Download An upper respiratory tract infection

Microbiology Lab
Respiratory tract
infection
Done by :
Yasmin El Helu
Rana Abu Zuhri
Asmaa Abu Shamla
Fungal infection
of
the respiratory tract
Aspergillosis
Is an allergic reaction, invasive infection or growth caused
by Aspergillus fumigatus.
Inhaling of certain species of this fungi’s mold spores can
lead to dire consequences, particularly by those
with weak immune systems.
Aspergillosis takes on different forms: Allergic bronchopulmonary aspergillosis
allergic reaction to aspergillus, developing in those with preexisting lung problems, such as asthma or cystic fibrosis.
Invasive pulmonary aspergillosis
The most severe form of the disease by aspergillus mold spores.
Almost exclusively affecting those with weakened immune
systems, this infection spreads rapidly.
It comes with a high risk of invading and damaging tissue
throughout your body, especially your lungs , brain , heart and
kidneys.
Aspergilloma
•
Is a fungus ball, occurring in those who had a previous lung
disease.
• Lungs that have air space damage caused by emphysema,
tuberculosis, histoplasmosis, cystic fibrosis, sarcoidosis, lung
cancer or other lung diseases develop pulmonary aspergilloma.
Histoplasmosis
 Is an infectious disease caused by inhaling the spores of a
fungus called Histoplasma capsulatum.
 Histoplasmosis is not contagious.
 Primarily affects a person's lungs, and its symptoms vary
greatly. The vast majority of infected people are
asymptomatic , or can appear as a mild, flu-like
respiratory illness .
 People with weakened immune systems are at the
greatest risk for developing severe and disseminated
histoplasmosis.
Fungal Sinusitis
Fungi involved in sinusitis include:
• Aspergillus is the most common cause of all
forms of fungal sinusitis.
• Other fungi include, Alternaria,
Cryptococcus, Candida, Sporothrix,, and
Mucormycosis.
Thrush
Is an oral infection with the fungus Candida albicans,
which causes yellow, raised sores in the mouth,
sometimes extending to the throat (cause of sore
throat).
Bacterial infection
of
the respiratory tract
Respiratory tract infection caused by
Bacteria:1-Upper respiratory tract infections.
2- Otitis media
3-Lower respiratory tract infections.
4-Tuberculosis (TB).
• The upper respiratory tract: includes the
sinuses, nasal passages, pharynx, and larynx.
• An upper respiratory tract infection : is an
infectious process of any of the components of the
upper airway.
 Upper respiratory tract infection (URI):  Represents the most common acute illness evaluated in the
outpatient setting.
 Viruses account for most URIs.
 Bacteria account for up to 25 percent of upper respiratory
tract infections.
 Bacterial primary infection or superinfection may require
targeted therapy.
Specific manifestations of URIs:Rhinitis, pharyngitis, sinusitis, epiglottitis, laryngitis, and
tracheitis .
Pharyngitis :-
Is defined as an infection or irritation of the pharynx and/or
tonsils.
 The etiology is usually infectious:1- Viral origin, which is the most common cause. These cases
are benign and self-limiting for the most part.
2- Bacterial origin, which is self-limiting, but are concerning
because of suppurative and nonsuppurative complications.
3-Fungal origin
 Non-infectious
allergy, trauma(mechanical, chemical or thermal irritation), toxins,
and neoplasia.
Bacteria causes pharyngitis:1-Streptococcal pharyngitis
 Caused by group A beta hemolytic streptococcus (GAS)-(Streptococcus
pyogenes).
 The most significant bacterial agent causing pharyngitis in both adults and
children.
 Symptoms include fever ,sore throat,, and enlarged lymph node.
 It is the cause of 37% of sore throats among children.
 A definitive diagnosis is made based on the results of a throat culture
A culture positive
case of streptococcal
pharyngitis with
typical tonsillar
exudate in a 16 year
old.
Note the redness
and edema of the
oropharynx, the
petechiae, or small
red spots, on the
soft palate. This is an
uncommon but
highly specific
finding in
streptococcal
pharyngitis.
2-Fusobacterium necrophorum
• Are normal inhabitants of the oropharyngeal flora.
• responsible for 10% of all acute sore throats , 21% of all
recurring sore throats, and 23% of peritonsillar abscesses
• In 1 out of 400 untreated cases, Lemierre's syndrome occursKnown as (human necrobacillosis)- It’s a form of
thrombophlebitis.
