Virology 1 Flashcards
Family Poxviridae what is the main sub-family and characteristics
Chordopoxvirinae
- pox viruses of vertebrates
Poxviridae pathogenesis of the lesion and where find
Typical “pock” lesion
1) Begins as a raised, reddened macule
2) Progresses to form a papule
3) Becomes a fluid filled vesicle
4) Ruptures to form a crater (pock)
5) Scarring - if survive life-long
- Clinical signs referrable to skin lesions in localised disease, or to organ damage in generalised disease (such as sheeppox)
Poxviridae features in environment, carriers, duration of immunity
- Pox viruses are very resistant in the environment - envelope but large and sturdy envelope
- Infectious virus survives for years in infected material (scabs)
- Surviving animals are NOT long term carriers
- Duration of immunity < life span of recovered animal - possible for life with new research
○ Generally older animals are protected as exposed as young animals, so mainly see in younger animals as the environment becomes a carrier - Reinfection possible
Poxvirus transmission between animals may be, list the 3 types
1) Via abraded skin - skin lesions
2) Respiratory route by droplets - in outbreak situation in close proximity
3) Mechanical transmission - vectors, skin lesions
Orthopoxvirus what is the family within and List 4 viruses within
Poxvirus -> Chordopoxvirinae -> Orthopoxvirus
1) Smallpox virus - major cause of human morbidity and mortality
2) Vaccinia virus
3) Cowpox virus
4) Monkeypox
Monkeypox what type of virus what are the hosts involved, what type of disease
Poxviridae
- transmitted through primates including humans, rodents are also hosts
- Is an emerging disease, wasn’t such an issue when the smallpox vaccination was circulated as some cross-protection, now herd immunity is low so monkey pox is attacking mainly younger children and generations
Capripoxvirus what type of virus, what are the 3 diseases
Poxviridae
• Sheeppox
• Lumpy skin disease
• Goat pox
Sheeppox, goatpox, lympy skin disease what type of virus, where present, what type of spread
Capripoxvirus
- Endemic in SE Europe, Middle East, Africa and Asia
- Endemic: generalised disease and mortality uncommon
- In outbreaks can get respiratory spread, systemic disease - more serious clinical signs
Sheeppox, goatpox, lympy skin disease what type of virus and pathogenesis
- Virus shed from skin lesions and nasal/ocular discharge
○ Infection via skin abrasions or inhalation of aerosols - Replicates locally in skin
- Replicates in lungs following inhalation
- Spread to regional lymph nodes
Sheeppox, goatpox, lympy skin disease what type of virus clinical signs and mortality
Capripoxvirus Clinical Signs - Incubation period ~ 1 week - Fever, oedema of eyelids, conjunctivitis and nasal discharge - Skin lesions - (Lung consolidation and haemorrhage - with larger outbreaks and repsiratory transmission Mortality: - Up to 50% in indigenous breeds - Up to 100% in European breeds
Molluscipoxvirus and
Avipoxvirus what type of virus and importance
- Molluscipoxvirus - significantly zoonotic
* Avipoxvirus - Fowlpox virus and other avian pox viruses- Used as a vector for vaccines such as equine influenza
Fowl pox what type of virus and the 3 transmission
1) Mechanical transmission by mosquitoes
2) Physical touch - skin abrasion - remain infectious in scab material for a long time
3) Aerosol transmission
Parapoxvirus what type of virus, what are the 3 also calld
Poxviridae -> Chordopoxvirinae
1) Orf virus (scabby mouth)
2) pseufocowpox virus
3) bovine papular stomatits virus
Orf (Scabby Mouth) where occur, what does it lead to and transmission
• Occurs worldwide • (Contagious pustular dermatitis) • (Contagious ecthyma) Pathogenesis • Epitheliotropic virus • Proliferative wart‐like lesions Replicates in epidermal keratinocytes • Papular lesions progress to vesicles, pustules and then scabs • Lesions heal within 4 weeks (if no secondary bacterial infection)
Orf (Scabby Mouth) epidemiology and control
Epidemiology
• Transmission via abrasions
• Primarily a disease of young sheep
• Maintained in flocks by chronic carriers
• Lesions on lips and muzzle (feet, genitalia and teats)
• Can be zoonotic
Control
• Virulent vaccination
• Scarification of axilla of ewe prior to lambing - scratch into skin
What is the main virus in Leporipoxviruses, host and disease
Myxomatosis
• Poxvirus disease of rabbits
• Causes benign fibromas in wild rabbits but severe generalised disease in european rabbits - highly fatal 90% often within 48 hours
•
Was the biological control of Myxomatosis a success or fail
Success - dramatic decrease in numbers of rabbits and maintained at this lower level, also still killing rabbits today
Fail - getting increased genetic resistance and now using calicivirus instead
Family Asfarviridae what type of genome, features, how long survive and the main disease
• Complex double stranded DNA virus
• Enveloped
• Stable in environment over wide range of temperatures (4‐20oC) and wide range of pH
• May persist for months in meat of infected pigs
African swine fever virus
African swine fever virus within what family, what infect, mortality and control
Family Asfarviridae
• Infect only Suidae (all members tested) and soft ticks
Mortality/control
• Die of extensive haemorrhages due to platelet damage and complement activation ‐haemorrhage in all organs, lymph nodes resemble blood clots
• Survivors may be normal or chronically ill ‐ all are carriers
• No neutralizing antibody produced
