Viral RTIs Flashcards by Brynn Walker

How are viral RTIs transmitted?

Droplet (not aerosol transmission) and then contact (inoculation) with the eyes or nose
- can survive on fomites and non porous surfaces for hours

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in what types of places are outbreaks of viral RTIs common?

daycares, long term care facilities, in the community in general

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based on the study discussed, what is the relative role of hands in the transmission of parainfluenza virus? what about rhinovirus?

relatively low for parainfluenza but high for rhinovirus

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is it easy or difficult to transmit rhinovirus by kissing?

difficult actually

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Cold viruses can linger on hotel room surfaces for how long after contamination…

18 hours

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In the rhinovirus/hotel room study, what were common locations to be contaminated?

door handles, light switches, faucets, telephones and TV remote controls

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What two viral and two host characteristics controbute to the severity of a RTI?

virus: inoculum size and virulence traits
host: immune system and any comorbidities

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What is the most common viral cause of an RTI? which one is #2

rhinovirus

2. coronavirus

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What are a couple other common viral causes of RTIs? which two cause severe disease?

Coronavirus, parainfluenza virus, adenovirus

Respiratory syncytial virus (RSV) and Influenza virus (FluA and FluB) cause severe illness

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What type of viruses can cause RTIs in immunocompromised individuals?

Herpes virus family (HSV, VZV, CMV, EBV)

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What predisposes immunocompromised patients to developing antiviral resistance?

prolonged periods of virus shedding

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What is the best form of specimen collection for upper respiratory tract infections ?

Nasopharyngeal swabs or aspirates

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What is the best form of specimen collection for lower respiratory tract infections?

Bronchial alveolar lavages (BAL)

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What kind of swab is the best to use? what kind of media is required?

a flocked swab is best

transport media (doesn’t support growth) is required

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What is the best laboratory diagnostic technique for detecting respiratory viruses?

Molecular methods like quantitative RT-PCR

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What trio of diseases can quantitative RT-PCR be used to quickly diagnose? How long does it take?

FluA/B/RSV

about 45 min

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What is conventional multiplex RT-PCR used for? how long does it take?

used if the typical RT-PCR does not detect Flu A/B or RSV then it can be used to screen for 15 different RTI causing viruses simultaneously

About 6 hours

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what family of viruses does rhinovirus belong to? what type of genome does it have? what morphology?

Picornaviridae family

ssRNA(+), non-enveloped

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How many different serotypes of rhinovirus are there?

> 100 serotypes

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what family of viruses does coronavirus belong to? what type of genome does it have? what morphology?

Coronaviridae family

ssRNA(+), enveloped

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What are two coronaviruses that have caused more severe illness?

SARS and MERS-CoV

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what family of viruses does enterovirus belong to? what type of genome does it have? what morphology?

Picornaviridae family

ssRNA(+), non-enveloped

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How many species and how many serotypes of enterovirus are there?

12 species

> 100 serotypes

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Enterovirus typically causes mild respiratory illness but has been linked with more sever cases of…

Study These Flashcards

aseptic meningitis*, myocarditis, acute flaccid paralysis (polio type illnesses with paralysis)

what family of viruses does Respiratory Syncytial Virus (RSV) belong to? what type of genome does it have? what morphology?

Paramyxoviridae family ssRNA-, enveloped

RSV is the most common cause of...

bronchitis in children

Do people have longterm immunity to RSV?

no, this is why adults can get it from children relatively easily

What is the name of the preformed monoclonal antibody used to treat RSV? what type of antibody and what type of immunization is this?

Palivizumab IgG Passive immunization

what family of viruses does Parainfluenza virus belong to? what type of genome does it have? what morphology? How many types are there?

Paramyxoviridae family ssRNA(-), enveloped 4 types (1 to 4)

What is an example of a DNA virus we discussed?

Adenovirus

Is adenovirus enveloped or non-enveloped

Enveloped

How many types of adenovirus have been identified?

over 60

What are 4 symptomatic presentations of an adenovirus infection?

URTIs or LRTIs Conjunctivitis Hemorrhagic cystitis Diarrhea

What two types of adenovirus cause diarrhea?

40 and 41

what family of viruses does Influenza virus belong to? what type of genome does it have? what morphology? How many types are there?

Orthomyxoviridae ssRNA- , enveloped **Segmented genome

How many types of Flu are there?

3 - A, B, and C (C is very rare)

Which of the types of flu has pandemic potential? Which causes more severe disease?

Flu A does both

What two surface structures are used to subtype the different flus?

Hemagglutinin (HA) | Neuraminidase (NA)

What symptoms are common for the flu but rare for other respiratory infections?

Flu: headache, fever, malaise, fatigue, weakness, muscle aches Others: nasal congestion and discharge

What are the two classes of antiviral treatments of influenza? what is an example of each?

1. M2 inhibitors - Amantidine | 2. Neuraminidase inhibitors -oseltamivir and zanamivir

How does amantidine work?

prevents the formation of M2 proteins which are required to make proton channels for the virus to uncoat

Why isn't amantidine used anymore?

1. All Flu B strains are resistant naturally because they don't have M proteins 2. All H3N2 Flu A human strains are resistant naturally 3. Pandemic H1N1 is resistant

What is the issue with the neuraminidase inhibitors?

need to be used within 48 hours of infection which is very difficult to manage clinically

What are the trivalent/quadrivalent flu vaccines effective against?

Influenza A (pH1N1) Influenza A (H3N2) Influenza B - Victoria and Yamagata lineages

Why does the flu vaccine need to be updated every year ?

because of antigenic drift

What is antigenic drift? in what strains does it occur?

can occur in both Flu A and Flu B Due to mutation over time in surface glycoproteins

What is the role of hemaggluttinin (HA) ? what does it bind?

Hemagglutinin (HA) binds sialic acid receptors on cells to facilitate entry

What is the role of neuraminidase (NA)?

Neuraminidase (NA) cleaves HA/sialic acid = vial release

What is antigenic shift? in what strains does it occur ?

Genetic reassortments between avian/swine/human Only in Flu A

What is the result of antigenic shift?

pandemics due to no existing immunity to the viral antigens

What is the natural reservoir of influenza?

Aquatic birds

which animal acts as the "mixing ground" for flu viruses? why?

pigs because they have both avian and human Flu receptors

how many different HA and NA types are there naturally in birds?

18 HA and 9 NA in birds naturally

which strain of pandemic flu was a triple reassortment?

H1N1 | - avian, human, and swine

What strain of flu is avian flu?

H5N1

How is avian flu transmitted ? When are people most likely to be exposed?

direct contact with infected poultry, or objects contaminated by their feces Exposure is most likely during poultry slaughter and cooking preparation

Can avian flu be transmitted from human to human?

What is the difference in disease severity and spread between H1N1 and H5N1?

H1N1 spreads quickly but rarely fatal | H5N1 spreads very minimally but tends to be fatal

What is H7N9?

An avian flu that was first reported in humans in March 2013, in China – linked to 144 cases; 46 deaths H7N9 vaccine developed in Oct 2013

Viral RTIs Flashcards

(59 cards)