Fusobacterium
necrophorum bacteria
cultured in a thioglycollate
medium for 48 hours.
F. necrophorum is a
nonmotile, gram-negative
anaerobe that normally
inhabitants the pharynx,
gastrointestinal tract, and
female genital tract.
• 3- Diphtheria
life threatening upper respiratory infection caused by
Corynebacterium diphtheriae which has been largely
eradicated in developed nations since the introduction of
childhood vaccination programs, but is still reported in the
Third Worldand increasingly in some areas in Eastern Europe.
• Clinical criteria
 Upper respiratory tract illness with sore throat
 Low-grade fever
 An adherent pseudomembrane of the tonsil(s), pharynx, and/or
nose.
Epiglottitis:• Inflammation of the epiglottis , swelling of this structure can
interfere with breathing and constitutes a medical emergency .
• The infection can cause the epiglottis to either obstruct or
completely close off the trachea.
• Caused by:Haemophilus influenzae type B, although some cases are
attributable to Streptococcus pneumoniae , Streptococcus
agalactiae, Staphylococcus aureus, and Streptococcus pyogenes
Acute H influenzae
type b epiglottitis
with striking
erythema and
swelling of the
epiglottis.
`
Tracheitis:Although the trachea is usually considered part of the lower respiratory tract,
in ICD-10 tracheitis is classified under "Acute upper respiratory infections".
Bacterial tracheitis
• A bacterial infection of the trachea and is capable of
producing airway obstruction.
• One of the most common causes is Staphylococcus
aureus and often follows a recent viral upper
respiratory infection.
• It is the most serious in young children, possibly
because of the relatively small size of the trachea that
gets easily blocked by swelling.
Sinusitis
The bacteria most commonly implicated in sinusitis
include:
• Streptococcus pneumoniae. This bacterium is found
in up to 45% of adults and children with sinusitis.
• H. influenzae (a common bacterium associated with
many upper respiratory infections). This bacterium
causes about 25% of sinusitis cases in children.
• Moraxella catarrhalis. Over 75% of all children
harbor this bacterium, which causes about 25% of
sinusitis cases.
Other possible bacteria include:
• Other streptococcal strains
• Staphylococcus aureus
• P. aeruginosa, Klebsiella pneumoniae, Proteus
mirabilis, Enterobacter species, and Escherichia coli
• Fusobacterium nucleatum and Prevotella intermedia)
Bacterial
lower
respiratory tract
infections
Lower respiratory tract infection
• The lower respiratory tract consists of
the trachea ,bronchial tubes, the
bronchioles, and the lung.
• Lower respiratory tract infections are
generally more serious than upper
respiratory infections.
• LRIs are the leading cause of death
among all infectious diseases.
• The most common LRIs are bronchitis,
pneumonia, and empyema.
Acute Bronchitis
• Bronchitis is the inflammation of the mucus
membranes of the bronchi.
• Usually caused by viruses and rarely by
bacteria.
• Characteristic symptoms include cough,
sputum production, shortness of breath
,wheezing.
• Bacteria like 1. mycoplasma pneumoniae,
2.streptococcus pneumoniae, 3.bordatella
pertussis and 4.chlamydophila pneumoniae
account for about 10% of acute cases .
• Diagnosis is by clinical examination
and sometimes microbiological
examination of the sputum.
• Treatment for acute bronchitis is
typically symptomatic, as viruses
cause most cases of it, antibiotics
should not be used unless
microscopic examination of gramstained sputum reveals large
numbers of bacteria.
Chronic bronchitis
• Chronic bronchitis, a type of chronic
obstructive pulmonary disease .
• Cigarette smoking is the most
common cause, followed by air
pollution and occupational exposure
to irritants.
Pneumonia
• Pneumonia can be generally defined as
inflammation of the lung parenchyma, in which
consolidation of the affected part and a filling
of the alveolar air spaces with exudate.
• Often pneumonia begins after an upper
respiratory tract infection (an infection of the
nose and throat) ,pneumonia begin after 2 or 3
days.
• Sign and symptoms: fever ,rigors ,cough,
dyspnea ,chest pain, hemoptysis
Typical pneumonia
• Streptococcus pneumoniae, or
pneumococcus, is Gram-positive,
alpha-hemolytic, bile-soluble
aerotolerant anaerobic member of
the Streptococci.
