Microbio- viriology Flashcards
What did Pasteur develop?
vaccine against rabies
What did Chamberland develop?
a filter to remove bacteria from water
What did Ivanoski discover?
there was filterable infectious agents
What did Beikerinck discover and what were Loeffler & Frosh the first to prove?
Beikerinck discovered that the agent multiplied only in cells
Loeffler & Frosch were the first to prove viral infections in animals
What was Stanley the first to see under a microscope?
the viral structure under EM with tobacco virus
what type of parasite are viruses and what are two characteristics of it?
obligate intracellular
inert outside host cells
hijack and utilize host cellular metabolism to make energy or proteins
what are 6 characteristics of viruses?
small and filterable (pore size 0.2 um) found in almost every ecosystem on earth non-living entities survive hours to days outside host cells shows reduced infectivity with increased time outside host cells don't have standard cellular organelles
define virology
the study of viruses and viral diseases
define virologist
someone who studies viruses
define veterinary virology
the study of viruses in non-human animals
what are 3 reasons why studying veterinary virology is important?
viruses cause high rates of mortality and morbidity in animals
viral diseases in animals cause financial losses to livestock and poultry industries and national and global economy
some viruses are zoonotic
what is the host range of viruses (5) and what is an important fact about host range?
vertebrates, invetrebrates
protists
bacteria, fungi
most viruses are host specific
define bacteriophages and what is an example of the use of bacteriophages?
viruses that infect bacteria
phage therapy to kill bacteria- treatment of wound and skin infections
define onolytic viruses, what can they be used for and what are 6 examples?
viruses that infect and kill cancer cells
oncolysis- stimulation of host anti-tumor immune response
adenovirus, reovirus, measles, vaccinia, Newcastle disease virus, Herpes
what are the 5 components of the virus structure?
nucleic acid capsid capsomere envelope envelope proteins
what is the viral genome made of?
RNA or DNA
what is the capsid and what are 3 characteristics?
protein shell that encases the viral genome most viruses have one capsid (reoviruses have double layered capsid) usually symmetrical (Helical, icosahedral, complex) functions: protection, antigenic sites, attachment
what is the capsomere?
basic subunit protein of the capsid
what is the nucelocapsid?
capsid + viral genome
what is the envelope and what are two functions?
lipid bilayer with embedded (glyco)proteins
facilitates virus entry into host cells
helps virus to adapt fast and evade host immune system
define virion
a coplete virus particle that consists of an RNA or DNA core with a protein coat, sometimes with an envelope
the extracellular infective form a virus
define virus
any aspect of the infectious agent and includes:
the infectious (virion) or inactivated virus particle
viral nucleic acid and protein the infected host cell
define viroid
infectious particle smaller than any known viruses
an agent of plant diseases
particle consists of an extremely small circular RNA molecule, lacks the protein coat
What are the ways to classify viruses? (4)
envelope: naked, enveloped
capsid symmetry: icosahedral, helical, complex
nucleic acid: DNA, RNA, both DNA & RNA
genomic architecture: linear, circular, segmented; ss, ds, ds with regions of ss; sense (+,-,+/-)
define icosahedral capid symmetry
protomers aggregate to form capsomeres which are either hexons or pentons
define helical capsid symmetry and what is the difference when in animals vs plants?
capsomeres and nucleic acid wind together to form a helical or spiral tube
animal= enclosed in a lipoprotein envelope
plants= naked
define complex capsid symmetry, what are two examples and characteristics of them?
virions are composed of several parts, each with separate symmetries and shapes
bacteriophage= icosahedral head and helical tail
pox virus= produces more than DNA and capsid, has additional genes that encode for enzymes
define sense and strandedness for genome architecture, and what is it a reflection of?
sense: polarity of the genome (+ or -)
strandedness: ds or ss
reflection of different replication strategies
what are three possible effects of viruses on infected host cells?
abnormal cell growth
cell damage/death
no apparent changes
what is the result of abnormal cell growth from infected host cells and what are 2 examples?
cancer
Thymic lymphoma in Feline Leukemia Virus
large skin lesions from Papilloma Virus in giraffe
what are 3 results of cell damage/death from infected host cells and what is an example?
lysis= cell bursts open and everything inside the cell spills out- causes severe inflammation
cell membrane alteration
apoptosis= phagocytes eat the material from the killed cell- no inflammation
infectious canine adenovirus induces damage/death of hepatocytes
what are 3 results of no apparent changes of infected host cells and what is an example?
persistent
latent
immuno-suppression
herpes virus
what is an important reservoir host for viruses and why?
bats
important risk in human and animal public health- more than 60 viruses have been detected in bats
what are 4 types of disease transmission and what are examples for each?
horizontal- squirrel pox virus, blue-tongue virus
vertical- canine herpes virus, BVD
cross-species- malignant catarrhal fever: transmitted to cattle from sheep/goats
zoonosis- rabies, SARS, buffalo pox
what are 6 types of routes of transmission?
abiotic environmental factors (wind/water) animal vectors direct contact indirect contact droplets airborne fecal oral
what are the 6 steps of viral replication?
