Viral infections of the lower respiratory tract Flashcards
Lower respiratory tract infection (LRTI) is a significant cause of morbidity and mortality in (children or adults?)
Children
_________ account for a significant proportion of LRTI especially in children
Viruses
Types of lower respiratory tract infection
Mention 3
Pneumonia
Acute Broncholitis
Acute Bronchitis
Types of lower respiratory tract infection
Pneumonia
Infection of the ________ .
Symptoms include fever, respiratory distress and _______.
Often not much clinical “_________”.
RSV, Adenovirus, Influenza
lung tissue itself
cyanosis
consolidation
Types of lower respiratory tract infection
Acute Broncholitis
___________ and _______ of ____________
Complete plugging of ———— with ___________ leads to _________
fever and coryzal symptoms, respiratory distress and wheezing.
Can be life-threatening in______ and _______
Respiratory Syncitial virus, Parainfluenza viruses
Inflammation and narrowing of terminal bronchioles
bronchioles; air resorption ; patchy collapse
babies and small children.
Bronchiole diameter is (smaller or larger?) during inspiration than during expiration and this leads to _____________ (proximal or distal?) to bronchiole.
Larger
hyperinflation of air sacs
Distal
Types of lower respiratory tract infection
Acute Bronchitis
Inflammation of _____, accompanied by fever, cough, wheezing and “________ “.
RSV, Para-influenza viruses, Adenovirus
bronchi
noisy chest
Epidemiology
_______ account for the largest proportion of childhood pneumonia.
Viruses
Epidemiology
______ is the most frequent cause of lower respiratory tract infection in infants and children
RSV
Epidemiology
The ______ viruses are the most common viral cause of pneumonia in adults
influenza
Epidemiology
___________ is second in importance only to RSV as a cause of lower respiratory tract disease in children and pneumonia and bronchiolitis in infants younger than 6 months
Parainfluenza virus (PIV)
Host defence
Mechanical barriers are _____ from the nostrils that filter particles larger than _______, and ______ clearance,
_______ branching of the central airways that helps the ______-micron particles to become impacted in the mucosa.
Humoral immunity is represented by mucosal immunoglobulin _______
Phagocytic cells consist of polymorphonuclear (PMN) cells;
hairs; 10 microns; mucociliary
Sharp-angle; 5- to 10
A (IgA),
Host defence
Phagocytic cells consist of polymorphonuclear (PMN) cells;
Alveolar, interstitial, and intravascular _______; and respiratory ________ cells.
_____________ provide the first defense involved in internalizing and degrading the viral pathogens.
They act as _________ and ________ cells.
macrophages; dendritic
Alveolar macrophages
antigen-presenting and opsonin-producing
Pathogenesis
Transmission is by _________ nuclei during _____,________
Touching _______ which are contaminated with the virus
droplet; coughing, sneezing
formites
Pathogenesis
Viral multiplication in the ________ of the upper airway
Secondarily infect the lung by means of ________ or _______ spread.
epithelium
airway secretions or hematogenous
Pathogenesis
Severe pneumonias may result in extensive ________ of the lungs with varying degrees of _________
Some patients developing _________ and diffuse _____________
consolidation; hemorrhage
bloody pleural effusions
alveolar damage
Pathogenesis
Respiratory viruses damage the respiratory tract and stimulate the host to release multiple __________ such as:
histamine, leukotriene C4, and virus-specific _____ in RSV infection and bradykinin, interleukin (IL)–1, IL-6, and IL-8 in _________ infections.
humoral factors
IgE
rhinovirus
Pathogenesis
RSV infections can also alter __________ _____ease bacterial adherence to respiratory epithelium, reduce ___________, and alter bacterial phagocytosis by host cells
bacterial colonization patterns,
incr
mucociliary clearance
Orthomyxovirus
Influenza virus ___,___,__
_______, pleomorphic, 80–120 nm in diameter (______ nucleocapsid, 9 nm)
______ stranded segmented (___)
______ sense RNA, 13.6 kb overall size
A, B, C
Spherical; helical
Single; 8
negative
Orthomyxovirus
______ structural proteins, ____ nonstructural
Envelope contains viral _______, and _________ proteins
Nine; one
hemagglutinin and neuraminidase
Orthomyxovirus
The 2 glycoproteins are the important antigens that determine _________ of influenza viruses and _______
antigenic variation
host immunity
Influenza virus
Influenza A virus consist of _____ and ______ strains
The ______ and ______ proteins, are used to divide influenza viruses into types A, B, and C.
