +?
purple
What color is Gram -?
pink
What are the steps in Gram Staining?
- crystal violet
- Gram’s iodine
- ethanol or acetone
- safranin
What is Crystal Violet?
stains both + and - bacteria
What is Gram’s Iodine?
fixes stain in Gram + bacteria
What is Ethanol or Acetone?
washes the stain from Gram - bacteria
What is Sanfranin?
- counterstain
- re stains Gram - bacteria
- doesn’t interfere with previous stain in Gram + bacteria
What are Gram + Cocci?
- Staphyl Coccus
- Streptococci
What are Gram + Rods?
- Coymbacterium
- Listeria
- Erysiplothrix
- Archanobacterium
- Rhodococcus
What are Gram + Endospores?
- Clostridium
- Botulism
What are Gram + Anaerobes?
Actinomyces bovis
What are Gram + Acid Fast?
tuberculosis
What are Gram - Enteric Rods?
- Klebsiella
- Proteus (UTI)
- E. Coli (UTI)
- Slamonella
- Shigella
What is the Glycocalyx?
- network of polysaccharides
- surrounds cell wall
- varies in complexity
- protects from engulfment by macrophages
- act as antigens
- cell recognition
- allows attachment to inert surfaces (teeth, rocks, etc)
What are Endospores?
- highly resistant, dorminant structures
- consist of: central core of cytoplasm (contains DNA)and ribosomes surrounded by cortex layer
-protected by impermeable and rigid coat
What extreme physical and chemical stresses can Endospores survive?
- UV light
- gamma radiation
- detergents/disenfectants
- heat
- pressure
- drying
What are Pathogens?
- bacteria or other agent that forms a parasitic association with other organisms
- major cause of death in humans and animals
What are examples of Pathogens?
- tetanus
- food borne illness
- leprosy
- tuberculosis
- E. Coli
What is an Obligate Pathogen?
- always cause disease
- ex: Rickettsia, Chlamydia
What are Opportunistic Pathogens?
-primarily associated with immune suppressed hosts
How do you treat Pathogens?
- antibiotics
- Bacteriocidal (kills)
- Bacteriostatic (inhibits growth)
What are Examples of using Antiseptic measures against Pathogens?
- sterilizing skin prior to needle puncture
- proper care of indwelling cathethers
- sterilization of surgical and dental instruments
What would you use Antiseptics on?
living tissue
What would you use Disenfectants on?
non living things
How do Bacteria reproduce?
- asexually
- by binary fission
- double every 9.8 minutes
How is Bacteria cultured?
- with solid or liquid media
- Solid: agar plates (sheeps blood)
- Liquid: measurement of growth, large volumes needed
- Selective Media: used to ID specific organisms
What are characteristics of Modified Live Vaccines (MLV)?
- strong, long lasting
- immune response achieved with fewer doses
- adjuvants arent necessary
- quicker immune responses
- less chance of allergic reaction
- effective only 1 hour after mixing
What are characteristics of Killed Vaccines?
- more stable in storage
- unlikely to contain pathogens
- unlikely to cause disease
- produce little to no cellular and mucosal immunity
What are Adjuvants?
- chemicals, microbial components or mammalian proteins
- ehances the immune response to vaccine antigens
- Aluminum gels/salts
What are Core Vaccines for Canines?
- Canine Parvovirus type 2
- Canine Distemper Virus
- Canine Adenovirus type 2 (DAPP/DHPP)
- Rabies
General Guidelines: Canine Vaccines
Begin: 6-9 weeks of age
Frequency: q 2-4 weeks
End: atleast 1 dose given at 14-16 wks or older
Revaccination: at 1yo or 1y after last puppy vaccination
What age is Rabies Vaccine given in canines?
12wks
What is the Duration of Immunity?
- atleast 5 to 7 years
- TODAY: 3yr revaccination program
General Guidelines: Feline Vaccinations
Begin: 8-10wks
Frequency: q 2-4 wks
End: last dose at 14-16wks
What are the Feline Core Vaccines?
- Feline Parvovirus
- Feline Calicivirus
- Feline herpes virus
- Rabies
- FVRCP
What is Immunology?
ability of the body to fight infections and/or foreign invaders by producing antibodies or killing infected cells
What are the 2 categories of Immunology?
- Nonspecific
- Specific
What is the Immune System?
system in the body responsible for maintaining homeostasis by recognizing harmful from non harmful organisms and producing a appropriate response
What are Foreign Invaders?
- aka pathogens
- viruses, bacteria or other living things that cause disease/immue response
- aka Antigens
- soluble sugstances: toxins and foreign proteins
What are the parts of the Immune System?
- blood
- bone marrow
- thymus gland
- normal functioning:nutrition, stress sanitation and age
What is Non Specific Immunity?
-includes species resistance, mechanincal/chemical barriers, and inflammation
What is the First Line of Defense?
- skin
- provides physical and chemical barriers
- physical:hard to penetrate. made of indigestible keratin, hairs
- chemical:tears, sweat, mucous, saliva, enzymes, sebum
What is the Second Line of Defense?
- inflammatory response
- signs of inflammation: redness, heat, pain, swelling