attachment penetration uncoating replication assembly release
what are three characteristics of viral genome?
contains only few genes
genes encode for structural components (capsid proteins)
genes encode for enzymes necessary in the virus life cycle, mainly for nucleic acid synthesis (reverse transcriptase)
what kind of parasites are viruses and what can’t they do?
obligate intracellular
can’t make energy or proteins by themselves
when are proteins & enzymes synthesized and functional and what kind of enzymes are produced by the host cell (4)?
when virus is inside the host cell
enzymes are supplied by the host cell (protein synthesis, ribosomes, tRNA and energy production)
what is the first step of viral replication and what is it the process of?
attachment/adsorption
attachment of the virion to the host cell surface
what type of interaction is involved in the attachment step of replication, what is the interaction between, and what does it determine?
specific interaction
between capsid proteins or envelope spikes and host cell receptors
determines host-specificity and tissue-specificity of viruses
what is the role of receptors?
selectively bind specific substance and mediate its entry or action into the cell
what is a characteristic of animal virus attachment?
attachment sites are distributed all over the viral surface
what is the 2nd step of viral replication and what is it a process of?
penetration/entry
bringing the viral genome to the other side of the host cell’s plasma membrane by entry of a portion of the virion
what two things are penetration/entry dependent on?
energy and temp
what is the host cell classified as if virus can enter the cell?
susceptible to a virus
what are the 3 different mechanisms of penetration/entry?
endocytosis membrane fusion direct penetration (pore or antibody mediated)
what is endocytosis a process of and how it it done, and what type of viruses use this method?
the virus gains entry into the host cell without passing through the cell membrane
active transport in which the virus is engulfed by an energy-using process
enveloped and naked
what is membrane fusion the process of, what is it mediated by (2) and what viruses use this method?
merging (fusion) of the virus envelope with the host cell lipid bilayer membrane
mediated by pH independent or dependent fusion proteins that are anchored on the virus surface
enveloped
what is direct penetration the process of, what is it restricted to and what viruses use this method?
virual genome injection into the host cell’s cytoplasm after initial attachment
restricted to viruses in which only the genome is required for infection (mostly + sense RNA viruses)
naked
what is pore-mediated direct penetration?
creation of pore in host membrane mediated by viral pore-forming peptide associated in viral capsid
what is the 3rd step of viral replication, what is it the process of and what is it mediated by (2)?
uncoating
capsid protein removal and the release of viral genome in the host cell
mediated by cell pH and lysosomal enzymes
how does uncoating affect the infectivity of virions, how do large viruses differ during the uncoating step?
loss of infectivity of virions
large viruses have their own uncoating enzymes
what is the 4th step of viral replication, what is it a process of and what is the flow of genetic info?
replication/synthesis
genomic expression of the viruses, using host cellular machinery to replicate and make functional and structural proteins
flow of genetic info: transcription to translation
what are 5 key enzymes in genetic info flow and what are they involved in?
DNA polymerase= DNA replication (DNA-> DNA)
RNA polymerase= transcription (DNA-> RNA)
Reverse transcriptase= reverse transcription
Ribsomal enzymes= translation (RNA-> protein)
RNA dependent RNA polymerase= RNA replication (RNA-> RNA) - sense RNA
what is essential for viral protein synthesis, what are two stages of protein synthesis and what do they include?
mRNA synthesis
- early protein synthesis= enzyme polymerase, which makes copies of genetic material from progeny viruses
- late protein syntheses= capsid and/or envelope proteins
what do strategies for genomic differ between and what are two types?
differ between taxonomic groups of viruses
Strandness & sense
location of production of mRNA
what are the two locations for production of mRNA, what type of viruses use each, and what are exceptions for each?
nucleus (using host cell’s DNA- dependent RNA polymerase= DNA viruses (except pox virus, uses cytoplasm)
cytoplasm= RNA viruses (except influenza virus- use nucleus and retrovirus- uses reverse transcriptase)
what is the 5th step of viral replication, what is it the process of, what organelle does it involve and where can it take place (3)?
assembly & maturation
packing the viral genome and proteins into new virions following a specific order
Golgi complex
may take place in nucleus, cytoplasm and/or host cell membrane (mostly for enveloped viruses)
what is the 6th step of viral replication, what is it a process of and what are three different mechanisms?
release/shedding
expulsion and release of progeny virions following replication in infected host cells
budding (enveloped), exocytosis, cell lysis (naked)
what is the process of budding in viral replication and what does it create during the process?
pinching off of the new virus from the host cell’s membrane
creates an envelops during the process
what organelle is used in exocytosis, what viruses use this method and how?
goes through Golgi
enveloped= normal
naked= vesicle from Golgi fuses with virion
what is the process of cell lysis during the 6th step of vial replication, what type of viruses require this method and what is another term for this process?
host cell membrane rupture, actively induced by many viruses
bacteriphages require cell lysis to be released from the infected cell
Lytic replication
what are the 5 steps of the life cycle of an animal virus?
