Major RNA viruses Flashcards
What are the components of a naked virus?
Capsid and nucleic acid
What are the components of an enveloped virus?
Envelope of glycoproteins
Spikes
Capsid
Nucleic acid
How are capsids symmetrical?
Identical proteins “capsomeres”
Based on icosahedral or helical structure
What is the purpose of the capsid?
Protects the genetic material
Recognized when its attached to the host
What RNA viruses are +ssRNA, enveloped and icosahedral?
Flavivirdae
Togaviridae
Retroviridae
What RNA virus is +ssRNA, enveloped and helical?
Coronaviridae
What RNA viruses are +ssRNA, nonenveloped and icosahedral?
Picornvaviridae
Caliciviridae
What RNA viruses -ssRNA, enveloped and helical?
Orthomyxoviridae Paramyxoviridae Rhabdoviridae Filoviridae Bunyaviridae Arenaviridae
What RNA viruses are dsDNA, nonenveloped and icosahedral?
Reoviridiae
All RNA viruses replicate in the cytoplasm except;
Orthomyxoviridae and Retroviridae
All RNA viruses are single stranded except:
Reoviridae
All RNA viruses and evveloped except;
Picornaviridae
Caliciviviridae
Reoviridae
All -ssRNA viruses are ___ in shape.
Helical
Why do RNA viruses have a high rate of mutation?
Because they lack DNA polymerase
What are the three genus classifications for Picornaviruses?
Enterovirus
Rhinovirus
Hepatovirus
What are the species within enterovirus?
Poliovirus 1-3 Echovirus 1-34 Coxsackievirus A 1-24 Coxsackievirus B 1-6 Enterovirus 68-71
What is the species within Rhinovirus?
Human Rhinovirus 1-115
What is the species within Hepatovirus?
Hepatitis A virus
What are some characteristics of Picornavirus?
Small is large
Large family
Replicate in cytoplasm
Non-enveloped, +sslinear, icosahedral
What are the only susceptible host for poliovirus?
Humans
The 3 serotypes of polio have ___ homology.
33-66%
What are the two vaccine types for polio?
IVP (Salk) inactive
OPV (Sabin)
Who many infections of polio are type 1?
70 - 90%
How is polio transmitted?
Ingestion (fecal-oral)
Where does polio infect once in the body?
Cells of the oropharyngeal and intestinal mucosa
Where does polio replicate?
In the lymph nodes and GALT
Which is more common, a primary or secondary viremia of polio?
Primary (95%)
How many cases of polio spread to the CNS?
1%
Where is polio spread?
Feces
What are the clinical manifestations of polio?
Meningitis (aseptic)
Encephalitis
Paralytic poliomyelitis
If polio has attacked the anterior horn of of the spinal cord what happens?
Flaccid paralysis
What happens if polio attacks the medulla?
Paralysis of the diaphragm - you ded
What viruses are a common cause of lymphocytic meningitis?
Enterovirus Coxsackie virus A & B Echovirus Poliovirus Arbovirus HIV HSV-2
What are the three types of paralytic polio?
Spinal (80%)
Bulbar (2%) muscle weakness
Bulbospinal (15%) combo of both
How is polio diagnosed?
Isolation of virus from stool or CSF
How is polio treated?
No specific treatment
- pain and muscle spasm treatment
- orthopedic support
Which of the polio vaccines were effective against all 3 strands?
Both Salk and Sabin
What are the good things about OPV for polio?
Oral
Lifelong immunity
No boosters needed
Contributes to herd immunity
What are the bad things about OPV for polio?
Risk of vaccine associated polio
Immunocompromised can’t have it
What are the good things about IPV for polio?
No risk of vaccine associated polio
Safe for immmunocompromised
Easier to store and transport
What are bad things about IPV for polio?
Booster needed
Injection
Large dose needed
How is Coxsackievirus transmitted?
Ingestions (fecal-oral) and highly contagious
What is the vaccine for coxsackie?
None
What is the treatment for coxsackie?
None
just wash your hands and don’t get it
What coxsackie virus type causes hand, foot and mouth disease and what are the symptoms?
A9, A16
Vascular rash on hands, feet, mouth and tongue with mild fever
What coxsackie virus type causes hemorrhagic conjuctivitis and what are the symptoms?
A24
Eye pain followed by redness, tears, swelling and sensitivity
Contagious
What coxsackie virus type causes poliomyelitis like symptoms?
A7
What other diseases do coxsackie A virus cause?
Aseptic meningitis
Herpangina
What are the characteristics of coxsackie B?
Worldwide distribution
All but one type found in the US first
What coxsackie virus type B might be associated with hand, foot and mouth disease?
B2 and B5
What coxsackie virus type cases juvenile diabetes (IDDM)?
B4
What other diseases does coxsackie type B cause?
Pleurodynia
Myocarditis
What are the symptoms for herpangina?
Fever, sore throat, anorexia, vomiting
Vesicular ulcerating lesions on soft palate and uvula
What are the symptoms for pleurodynia?
Acute onset of fever, unilateral low thoracic chest pain
Pain is called “devil’s grip”
Males have testicular pain
Describe the characteristics of Rhinovirus.
Most common cause of the common cold
More common in the summer
Infection localized in the nose
How is rhinovirus transmitted?
Respiratory secretions
What are the symptoms of rhinovirus?
Runny nose
What is the treatment for rhinovirus?
None
What was Hepatitis A originally known as?
Enterovirus 72
How is Hep A transmitted?
Fecal-Oral
What are the symptoms of Hep A?
Sudden fever and jaundice
What does Hep A infect?
Intestinal epithelial cells and spread to liver
What causes the life long immunity to Hep A?
IgG anti hep A
What is the treatment for Hep A?
None
What are the characteristics of caliciviridae?
