Adenovirus By: Miriam

Ramez

Causes a variety of upper and lower respiratory tract diseases such as:PharyngitisConjunctivitis (pink eye)Common coldPneumoniaKeratoconjuctivitisHaemorrhagic cystitisGastroenteritisCancers in rodents but not in

humans

Important properties:

Medium-sized (90-100nm)Non-enveloped (largest)Double stranded linear DNA Icosahedral nucleocapsidOnly virus with a fiber protruding from each of

the 12 vertices of the capsid.Fiber is organ of attachment and is a

hemagglutinin (main type specific antigen)All have a common group antigen located on

hexon protein41 antigenic types

Summary of replicative cycle: Virus attaches to cell surface via its fiber. The virus enters the cell and uncoats. Viral DNA moves to the nucleus. Host cell DNA-dependent RNA

polymerase transcribes early genes, splicing of introns producing a functional mRNA.

Early mRNAs is translated into non-structural proteins in the cytoplasm.

After DNA replication in nucleus, late mRNA is transcribed and translated into structural virion proteins.

Viral assembly occurs in nucleus, and virion released by lysis of cell

Transmission:

1)Aerosol droplets.2)Fecal-oral route.3)Direct inoculation of conjunctivas by tonometer or fingers.

Epidemiology:

o In military due to close contact.

oAdenovirus infection typically affects children from infancy to school age.

oSerotypes 3,4,7,21 causes respiratory disease.

o8,19 causes keratoconjuctivitis.

o11,21 causes haemorrhagic cystitis .

o40, 41 causes infantile gastroenteritis.

Pathogenesis and immunity:Infect mucosal epithelium of several

organs of the upper and lower respiratory tract, gastrointestinal tract, and conjunctivas.

Immunity is based on neutralizing antibody is type-specific and life long.

Latent infection occurs particularly in adenoidal and tonsillar tissues of throat.

Clinical findings:

Upper respiratory tract: pharyngitis, pharyngoconjunctival fever, and acute respiratory disease characterized by fever, sore throat, coryza(runny nose), and conjunctivitis.

Lower respiratory tract: bronchitis and atypical pneumonia.

Haemolytic cystitis: haematuria and dysuria Gastroenteritis with non-bloody diarrhea

mainly in children younger than 2 years of age Most infections resolve spontaneously and

half of them are asymptomatic.

Diagnosis:

Isolation of virus in cell culture.

Detection of four fold increase in antibody titer.

Complement fixation and hemagglutinin inhibition are most important for serologic tests.

Treatment and prevention: No antiviral treatment,

only symptomatic. 3 live non-attenuated live

viruses against serotypes 4, 7, and 21.

Administered separately because they interfere with each other when given together.

Vaccines delivered in an enteric coated capsule which protects live virus from inactivation by stomach acid.

References:

Clin Microbiol Rev. 2014 Jul; 27(3): 441–462.PubMed.http://kidshealth.org/parent/infections/lung/adenovirus.html#http://www.cdc.gov/adenovirus/about/transmission.html