Orthomyxovirdae and Bunyavirdae Flashcards
Orthro =_______
myxo= _______
viridae= ______
direct, muocus, virus
General properties of Orthomyxoviridae
*____________, usually _______ but can be filamentous
* 80-120 nm in diameter
* Genome: - _________, (____ ve sense ____ stranded RNA)
* - ______ genome, encapsidated by nucleoprotein (NP)
- 7-8 segments coding for 11 proteins
* -genome total size is 13.5Kb
* Three types of influenza viruses: A, B, and C
* Only influenza ___ viruses are classified by subtype
main surface glycoproteins
-Hemagglutinin (HA)
-Neuraminidase (NA). eg H1N1
Enveloped, rounded, segmented, -, single, linear, A
Orthomyxoviridae
Label accordingly
General properties of Orthomyxoviridae cont…
* Humans can be infected with influenza types ?
* Animals can be only infected with influenza type ___
* Subtypes of influenza A that are currently circulating
among people worldwide include (?) viruses
* 16 distinct _______ H1 to H16
* 9 distinct _________ N1 to N9
* The host immune response is directed against the ___ & __
* _______ ______: -natural host for all known subtypes of
influenza A viruses; do not become sick when they are infected with avian influenza A viruses
* ________ poultry, such as ______ and ______, can
become very sick and die from avian influenza
A, B, and C viruses
A
H1N1, H1N2, and
H3N2
Hemagglutinins
Neuriminidases
H, N
Wild birds
Domestic, turkeys, chickens
Name the genera within the family Orthomyxoviridae
Classification regimen of influenza viruses
* Type A, B or C/place isolated/number of isolate/year isolated
* In the case of influenza A, also: HA subtype (H) and NA subtype (N)
* For example, the three strains for the 2007/2008 vaccine are:
-A/Solomon Islands/3/2006 (H1N1)
-A/Wisconsin/67/2005 (H3N2)
-B/Malaysia/2506/2004
What is the host range of influenza viruses?
Pay attention to the overlap
Influenza virus surface antigens (HA and NA)
Replication cycle of Influenza virus cont
Describe the replication cycle of the influenza virus
Infection of host cells with the influenza virus is mediated by specific interactions between the viral __________ (HA) and cell oligosaccharides containing _____ acid (SA) residues
Avian and human influenza viruses bind to ?
haemagglutinin, sialic, alpha-2, 3 and alpha-2, 6 sialic acid-linked receptors, respectively
What is the difference between Orthomyxovidae and Paramyxovidae?
Transmission and symptoms of seasonal Influenza
- Chills
- Body aches, especially throat and joints
- Coughing and sneezing
- Extreme fever
- Fatigue, headache, and nasal congestion
*** Though similar symptoms occur with a
cold, they are much more severe with the
flu!
Describe influenza antigenic changes
- Swine influenza common strains (3?)
- _______ virus circulated in 1957-1967
- ______ virus appeared in 1968 and completely replaced the H2N2 virus
H1N1, H1N2, H3N2
H2N2
H3N2
Where does influenza A virus come from?
Ecology, maintenance, and spread of H5N1 viruses
What is an influenza pandemic?
* Influenza pandemics are worldwide epidemics of a
newly emerged strain of influenza
* Few, if any, people have any immunity to the new
virus
* This allows the new virus to spread widely, easily,
and to cause more serious illness
* Pandemics occur when a new avian influenza strain
acquires the ability infect people and to spread
easily person to person
* This can occur in two ways:
– Reassortment (an exchange of seasonal and
avian influenza genes in a person or pig infected
with both strains)
– Mutation (an avian strain becomes more
transmissible through adaptive mutation of the
virus during human avian influenza infection)
Two cocirculating subtypes of swine influenza virus are endemic in pig population: ?
* Infection of the swine influenza virus is limited to the?
H1N1 and N3N2, respiratory tract
See study guide for viruses
The 2009 H1N1 and the H3N2 viruses : high levels of resistance to ___________ and ___________
amantadine, Rimantadine
Control of influenza virus
* Influenza vaccines are available for pigs, horses, dogs and, in some countries,
birds
* The vaccines do not always prevent infection or virus shedding, but the disease
is usually milder if it occurs
* Influenza vaccines may change periodically to reflect the current subtypes and
strains in a geographic area.
* In general, swine and equine viruses display less antigenic drift than human
viruses, and these vaccines are changed less often.
Prevention & Treatment of the Flu
* Get the flu vaccine each year due to high mutation rate of
the virus.
* Practice good hygiene and personal health habits.
* Cover your mouth when while sneezing and wash your
hands regularly as the virus spreads through aerosols.
* Since the flu is a virus, antibiotics won’t work unless there is a secondary bacterial infection.