adsorption entry: endocytosis biosynthesis of viral components assembly budding
what are the 7 steps of the life cycle of DNA viruses?
virion attaches to host cell
virion enters and its DNA is uncoated
a portion of the DNA is transcribed, producing mRNA that encodes for early viral proteins
DNA is replicated and come viral proteins are made
Late translation, capsid proteins are made
virions mature
virions are released
what is the life cycle of Pox virus?
ds DNA replicates in cytoplasm
large virus, more genes= carry own RNA polymerase
what are the two forms of the life cycle of RNA viruses?
plus sense= direct translation into proteins used in translation
minus sense= transcribe neg to pos sense then translated
what is a term used to describe retroviruses, what does it mean, how are retroviruses characterized and what is their life cycle?
provirus= virus genome that is integrated into the DNA of a host cell
characterized by 2 identical strands of RNA
reverse transcriptase into viral DNA, the new viral DNA is transported into the host cell’s nucleus and integrated as a provirus
can replicate indefinitely and produce many viruses to be released in the host
What are influenza viruses characterized as, where does replication occur and what is the life cycle?
characterized by spiked envelope and segmented genome
replication occurs in the nucleus
attach to target epithelial cell, cell engulfs the virus by endocytosis
viral contents are released and RNA enters the nucleus to be replicated by the viral RNA polymerase into mRNA to make proteins
new viral particles are released into the ECF, the cell is not killed and continues to make new viruses
what is a term used to describe bacteriophages replication, what does it mean and what are two methods of replication?
prophage= virus genome of bacteriophage that is integrated into the DNA of a host cell
Lytic cycle= phage infects cell, phage DNA circularizes separate from host DNA, gets replicated and makes proteins and assembles new virus, which is released during cell lysis
lysogenic cycle= phage infects cell, phage DNA becomes incorporated into host genome. the cell divides and prophage DNA is passed on to daughter cell. under stressful conditions, can turn to lytic cycle
what does the timing of the one-step growth cycle depend on and what are two examples?
depends on virus and host
bacterial viruses= 20-60 min
animal viruses=8-40 h
what are the 4 stages of the virus growth curve and what does the growth look like in each stage?
adsorption & entry= decline
uncoating & replication= steady at 0
maturation: intracellular viruses= exponential growth, extracellular viruses= slightly higher than 0 plateau
release: intracellular= leveling out, extracellular= exponential growth
what is the eclipse period and when does it occur?
infectivity of the virus disappears due to uncoating
during uncoating & replication phase
what is latent period and when does it occur?
replication of viral nuclei and protein
during uncoating & replication to maturation phase
what is the maturation period?
assembly of viral genome and protein into mature virus particles.
if at this time cells are broken, active virus can be detected
define viremia and what are 4 types?
virus spread via the bloodstream
passive, active, primary secondary
define passive viremia and what are 2 examples?
direct inoculation of virus in host’s bloodstream and no replication at site of entry
contaminated syringe, bite of arthropods
define active viremia
viremia following virus replication in host
define primary viremia
spreading into the blood from infected area
define secondary viremia
spreading to other organs/tissues
what are three different courses of infection in host?
acute
latent
persistent
define acute infection in host and what are 3 examples?
rapid onset of disease and symptoms with brief duration
influenza virus, pox virus, enteric viruses
define latent infection in host and what are 3 examples?
virus remains in asymptomatic host cell for long periods
retroviruses, FIP, Feline herpes virus
define persistent infection in host and what are 3 examples?
disease process over a long period, generally fatal
chronic= bovine viral diarrhea virus (BVD)
slowly progressing= lentiviruses, Jaagsiekte Sheep retrovirus
the threshold of virus is required to activate what during the virus spread in host?
adaptive immune response
what are 5 mechanisms of injury for virus spread in host?
inhibition cytopathic effect neoplastic transformation drive host cell to apoptosis non-cytocidal changes (persistent)
what are three types of inhibition in mechanisms of injury?
host cell nucleic acid synthesis
host cell RNA transcription
host cell protein synthesis
what are two cytopathic effects in mechanisms of injury?
toxic viral proteins
interference will cell membrane function
what are 4 reasons to why it is important to diagnose viral infections?
viral disease diagnosis to determine what antiviral chemotherapy is available
screening of blood donors
proper management of diseases
early detection of epidemics
what are the two methods of lab diagnosis and what are examples of each?
direct: virus isolation, genome detection, antigen detection
indirect: serology for IgM and IgG
what are 5 samples that are required for diagnosis of viral infection?
blood sputum/bronchial washes feces cerebrospinal fluid biopsy/necropsy tissues
what are three uses of blood samples in diagnosis of viral infection?
antibodies
virus if the animal is still in viremic stage
virus in blood cells
what type of samples are used in biopsy/necropsy tissue diagnosis?
for culture= fresh
for antigen= may be formalin fixed
what are 4 methods for lab diagnosis of viral infections and what are examples for each?
