Orthomyxo,Paramyxo,Picorna,Bunya,Toga,Reo,Arena Flashcards
Influenza A is in what viral family?
Orthomyxovirus
What is antigenic drift?
Minor changes
-Point mutations in H&N genes
*Drift produces annual outbreaks and epidemics
What is antigenic shift?
Major changes
-Genetic reassortment between strains
*Shift produces worldwide outbreaks (Pandemics) every 10-20 years
What is the most common cause of death related to Influenza A?
Secondary bacterial pneumonia
What are the Influenza A surface antigens?
- Hemagglutinin (H)
- Neuraminidase (N)
What does Hemagglutinin bind to?
Sialic acid containing receptors on respiratory epithelial cells
-Expressed on infected cells (basis for the hemadsorption test)
What viruses are Hemadsorption positive? (3)
- Influenza A&B
- Parainfluenza
- Mumps
What is the current gold standard for diagnosis of Influenza A/B?
Culture
-being replaced by PCR
Rapid antigen tests for influenza A/B (DFA) are capable of providing results in 30 minutes, what is the overall sensitivity?
50-80% sensitivity
-High specificity
What is the most common causes of croup in children?
Parainfluenza 1
What viruses are in the Paramyxovirus family? (5)
- Parainfluenza
- Measles (morbillivirus)
- Mumps
- RSV (pneumovirus)
- Human metapneumonvirus
The morbillivirus causes what? (3)
- Classic measles
- Atypical measles
- Subacute Sclerosing Panencephalitis (SSPE)
Classic Measles:
- Prodrome
- Rash
- Complications
- Cough, Coryza, Conjunctivitis (+/- Koplik spots)
- Descending rash (Head 1st)
- Otitis media, pneumonia, myocarditis
Who is susceptible to Atypical Measles?
Teenage patients who received only 1 vaccination
What is the risk of SSPE?
-Average incubation?
- 0.001%
- 7 years
What does the Mumps virus cause? (5)
Parotitis, sometimes with:
-meningoencephalitis, orchitis, myocarditis, pancreatitis
What is the most common cause of pneumonia & bronchiolitis in infants and toddlers?
RSV
What is true regarding immunity to RSV?
Short lived
- recurrence throughout childhood is the rule
- Infections are progressively less severe
How do you diagnose RSV in culture?
Formation of syncytia in Hep2 cells
Human metapneumovirus is a significant cause of what?
Lower respiratory tract infections
*PCR preferred diagnostic modality
Enterovirus and Rhinovirus are part of what viral family?
Picornaviruses
-small (pico) RNA (rna) viruses
What viruses belong to the Enterovirus family? (4)
- Poliovirus
- Coxsackie A/B
- Enterovirus
What does Poliovirus cause?
Poliomyelitis
-Destruction of spinal ventral horn motor neurons
What does Coxsackie A virus cause?
- Herpangina (painful oral infection)
- Hand, Foot, and Mouth
What does Coxsackie B virus cause?
- Grippe (epidemic pleuodynia)
- Myocarditis
- Pericarditis
What does enterovirus cause?
Most common cause of viral meningitis (aseptic)
What is the most common cause of the common cold?
Rhinovirus
What does rhinovirus culture require?
Incubation at 32 degrees
-RT-PCR is preferred
What viruses are part of the Bunyaviridae family? (4)
- Hantavirus
- Bunyavirus
- Nairovirus
- Phlebovirus
How is Hantavirus acquired and what does it cause?
- Aeroslized rodent shit
- Hantavirus pulmonary syndrome
What does Bunyavirus cause?
California encephalitis
What does Nairovirus cause?
Crimean Congo Hemorrhagic fever
What does Phlebovirus cause?
Rift Valley Fever
What viruses are part of the Togaviridae family? (3)
- Rubella
- Alphavirus
- Flaviviruses
What does rubella virus cause?
German Measles
-Febrile illness with rash
Rubella virus is generally benign but may have consequences in what circumstances?
-What are the implications? (6)
Developing fetus with maternal infection (1st trimester)
- Sensorineural deafness
- Cataracts
- Glaucoma
- Micropthalmia
- Congenital heart disease (PDA)
- IUGR
- Microcephaly
What does Alphavirus cause?
Equine encephalitides
What viruses are part of the Flavivirus family? (5)
- HepC
- Dengue
- Yellow Fever
- St. louis encephalitis
- West Nile virus
Dengue and Yellow fever are most commonly transmitted via what?
Aedes mosquitos
A. aegypti or A. albopictus
Yellow fever is viscerotropic for what organs? (4)
- Heart
- Kidney
- GI tract
- Liver
What is the most characteristic liver findings in Yellow Fever? (4)
- Midzonal necrosis
- Councilman bodies
- Microvesicular fatty metamorphosis
- NO inflammation
What is the most common cause of viral gastroenteritis?
Rotavirus (family Reoviridae)
What are other common causes of viral gastroenteritis? (3)
- Calciviruses (Norwalk-like agent)
- Adenoviruses (40&41)
- Astrovirus
What virus causes Lymphocytic Choriomeningitis?
Arenaviridae
Arenaviridae virus:
- Viral Particles
- Transmission
- Virus particles contain host cell ribosomes, giving them a granular appearnce
- Parasites of rodents that shed virus in their urine and feces – Hamsters and House mice are the hosts to LCM virus
