Viral Respiratory Infections Flashcards
What is the most important type of antigenic variation involved in altering the influenza virus?
RNA recombination involving the entire genome encoding segments of H & N gene, called antigenic shift i.e. NOT point mutation (antigenic drift)
Why is intranasal Zicam not recommended? What viruses can it really benefit?
leads to a loss in sense of smell; rhinovirus
What is the H (hemagglutinin) portion of the influenza virus for?
Viral ATTACHMENT
What is the N (neuraminidase) portion of the influenza virus for?
viral PENETRATION and release into host cells
What are the two treatments for Type A influenza that act as hemagglutinin inhibitors?
Amantadine and Rimantadine
What are the two treatments for Type A and Type B influenza that act as neuraminidase inhibitors?
Oseltamivir (Tamiflu) and Zanamivir
How would you describe the causitive agent of chlamydia?
Obligate intracellular parasite that acts by removing ATP from the host
What is different about the genome of RSV and parainfluenza from influenza?
It’s not segmented so it does not alter as quickly
What is the most common cause of croup?
PIV type 1>PIV type 2»>RSV
What is the clinical presentation of croup?
Fever, barking cough,in 6-18 months old
What is the PIV agent like?
It’s a paramyxovirus, nonsegmented, negative sense ssRNA, enveloped,
What is the name of the RSV protein that causes syncytia formation?
Novel Fusion protein causes syncytia formation
What is the incubation period for PIV? Longer or shorter than Influenza? Where does it usually replicate?
2-6 days, longer; upper respiratory airways, can affect lower airways in small children
What is the CP of PIV?
Harsh cough, rhinitis, sore throat, SOB, worse at night in children
What types of PIV show seasonality?
Types 1 and 2, 3 does not because it’s endemic (most children have the type 3 antibody by the age of 1)
Is there lifelong immunity in PIV?
No, usually it shows up as a minor cold in adults that they can pass onto their children
How do you diagnose PIV?
after direct viral isolation from nasal washings or throat swabs fluroescent antibody test (FAB) usually clinical though. If you get NO SIGNAL on the test, watch where you got the sample from. If you get a neg, go back and do test. Just do it right!
What separates PIV from RSV as far as cell structure goes (from picture)?
PIV has H and N, RSV has attachment proteins and small hydrophobic proteins
What is the clinical presentation of RSV?
cough, dyspnea, cyanosis, croup (panic may exaccerbate dyspnea)
What are the symptoms of RSV caused by?
Inflammatory response to infection, IgE cells and T cells
What is the most common way to diagnose RSV? Least common?
Rapid antigen tests, serology is the least likely to be used.
What is used for prevention of RSV in high risk patients?
Monoclonal immune globulin (palivisumab)
What is the most common etiology of lower respiratory tract infection in children under 4?
RSV, OUTBREAKS EVERY WINTER!
What is the peak incidence of RSV?
Infants less than 1, 2-3 is the highest hospitalization rate
What two ways can SARS be spread?
respiratory and fecal-oral (think civic cats)
What is the scarier respiratory virus?
MERS
Although PIV is the most common cause of croup, what is the actual incidence of croup in the population of PIV infected people?
2-3%
What are two complications that arise from PIV?
Otitis media, parotitis
Which types of PIV are epidemic? Endemic?
Type 1 and 2 are epidemic, 3 is endemic
What is SARS an example of?
An emerging infection, now presumed to be extinct
