Herpesviridae Flashcards
Bovine
Bovine herpesvirus type 1
- iBR: encephalitic, respiratory, reproductive forms
Bovine herpes virus type 2
- mammillitis
Bovine Herpesvirus type 3
- malignant catarrhal fever (american and african form)
Porcine
Pseudorabies virus
- Aujeszky’s disease: swine, respiratory, fetal death, abortions, mummies, high mortality in young
- highly fatal pruritis, paralysis in dogs, cats, ruminants, raccoons, rabbits, birds
Pseudorabies virus does not infect _____ or ______
Humans or horses
Equine
Equine herpesvirus type 1 - rhinopneumonitis (respiratory, reproductive) Equine herpesvirus type 2 - pharyngitis of young horses Equine herpesvirus type 3 - coital exanthema Equine herpesvirus type 4 - rhinopneumonitis (respiratory, reproductive)
Canine
Canine herpesvirus
- fatal hemorrhagic disease of pups
Feline
Feline viral rhinotracheitis
- URT disease
Feline herpesvirus 1
Feline urolithiasis virus, feline herpesvirus 2
- experimental, urolithiasis resulting in uremia
Avian
Infectious laryngotracheitis virus - URT disease - bleed to death in the trachea Marek's disease virus - oncogenic, neural, ocular, visceral lymphomatosis Duck plague virus - enteric, respiratory, CNS Herpesvirus infection of pigeons - coryza, laryngeal and pharyngeal ulcers
Human, primates
Herpes simplex virus type 1 - oral blister Herpes simplex virus type 2 - genital blisters - reportable! Herpes zoster - chicken pox, shingles Epstein barr virus - mononucleosis, chronic fatigue syndrome, oncogenic Herpes simiae "B" virus - old world monkeys: epithelial blisters - humans: fatal encephalitis
Fish
Channel catfish virus
- mortality in young fish
Herpes vaccines are available for
- bovine
- porcine
- feline
Humans zoster is a genetically modified form of ______
Porcine
What is the difference between types 1 and 2?
DNA dependent polymerase operates and different temperatures
What step of viral replication causes viral eclipse?
Uncoating
- no evidence of viral particle can be seen in transmission electron microscopy
Recrudescence
Re-establishment of productive infection
- viral particles are produced
Release
Results in cytocidal infections or persistent or oncogenic infections
DNA characteristics of herpesvirus
Double stranded, linear, positive sense, single segment
Virion
- enveloped
- icosahedral
- 162 capsomeres
Nucleic acid
80-150x10^6 molecular weight
- can produce >20 proteins
Where does budding occur?
At the inner lamella of the nuclear membrane
Herpesvirus can occur in which host type?
Warm, cold blooded, and invertebrate animals
- >500 known herpesviruses
Some herpesviruses are ______
Neoplastic
- oncogenic
Transmission
Primary contact with a moist mucosal surface
- transplacentally, intrapartum, lactogenic, transfusions, transplants, air, and water
Many herpesviruses cause ______ infections
Fetal
- type of placentation makes no difference
- fetal or embryonic deaths occur
- MLV vaccines cause abortions in all animals
Alphaherpesvirinae
- host range: variable in vivo and in vitro
- reproductive cycle: short
- CPE: rapid spread leading to mass destruction of cells
- latency: frequent, no exclusively in ganglia
Betaherpesvirinae
Ex: feline urolithiasis virus
- host range: narrow in vivo, species specific
- repro cycle: long
- CPE: slow, progressive lytic foci, cytomegalia, IC and IN inclusions
- latency: in epithelial glands of secretory glands, RES, kidney, salivary and adrenal glands
Gammaherpesvirinae
Ex: EBV, MCF, MDV
- host range: in vivo is limited to taxonomic orders, in vitro is limited to lymphoblastoid cells (B and T cells)
- repro cycle: variable
- CPE: variable
- latency: frequent in B and T cells
Herpesvirus latency occurs following _______
Uncoating of virus in cells
Why does viral recrudescence occur?
- fever
- concurrent infection
- stress (affective and physical)
- UV radiation
- immune suppression
- drug therapy
Episome formation
Small, circular closed pieces of DNA that are not inserted into host chromosomes
- creates sticky ends so gene exists as a plasmid
What is needed for viral recrudescence and pathogenicity to occur?
Thymidine kinase
- TK negative cell lines do not show CPE
Insertion into host chromosome
Occurs at germ line, resulting in somatic cell oncogenesis and teratogenesis
- requires restriction endonuclease enzyme that cleaves DNA at palindromic sequences = sticky end exposure
Primary infection by HSV-1
Clinical symptoms in peripheral and CNS, URT, and GIT
- leading cause of corneal blindness
- BHV-1 similar biological properties
Latency of HSV-1 and BHV-1 is established in _______
Sensory neurons of trigeminal ganglia
LAT and LR gene
Responsible for latency in HSV and BHV
- inhibit apoptosis
- viral transcripts that are abundantly transcribed in latency infected neurons (regulate latency)
Chromosomal changes
Mitotic mechanism defects - nucleolar persistance: herpes - change in number: reovirus and parvovirus Chromosome breaks - chromatid - chromosome - puverization: SV40, parvovirus
Organogenesis
Development of organs in the fetus
- stage of gestation most susceptible to malformations
What type of congenital infection occurs only with persistent infection of germinal epithelium?
Trans-ovarian
Morula infection
Occurs thru endometrial secretions
- receptors are changing/developing at this stage
- zona pellucida is not present
- important for international trade!
- can be infected by herpes, blue tongue, parvo, paramyxoviruses
Semen
All viruses found in seminal fluids
- only retroviruses infect sperm cells
Why is the placenta not an effective barrier to viruses?
Numerous distended intracellular spaces