**Inactivated subunit (TIV)
– intramuscular – trivalent – split virus and subunit types – duration of immunity 1 year or less
*** Live attenuated vaccine (LAIV)
– intranasal – trivalent – duration of immunity at least 1 year – A new vaccine is formulated annually with the types
and strains of influenza predicted to be the major problems for that year (predictions are based on world wide monitoring of influenza)
__
The highly pathogenic avian influenza virus (HPAI)-standard Quarantine measures- Zooning
* Infected Zone: Minimum __ km
Premises Zones and Areas
radius of the infected premises
* Buffer Zone: The area between __
km and ___ km of the infected
premises will be considered the
buffer zone
* Control Zone: Infected and buffer
zone > ___ km
Infected Zone
Buffer Zone
Surveillance Zone
* Surveillance Zone: at least 10 km
+
= Control Area
+
= Free Area
and may be wider
3, 3, 10, 10
Recommended measures for the control of HPAI-Farm level
* Keep poultry away from areas frequented by wild fowl
* keep control over access to poultry houses by people and equipment
* Maintain sanitation of property, poultry houses and equipment
* Appropriate disposal of manure and dead poultry
* Generally ‘stamping out’ (culling) to eradicate the disease
* Appropriate disposal of carcasses and all animal Burial : fast and cheap, but concerns about environment increasing -Burry the dead carcasses and overlaid with lime stone
Incineration: several types of incineration units were used with varying
degrees of success
Diagnosis of influenza viruses
* Samples: _____ secretions or epithelial cells (______ swab)
* Detection of viral particles by ___
* Isolation on cell _____ or ____ (______ sac inoculation, 9-11 days)
* Detection of Viral RNA: ?
* Detection of Viral Ag by: ?
* Detection of viral Abs: ?
* Seroconversion
nasal, throat, EM, culture, ECE, allantoic, RT-PCR , HA test, ELISA, FAT, ELISA, IF
Tospovirus affects ?
Plants
Tomato spotted wilt virus
Phlebovirus affects?
Vertebrates
Sandfly fever Sicilian virus, RFV
Virion - Bunyaviruses
-__________, ___________, 80-100 nm in diameter
-Virion have _________ spike but no ________ protein in their envelope
The nucleocapsid segments with ________ symmetry
Genome: segmented, __________ sense, _____sRNA -Three segments (?) -5’ capped
-Cytoplasmic replication
-_________ into Glogi vesicles
-____________ for vertebrates
-______-________ persistent infection in invertebrates
-Genetic _________ occurs between closely related viruses
Virion - Bunyaviruses
-Spherical, enveloped, 80-100 nm in diameter
-Virion have glycoprotein spike but no matrix protein in their envelop
The nucleocapsid segments with helical symmetry
Genome: segmented, negative sense, ssRNA -Three segments (L, M, and S) -5’ capped
-Cytoplasmic replication -Budding into Glogi vesicles -Cytocidal for vertebrates
-Non-cytocidal persistent infection in invertebrates
-Genetic reassortment occurs between closely related viruses
Bunyaviridae
1. Segmented or non-segmented?
2. Positive or negative sense?
3. ________ stranded RNA genome
segmented (Three segments: L: large M: Medium S: Small), negative, single
An enzootic disease is ________ present in an animal population, but usually only affects a ____ number of animals at any one time
constantly, small
An Epizootic: an ________ of disease affecting ______ animals of one kind at the same time
outbreak, many
Rift Valley -RVFV- Kenya, Africa
* 1900’s: First recognized in sheep * 1930: Agent isolated * Sporadic outbreaks in Kenya * Requires mosquito transmission from animal to animal * Fever-causing disease
– Sheep, cattle, goats
– High abortion rates
– Death in young animals * Can affect humans
– Flu-like symptoms * Requires mosquito transmission from animal to animal * Fever-causing disease
– Sheep, cattle, goats
– High abortion rates
– Death in young * Can affect humans
– Flu-like symptoms
RVFV-Distribution: Vector
* _________ – Aedes species
– ________ lays eggs in ____-prone areas
– RVF virus passed from female mosquito to
her _____
– Eggs dormant in soil for long periods
– Heavy ____, eggs hatch
– Feeds on animals and people
* Species affected? * High levels of virus in ____ * Amplify (boost) virus
– Infect other mosquitoes
– Establish disease in environment
– May lead to large outbreaks * Humans
– Possible source of virus for mosquitoes
Mosquitoes, Mosquito, flood, eggs, rainfall, Cattle, sheep, goats, blood
Aino Virus
* Akabane and Aino viruses are closely related arboviruses of the
genus Orthobunyavirus, within the Simbu serogroup in the family Bunyaviridae
* Linked to fetal deformities in ______, ______, and _______
* Transmitted between animals by ______ vectors
* Biting ______ (gnats) in the genus Culicoides abortions, stillbirths, premature
births, and birth defects including arthrogryposis, scoliosis, sunken eyes,
cataracts, maxillary retraction and dental irregularities
* Arthrogryposis, hydranencephaly, and cerebellar hypoplasia or agenesis
- Akabane and Aino viruses are closely related arboviruses of the
genus Orthobunyavirus, within the Simbu serogroup in the family Bunyaviridae - Linked to fetal deformities in cattle and sheep, goats
- Transmitted between animals by insect vectors
- Biting midges (gnats) in the genus Culicoides abortions, stillbirths, premature
births, and birth defects including arthrogryposis, scoliosis, sunken eyes,
cataracts, maxillary retraction and dental irregularities * Arthrogryposis, hydranencephaly, and cerebellar hypoplasia or agenesis
What virus can be seen below?
Orthomyxoviridae