virus culture & isolation: TCID50 assays, fluorescent Ab staining, cytoplathic effect
detection of virus specific antibodies: hemaggultination, ELISA, agar gel immunodiffusion, immunochromatography
detection of viral antigen: western blot, immunoflorescence, ELISA
detection of viral genome: PCR, deep sequencing of viral strain genome
what do virueses need to grow in culture and what kind of media do they not grow on?
need hose cells to replicate
no growth on artificial media
what are three difference cell lines, what are they derived from and how long do they grow?
primary= derived from tissues, die after few generations diploid= developed from human embryos, grow for 100 generations continuous= transformed (cencerous) immortal cell lines (HeLa nad Vero cells)
what two things are viral culture determinants of and what are three examples?
infectivity and virulence of viruses
TCID50= tissue culture infectious dose: number of viruses required to cause infection in 50% cell culture
LD50= 50% lethal doae: number of microbes or amount of toxin required to cause terminal acute infections in 50% of animals infected
ID50= 50% infectious dose: number of microbes required to cause infection in 50% of the animals
what are other methods of detecting viruses? (4)
electron microscopy
fluorescent antibody staining
immunocytochemistry
virus induced cytopathic effects
what are 6 virus-induced cytopathic effects and what is an example?
changes in size and shape transformation (cancer) cytoplasmic inclusion bodies nuclear inclusion bodies cell fusion cell lysis Negri bodies in nerve cells from rabies virus infection = cytoplasmic inclusion bodies
what is a method to culture viruses and what are 3 uses for this method?
embryonated chicken eggs
virus isolation, identification & production of vaccines
what are 5 advantages and 2 disadvantages to using embryonated chicken eggs?
A: readily available & cheap, easy to maintain, sheltered from natural diseases, immature immune system= no defense against virus, different inoculation routes
D: use only specific pathogen free eggs, site of inoculation differs depending on virus type
what is candling?
method using a bright light behind the egg to study growth & development of embryo inside
what are 6 methods to detect viral infection in embryonic eggs?
mortality, deformity or haemorrhages in embryo lesions on the membrane (pocks) oedema of developing membranes inclusion bodies in embryo tissues presence of viral antigens in egg fluids haemagluttination assays
what is taxonomy, what are two methods and what are they based on?
science of naming, describing and classifying organisms
Baltimore’s classification (viral genome)
ICTV (genome, replication strategies, morphology)
what vaccine is available for adenoviridae?
CAV2-attenuated live virus strains cross-protect against CAV1)
what are 3 strains of Adenoviridae and what do they cause?
canine adenovirus 1- infecrious canine hepatitis
canine adenovirus 2- infectirous tracheobronshitis (kennel cough)
several adenoviruses- respiratory infections in cattle, sheep, goats , pigs , horses
what does CAV1 cause (4)
affects liver, kidneys, eyes and vascular endothelium
hepatitis & vasculitis
keratoconjunctivitis
potential fatal in pups
what is a characteristic of poxviridae, and what is a hallmark of infection?
cytoplasmic replication
presence of intracytoplasmic inclusion bodies
define pox, what do many poxviruses manifest as?
any of several viral diseases producing a rash of pimples that become puss-filled and leave pockmarks on healing
manifest as skin lesions
what is the genus of Fowl pox & pigeon pox?
Avipoxvirus
what is the genus of swine pox, and how is it transmitted?
Suipoxvirus biting louse (haematopinus suis)
what is the genus of rabbit myxomatosis?
Leporipoxvirus
what is the genus and species of squirrel fibroma and what species of squirrel are affected?
genus Parapoxvirus
species Squirrel parapoxvirus
red squirrels
what is the genus for goatpox, sheeppox, and bovine lumpy skin disease?
Capripoxvirus
what is the genus and species of ORF, what does it cause (5), in what species (2) what is a characteristic of a symptom and what is an important fact about the disease?
genus parapoxvirus speces Orf virus orf, scabby disease, contagious pustular dermatitis, thistle disease, sore mouth sheep and goat Iris-like lesion zoonotic
what is the genus and species of cowpox, what 2 species can it infect and what is an important fact about the disease?
genus orthopoxvirus
species cowpox virus
affects cattle and cats
zoonotic
what is the genus and species of small pox, what are two different variants of the virus and what do they each cause?
genus orthopoxvirus
species variola virus
major: mortality rate > 30%
minor: smallpox, red plague
what is vaccinia virus?
a weakened form in smallpox vaccine= cross-protective immune response
what is a concern with smallpox virus even though it is irradiated?
bio terrorism
what is the genus and species of monkeypox, what is an important fact about the disease, how is it transmitted and where is it found?
genus orthopoxvirus species monkeypox virus zoonotic transmitted to humans by rodents and direct contact with and animal's blood or through bite central and west Africa
what is a characteristic of parvoviridae?
linear ss DNA
what are 6 strains of parvoviridae and what do they cause?
