Q. What is Adenovirus?
A. • Adenovirus = non‑enveloped icosahedral virus with double‑stranded DNA (≈36 kb)
• Size 70–90 nm, fiber proteins on capsid give “spike” appearance
Q. How is it transmitted?
A. • Respiratory droplets, aerosols, close contact
• Fecal‑oral route, contaminated water, swimming pools
• Fomites (towels, toys, instruments)
Q. How many types/serotypes?
A. • >50 serotypes, grouped into species A – G (A, B, C, D, E, F, G)
• Species C common in children (pharyngitis, conjunctivitis)
• Species B (type 3, 7) → severe respiratory disease, keratoconjunctivitis
• Species E (type 4, 7) used in oral vaccine for military
Q. What is the morphology?
A. • Naked icosahedral capsid, 12 pentons each with a fiber protrusion
• Linear dsDNA genome, terminal protein attached to 5′ end
• Replicates in nucleus, uses host DNA polymerase
Q. What is the step‑wise pathogenesis?
- → Virus enters through nasal, ocular or oral mucosa
- → Binds to CAR (coxsackie‑adenovirus receptor) via fiber, then integrins via penton base
- → Endocytosis → low‑pH endosome → capsid disassembly, DNA released into cytoplasm
- → DNA transported to nucleus → early gene transcription (E1A, E1B) → inactivates p53, pushes cell into S‑phase
- → Viral DNA replication (DNA‑dependent DNA polymerase)
- → Late gene expression → structural proteins, assembly in nucleus
- → Virions packaged, nuclear membrane breaks → cell lysis → release of new virions → inflammation and tissue damage
Memory trick for pathogenesis: “Enter‑Bind‑Unwrap‑Push‑Copy‑Build‑Burst” (Enter, Bind, Unwrap, Push cell cycle, Copy DNA, Build capsid, Burst out)
Q. What are the main clinical manifestations?
A. • Respiratory: common cold, pharyngitis, laryngotracheobronchitis (croup), bronchitis, pneumonia, especially in infants & immunocompromised
• Ocular: epidemic keratoconjunctivitis, follicular conjunctivitis (“pink eye”)
• Gastro‑intestinal: watery diarrhea, vomiting, abdominal pain (especially serotypes 40, 41)
• Urinary: hemorrhagic cystitis (mainly serotype 11)
• Others: meningitis/encephalitis, myocarditis, hepatitis, pancreatitis (rare)
Q. What complications can occur?
A. • Severe or necrotizing pneumonia → ARDS, respiratory failure
• Chronic lung disease in premature infants
• Corneal scarring → visual loss after keratoconjunctivitis
• Persistent diarrhea → dehydration, electrolyte loss in children
• Disseminated disease in transplant or HIV patients (multi‑organ failure)
Q. How is Adenovirus disease diagnosed in the lab?
A. 1. → Virus isolation in cell culture (HEp‑2, A549) → characteristic cytopathic effect (rounding, balloon cells)
2. → Antigen detection: direct immunofluorescence or ELISA on throat swab, conjunctival scrapings, stool
3. → PCR (real‑time) – most sensitive, detects viral DNA in respiratory secretions, stool, urine, CSF
4. → Serology – rise in IgM or four‑fold rise in IgG between acute and convalescent sera (used for epidemiology)
Memory rhyme for diagnosis: “Culture, Flash (antigen), Amplify (PCR), Titer (serology) – C‑F‑A‑T”
Q. What is the management?
A. • Mainly supportive: hydration, antipyretics, cough & pain relief
• Oxygen & ventilatory support for severe pneumonia/ARDS
• Antiviral (cidofovir or brincidofovir) reserved for immunocompromised or life‑threatening disease
• No routine antibiotics (unless secondary bacterial infection)
Q. How can infection be prevented?
A. • Strict hand‑washing with soap or alcohol‑based sanitizer
• Disinfect surfaces (bleach, alcohol) especially in daycare, schools, hospitals
• Avoid sharing towels, eye makeup, swimming in contaminated pools
• Isolation of infected patients during acute phase (≈10 days)
• Oral live‑attenuated vaccine (type 4 & 7) for military recruits – not in general population
Q. Quick recall mnemonic for sites of disease – “R‑O‑G‑U‑M”
R – Respiratory (cold, pneumonia)
O – Ocular (conjunctivitis, keratitis)
G – Gastro‑intestinal (diarrhea)
U – Urinary (cystitis)
M – Miscellaneous (meningitis, myocarditis)