Picornaviridae Togaviridae Arenaviridae Flashcards by Christine Parascandola

Morphology and Structure of Picornaviruses

Virion: non-_________, _____, (23-25 nm), __________ symmetry
* Genome:
– (___Ve) sense RNA, 7.2-8.4 kb
* RNA is _________
– Ten genes, eleven proteins (poliovirus)
* VP1, VP2, VP3, VP4 structural proteins
– VP____ interacts with viral RNA
* 2A, 2B, 2C proteases
* 3A, 3B, 3C, 3D RNA replication
– __________ replication

enveloped, small, Icosahedral, +, polyadenylated, 4, Cytoplasmic

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Picornaviruses

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Morphology and Structure of Picornaviruses

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Members of the Picornaviridae Cause Many Serious Diseases
of Man and Animals
1. Genus Apthovirus
- ____ and _____ disease, most destructive in Africa
2. Genus Rhinovirus
- cause ______ tract infections, acid labile, cause _____ in humans (110 types) and pigs
3. Genus Enterovirus
- _______ type member, 3 major types cause paralysis
4. Genus Hepatovirus
- Hepatitis __, contagious ___ infections
5. Genus Cardiovirus
- ____ group, cause ____ and ____ inflammation, acid labile, source is a ____ reservoir

Foot, mouth, respiratory, colds, Poliovirus, A, liver, EMC, heart, brain, rodent

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A Phylogenetic Tree of the Picornaviridae

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General properties of Picornaviruses

Hepatitis = inflammation of liver, multiple causes
In viral hepatitis: ABCDEF
Hepatitis E = zoonotic virus, transmitted from pigs to humans

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Genome structure and organization of Picornaviridae

How can we use/maximize benefits from genetic material?
Structural proteins = 5’ end
no structural = 3’ end
Can crop genome organization, put under one another
Vp4, etc encode P1
What encodes P2 and P3?

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Genome structure and organization of Picornaviridae

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Picornavirus Members Bind to Many Different Host Receptors

Car = coxaci adenovirus receptor
Virus uses receptors to enter cell

I am-1, Vcam-1, CD55

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Replication of Picornavirus RNA

Positive sense RNA virus
Review replication of positive sense viruses
Lipid bilayer structure
Bottom left picture: receptor and key have to match in order for virus to enter

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Geographical distribution of Foot and Mouth Disease

Family
Genus
7 distinct serotypes
Not cross protective = one vaccine agonist and one strain will not protect against other strains
Memorize names
Carribbean, Oceania, north and Central America = free b/c strict control measures.

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FMDV-Host Range
All _________-_________ domestic animals including:

Most _______-footed wild animals:

cloven, hoofed

-Cattle
Buffalo
-Sheep
-Goats
-Swine

cloven

-Deer
-Bison
-Feral hogs
-Antelope

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Armadillos are not only ________ but are capable of transmitting ______ to ___________ and _____ species of animals. FMDV is not reported in _____-toed animals such as as?

INSERT picture from this slide

susceptible, FMDV, each other, other, Odd, Horses, Zebras and Rhinos

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Some epidemiological hints-FMDV
1. __________ 100% in susceptible animal population located in the U.S., Canada, Mexico, others.
2. _________ less than 1%
- Higher in _______ animals and highly _______ virus strains
- Animals generally _________ to prevent spread (e.g. incineration)

Incubation period depends on which _____ of FMD virus (___ serotypes), _______, and the route of ____. Can be as short as __-__ days in close contact or as long as ___-___ days from windborne
infection. Experimentally shown to be as short as?