Naked, Icosahedral +ssRNA
Resistant to heat and detergent but not pH
What is Norovirus associated with in terms of transmission?
Contaminated water and food supply due to fecal oral transmission
What kind of places would you expect to see norovirus?
Potlucks and cruise ships
Is norovirus highly contagious?
Yes
How do you isolate norovirus?
The the stool or vomit of infected pts
What does norovirus cause?
Acute gastroenteritis 12 0 24 hours after ingesting infected substance
Self-limits after 1 or 2 weeks
How can you prevent norovirus?
Good hygiene
How is Hepatitis E virus transmitted?
Fecal-oral
What is hep E associate with in terms of transmission?
Contaminated water and epidemic hepatitis
What happens if a pregnant woman get hep E?
She has a high chance of dying or will have a spontaneous abortion
Reovirus is very diverse. What can it infect?
Mammals, birds, fish, reptiles, amphibians and plants
What does the REO stand for in reovirus?
Respiratory Enteric Orphan virus
What are the two forms of reovirus humans are mostly infected with?
Rotavirus
Orbivirus (coltivirus?)
How is rotavirus transmitted?
Ingestion, fecal to oral
How many children have rotovirus antibodies?
Almost all of them all over the world
What is the most common cause of death due to infantile diarrhea?
Rotovirus
When does rotovirus generally occur during the year?
Winter
Year round in the tropics
How many type of rotovirus are there and which is the most commmon?
A, B, C, D, E
A is most common
What does rotovirus type A cause?
Infantile diarrhea with vomiting and fever
What does rotovirus type B cause?
Adult onset of severe diarrhea (epidemic in east Asia)
What are the three major type of flavivirdae?
Pestivirus
Hepatitis C virus
Flavivirus
What are the viruses within flavivirus?
Yellow fever Japanese encephalitis St. Louis encephalitis West Nile encephalitis Dengue
How can you classify dengue?
Enveloped, +ssRNA
What serotypes exists for denge?
DENV-1, 2, 3, 4
How is denge transmitted?
Aedes aegypti (mosquito)
What are the typical uncomplicated (classic) symptoms of dengue?
Fever within 4-7 days exposure Severe headache Severe joint and muscle pain Nausea and vomiting Rash
What are the symptoms of hemorrhagic fever in dengue?
Symptoms of classic Gingival and nasal bleeding Inc menstrual flow GI bleeding Hematuria
How do you diagnose dengue?
ELISA serology and antigens
Tourniquet test
How is dengue managed?
Self-limiting fever control (avoid aspirin)
Insect repellent
No antiviral treatment
No vaccine
What virus is a common form of blood-borne hepatitis is hospitals?
Hepatitis C
What does it mean when Hep C is in the chronic state?
Cirrhosis
End-stage liver disease
Hepatocellular carcinoma
What is the main symptom of Hep C?
Jaundice
What is the treatment for Hep C?
Pergylated IFNalpha with ribavirin
What are the who types of togaviridae?
Rubivirus and Alphavirus
What type of togaviridae is rubella?
Rubivirus
What are the different type of alphavirus?
Chikungunya
Eastern equine encephalitis virus
Western equine encephalitis virus
Venezuelan equine encephalitis virus
How is rubella transmitted?
Respiratory droplets
How is rubella general transmitted?
Maculopapular rash that starts on the face and spreaks to trunk then extremities
May have occipital and post auricular lymphadenopathy
Why is rubella dangerous if a pregnant mother contracts it?
It can cross the placenta is viremic and all germ layers may be infected
The early in the pregnancy the more dangerous it is, vaccine cannot be given
What viruses are included in filoviridae?
Ebola
Marburg
Cuevavirus
What symptom is associated with the viruses in filoviridae?
Hemorrhagic fever
Early: muscle aches, fever, vomiting, red eyes, skin rash
Acute: bleeding and skin hemorrhage
What is the treatment and vaccine for filoviridae?
None
How is orthomyxoviridae characterized?
Enveloped, -ssRNA, segmented
What are the three types of orthomyxoviridae?
Influenza A, B and C
Which influenza type infects humans only?
B
all can infect but B is exclusive
What is antigenic drift?
Small, constant point mutations
Gradual changes to amino acid composition
Leads to epidemics
Annual vaccinations
Which types of flu participate in antigenic drift?
A, B, C
What is antigenic shift?
Substitution of a gene segment with segments from another flu virus from a different host = reassortment
Pandemics
Less common
Which type of flu participates in antigenic shift?
A
How do you name a type of influenza?
Host origin, geographic location of first encounter, strain number and isolation year
ex. A/California/7/2009 (H1N1)
How is influenza transmitted?
Person to person, direct contact and aerosol droplets
What does influenza infect in the body?
Respiratory epithelial cells
How long does the flu incubate?
1 to 4 days
What are some complications of the flu?
Bronchitis and pneumonia
What treatments are there for the flu?
Amantidine (no longer affective)
Zanamivir (Relenza)
Oseltamivir (Tamiflu)
What type of virus in rubulavirus and what does it cause?
Paramyxoviridae, mumps
What are the structural components of a paramyxoviridae?
Surface G protein Fusion protein Matrix protein Phosphoprotein Nucleoprotein Polymerase
What acute viral illness does the mumps cause?
Parotitis and orchitis
How are the mumps transmitted?
Respiratory
What is the incubation period for he mumps? when is it viremic?
14 - 18 days
12 - 25 days
What are the symptoms of the mumps?
Nonspecific, myalgia, headache
Parotitis (30-40%)
What type of paramyxoviridae causes the measles?
Morbilivirus
What are the clinical signs of the measles?
Cough, coryza, conjuctivits
Koplic spots
Maculopapular rash
What type of paramyxoviridae causes respiratory syncytial virus?
Pneumovirus