• S. pneumoniae was recognized as a
major cause of pneumonia.
Atypical pneumonia
• The bacteria responsible for causing atypical pneumonia are:
1.Chlamydophila pneumoniae, 2.Mycoplasma pneumoniae and
3.Legionella pneumophila.
• Most forms of atypical pneumonia are characterized by mild
symptoms;
• However, the pneumonia caused by
Legionella sometimes result in severe
symptoms. The mortality rate of
Legionella induced pneumonia is quite high.
Community acquired pneumonia
• Community acquired pneumonia : is the 4th most widespread
cause of fatality.
• 85 percent of the CAP episodes occur due to typical pathogens
like 1.Haemophilus influenza, 2.Moraxella catarrhalis and
3.Streptococcus pneumoniae.
• The other 15 percent of the CAP cases occur due to atypical
pathogens like 1.Legionella species, 2.Chlamydia pneumoniae
and 3.Mycoplasma pneumoniae.
• In rare cases the condition can also be triggered by:
1.Acinetobacter, 2.Pseudomonas aeruginosa and
3.Enterobacter.
Hospital-Acquired Pneumonia
• Develops at least 48 h after hospital
admission.
• The most common pathogens are :
• 1.gram-negative bacilli mainly : Enterobacter
sp, Klebsiella pneumoniae, Escherichia coli,
Serratia marcescens, Proteus sp,
Acinetobacter sp.
• 2.Staphylococcus aureus,
• 3. Haemophilus influenzae.
• Pseudomonas aeruginosa, which is especially common in
pneumonias acquired in intensive care settings and in
patients with cystic fibrosis, neutropenia, advanced AIDS,
and bronchiectasis.
• Drug-resistant organisms are an important concern.
• Etiology: The most common cause is microaspiration of
bacteria that colonize the oropharynx and upper airways in
seriously ill patients.
Other types
• Tuberculosis can cause pneumonia in some people,
especially those with a weak immune system.
• Pneumonia caused by Yersinia pestis is usually called
pneumonic plague.
Diagnosis:
• Chest x-ray and clinical criteria.
• Sometimes bronchoscopy, blood cultures.
Treatment:
• Empirically chosen antibiotics active against resistant gramnegative and gram-positive organisms
• If the diagnosis is suspected, treatment is with antibiotics
that are chosen empirically based on local sensitivity
patterns.
Empyema
• Is a collection of pus within a naturally existing anatomical
cavity, such as the lung pleura.
• It must be differentiated from an abscess, which is a
collection of pus in a newly formed cavity.
• Most pleural empyemas arise from an infection within the
lung ‘pneumonia’. However, it can also arise from
1.penetrating chest trauma, 2.esophageal rupture,
3.complication from lung surgery, 4.or inoculation of the
pleural cavity after thoracentesis.
• Symptoms include: cough, fever, chest pain, sweating and
shortness of breath, clubbing of the fingers.
• Diagnosis is confirmed by thoracentesis; pus may be
aspirated from the pleural space.
• The pleural fluid typically has a leukocytosis, low pH ,low
glucose ,a high LDH (lactate dehydrogenase), elevated
protein and may contain infectious organisms.
Treatment
Appropriate antibiotic selection
should be based on the Gram stain
and culture of the pleural fluid;
however, because a large number
of patients may have already
received antibiotics at the time of
thoracentesis, an empiric selection
of the most appropriate antibiotics
is necessary.
Otitis media
• Inflammation of the middle ear.
• It occurs in the area between the tympanic membrane
and the inner ear, including the eustachian tube.
• The most common bacterial pathogen is
Streptococcus pneumoniae.
• Others include 1.Pseudomonas aeruginosa,
2.nontypeable Haemophilus influenzae, and
3.Moraxella catarrhalis.
• Among older adolescents and young adults,
the most common cause of ear infections is
Haemophilus influenzae.
Tuberculosis
• Tuberculosis (TB) is an
infectious disease caused by
the bacteria Mycobacterium
tuberculosis, and
mycobacterium kanasasii,
M.avium-intracellulare.
• TB disease most often affects
the lungs, but can occur
anywhere in the body
Symptoms
• The most common symptom of contagious TB
disease is a cough that lasts for more than a three
weeks, sometimes producing mucous and/or blood.
• Other symptoms may include fatigue, loss of
appetite, weight loss, fever, and night sweats.
