Chapter 3.24 Orthomyoxoviridae and paramyoxoviridae Flashcards
What are the similarities between orthomyxoviridae and paramyxoviridae?
similar structures, ability to absorb glycoprotein receptors in the upper respiratory tract
What viruses are in orthomyxoviridae group?
influenza viruses
“ORdinary flu”
What viruses are in the paramyxoviridae group?
influenza-like viruses and PARAde of different diseases- parainfluenza virus, mumps, measles, metapneumovirus and respiratory syncytial virus
How does influenza spread?
small-particle respiratory aerosols
What is the shape of orthomyxoviridae?
spherical virions, 8 negative stranded RNA put together by nucleocapsid protein (NP) surrounded by outer membrane of glycoprotein spikes
What 2 types of glycoproteins are present in outer membrane of orthmyxoviridae?
Hemagglutinin Activity (HA) and Neuraminidase Activity (NA)
What anchors the glycoproteins to the inside of the virus?
M proteins (membrane proteins)
Where dose hemagglutinin (HA) attach?
sialic acid on erythrocytes causing heme-agglutination and upper respiratory tract cell membranes
Where is Neuraminidase present?
mucin which covers mucosal epithelial cells and is important in upper respiratory defense barrier
What is the function of neuraminidase?
disrupt mucin barrier
What are the types of influenza virus?
A, B, and C
Type A infects human, mammals, and birds
Type B and C have only been isolated from humans
Who suffers more serious consequences of influenza?
the elderly and immunocompromised
What is relation of influenza viral infection to bacteria?
virus lowers host defenses against bacteria
*secondary pneumonia by Staph aureus, and strep pneumoniae
What is Reye’s Syndrome?
children who are given aspirin when they have influenza or varicella can develop severe liver and brain disease
What are the 4 diagnostic tests for influenza?
- Virus isolation- culture of virus to determine genetic and antigenic analysis
- Detect viral proteins- help to choose anti-viral
- Detection of viral nucleic acid (RNA)
- Serological diagnosis
What is the clinical manifestation of H5N1?
high fever and flu-like illness with lower respiratory symptoms, clinical pneumonia with patchy infiltrate on chest radiogram
*can progress to Acute Respiratory Distress Syndrome
What are “flu-like” symptoms?
headache, myaldias, diarrhea, abdominal pain, vomiting, sore throat, rhinnorhea
What are lower respiratory symptoms?
cough, shortness of breath, sputum production
What is Acute Respiratory Distress Syndrome?
non-cardiogenic pulmonary edema which has low blood oxygen levels, infiltrates part of the lung and no heart failure
Where is the vector for H5N1 and H7N9?
avian
What is the structure of paramyxoviridae?
negative stranded RNA in a singe strand, HA and NA are part of the same spike (not different), have fusion (F) protein
What is the function of fusion protein in paramyxoviridae?
causes infected host cells to fuse together into multinucleated giant cells
What are the 5 paramyxoviridae viruses that cause human disease?
parainfluenza virus, respiratory syncytial virus, metapneumovirus, mumps virus, and measles virus
What are the major 3 things to think about for the paramyxoviridae viruses?
- Lungs- all adsorb in upper respiratory
- Kids- most infections occur in children
- Viremia- dissemination of virions in blood
What infection is caused by parainfluenza virus?
upper respiratory infection in adults
lower respiratory infection in children and immunocompromised individuals
What are the clinical symptoms in adults from parainfluenza virus?
Range from (mild) rhinitis, pharyngitis, sinus congestion to (severe) bronchitis, and flu-like symtpoms
What is Croup?
parainfluenza infection of the larynx and other upper respiratory structures that occurs in children
What are the clinical symptoms of croup?
swelling of upper respiratory structures causing narrow of airway, stridor (wheezing sound), and barking cough
What infection is caused by Respiratory Syncytial Virus (RSV)?
respiratory infections that causes formation of multinucleated giant cells
Who is RSV most common in?
young children
*number 1 cause of pneumonia in young children (especially 6 mo. or less)
What infection is caused by metapneumovirus?
lower respiratory infection in young children (1 year old)
Where does the mumps virus replicate?
upper respiratory tract and regional in lymph nodes and spread via blood stream to distant sites
What organ is most frequently involved in the mumps?
parotid gland
What is the clinical presentation of a person with mumps?
parotid gland swells and is painful
- 3 weeks after initial exposure
- testes are often infected
What is the significance of male with mumps?
can develop orchitis where the testes enlarge and stretch the capsule causing severe pain
What vaccine is used for the mumps?
MMR vaccine (mumps, measles, and rubella)
What is another name for rubeola?
measles
How does measles virus spread?
nasopharyngeal secretions or direct contact
What is the clinical presentation of a patient with measles?
Incubation- Days 1-10
Early (Days 8-12)- conjunctivitis, swelling of eyelids, photophobia, high fever, hacking cough, rhinitis, malaise
Intermediate (Days 10-12- Koplik’s spots
Late (Days 10-16)- Measles Rash
What are Koplik’s spots?
small red-based lesions with blue-white centers in the mouth of person with measles
*a day or 2 before measles rash
What does the Measles rash look like?
red, flat to slightly bumpy (maculopapular) that spreads from the forehead to the face, neck, torso, and feet
What organs can become involved in measles virus?
lung damage, eye damage, heart damage, and encephalitis
What can be involved if a pregnant woman has measles virus?
spontaneous abortion and premature delivery
*no birth defects
What is Subacute sclerosing panencephalitis (SSPE)?
slow form of encephalitis caused by measles virus
What is the clinical presentation of a child with subacute sclerosing panencephalitis?
Slowly pressing central nervous system disease with mental deterioration and incoordination
*occurs many years after measles infection
What is the vaccine used for measles?
MMR vaccine