• No vaccine
• Risks of international spread ‐ live pigs, pig meat, food scraps
Herpesviruses common characteristics, what length of infection
• Enveloped double stranded DNA
• Labile in environment - FRAGILE
○ Easily inactivated by heat,
○ detergents, pH, drying
• Close or mucosal contact for transmission (droplet)
• Lifelong latent infection, remain dormant
What does the envelope on the virus initiate
Envelope - doesn’t provide protection
- Does provide glycoproteins needed to initiate infection and disease
- Also attachment - start of the virus life-cycle
Describe the latency of Herpesviruses
• Persistent infection with continuous or periodic shedding
• Copies DNA in infected cells (often neurons)
• No viral gene expression
○ Generally doesn’t cause large amounts of disease unless immunocompromised • Reactivation during periods of stress leads to shedding (source of virus)
○ May be sub‐clinical - due to pathogen host relationship
○ Recrudescent disease - rival of the infection and disease
What are the 3 sub-families of herpesviridae and which is the one with horses
1) Alphaherpesvirinae
2) Betaherpesvirinae
3) Gammaherpesvirinae - equine herpes virus 1 and 2
Bovine herpesvirus 1 what are the 7 general clinical disease it leads to
1) rhinotracheitis
2) vulvovaginitis
3) balanoposthitis
4) conjunctivitis
5) abortion
6) enteritis
7) generalised disease of newborn calves
Rhinotracheitis clinical signs list 5, how long to recover and major issue
• Nasal discharge • Hyperaemic nasal mucosa • Dyspnoea • Coughing • Recover within 5‐10 days PROBLEM - Predispose to other bacterial secondary infections
Vulvovaginitis Clinical signs list 4 and how spread
• Frequent micturition • Swollen vulval labia • ± vulval discharge • Hyperaemic vestibular mucosa with pustules CAN GET SPREAD VIA GENITAL ROUTE as well
Bovine herpesvirus 2 what also called and two forms of clinical diseases
Bovine mammillitis virus (Pseudo‐lumpy skin disease virus)
- Causes a two forms of clinical diseases
1. Mammillitis. Lesions localised to the teats.
2. Generalised skin lesions. Nodules & necrosis of the superficial epidermis - Looks like lumpy skin which is an important trade disease
Bovine herpesvirus 5 what also called and what does it called
Bovine encephalitis virus
- Causes fatal meningoencephalitis in calves thought to be due to direct neural spread from nasopharynx via trigeminal nerve
Equine herpesvirus 1 EHV1 how is it present in the population, what animals most at risk, general disease, infection via
- Most important viral cause of abortion in horses worldwide - group at risk are pregnant mares
- Endemic in all horse populations - not going to prevent infection of foals just want to prevent pregnant mares from having the activation of latent or getting activated virus
- Causes respiratory disease, abortion and neurological disease
- Infection via respiratory tract
EHV1 abortions what signs, when occur and what are the 2 causes
- No premonitory signs
- Usually late gestation - last trimester
- Most commonly a single abortion
- Outbreaks occur when index case is poorly managed
Caused by: 1. Mare gets infected from other mare 2. latent infection in mare becomes active leading to abortion - The aborted foetus has extremely high levels of virus, need to keep other horses away
List 2 control mehtods to minimise risk of EHV1 abortions
1) Pregnant mares be kept separate from other horses - can have in other horses not high risk
2) Small groups based on foaling date - decrease risk of abortion via exposure to virus
○ If one mare aborts separate down into smaller groups to further decrease risk of exposure if possible
EHV1 Epidemiology how long is aborting mare infectious
- Aborting mare is infectious for 1‐2 days from reproductive tract and up to 2 weeks from the respiratory tract - need to separate from every other horse
○ Latent infection (as are many others in the herd) - if wasn’t already infected (likely)
○ Breed again on first oestrus after foal heat)
What are the spreads of disease in EHV1
- Mare to foal spread - pre-weaning
○ Colostrum or aerosols - Foal to foal spread - pre-weaning
- Foal to foal spread - post-weaning
Equine herpesvirus 4 what also called, what disease, cause, what age most susceptible and control
Equine rhinopneumonitis
- Causes acute respiratory disease characterised by nasal discharge and lymphadenopathy
- Foals infected early in life
- Weanlings and yearlings show most severe clinical signs
Combined EHV1 and EHV4 vaccine available
Feline herpesvirus 1 what also called, what disease cause, when seen and control
- Causes acute respiratory disease characterised by nasal discharge, ocular discharge, sneezing, dyspnoea and occasional oral ulcers
- Seen most frequently in multi‐cat households and catteries
○ Infected by activated virus within a latent adult, kittens haven’t developed immunity yet - Inactivated and live attenuated vaccines available
Gallid herpesvirus 1 what also called, host, what leads to
Infectious laryngotracheitis (ILT)
- Most common in young chickens (although all ages susceptible)
- Causes acute respiratory disease characterised by nasal and ocular discharge, sneezing, dyspnoea, loud gasping and coughing
Family Adenoviridae what type of disease, what type of virus and host range
- Respiratory and gastroenteric disease
- Mild or sub-clinical in most cases
- dsDNA viruses
- Non-enveloped - more stable in environment
- Narrow host range
What is the main genera in family adenoviridae
1) Mastadenovirus -