human parvovirus B19: erythema infectiosum (5th disease) in children, polyarthropathy in adults
Feline panleukopenia virus (FVP): feline infectious enteritis in kittens with panleukopenia and cerebellar hypoplasia
mink enteritis virus (MEV): leukopenia dn enteritits in mink
Aleutian disease virus (ADV): fatal disease in mink & ferrets with splenomegaly, lethargy, bleeding, spontaneous abortion & death
goose parvovirus (GP) & Muscovy Duck parvovirus (MDP): gloose plague, hepatitis and Derzy’s disease. causes myocarditis, hepatisis & myositis
Porcine Parvovirs (PPV): reproductive failure with no maternal signs
what is the genus and species of canine parvovirus and what % fatal is it to puppies?
genus Protoparvovirus
species Canine parvovirus 2
80% fatal
what does parvovirus infections of the fetus (pig or cat) or newborn (dog or cat) result in?
widespread infection and tissue destruction= developmental defects
what is a classic syndrome of porcine parvovirus infection?
SMEDI syndrome:
stillbirth, mummification, embryonic death & infertility
what is a characteristic of herpesviridae?
latent infection
what are 7 species of herpesvirus, what disease do they cause and how are they transmitted?
suid: Aujezky’s disease & pseudorabies, nose-to-nost contact & aerosols
bovine: infectious bovine rhinotracheitis (IBR), nose-to-nost contact & aerosoles
Gallid (1 &2): Avial laryngotracheitis & Marek’s disease, aerosolized dust
Canine: hemorrhagic disease in puppies, airborne (sneezing)
Human (3- varicella zoster virus): chicknpox (varicells), direct contact & airborne transmission
Herpes simplex (1 & 2): cold sore & genital herpes, direct contact with lesions & fluids, sexual
human (4= Epstein- barr virus): infectious mononucleosis (kissing disease),, saliva, sexual, transplacentary
what is the typical symptom of IBR?
red nose
what are the two symptoms of Marek’s disease?
ocular lymphomatosis: lymphocyte infiltration of the iris, unequal pupils, blindness
cutaneous: swollen feather follices
what is a typical fact about symptoms caused by herpesvirus, and what is species-jumping virus mean, and why?
different symptoms depending of the virus type and host
species-jumping= not species specific
recombinant= genetic material of two different viruses
what is a characteristic of papillomaviridae, what are two forms of infection?
highly host and tissue specific
infections are asymptomatic or causing benign tumors (warts or papillomas)
lesions may become malignant
what are 2 strains of polyomaviridae?
Budgerigar fledgling disease polyomavirus (BFD)
simian polyamvirus S40 (SV40)
what does BDV and SV40 infect?
BFD: birds
SV40: cancer-causing monkey virus hidden in polio vaccines
what are 2 characteristics of hepadnviridae virus, what is a strain and what are two forms of disease?
partially ds circular DNA
reverse transcriptase
hepatitis B virus: acute or chronic
what is a special characteristics of the genome in Retroviridae and how is it replicated?
pseudodiploid genome= 2 identical linear + sense ss RNA strands
RNA is reverse-transcribed to DNA-intermediates and then inserted in host genome as provirus
what are the three important viral enzymes and what do the do?
reverse transcriptase
integrase: integration of viral DNA into host’s genome
RNA polymerase 2: proteolytic cleavage during virion maturation
what do retroviridae require for building the genetic material, what is an exception?
active cells
except Lentivirus: can integrate in non-dividing host cells
what diseases are retroviridae associated with (2)
immunodeficiency syndrome
cancer
define oncovirus and what % is associated with it worldwide?
any virus with DNA or RNA genome causing cancer
15%
define proto-oncogene
gene that encodes for proteins regulating cell growth and differentiation and that can become an oncogene
define oncogene
gene potentially causing cancer
what are two mechanisms of transformation for RNA viruses?
proto-oncogenes mistakenly incorporated into provirus
disruption of cellular proto-oncogenes (viral promoter triggers overexpression)
What is the genus and species of Avian Leukosis, what is its host, and what does it cause (2)?
genus Alpharetrovirus, species Avian sarcome leucosis virus (ASLV or ALV)
poultry
lymphoid leukosis and lymphoma (blood cell tumor from lymphocytes)
what is the genus and species of Enzootic nasal tumor, what are its hosts (2) and what does it cause?
genus Betaretrovirus, species Enzootic nasal tumor virus (ENTV)
sheep & goats
tumors in the nasal epithelium
what is the genus and species of Jaagsiekte, what are its hosts (2), what does it cause, and what are 2 key symptoms?
genus Betaretrovirus, species Jaagsiekte sheep retrovirus (JSRV)
sheep & goats
contagious lung cancer or ovine pulmonary adenocarcinoma
respiratory distress when you chase the animal and white sputum coming from the nose
what is the genus and species for Bovine leukosis, what is its host and what does it cause?
genus Deltaretrovirus, species Bovine Leukemia Virus (BLV)
cattle
enlargement of lymph nodes( retro-ocular profusion of conjunctival membrane)
what is the genus and species of Feline Leukemia, what is its host, how is it transmitted (2) and what does it cause, what is a common symptom?