Morbidity, Mortality, young, virulent, destroyed, strain, 7, dosage, entry, 2-3, 10-14, 18-24 hour

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Worldwide distribution of FMDV
Get notes

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FMDV-Clinical Signs
 Incubation period: 2 to 14 days
** ____ and _____
** Feet, mouth, nares, muzzle, teats
 Progress to erosions
 Lameness, reluctance to move,
sloughing of hooves
 Abortion
 Oral lesions (vesicles)
 Tongue, dental pad, gums, soft
palate, nostrils, muzzle
** Excess _______, _____, nasal _____
** ____, ____ of body condition
 Erosion and ulceration on the teat
of the udder
 Death in young animals

Fever, vesicles, salivation, drooling, discharge, Lethargy, loss

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FMDV-Clinical Signs cont…

Post photos

Sloughing of hoof —> regeneration occurring; occurs in severe cases
Hard palate, interdigital space.

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Transmission of FMDV
Entire chart

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Temporal progression of foot-and-mouth disease (FMD) in naïve and vaccinated cattle

See difference between pattern of disease in vaccinated versus unvaccinated

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FMDV-Clinical Signs: Sheep and Goats
Mild form
 Fever, Lameness
 Erosion and ulceration in the mouth

This one

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FMDV

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Epidemiology of FMDV

Recovered animal good immunity for awhile
Death/slaughter

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FMDV-Post Mortem Lesions
 Single or multiple vesicles
 Various stages
of development
 White area, 2mm-10cm
***____ filled blister
 Red erosion, fibrin coating
 Dry lesions
 Sloughed hooves
____ heart appearance = image **

fluid, Tiger

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FMDV-Laboratory Diagnosis
 ________ diseases are clinically indistinguishable!
 Suspect animals with ______ or ______ and vesicles
 Tranquilization may be necessary
 Laboratory testing essential

Vesicular, salivation, lameness

Ante mortem sample: saliva b/c rich in virus since it is secreted in saliva
Post mortem sample:

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Principles of FMDV diagnosis

This slide

Differential diagnosis of Vesicular diseases based on the naturally occurring diseases in different domestic species of animals

Highlighted portion R = resistant S= susceptible

Study

Clinical Comparison: Snout in pigs Morphology differs between types

Clinical Comparison: Feet

Differential Diagnosis of FMDV in various animal species

Put family

Porcine enteroviruses (PEVs) ______ disease ______ disease Reproductive diseases porcine enteroviruses * **Two distinct serotypes (PEV___ and ___) was first reported in 1979 * It is associated with the _______ strain of porcine enterovirus, serotype PEV___ * Most infections with porcine enteroviruses, which belong to the family _________, cause no apparent disease, but some strains are capable of causing ** ___________: (**_____ and _______) * Reproductive disorders (stillbirths, foetal mummification, embryonic death and infertility

Teschen, Talfan 9, 10, neurotropic, 1 Picornaviridae, polioencephalomyelitis, Teschen and Talfan

PEV - Pigs with _________ paralysis, adopts a ____-sitting posture Put image

posterior, dog

Encephalomyocarditis virus (EMCV) * EMCV is resistant to many environmental conditions and remains stable at pH 3–8 * EMCV has a broad host range and has been isolated in over 30 species of mammals and birds. * Rodents are thought to be the reservoir species. * In neonatal pigs, mortality rates can reach ____% * Pig-to-human transmission has not been documented * Ingestion, either of EMCV-infected carcasses (rats or mice) or of food/water contaminated by infected carcasses, is thought to be the primary route of transmission in swine. Direct pig-to-pig transmission has not been demonstrated. * Sudden death can occur in _______. Lethargy, fever, anorexia, dyspnea, vomiting, and paralysis

100, neonates

FMDV disease in Humans  Very low incidence  40 cases since 1921 ***** Most reports ended when FMD was eradicated in _____  NOT a public health concern  Incubation period: 2 to 6 days  Clinical signs  Mild headache, malaise, fever ***** _____, ______ sensation of fingers, ____, ____ prior to _____ formation  Clinical disease rare ***** Infected by ____ contact, ingestion of unprocessed ___/____ products ****** Type ___, __, rarely A  Transmit virus to animals  Rarely harbor virus in respiratory tract for 1-2 days ****** Low risk of _______ carriage  Contaminated boots, clothing, vehicles

Europe, Tingling, burning, palms, feet, vesicle direct, milk, dairy, O, C, prolonged