_________ in HA and NA, are used to subtype the viruses.
human and animal
nucleocapsid (NP) and matrix (M)
Antigenic variations
Influenza virus
Only type ___ has designated subtypes.
_____ subtypes of HA (_______) and ___ subtypes of NA (_______), in different combinations.
A
15; H1–H15
9; N1–N9
Influenza virus
_______ HA ( _________ ) and ___ NA (_______) subtypes have been recovered from humans.
Four
H1–H3, H5
two; N1, N2
Influenza virus
Influenza A(_____) and A(______) subtypes are currently circulating among humans
H1N1; H3N2
Influenza virus
Antigenic drift
Accumulation of _______ in the gene, resulting in _________ in the protein.
Sequence changes can alter __________ on the molecule such that a virion can escape _______ by the host’s immune system
point mutations; amino acid changes
antigenic sites ; recognition
Influenza virus
Antigenic shift
_______ changes in the sequence of a viral surface protein, changes
That are ______ to ____________
The ________ genomes of influenza viruses reassort readily in ______________ cells.
Drastic; too extreme; be explained by mutation.
segmented
doubly infected
Influenza virus
Antigenic shift
The mechanism for shift is ________ between ______ and _____ influenza viruses.
Can result in a _________
genetic reassortment
human and avian
pandemic
Influenza B and C viruses exhibit antigenic shift
T/F
F
Influenza B and C viruses do not exhibit antigenic shift
Influenza
Is a/an (acute or chronic ?) viral infection that spreads easily from person to person.
Viruses circulate ______ and can affect ____ age group.
Annual epidemics peak during ______ in ________ regions.
Acute ; worldwide; any
winter; temperate
Influenza
Serious public health problem that causes severe illness and death in high risk populations.
children younger than age ____ years,
adults aged _____ years or older
_________ women,
certain medical conditions, such as chronic heart, lung, kidney, liver, blood or metabolic diseases (such as diabetes), or ————- immune systems.
2; 65
pregnant
weakened
Influenza
Influenza virus spreads from person to person by ____________ or by _______ with contaminated hands or surfaces
airborne droplets
contact
Epidemiology of influenza
Influenza occurs ______ with an annual attack rate estimated at __%–__% in adults and __%–__% in children.
globally; 5–10; 20-30
Epidemiology of influenza
Illnesses can result in hospitalization and death mainly among high-risk groups (the very young, elderly or chronically ill).
T/F
T
Epidemiology of influenza.
Worldwide, these annual epidemics are estimated to result in about ___________ cases of severe illness, and about __________ to ________ deaths.
3 to 5 million
250 000 to 500 000
Clinical features of Upper respiratory tract infection
chills, headache, and dry cough followed closely by high fever, generalized muscular aches, malaise, and anorexia.
T/F
T😂
Clinical features of Pneumonia
May be complicated by secondary bacterial infection
Eg ________ and _______
S. aureus, H. influenzae
Treatment of influenza
May reduce severe complications and deaths.
Ideally they need to be administered early (within ______ of onset of symptoms)
48 hours
Treatment of influenza
Neuraminidase inhibitor
oselta_____ and zana_____ , pera_____ and lanina____
Adamantanes
aman______ and riman_____
mivir; mivir; mivir; mivir
tadine; tadine
Prevention and control
___________ viral vaccines
Inactivated
Prevention and control
Vaccine composition ———- that targets the _________ most representative virus types in circulation
_____ subtypes of influenza A viruses and ——- B virus.
Hand hygiene
biannually
3 (trivalent)
two; one