genus Gammaretrovirus, species Feline leukemia virus (FeLV) feline transmission: nasal discharge or saliva immunosuppression of lymphomas, death white gums
what kind of infection is possible in feline leukemia and what is a risk factor for those infected?
infection in utero
asymptomatic carriers are risk to others
what is another name for Equine infectious anemea, what is the genus and species, what is the host, how is it transmitted, and what does it cause and what is an important fact of the disease?
swamp fever
genus Lentivirus, species Equine infectious anemia virus (EIAV)
equids
mechanical transmission through stable fly
anemia, thrombocytopenia, fever, weight loss, swelling of legs
USA reportable disease
what is the genus and species of feline immunofeficiency, what is its host, where is it an endemic, what disease is it closely related to, and how is it transmitted?
genus Lentivirus, species Feline immunodeficiency virus (FIV)
cats, endemis in African lions
HIV
transmission though bite injuries (saliva)
what cells does feline immunodeficieny infect (4) and what cause
infects CD4 T-sells, CD8 T-cells, B-cells, macrophages
Depletion of CD4 T-helper cells on the long term
viral infection attacks immune system-> anemia and low WBC counts-> secondary infections, cancer, neurological disease
how is FIV detected and controlled?
detection: presence of antibodies= seropositive
control: spaying or neutering cats
what are 2 characteristics of Rhabdoviridae?
bullet-shaped
negri body: eosinophilic, inclusion bodies found in cytoplasm of nerve cells infected by Rabies virus
what is the transmission of rabies and where is it present, what are 2 exceptions?
animal bite
present in all countries except for Australia and Antarctica
what is the genus and species for rabies, what are its hosts (4), where does it replicate and shed, and what is the pathway of the infection?
genus Lyssavirus, species Rabies virus
host: dogs, cats, bats, mongooses
virus replicates and sheds in saliva
animal bits-> initial replication in muscles-> transport through peripheral nerves-> CNS= neuronal infection
what is the speed of infection, incubation and 3 phases of disease after it reaches the brain?
slow-moving virus
incubation: 3-8 weeks
prodominal, furious, paralytic
what is the time frame of the prodomal phase and what are the symptoms? (5)
2-3 days
nervousness, anxiety, solitude, different behavior, licking of bits site
what is the time frame of the furious phase and what are the symptoms? (5)
1-7 days
restless, irritable, hyperresponsive to visual and auditory stimuli, roaming, disoriented
what are the symptoms of the paralytic phase? (5)
salivate (inability to swallow), deep labored breathing, paralyzed facial muscles, respiratory failure, death
how is rabies detected?
direct fluorescent antibody test to look for presence of the virus in brain tissue
what is a characteristic of orthomyxoviridae, how many genera are there, and what are the 3 main genera defined by?
envelope with spikes, release by
seven genera
defined by antigenic differences in nucleoprotein and matrixprotein
what are the envelope spikes called for orthomyxoviridae and what are the 2 types?
glycoprotein spikes
NA=neuraminidase= N
HA= haemagglutinin= H
what are the 3 main genera of orthomyxoviridae, which one causes a pandemic and who do they infect?
influenza virus A: humans, birds, mammals (flu pandemics)
influenza virus B: humans, seals
influenza virus C: humans, pigs, dogs
what are inflenza A virus subtypes defined by, and what is the most deadly subtype?
defined by H & N spikes
H1N1
define reassortment
mixing of genic material of species into new combinations, resulting in a reassortant virus
define antigenic drift
small changes in the genes that happen continually over time as the virus replicates (influenza A, B)
what are two characteristics of antigenic drift?
closely related viruses share antigenic properties= cross-protection
accumulation of changed overtime= immune system no longer recognizes the virus
define antigenic shift
abrupt, major genetic changes in influenza A viruses, resulting in a new HA and/or new NA protein= new influenza A subtype
what subtypes of influenza virus causes swine flu, how is it transmitted and how can spread to human be prevented?
influenza A (common) & C virus (rare)
transmitted via direct contact (virus survives up to 3 months in pigs)
prevent spread to humans with vaccination of pigs and sanitary control
what is a characteristic of filoviridae, and what type of infection does it cause?
pleomorphic of filamentous cytopathic infection (structural changes) in cultured cells and in target organs of host
what is the genus of Ebola, what does it cause, what is the fatality rate, when did an outbreak occur and what is the pathway of infection?
genus Ebolavirus haemorrhagic fever fatality rate 50-90% outbreak 2014-2016 infection of monocytes-> release of cytokines-> endothelial injury-> haemorrhage
what is the genus of Marburg Haemorrhagic fever, what does it cause, who is at risk and how is it transmitted?
genus Marburgvirus
haemorrhagic fever in humans and non-human primates, bleeding all over the body
risk: hospital staff, vets, travelers, close contact to fruit bats and non-human primates
transmission animal to human: bat fecea and aerosols
transmission humans to human: direct contact body fluids
what are 2 methods to prevent human disease from Marburg?
barrier nursing techniques= prevent direct contact
awareness
what is a characteristic of reoviridae, and what does REO stand for?