FMDV-Vaccination  Killed vaccine, serotype specific  North American Foot-and-Mouth Vaccine Bank  ______ ______, NY  Monitor disease outbreaks worldwide  Stock active serotypes and strains  Essential to isolate virus and identify the serotype to select correct vaccine ***FMD ___ vaccine: Aftovac pure *** _______ Vaccine: Aftovax - vaccinate only healthy animals

Plum Island, VRI, Inactivated

Features of ideal FMDV vaccines

Recommended actions in FMDV outbreaks  Confirmatory diagnosis  _________  Must properly destroy exposed?  Products:  2% sodium hydroxide (lye)  4% sodium carbonate (soda ash)  5.25% sodium hypochlorite (household bleach)  0.2% citric acid  Areas must be free of organic matter for disinfectants to be effective

Depopulation, cadavers, litter, animal products

Bovine enterovirus (BEV) **** Belongs to the genus __________ **** ____ (18–30 nm), non-_______ viruses with an ________ capsid ****** Only two serotypes, BEV-__ and BEV-__ are now recognized * Isolation of BEV from feces and various tissues from apparently healthy animals or from animals with clinical signs that ranged from mild to moderate diarrhea to reproductive disease ******* Sometimes the mucosa of the ____ _______ and ______ had multiple foci of _______ and _____ * Virus isolation from intestinal lesions followed by electron microscopy yielded an approximately 27 nm, nonenveloped, cytopathic, virus

Enterovirus, Small, enveloped, icosahedral, 1, 2, spiral, colon, cecum, hemorrhage, ulceration

****Avian encephalomyleits virus (AEV) OR __________ ________ ___ ***** Viral infection of the _______ system of many _____ birds, chickens, turkeys, quail, pheasants, and pigeons ****** Causes ______ manifestations such as ataxia, tremors, and paralysis * Vertical and horizontal transmissions have been documented. * Microscopic lesions in the CNS in the brain (cerebral peduncle, cerebellum, brain stem) and spinal cord ***** Degeneration and necrosis of _____, perivascular lymphocytic cuffing, and gliosis with the formation of glial nodules ******* __________ of neurons in the ________ _______ = AEV

Tremor virus A, nervous, naive, nervous, neurons, Chromatolysis, medulla oblongata

Picture for AEV

AEV strain classification and Pathogenicity ******Pathotype-I: presented by _____ ___ strains: enterotropic ******* These strains infect chickens readily via the ____-____ route, multiply in the intestine, and shed in feces. ****** Pathotype-II: ______-adapted strains constitute the other pathotype **** They do not infect via the oral route except with very ___ dose, and do not spread _____ ******* _________ accumulations occur in viscera, particularly the ________ is characteristic

natural, field, oral-fecal, Embryo, high, horizontally, Lymphocytic, pancreas

Duck Viral Hepatitis (DVH **** (DVH) is an acute, highly contagious, viral disease typically affecting __________ less than six weeks of age **** Short incubation period, sudden onset, high mortality, and characteristic liver lesions **** should not be confused with duck hepatitis B virus (Hepadnaviridae) ***** DHAV-1: now classified in the genus _____________ ****** Two antigenically distinct genotypes have been identified in Taiwan (DHAV-___) and identified in China and South Korea (DHAV-____). ***** DVH propagated in chicken and duck embryos, and they do not produce hemagglutinins

ducklings, Avihepatovirus, 2, 3

In cases of duck viral hepatitis virus, the _____ is enlarged and covered with _______ foci up to 1 cm in diameter ***** Spleen may be _____ and ______. ***** Kidneys may be ______, and renal blood vessels ______

