Docstoc

Viral infection of the respiratory tract

Document Sample
Viral infection of the respiratory tract Powered By Docstoc
					Viral infection of the respiratory tract --- 1


    DR. MOHAMMED ARIF
    ASSOCIATE PROFESSOR
    CONSULTANT VIROLOGIST
    HEAD OF THE VIROLOGY UNIT
 Respiratory tract infection



 Respiratory tract infections are common in both children and adults.


 Mostly caused by viruses. ًّٓ‫ي‬


 Mostly are mild and confined to the upper respiratory tract(URT).


 Mostly are self limiting. ‫ال تحتاج عالج‬


 URT-infection may spread down ward and causes more severe infection
  and even death.
Clinical manifestations ‫المظاهر االكلينيكيه‬



 Common cold (coryza ‫ ,صكاو‬rhinitis).
 Pharyngitis. ‫التهاب البلعىم‬
 Tonsilitis.
 Sinusitis ‫ & انتٓاب انجٍٕب‬otitis media ‫.انتٓاب االرٌ انٕسطى‬
 Croup ‫ ( يشض انخإَق‬acute laryngotracheobronchitis).
 Acute bronchitis.
 Acute bronchiolitis.
 Viral pneumonia.
 Influenza ( Flu ) . ّ‫نٓا ششائح يُفصه‬

Respiratory tract .
                                                   : ‫نكم إَاع انفٍشٔسات‬
                                  ‫اػشف انؼائهّ فقط َٕٔع انحًط انُٕٔي ٔاػشف ْم انفٍشٔط‬
1- Rhinoviruses .                           Enveloped or unenveloped
                                              ‫االشٍاء االظافٍّ سٍتى االشاسِ نٓا‬


                                                        : ‫انذكتٕس ٌقٕل‬
 Family: Picornaviridae.
                                                    ِ‫اي خط ػشٌط يؼُا‬
                                                             ‫يٓى‬
 Genus : Rhinovirus . ّ‫ال تحفظ‬


 Unenveloped.


 Small icosahedral ‫ له عشرين وجه‬particle, 20 - 30 nm in diameter .


 The viral genome is ss-RNA, with positive polarity .


 More than 100 types .
EM of rhinoviruses .
Corona ‫ التاجيه‬viruses .


 Family: Coronaviridae .


 Irregular in shape .


 Enveloped with club shaped glycoprotein spikes ‫. سثة تسًٍتٓا تانتاجٍّ ٔجٕد‬


 Helical nucleocapsid .


 The viral genome is ss-RNA, with positive polarity.
EM of corona viruses .
       Rhino and corona viruses are the major
       cause of common cold. ) ‫معلومه مهمه جدا ( سؤال‬


 Common cold :


 inflammation of the nose and throat (nasopharynx) ,
  characterized by watery nasal discharge and sneezing.



 It is a highly contagious ‫ يؼذي‬disease.
General characteristics of rhinoviruses .


 They replicate in the nasopharynx .


 They are sensitive to acids . ‫يؼهٕيّ يًّٓ سكض ػهٍٓا انذكتٕس- نزنك تًٕت ْزِ انفٍشٔسات‬
   - ِ‫يثاششِ ػُذ دخٕنٓا انًؼذ‬

 Shed ٌ‫ سٍال‬in large amounts in nasal secretion.


 Transmitted by inhalation of respiratory droplets during sneezing and
  coughing

 The optimal temperature for their replication is 33-35 c .
 Do not efficiently ‫ تشكم فؼال‬replicate at body temperature .
Common cold
Transmission


 By inhalation of respiratory droplets, during sneezing and coughing.


 Through contaminated hands.




 Target group:

 both children and adults.
Clinical features


 IP: 1-3 days. ) ‫ال تحفظٓا ( انكالو ػاو نكم انفٍشٔسات‬


  Symptoms:

 Watery nasal discharge.


 Sneezing.


 Mild sore throat.


 Fever is not common. ‫معلىمه مهمه جدا‬
Prognosis and lab. diagnosis


Prognosis:

 Self-limiting disease.
 Recovery is complete.


Lab. Diagnosis:

 Not needed, diagnosis is made on the basis of clinical symptoms.
Treatment


 There is no specific anti-viral drug therapy.


 Treatment is supportive.
2- Parainfluenza viruses .


 Family : Paramyxoviridae .
 Genus :Respirovirus. ًّٓ‫غٍش ي‬


 Large, 150-300 nm in diameter .


 Pleomorphic ‫ , يتؼذد االشكال‬helical nucleocapsid .


 Enveloped with two glycoprotein spikes, HN and F ‫. االحمر قراءه فقظ‬


 The viral genome is ss-RNA with negative polarity .
Parainfluenza viruses . ‫قراءه بتركيز‬


 The HN has both hemagglutinine and neuraminidase activities .


 Attachment proteins . They bind to specific receptors on the cell
  membrane .

 The F ( fusion ), mediates cell entry by the fusion process


 The viral genome is ss-RNA, with negative polarity .
Respiratory syncytial virus ( RSV ) .



 Family : Paramyxoviridae .
 Genus : Pneumovirus . ‫الغير مهمه‬


 Large , 150-300 nm .


 Pleomorphic, helical nucleocapsid .


 Enveloped with two glycoprotein spikes, G and F .


 The viral genome is ss-RNA with negative polarity .
RSV . ‫قراءه بتركيز‬



 The G protein, lack hemagglutinine and neuraminidase activities .
  Attachment protein.