linear ds RNA,
Respiratory Enteric Orphan
what is the genus and species of Bluetongue, how is it transmitted, what is its host and what does it cause?
genus Orbivirus, species Bluetongue virus
transmission: arthropod bite
host: sheep
acute disease with high morbidity and mortality in susceptible breeds, but non-contagious
torticollis= “dancing disease”
what is the genus of Viral diarrhea, how is it transmitted, what is its host (3) and why does it cause economic losses?
genus Rotavirus
transmission: fecal-oral
host: children, infants, young of many animals
economic losses due to rota viral enteritis in intensively-reared piglets and calves
what is a characteristic of Paramyxoviridae?
non-segmented, one serotype= long term immunity
what is the difference between Orthomyxo and paramyxoviruses?
ortho: segmented genome allows for antigentic shift
para: non-segmented, one serotype= long term immunity
what diseases does Paramyxoviridae cause in humans (2) and animals (3)
humans: measles, mumps
animals: canine distemper, rinderpest, newcastle disease
what is the genus and species of canine distemper, what parts of the body does it attack (3) what are its hosts (2)?
genus Morbillivirus, species Canine distemper virus
attacks respiratory, GI and nervous system
hosts: canines and other carnivores
what are the symptoms of canine distemper (9) and what is another name for the disease based on an identifying symptom?
fever, loss of appetite, vomiting, nasal discharge, coughing
circling, muscle twitched, seizures, convulsion
hardening of food pads= hard pad disease
what is the genus and species of Rinderpest, what is its host, what 3 symptoms is it identified with, what virus emerged from it and what is an important fact about the virus?
genus Morbillivirus, species Rinderpest virus host: cattle 3 D's: dead, discharge, diarrhea measles global eradication
what is the genus and species of Newcastle Disease, what is its host, what are 7 symptoms?
Genus Alvulavirus, species Newcastle disease virus
host: birds
gasping, coughing, depression
muscular tremors, swelling of tissue around eyes & neck, torticollis
reduced egg production & misshapen eggs
what is a characteristic of Coronaviridae?
envelope with peplomers (petal-shaped spikes),
what is the genus and species of Feline infectious peritonitis (FIP), what are 2 forms of the virus and what is its transmission?
genus Alphacoronavirus, species Feline coronavirus (FCoV)
2 forms: Feline Enteric Cronavirus (FECV) & FEline Infectious Peritonitis virus (FIPV)
transmission: fecal-oral (shelters)
what are two diseases of FIP and what are characteristics of each?
Dry/non-effusive FIP: loss of appetite, weight loss, yellowing inside eyes, iris color change, 15% neurological signs
Wet/ effusive FIP: damaged and leaking blood vessels, Ascites, difficult breathing
what is the genus and species of Severe Acute Respiratory Syndrome (SARS), what are its symptoms and when was it first recorded in humans?
genus Betacoronavirus, species SARS coronavirus
initial flu-like symptoms: fever, headache, muscle pain
14 days: respiratory symptoms dyspnea, pneumonia
outbreak in China in 2002
what is a characteristic of Flavivirdae, what does Flavus mean, how is it transmitted?
surface proteins organized in icosahedral-like symmetry
flavus= yellow
transmission via vector (mosquitoes, ticks)
what is the genus and species of west nile fever, what is its natural host, what can it cause in humans and in horses?
genus Flavivirus, species West Nile virus
host: birds
humans: fatal neurological symptoms
horses: severe disease or death
what is the genus and species of Bovine Viral Diarrhea (BVD) what effect does it have (2) what does an infection of susceptible dam result in?
genus Pestivirus, species Bovine viral diarrhea virus
immunosuppressive effect
direct effect on respiratory system & fertility
persistent infected fetus
what form of BVD causes disease and what is the disease?
cytopathic BVDV
fatal mucosal disease
what is the genus and species of Zika fever, what are the 5 sympoms and how is it transmitted (2)?
genus Flavivirus, species Zika virus
fever, red eyes, rash, joint pain, headache
transmission: day-time active mosquito, sexually
Togaviridae: what are 2 genuses, how are they transmitted and what do they cause?
hosts: humans, mammals, birds, mosquitoes
Genus Rubivirus: respiratory transmission, congenital rubella
Genus Alphavirus: arthropod bite, Eastern equine encephalitis, Chickungunya
define arbovirus, how are they maintained in nature, what is an important fact about them and what are its 3 hosts for maintenance?
arthropod borne virus= virus that replicates in and is transmitted by arthropods
maintain in nature by going through a cycle between a host and a vector
zoonotic
maintenance enzootic cycle in birds, rodents, non-himan primates
define enzootic and epizootic
enzootic: endemic in animal population
epizootic: epidemic outbreak of a disease in animal population
Picornaviridae: what is important about its cell tropism?
cell tropism: different viruses that attack different cells
what are Picornaviridae’s 4 different cell tropism species and where do they infect?
