Module 5: Zoonotic Influenzas Flashcards
Which influenza virus is most likely to be transmitted zoonotically?
Influenza A virus
What is defined as a family of negative-sense RNA viruses?
Orthomyxoviridae
What type of influenza virus is the following describing?
- Infect birds and other animals as well as humans
- Are a source of seasonal influenza epidemics and all pandemics
A virus
What type of influenza virus is the following describing?
- Infect humans only (maybe) and do not cause pandemics (can cause epidemics, but generally less severe than “A”)
B viruses
What type of influenza virus is the following describing?
- Infect humans and swine and DO NOT cause pandemics
- Usually cause only mild disease
C viruses
What type of influenza virus is the following describing?
- Identified in swine and cattle. Other species??
D viruses
This is describing:
- (-) Stranded RNA Virus (mutate, no proof reading mechanism)
- lipid Enveloped pleomorphic virus (susceptible to disinfectants)
- Segmented Genome
- Hemagglutinin (18) and neuraminidase (11) are the major surface proteins
Influenza A virus
The endemic infections of the influenza A virus are mostly seen in:
- Humans
- Birds (wild and domestic)
- Pigs
- Horses
- Dogs
The sporadic infections of the influenza A virus are mostly seen in:
- Whales
- Seals
- Mink
- Camels
- Ferrets
- CATS
Influenza A Virus
Minor antigenic changes over time due to point mutations
- Negative sense RNA virus
- RNA-dependent RNA polymerase
- No proof-reading during replication
Antigenic Drift
Influenza A Virus
Major antigenic changes due to genomic reassortment
- Segmented Genome
- When one cell is infected by multiple influenza A viruses, gene segments can be shuffled
Antigenic shift
Which is the best way to describe the concept of antigenic drift as it applies to influenza viruses?
Antigenic drift is the result of accumulating point mutations in the RNA segments of the influenza virus coding for HA and NA
Which of the following reservoir species of influenza A virus maintains the greatest variation in HA-NA combinations resulting in the greatest diversity of virus subtypes?
- Pigs (swine influenza)
- Horses (equine influenza)
- Dogs (canine influenza)
- Humans (seasonal influenza)
- Birds (avian influenza)
Birds (avian influenza)
Pandemic influenza occurs when a new strain of influenza emerges where:
- there is little or no immunity to the virus in the human population
- the virus is able to spread efficiently from person to person
(a pandemic virus may cause mild to severe disease)
(T/F) Wild birds are considered to be the primary reservoir for influenza A viruses
True
Aquatic birds generally do not show any clinical signs of infection, but where do viruses replicate and shed into the environment?
Intestinal tract
Disease in domestic poultry
____________ pathogenic viruses cause severe disease in domestic poultry and can cause mortality rates of up to 100% in affected flocks
Highly
Disease in domestic poultry
____________ pathogenic viruses generally cause decreased egg production or mild upper respiratory disease in domestic poultry and do not typically cause death
Low
Influenza A viruses cause outbreaks of respiratory disease in __________ herds
swine
(T/F) Although mortality is relatively low, equine influenza spreads rapidly, can result in extended recovery time for infected animals, and can significantly harm equine populations, especially in the racing industry.
True
- Is a recently recognized and emerging respiratory disease in dogs
- It was initially recognized in racing greyhounds and is now endemic in certain areas of the United States.
Canine Influenza
What is considered to be the primary natural reservoir of influenza A viruses, but various subtypes have become established in different species, including humans, swine, horses, and dogs?
Wild birds (especially wild waterfowl)
(T/F) While most influenza viruses are species-specific, the transmission of viruses from one species to another can occur
True
Interspecies transmission can result in the formation of novel _________ or ___________ viruses
pandemic, panzootic