• Chest pain may also occur.
Diagnosis:
• Tuberculosis is diagnosed by finding Mycobacterium
tuberculosis in a clinical specimen taken from the patient,
either by acid fast stain or sputum culture(6 weeks).
• While other investigations may strongly suggest
tuberculosis as the diagnosis, they cannot confirm it .
Treatment:
• the standard "short" course treatment for TB is isoniazid,
rifampicin ,pyrazinamide, and ethambutol for two months,
then isoniazid and rifampicin alone for a further four
months.
Viral Infections of the
Respiratory Tract
Made by:
Asma’a Abu Shamlah
To:
Dr. Ayham Abu Laila
• Respiratory tract infections are common in
both adults and children.
• Most are probably viral induced -at least
initially, and are fairly mild, self- limiting
and confined to the upper respiratory tract
(URT).
• However, in infants and children, URT
infections may spread downwards and
cause more severe infections and even
death.
The respiratory tract infections are
classified according the anatomic division in
to:
1.
upper respiratory tract infections (URTI)
which involve the airway above the glottis or vocal cords
(nose, sinuses, pharynx or larynx).
This commonly includes: rhinitis, sinusitis, tonsillitis,
pharyngitis, laryngitis, otitis media epiglottitis and the
common cold.
•
Over 200 different viruses have been isolated in patients
with URIs. The most common virus is called the rhinovirus.
Other viruses include the coronavirus, parainfluenza virus,
adenovirus, enterovirus, and respiratory syncytial virus.
2.
•

lower respiratory tract infections :
which involve the trachea, bronchial tubes, the bronchioles, and the
lungs (below the glottis).
Lower respiratory infections, such as pneumonia and bronchitis ,
tend to be far more serious conditions than upper respiratory
infections (such as the common cold) and are the leading cause of
death among all infectious diseases.
Influenza affects both the upper and lower respiratory tracts, but
more dangerous strains such as the highly pernicious H5N1 tend to
bind to receptors deep in the lungs.
1. Upper Respiratory Tract Viral
Infections
•
Common
Cold
The common cold (also known as nasopharyngitis or acute
viral rhinopharyngitis ) is the most frequent infectious
disease in humans with the average adult contracting two
to four infections a year and the average child contracting
between 6–12.
• Common symptoms include a cough, sore throat, runny
nose, nasal congestion and fever. Sometimes this may be
accompanied by conjunctivitis (pink eye), muscle aches,
fatigue, headaches, shivering, and loss of appetite.
• There is currently no known treatment that shortens the
duration; however, symptoms usually resolve
spontaneously in 7 to 10 days, with some symptoms
possibly lasting for up to three weeks.
• Collectively, colds and other upper respiratory tract
infections (URTI) with similar symptoms are included in
the diagnosis of influenza-like illness.
• Due to the many different types of viruses and their
tendency for continuous mutation, it is impossible to gain
complete immunity to the common cold.
The causes of the common cold are:
1. Rhinovirus which cases 30–50% of cases.
2. Coronavirus causes 10–15% of cases.
• Human rhinovirus is a type of picornaviruses with 99
known serotypes. It is the most common viral infective
agents in humans.
Rhinovirus infection proliferates in temperatures
between 33–35 °C, and this may be why reproduction
occurs primarily in the nose .
• Coronaviruses are enveloped viruses
with a single-stranded RNA genome and
a helical symmetry.
• Others causes of common cold include:
influenza viruse (5–15%), human
parainfluenza viruses, human respiratory
syncytial virus, adenoviruses,
enteroviruses, and metapneumovirus.
Tonsillitis
•
•
•
•
•
Tonsillitis is an inflammation of the tonsils with symptoms
include :
red and/or swollen tonsils
white or yellow patches on the tonsils
tender, stiff, and/or swollen neck
sore throat with painful or difficult swallowing
cough, headache, sore eyes, body aches, otalgia, fever, chills
and nasal congestions.
 Acute tonsillitis is caused by both bacteria and viruses with
bacterial tonsillitis is quite common.
 While no treatment has been found to shorten the duration of
viral tonsillitis, bacterial causes are treatable with antibiotics.
The most common causes of viral tonsillitis are:
•
•
The common cold viruses (adenovirus, rhinovirus, influenza,
coronavirus, respiratory syncytial virus).