Enteroviruses: GI tract (Rhinovirus- common cold)
Aphtoviruses: epithelium
Hepatoviruses: liver
Cardioviruses: GI tract primary, then heart and CNS
what is the genus and species of foot and mouth disease (FMD), what are its 4 hosts, how its it transmitted, what are 3 symptoms and what 3 continents are it endemic in?
Genus Aphtovirus, species Foot and Mouth virus
host: pigs, cattle, sheep, goat
transmission: via excretions and secretions of infected animal
symptoms: high fever, blisters in mouth and feet, high mortality in young animals
endemic: Africa, Middle East, Asia
what is the genus and species of Poliomyelitis, what is its host, how is it transmitted, what is the progression of the infection and how does its speed of replication affect the immune system?
Genus Enterovirus, species Poliovirus
host: humans (young children)
Transmission: fecal-oral
multiplies in intestines-> viremia-> CNA-> deformations
very rapid replications= overwhelms the immune system
what are 3 genuses of Caliciviridae, how are they tranemitted and what do they cause in what animal?
genus Vesivirus: airborne transmission (cats)-> respiratory disease
genus Lagovirus: direct contact (rabbits)-> haemorrhagic disease
Genus Norovirus: fecal-oral (humans, mammals)-> acute gastroenteritis= very contagious
what is the genus and species of Feline calicivirus, what does it cause, what kind of infections are possible and what are 4 symptoms?
genus Vesivirus, species Feline Calicivirus
respiratory infection in cats
latent infections possible
sneezing, nasal discharge, stomatitis, pneumonia
define viral pathogenesis and viral disease
pathogenesis: the entire process by which a viral infection leads to disease
disease: effect on host of viral replication + immune response
what are the 4 pathogenic mechanisms of viral diseases
implementation of virus at portal of entry
local replication
spread of target organs
spread to sites to facilitate virus shedding
what are 6 influencing factors on infection cycle?
virus species viral tropism cell susceptibility virus susceptibility to host immune system host species host immune response
what are 3 requirements for successful infection?
sufficient virus
cells at site of infection must be accessible, susceptible, permissive
local host-anti-viral defense mechanisms must be absent or initially infective
what are the 2 most common routes of entry?
mouth/nose
lungs
define dissiminated virus infection
when spreading beyond primary state of infection
define systemic infection
when many organs of the body as a whole becomes infected
define local spread
newly released virions infect adjacent cells
define hematogenous spread and what are 4 types?
lymphatic system and blood
passive, active, primary, secondary
define neural spread
virus transported over long distances because no protein synthesis in the extended processes of neuronal cells
define neurotropic virus and what is an example?
can infect neuronal cells (neuronal or hematogenous spread)
herpes
define neruovirulent virus and what is an example?
can cuase disease within nervous system
rabies
define incubation period and what can it be used for?
time from the moment of virus infection till the symptoms of the disease appear
essential for investigation and control of viral diseases
define immune system
a complex network of cells, tissues, organs & metabolic responses
what is the simple mission of the immune system?
seek and kill invaders and thus protect the host
what are two forms of immunity, are they specific or non-specific and when do they appear?
innate: non-specific, constantly present
adaptive: specific, develops after virus exposure
what are 6 cells involved in innate immunity, 2 that are in adaptive immunity, and 2 that are in both?
innate: macrophage, NKC, dendritic cell, neutrophil, eosinophil, basophil
Adaptive: B & T cell
both: T cell & NK T cell
what are the 3 lines of defense against infection?
1: chemical & mechanical barriers, reflexes
2: innate immunity
3: adaptive immunity
what are 2 forms of recognition of innate immune system?
pathogen
infected cell
what is pathogen recognition in innate immune system?
recognition of pathogen associated molecular patterns (PAMPs) by pattern regonition receptors (PRR) on immune cells such as macrophages and dendritic cells
binding of PRRs & PAMPs trigger the release of what, what are 2 examples and what is the result (2)?
cytokines (chemical messengers)
interleukines & interferons
inflammation occurs & more immune cells are recruited or phagocytosis
what is infected cell recognition in innate immunity and what is the result?
NK cells recognize altered expression of MHC 1 molecules on the curface of virus infected cells
production of destructive proteins= apoptosis
what causes apoptosis?
changes in cell morphology
what are two forms of adaptive immunity, what type of cells to they activate and what is the result?
cellular: helper T cells-> cytotoxic T cells= apoptosis of infected host cells: B cells -> plasma cells -> antibody production= memory
define acyclovir
inhibits viral DNA replication without affecting host cell processes
define interferon
inhibits translation of viral RNA into protein
define immunoproflyaxis
prevention of disease by the production of active or passive immunity
define vaccination
the process of stimulating protective immune responses in animals against pathogenic viruses by exposing them to non-pathogenic forms or components of the virus
what are 3 types of virues?
live attenuated
inactivated
recombinant
define live attenuated vaccines
viable virus with reduced virulence
define inactivated vaccines
killed virus particles
define recominant vaccines
protein antigens induce immuneity against the virus
define adjuvants
formulations added to vaccines to improve their immunogenicity
potentiate immune responses to antigen and/or modulated towards desired immune response