Liver, hemorrhagic, enlarged, mottled, swollen, congested

Picture of DVH

Equine Rhinitis virus * The equine rhinitis-A virus and the equine rhinitis-B virus ****** Rhinovirus, differentiating _____ groups according to their characteristics: equine rhinovirus-1,equine rhinovirus-2, equine rhinovirus-3 and ***_____-stable equine picornavirus ****** Later the equine rhinovirus type ___ was renamed Equine Rhinitis A Virus (ERAV), being classified within the genus Aphthovirus, the other three were included in a new genus called ***** ________ Considering three serotypes of Equine Rhinitis B Virus(ERBV-1, ERBV -2, and ERBV-3). * Isolated from oral and nasopharyngeal secretions, plasma and urine ***** Main route of excretion seems to be urine ***** Clinical signs: fever (1 to 3 days), anorexia, serous to mucopurulent nasal discharge, ________, _______, cough, and ___________. ****** Diagnosis can be carried out directly by demonstrating the presence of the virus through viral _______ or detection of viral ____ by RT- PCR from nasopharyngeal swabs or urine in the case of ERAV ***** ___________: indirectly detecting increased specific antibodies against these viruses.

four, acid, 1, Erbovirus, pharyngitis, bronchitis, lymphadenopathy, isolation, RNA, Seroconversion

Equine Rhinitis virus

Picornaviruses infect humans

Large number of viruses cause Hepatitis syndrome. Hepatitis A, B, C, D, and F. Hep E is most important for us b/c it is zoonotic. Transmits from pigs, especially animals that eat liver and sausage, if transmitted can be transmitted to humans.

Poliovirus ***-Principally an infection of the __________ tract -Most people who get infected with poliovirus (about 72 /100) will not have any visible symptoms ***-About 25% with poliovirus infection will have ___-like symptoms ***-Very contagious and spreads through _____-to-_____ contact ***Clinical spectrum -Abortive poliomyelitis -Fever, malaise, headache, vomiting, etc. -Resolves in about a week ****Nonparalytic poliomyelitis (an aseptic meningitis) -Similar symptoms, but also back pain -Paralysis can occur in a small percentage of cases ***Paralytic poliomyelitis -Motor neuron damage -Mostly flaccid paralysis, but spasms in some -Recovery within 6 months, otherwise permanent *****Progressive postpoliomyelitis muscle atrophy (postpolio syndrome) Can appear decades after polio infection

gastrointestinal, flu, person, person

Poliovirus

Disappearance of Polio in the USA * Children under 5 years are more susceptible to Poliovirus infection * Two types of Poliovirus vaccines **** Inactivated Polio-vaccines (IPV): ____ vaccine ***** Oral Poliovirus vaccine (OPV): _____ vaccine

Salk, Sabin

Coxsachievirus-CVB3-Induced Myocarditis * Myocarditis: Inflammation of the heart muscle cells * 20% of sudden unexpected death in young adults ****** _______ cardiomyopathy Myocarditis Heart

Dilated

ALL Family: Togavirida General properties of Togaviridae * Morphology and structures * Classification * EE (EEV, WEV, and VEV) * SAV * Chikungunyavirus * Pathogenesis * Epidemiology 47 II.

Toga: from Latin toga “cloak” an outdoor overgarment, typically sleeveless, that hangs loosely from the shoulders

Classification of Togaviridae

****

General criteria of family Togaviridae __-__ kb of __VE sense, non- ________ RNA

10-12, +, segmented

Family: Togaviridae

Alphavirus structure * Envelope: lipid bilayer derived from the host cell plasma membrane * Contains 2 viral glycoproteins (E1 and E2) * The only proteins in the envelopes of alphaviruses are the viral ________, each anchored in the lipid at or near their C- terminus. * On the virion surface, E__ and E__ are closely paired and together form trimers that appear as "______" in an orderly array.

glycoproteins, 1, 2, spikes

Genome structure and organization of Togaviruses 51 * __Ve ____ RNA , ___-__ kbs long * The virion RNA: infectious and serves as both genome and viral messenger RNA * The whole genome: translated in a ___-______ polyprotein * Structural polyprotein: expressed through a __________ ______ * The 5'-terminus carries a ___ and the 3'-terminus has a _______ ___ * ~11.7kb, 4-8% total weight of particle * NSP encoded at the 5' end