It can also be caused by Epstein-Barr virus, herpes simplex virus,
cytomegalovirus, or HIV.
Under normal circumstances, as viruses enter the body through
the nose and mouth, they are filtered in the tonsils. Within the
tonsils, white blood cells of the immune system mount an attack
that helps destroy the viruses, and also causes inflammation and
fever.
The infection may also be present in the throat and surrounding
areas, causing inflammation of the pharynx.
 Adenoviruses from family Adenoviridae
are medium-sized nonenveloped
icosahedral viruses composed of a
nucleocapsid and a double-stranded
linear DNA genome.
There are 55 serotypes in humans,
which are responsible for 5–10% of
upper respiratory infections in children,
and many infections in adults as well.
 Human respiratory syncytial virus (RSV also called pneumovirus)
is the major cause of lower respiratory tract infection (especially
bronchiolitis) and hospital visits during infancy and childhood especially
in the temperate climates.
• Natural infection with RSV induces protective immunity which wanes
over time, and thus people can be infected multiple times.
• Severe RSV infections have increasingly been found among elderly
patients.
• RSV is a single-stranded RNA virus of the family Paramyxoviridae,
which includes common respiratory viruses such as those causing
measles and mumps.
 Epstein-Barr virus (EBV), also called human
herpesvirus 4 (HHV-4), is a virus of the herpes
family, which includes herpes simplex virus 1 and
2, and is one of the most common viruses in
humans.
• Infants become susceptible to EBV as soon as
maternal antibody protection disappears.
• It is associated with particular forms of cancer,
from which is nasopharyngeal carcinoma, and
there is evidence that infection with the virus is
associated with a higher risk of certain
autoimmune diseases.
• Many children become infected with EBV, and
these infections usually cause no symptoms or
are indistinguishable from the other mild, brief
illnesses of childhood.
 Herpes simplex virus 1 and 2 (HSV-1 and HSV-2) are
two members of the herpes virus family,
Herpesviridae.
• The structure of herpes viruses consists of a relatively
large double-stranded, linear DNA genome encased
within an icosahedral capsid, which is wrapped in an
envelope.
• Both HSV-1 (which produces cold sores) and HSV-2
(which produces genital herpes) are ubiquitous and
contagious. They can be spread when an infected
person is producing and shedding the virus.
• Sometimes, the viruses cause very mild or atypical
symptoms during outbreaks. However, as
neuroinvasive viruses, HSV-1 and -2 persist in the body
by becoming latent and hiding from the immune
system in the cell bodies of nerves.
 Cytomegalovirus is also a viral genus of
the Herpesviridae or herpesviruses family.
• The species that infects humans is
commonly known as human CMV (HCMV)
or human herpesvirus-5 (HHV-5). And like
all herpesviruses share a characteristic
ability to remain latent within the body
over long periods.
• (Although they may be found throughout
the body, CMV infections are frequently
associated with the salivary glands) .
Sinusitis
• Sinusitis is inflammation of the paranasal
sinuses, which may be due to infection,
allergy, or autoimmune issues, but most
cases are due to a viral infection. Drainage of
mucous secretions in these spaces may be
impaired and lead to secondary bacterial
infection. This resolve over the course of 10
days.
It is a common condition, with roughly 90%
of adults have had sinusitis at some point in
their life .
 By duration, sinusitis can be acute (going on less than
four weeks), subacute (4–8 weeks) or chronic (going on
for 8 weeks or more).
All three types of sinusitis have similar symptoms, and
are thus often difficult to distinguish.
(Viral sinusitis typically lasts for 7 to 10 days, whereas
bacterial sinusitis is more persistent.)
• Chronic sinusitis have symptoms of nasal congestion,
facial pain, headache, night-time coughing and many
others.
 And By location, sinusitis can be frontal, ethmoid,
maxillary and sphenoid sinuses.
 The major causes of sinusitis are Adenovirus and
Respiratory Syncytial Virus.
Pharyngitis (Sore Throat)
• Pharyngitis is an inflammation of the throat
or pharynx. In most cases it is painful. It is the
most common cause of a sore throat.
• Like many types of inflammation, pharyngitis
can be acute – characterized by a rapid onset
and typically a relatively short course – or
chronic.
• Pharyngitis can result in very large tonsils
which cause trouble swallowing and
breathing. Pharyngitis can be accompanied by
a cough or fever, for example, if caused by a
systemic infection.