 The F, Mediates cell entry , by fusion process .
Diseases ‫مهمه جدا جدا‬


 1- Croup ( acute laryngotracheobronchitis ) . Caused mainly
    by parainfluinza type I , II ‫مهمه جدا‬

 Parainfluenza types 1 and 2 are the major cause of croup in
    infants and young children .

 RSV .


   Influenza A .
Croup




 Acute inflammation of the larynx and trachea in infants and
 young children.

 Usually caused by viruses.


 Characterized by swelling of the epithelial cells lining the air
  way, so that the air way narrows and breathing becomes
  difficult.
Transmission



 By inhalation of respiratory droplets.




Target groups:

 Children between six months to three years.
Symptoms


 Usually preceded ‫ تسبق بـ‬by a cold symptoms.


 Fever.


 Respiratory distress ( difficult and labored breathing ).


 Barking spasmodic cough.


 Inspiratoty stridor.


 Hypoxia and cyanosis
Prognosis


 In mild cases, recovery is usual in 3-5 days.




 Small proportion of cases proceed ‫ تتطىر‬to bronchiolitis and pneumonia.
Lab. diagnosis




 Specimen, is nasopharyngeal aspirate (NPA).


 By direct demonstration ‫ ايضاح‬of the virus in the infected cells
  , inside the NPA.
Nasopharyngeal aspirate
2 -Bronchiolitis


 Inflammation of the bronchioles in infants and young
  children. Bronchioles become inflamed, edematous and
  obstructed by mucous .

 Viral etiology :


 Mostly caused by viruses.


 Respiratory syncytial virus ( RSV ) and parainfluenza virus
  type 3 are the major cause of bronchiolitis in infants. ‫المعلىمه‬
   ‫مهمه جدا وسؤااال‬
Bronchiolitis



 Influenza A viruses.
 Adenoviruses.




 Transmission : By inhalation of respiratory droplets.


 Target group : Infants less than 18-months.
Bronchiolitis

   Symptoms :


 Usually preceded by URT symptoms.


 Expiratory obstruction.


 Expiratory wheezing.


 Respiratory distress ( difficult & labored breathing ).


 Hypoxia and cyanosis
Bronchiolitis


 Prognosis and treatment.


 Most cases are mild ,recover completely & do not require
  hospitalization .Increasing respiratory distress, cyanosis, fatigue or
  dehydration are indication for hospitalization.

 Lab diagnosis.


  By direct demonstration of the viral antigens in the
  nasopharyngeal aspirate, using immuno flourescent
  technique.
Viral pneumonia


 Inflammation of the lung and alveoli.




 The most commonly caused viruses are:


 RSV and parainfluenza virus type-3 are the major cause of
  infantile ‫ االطفال‬pneumonia .

 Influenza A viruses.


 Adenoviruses.
5-Viral pneumonia


 Human metapneumovirus.
 CMV in the immunocompromised.
 Varicella-zoster virus in adults.


 Transmission : by inhalation of respiratory droplets during sneezing
  and coughing.


 Target groups: young children and the immunocompromised .
Viral pneumonia
Viral pneumonia


 Symptoms: usually preceded by the URT symptoms.


 Fever.
 Chills.
 Pharyngitis.
 Cough.
 Shortness of breath .
 Muscle aches .
 Fatigue.
 Chest pain .
Viral pneumonia

 Prognosis: Most cases are mild and get better without treatment.


 Some cases are more serious and require hospitalization.


 Complications: Respiratory failure, heart failure and liver
  failure.
Viral pneumonia

 Treatment : Specific anti-viral drugs are available for:

 CMV , ganciclovir.


 VZV , ganciclovir.


 Influenza A , amantadine and remantadine
 Lab. diagnosis


 For RSV , influenza & parainfluenza viruses :
  Detection of the viral antigen in the nasopharyngeal aspirate
  (NPA), using direct immuno fluorescence.

 For adenoviruses :


  Isolation of these viruses in tissue culture, followed by identification of
  the isolated virus.

  Specimens: NPA, throat swab, bronchial wash.
    Adenoviruses.


   Family : Adenoviridae.

 Icosahedral, 90-100 nm in diameter.


 Unenveloped ( naked ) .


 One spike ( fiber ) at each vertex.


 The viral genome is linear ds-DNA.


 51- human adenoviruses, grouped in 6-species A-F .
EM of adenoviruses ,
Adenoviruses


 Transmission:


 Respiratory infection ,by inhalation of respiratory droplets.


-- Through contaminated hands.
-- Direct contact with contaminated surfaces.

 Intestinal tract infection:
-- By the fecal oral route.
 Adenoviruses.


 Eye infection:


-- Through contaminated hands.
-- Using contaminated towels.
-- Using contaminated eye-drops, ophthalmic instruments.

 Target groups : Children and adults.
 Adenoviruses.


 Diseases associated with adenoviruses: ‫مهمه جدا جدا‬


 Keratoconjunctivitis. ‫االلتهاب الجاف للقرنيه والملتحمه بالعين‬


 Pharyngo -conjunctival fever.


 Acute respiratory diseases.


 Gastroenteritis.


 Urinary tract infection.
 Meningitis.
                       Adenoviruses.


 Prognosis:


 Self- limiting disease.
 Recovery is usual.
Adenoviruses.



 Treatment:


 There is no anti-viral drug therapy.
 Treatment is supportive.


   Lab diagnosis:

 By isolation of the virus in tissue culture, followed by
    identification of the isolated virus.
Adenoviruses.


 Prevention:
 There is no vaccine available yet.




                ً‫تاتغ انًحاظشِ فً انسالٌذات ف‬
                        : ‫انًهف االخش‬
                    ‫تتحذث ػٍ االَفهَٕضا‬

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:23
posted:8/7/2011
language:English
pages:45