+, SS, 10-12, non-structural, subgenomic mRNA, cap, PolyA tail

Replication cycle of Togaviruses

Human/animal Risks and Outcomes Human * Eastern equine encephalitis – ______ most at risk – Case fatality rate: 33% * Western equine encephalitis – _____ <1 year most at risk – Case fatality rate: 3% * Venezuelan equine encephalitis – ______ most often affected – Fatalities are rare Animal Risks and Outcomes * Case-fatality rate in horses – EEE ~ 90% – VEE ~ 50 to 90% – WEE ~ <30% * Vaccine available in the U.S

Elderly, Children, Children

EEEV is maintained in infection cycles which involves passerine birds and ditch mosquitoes (Culiseta melanura) * Periodic epidemic outbreaks of EEEV in wild birds involve mosquito species such as Aedes solicitants and Coquillettidia perturbans which feed both on birds and on mammals. * VEEV is maintained in sylvatic cycles involving rodents and mosquitoes (Culex species) in swampy habitats * The cycle of infection of WEEV involves mosquitoes, usually Culex tarsalis and indigenous wild birds.

Equine Encephalitis (Eestern EE, Western EE, Venezuelan EE) EEE, WEE, VEE  Mosquito-borne viral infections cause severe encephalitis in horses and humans  Some of these viruses also cause disease occasionally in other mammals and birds  All of them have the same epidemiological, pathological and control outlines * They occur in North, Central, and South America * Mosquitoes and birds or rodent act as reservoirs of each virus * * Viruses are primarily carried by birds or rodents and transmitted by mosquitoes

Head pressing

Transmission cycle of EEV and VEE

Transmission and pathogenesis of equine viral encephalitis ***______ & _______: considered **dead-end** hosts for EEE &WEE viruses; -direct horse-to-horse or horse-to-human transmission does not occur *** Unlike the EEE and WEE viruses, the **VEE virus: shed in the ____ and _____ secretions of infected animals, -transmission of disease by direct contact or aerosolization an infected equine is capable of infecting a susceptible animal or human * Infection follows the bite of infected mosquito ***** Virus replicate at site of ____ and regional _______ _____ * Generalized infection and viremia in which the virus replicates in the lymphoid tissues throughout the body ***** Virus entry into ____ after replication in the endothelial cells lining the blood vessels in the brain

Horses, humans, oral, nasal, bite, lymph nodes, CNS

Do not need to know this

ALL Clinical signs of equine viral encephalitis * Clinical sings: CNS involvements -sever depression, behavior change, -animal unable to stand on feet -central blindness, paralysis, and -death soon after the onset of clinical sings

Equine viral encephalitis

Diagnosis of equine viral encephalitis **** Ante mortem: * serology – Virus neutralization – Hemagglutination inhibition – ELISA – Complement fixation – Virus isolation **** Post mortem – Virus identified in tissues (brain) – Immunohistochemistry, ELISA, RT-PCR

Equine Encephalitis Summary * West Nile Encephalitis –*** Late ________ through ________ – ? signs –*** ______/________ common –****___% mortality * Eastern Encephalitis –*** ____ through late _____ –*** Brain (cerebral) signs always – 90% mortality * Western Encephalitis (similar to EEE; 30% mortality)

summer, December, Spinal cord/brain, Tremors, weakness, 30, Spring, summer

Salmoind Alphavirus- (SAV) * Genus Alphavirus, family Togaviridae * 4 structural capsid glycoproteins (E1, E2, E3, and **6K) by the 3′ end and 4 nonstructural proteins (nsP1-4) by the 5′ end **** E__ has an important function in receptor _______ to host cell mediating the internalization of the virus, playing major role in the final envelope formation and in the budding of new viruses * Six subtypes of salmonid alphavirus (SAV1–6) have been reported * Different subtype strains tested being serologically closely related members of the same viral species **** Sleeping disease: in rainbow trout is known to be caused by the ______ subtype of SAV (SAV__) **** SAV2 has been divided into two subgroups named ________ variant (SAV2 FW) and ______ variant (SAV2 MW) * SAV2 MW: responsible for pancreas disease (PD) in seawater-reared Atlantic salmon **** SAV3: has been isolated from _______ Atlantic salmon in Norway hence it is also named ________ _____ alphavirus (NSAV). It causes __________ disease in Atlantic salmon and sea-reared rainbow trout **** SAV3: has genomic organization identical to that of SAV__ and SAV____ * SAV3 has only been detected in Norway, where until 2010 no other subtypes were detected * Subtypes 4–6 of SAV (SAV4–6) have been detected in Scotland and Ireland in connection with PD outbreaks

