adenoviruses

1. ADENOVIRUSES
DR.FARIA ASHRAF

2. HUMAN ADENOVIRUSES
• Adenoviruses were first isolated in 1935 from
human adenoid tissues.
• Since then, more than 50 distinct antigenic
types have been isolated from humans and
many other types from animals.
• All human serotypes are included in a single
genus within the family Adenoviridae.

3. WHAT ARE ADENOVIRUSES
• Adenoviruses are a group of medium sized,
non enveloped, double stranded DNA viruses
that share a common complement fixing
antigen
• They infect both humans and animals

4. CLASSIFICATION
• Adenoviruses are divided into six groups (A to
F) based on: • physical, • chemical • biological
properties Antigenic structure divides
adenoviruses into: - 52 serotypes: - About 1/3
of the 52 known human serotypes are
responsible for most cases of Adenovirus
disease.

5. MORPHOLOGY
• Adenovirus are 70-75 nm in size
• The capsid contains 252 capsomeres arranged
as icosahedrons with 20 triangular facets and
12 vertices
• 240 are called as hexons
• 12 are called as pentons.

6. • Each penton unit consists of penton base
anchored in the capsid and projection or fibre
consists of a rod like portion with a knob
attached at the distal end
• The virus appears like a space vehicle.

8. • Adenoviruses are medium-sized (90–100 nm),
non enveloped (naked) icosahedral viruses
composed of a nucleocapsid and a double-
stranded linear DNA genome. There are over
52 different serotypes in humans, which are
responsible for 5–10% of upper respiratory
infections in children, and many infections in
adults as well.

9. WORLDWIDE DISTRIBUTION
• Over 50 serotypes are isolated
• Most of the recent isolates are from AIDS
patients
• Infections are common in children and world
wide prevalence.

10. CLASSIFICATION
• Contain two genera
• Mast adenovirus-Infects the mammals
• Aviaadenovirus-Infects birds
• Type 12, 18,and 31 cause sarcoma when
injected into new born hamsters.

11. PATHOGENESIS
• Adenovirus cause infections in
• Respiratory tract
• Eye, Urinary bladder, and Intestines
• More than one type of virus may cause
clinically different diseases

12. CLINICAL FEATURES
Adenoviruses most commonly cause
respiratory illness; however, depending on the
infecting serotype, they may also cause
various other illnesses, such as gastroenteritis,
conjunctivitis, cystitis, and rash illness.
Symptoms of respiratory illness caused by
adenovirus infection range from the common
cold syndrome to pneumonia, croup, and
bronchitis.

13. RESPIRATORY DISEASES
• The most important etiological association of
adenoviruses is with the respiratory diseases.
• They are responsible for 5% of acute
respiratory diseases in: young children and
much less in adults.

14. • Four different syndromes of respiratory infection
have been linked to Adenoviruses.
• 1. Acute febrile pharyngitis: most commonly seen
in infants and young children, symptoms include
cough, stuffy nose, fever and sore throat.
• 2.Pharyngoconjunctival fever: symptoms are
similar to those of acute febrile pharyngitis but
conjunctivitis is also present. It tends to occur in
outbreaks such as at children's summer camps
(swimming pool conjunctivitis).

15. • 3.Acute respiratory disease: is characterized
by pharyngitis, fever, cough and malaise. It
occurs in an epidemic form among young
recruits under conditions of fatigue and
overcrowding
• 4.Pneumonia: a complication of acute
respiratory disease in both children and
adults.

16. • Adenoviruses are responsible for 3-5% of
acute respiratory infections in children and 2%
of respiratory illnesses in civilian adults. They
are more apt to cause infection among
military recruits and other young people who
live in institutional environments. Outbreaks
among children are frequently reported at
boarding schools and summer camps

17. PHARYNGITIS
• Major cause of infections associated with
nonbacterial pharyngitis and tonsillitis
• Causes febrile common cold
Types 1 – 7 are common types

18. PNEUMONIA
• Adenovirus types 3 and 7 are associated with
pneumonia resembles like atypical pneumonia
in adults.
• Type 7 causes serious and even fatal
pneumonia in infants and young children

19. ARD
• Occurs usually in military recruits
• Serotypes 4,7,and 21 are agents commonly
associated.

20. PHARYNGOCONJUNCTIVAL FEVER
• Occurs in civilian population manifest with
syndrome of febrile pharyngitis and
conjunctivitis
Serotypes 3, 7, and 14 are associated.

21. EPIDEMIC KERATOCONJUNCTIVITIS
• Occurs as a serious epidemic
• Caused by serotypes 8, and less frequently
with 19, and 37.

22. OTHER MANIFESTATIONS
• Acute follicular conjunctivitis, types 3,4 and 11
are responsible
• Adenoviral and chlamydial conjunctivitis are
clinically similar
• Diarrhoea – not conclusively established
• Acute haemorrhagic cystitis in children and
types 11 and 21 are responsible
• Mesenteric adenitis and intussusceptions in
children.

23. DIAGNOSIS
• Diagnosis:
• Virus isolation
• Serology(Antigen detection)
• Polymerase Chain Reaction assay can be used
to identify adenovirus infections.
• Adenovirus typing is usually accomplished by
Hemagglutination-inhibition and/or
neutralization with type-specific antiserum.

24. LABORATORY DIAGNOSIS
• Direct detection: Virus particle by EM can be
detected by direct examination of fecal
extracts
• Detection of adenoviral antigens by ELISA.
Enteric Adenoviruses
• Detection of adenoviral NA by Polymerase
chain reaction: can be used for diagnosis of
Adenovirus infections in tissue samples or
body fluids.

25. Contd…
• Isolation: depending on the clinical disease,
the virus may be recovered from throat, or
conjunctival swabs or and urine.
• Isolation is much more difficult from the stool
or rectal swabs

26. TREATMENT
• Treatment of adenovirus infections is usually
supportive and aimed at relieving symptoms
of the illness. Bed rest may be recommended
along with medications to reduce fever and/or
pain . (Aspirin should not be given to children
because it is associated with Reye's
syndrome.)

27. • Eye infections may benefit from topical
corticosteroids to relieve symptoms and
shorten the course of the disease.
Hospitalization is usually required for severe
pneumonia in infants and for
keratoconjunctivitis (to prevent blindness).

28. PROPHYLAXIS
• Prevention: Vaccines were developed for
adenovirus serotypes 4 and 7, but were available
only for preventing ARD among military recruits.
• Strict attention to good infection-control
practices is effective for stopping nosocomial
outbreaks of adenovirus-associated disease, such
as epidemic keratoconjunctivitis. Maintaining
adequate levels of chlorination is necessary for
preventing swimming pool-associated outbreaks
of adenovirus conjunctivitis.

29. PREVENTION/CONTROL
• Careful hand washing is the easiest way to
prevent infection.
• Disinfection of environmental surfaces with
hypochlorite.
• The risk of water borne outbreaks of
conjunctivitis can be minimized by chlorination of
swimming pools.
• Epidemic keratoconjunctivitis can be controlled
by strict asepsis during eye examination.

30. EMERGING TOOL IN GENETIC ENGG
• Adenovirus vectors are used by researchers to
deliver genetic material into the cells. Not only
is this but they also being used by molecular
biologists for vaccination purposes. They are
mostly used in in-vitro experiments at this
time

31. THANKS