• Most acute cases are caused by viral infections
(40–80%), with the remainder caused by bacterial
infections, fungal infections, or irritants such as
pollutants or chemical substances.
• If the inflammation includes tonsillitis, it is called
pharyngotonsillitis. Another sub classification is
nasopharyngitis (the common cold).
• The most common viral cause is adenovirus.
Others are influenza Virus, Epstein-Barr virus,
Herpes simplex virus and common cold viruses.
Laryngitis
•
•
•
•
•
•
•
•
•
•
•
•
Laryngitis is an inflammation of the larynx. Symptoms are:
hoarse voice or the complete loss of the voice because of irritation to
the vocal folds (dysphonia).
Dry, sore throat
Coughing, which can be a symptom of, or a factor in causing laryngitis
Difficulty swallowing
Sensation of swelling in the area of the larynx
Cold or flu-like symptoms
Swollen lymph nodes in the throat, chest, or face
Fever
Coughing out blood
Difficulty breathing (mostly in children)
Difficulty eating
Increased production of saliva in mouth
•
•
Laryngitis is categorized as acute if it lasts less than a few days. Otherwise it is
categorized as chronic, and may last over 3 weeks.
The chronic form of disease occurs mostly in middle age and is much more
common in men than women.
Viral causes of acute laryngitis include:
• Adenovirus infection
• Influenza viruses
• Measles virus
• Mumps virus
• Parainfluenza viruses
• Respiratory syncytial virus
• Rhinovirus infection (common cold virus)
• Varicella zoster virus (chicken pox virus)
Croup
• Croup (or laryngotracheobronchitis) is a respiratory
condition that is usually triggered by an acute viral
infection of the upper airway.
• The infection leads to swelling inside the throat, which
interferes with normal breathing and produces the
classical symptoms of a "barking" cough and
hoarseness. It may produce mild, moderate, or severe
symptoms, which often worsen at night. Hospitalization
is rarely required.
• Viral croup caused by parainfluenza virus, primarily
types 1 and 2, in 75% of cases.
• Other viral etiologies include influenza A and B,
measles, adenovirus and respiratory syncytial virus
(RSV).
• Human parainfluenza viruses (HPIVs) are a
group of four distinct serotypes of enveloped
single-stranded RNA viruses belonging to the
paramyxovirus family.
• They are the second most common cause of
lower respiratory tract infection in younger
children.
• Together, the parainfluenza viruses cause
~75% of the cases of Croup
• In immunosuppressed people, such as
transplant patients, parainfluenza virus
infections can cause severe pneumonia,
which can be fatal.
2- Lower
Respiratory Tract Viral Infections
Tracheitis
• Tracheitis is most often caused by the bacteria Staphylococcus
auras. It frequently follows a recent viral upper respiratory
infection.
• It affects mostly young children, possibly because their small
trachea is easily blocked by swelling.
Symptoms:
• Increasing deep or barking croup cough following a previous upper
respiratory infection
• Crowing sound when inhaling (inspiratory stridor)
• 'scratchy' feeling in the throat
• Chest pain, Fever, Ear ache, Trouble breathing, Headache and
Dizziness (light headed) .
Bronchitis
• Bronchitis is inflammation of the mucous membranes of the bronchi . It
also can be divided into two categories, acute and chronic, each of which
has unique etiologies, pathologies, and therapies.
 Acute bronchitis is characterized by the development of a
cough, with or without the production of sputum, mucus.
•
It often occurs during the course of an acute viral illness
such as the common cold or influenza.
• Viruses cause about 90% of cases of acute bronchitis, whereas
bacteria account for less than 10%.
 Chronic bronchitis, a type of chronic obstructive pulmonary
disease, is characterized by the presence of a productive
cough that lasts for three months or more per year for at least
two years.
Bronchiolitis
• Bronchiolitis is an acute inflammation of the
bronchioles (a common disease in infancy)
usually caused by viruses.
• This is most commonly caused by respiratory
syncytial virus. Other viruses include
metapneumovirus, influenza, parainfluenza,
coronavirus, adenovirus, and rhinovirus.
 Human metapneumovirus (hMPV) is a negative
single-stranded RNA virus of the family
Paramyxoviridae.
• It may be the second most common cause
(after the respiratory syncytial virus) of lower
respiratory infection in young children.