2, binding, second, 2, freshwater, marine, farmed, Norwegian salmonid, pancreas, 1, 2

A- Young rainbow trout signs of Sleeping diseases (SD), including failure to keep position in water, distended abdomen, bilateral exophthalmia B- Skeletal muscle lesions during acute infection C- Skeletal muscle lesions during chronic infection D- Partially purified and then negative staining EM of SAV

Commercial vaccines against SAV

Box around type and delivery method norvax compact PD is highlighted

Chikungunyavirus-CV ***** CV: ___RNA virus belongs to _______, genus _______ * Chikungunya derives from a word in the Kimakonde/Makonde language, meaning “to become _________”, and describes the stooped appearance of sufferers with joint pain (arthralgia). **** CV: transmitted to humans via the bite of an infected __________ ****** Aedes spp., Aedes ______ and Ae. _______ ***** Nonhuman and human ______ are likely the main reservoirs of the virus, and human-to-vector to-human transmission occurs during outbreaks * CV: causes large outbreaks with high attack rates, affecting one-third to three- quarters of the population in areas where the virus is circulating **** CV: infection causes sudden onset of high _____ ____ pains * Headache, myalgia, arthritis, conjunctivitis, nausea, vomiting, or a maculopapular rash * No specific antiviral treatment is available for chikungunya

ss, Togaviridae, Alphavirus, contorted, mosquito, aegypti, Albopictus,, primates, fever, joint

Study all boxed + chikungunya

Vaccine against SAV

skipped

III: Family: Arenaviridae **** The first Arenavirus, _________ _______ virus (LCMV), was isolated in 1933 **** LCMV was found to be a cause of aseptic (nonbacterial) ________

Lymphocytic choriomeningitis, meningitis

study

General properties of Arenavirus * Virion: are pleomorphic, enveloped, -300 nm in size * Virion contains non-functional host-cell riboisomes ***** Virions contains at least two _______ _______ nuclocapsid with associated ____-dependant RNA polymerase * ****Genome: consists ____ segments, large 7.2, small 3.4 kb of SS RNA both _______ ****** Replication occur in the ________: generally noncytocydal; persistent infection ******* ________ from the plasma membrane ******* Genetic re-assortment occur between closely related viruses.

circular, helical, RNA, two, Ambisense, cytoplasm, Budding

Arenavirus

Genome structure and organization of Arenavirus

Replication cycle of Arenavirus

Arenaviruses * Arenaviruses are divided into two groups – New World and Old World viruses based on genetic differences as well as geographical distribution ***** New World viruses are found in the _______ Hemisphere North and South America ***** Ex: ______ virus ***** Old World viruses occur in the ______ Hemisphere, Africa, Europe, and Asia ***** Ex: _____ fever (LASV)

Western, Chapare, Eastern, Lassa

Classification and distribution of Arenaviruses

look at highlights

Transmission of Arenaviruses- Reservoirs & Vectors

study

Transmission of Arenaviruses (LASV) * The rodent hosts of Arenavirus species are chronically infected with virus * Some Arenavirus types appear to be passed from mother rodents to their offspring during pregnancy * Remain in the rodent population generation after generation * Most infections are transmitted among adult rodents, likely via fighting and inflicting bites.

78 LASV transmission and mortality rates in humans

Comparison of the disease phenotypes between OW and NW Arenaviruses

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Picornaviridae Togaviridae Arenaviridae Flashcards

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