• Compared with respiratory syncytial virus,
infection with human metapneumovirus tends
to occur in slightly older children and to
produce disease that is less severe.
• Co-infection with both viruses can occur, and is
generally associated with worse disease.
Pneumonia
• Pneumonia is an inflammatory condition of the
lung, especially the alveoli .
• There are many causes, of which infection is the
most common, infecting agents can be bacteria,
viruses, fungi, or parasites.
• Diagnostic tools include x-rays and examination of
the sputum.
• Pneumonia is a common disease that occurs in all
age groups. It is a leading cause of death among
the young, the old, and the chronically ill.
• The prognosis depends on the type of pneumonia,
the treatment, any complications, and the
person's underlying health.
• Viral pneumonia have been found to account for between 18—28% of
pneumonia.
• Viruses can also make the body more susceptible to bacterial infections;
for which reason bacterial pneumonia may complicate viral pneumonia.
• It is commonly caused by viruses such as influenza virus, respiratory
syncytial virus (RSV), adenovirus, and parainfluenza.
• Herpes simplex virus is a rare cause of pneumonia except in newborns.
• People with weakened immune systems are also at risk of pneumonia
caused by cytomegalovirus (CMV).
•
•
•
•
•
•
•
•
•
•
Influenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of
the family Orthomyxoviridae (the influenza viruses), that affects birds and mammals.
Symptoms of influenza can start quite suddenly one to two days after infection. Usually the
first symptoms are chills, but fever is also common early in the infection, with body
temperatures ranging from 38-39 °C. Other symptoms may also include:
Cough
Nasal congestion
Body aches, especially joints and throat
Fatigue
Headache
Irritated, watering eyes
Reddened eyes, skin (especially face), mouth, throat and nose
In children and bird flue, gastrointestinal symptoms such as diarrhea and abdominal pain.
(may be severe in children with influenza B).
• Although it is often confused with other influenza-like
illnesses, especially the common cold in the early stages
of the infection, but a flu can be identified by a high fever
with a sudden onset and extreme fatigue.
• Influenza is a more severe disease than the common cold
and is caused by a different type of virus.
• In occasional cases, even for healthy young adults, flu can
cause either respiratory distress syndrome or pneumonia.
And in general, in occasional cases, flu can cause either
direct viral pneumonia and/or secondary bacterial
pneumonia.
•
•
•
•
Types of influenza viruses
Influenza viruses are RNA viruses that make up three of the five genera of the
family Orthomyxoviridae:
Influenzavirus A
Influenzavirus B
Influenzavirus C
Structure of the influenza virion. The hemagglutinin (HA) and
neuraminidase (NA) proteins are shown on the surface of the particle.
There are 16 different H antigens (H1 to H16) and nine different N
antigens (N1 to N9). So, in theory, 144 different combinations of these
proteins are possible.
Influenzavirus A
•
•
•
This genus has one species, influenza A virus. Wild aquatic birds are the natural hosts
for a large variety of influenza A.
It is the most virulent human pathogens among the three influenza types and cause
the most severe disease.
The influenza A virus can be subdivided into different serotypes based on the type of
two proteins on the surface of the viral envelope:
The serotypes that have been confirmed in humans, ordered by the number of known
human pandemic deaths, are:
•
•
•
•
•
•
H1N1 which caused Spanish Flu in 1918, and Swine Flu in 2009
H2N2, which caused Asian Flu (Bird flu) in 1957
H3N2, which caused Hong Kong Flu in 1968
H5N1, which caused Bird Flu in 2004
H7N7, which has unusual zoonotic potential
H1N2, endemic in humans, pigs and birds
Influenzavirus B
• This genus has one species, influenza B virus. Influenza B almost
exclusively infects human and is less common than influenza A.
• This type of influenza mutates at a rate 2–3 times slower than type A
and consequently is less genetically diverse, with only one influenza B
serotype.
• As a result of this lack of antigenic diversity, a degree of immunity to
influenza B is usually acquired at an early age. However, influenza B
mutates enough that lasting immunity is not possible.
• This reduced rate of antigenic change, combined with its limited host
range (inhibiting cross species antigenic shift), ensures that pandemics
of influenza B do not occur.
Influenzavirus C
• This genus has one species, influenza C virus,
which infects humans, dogs and pigs,
sometimes causing both severe illness and
local epidemics. However, influenza C is less
common than the other types and usually
only causes mild disease in children.