ADENOVIRUSES

1. ADENOVIRUSES Human Adenoviruses

2. Human Adenoviruses • Adenoviruses were first isolated in 1935 from human adenoid tissues. • Since then, at least 49 distinctantigenic 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.

4. Morphology • DNA viruses, • icosahedral • Nonenveloped Antigenic structure • All human Adenoviruses share a common group-specific antigen. • Type specific antigens are important in serotyping.

5. Classification Adenoviruses are divided into six groups (A to F) based on: • physical, • chemical • biological properties Antigenic structure divides adenoviruses into: - 49 serotypes:

6. Pathogenesis: • Adenoviruses spread by: • direct contact, • respiratory droplets • feco-oral route.

7. Pathogenesis: • Adenoviruses infect and replicate in the epithelial cells of the: • pharynx, • conjunctiva, • urinary bladder • small intestine. They usually do not spread beyond the regional lymph nodes EXCEPT IN THE IMMUNE COMPROMIZED HOST.

8. Pathogenesis: • The virus has a tendency to become latent in lymphoid tissue, • The virus can be reactivated by immunosuppression.

9. CLINICAL SYNDROMES A. Respiratory diseases: B. Eye infections: C. Gastrointestinal disease D. Other diseases: E. Adenoviral infections of the immune compromised host

10. A. Respiratory diseases: Four different syndromes of respiratory infection have been linked to Adenoviruses. • Acute febrile pharyngitis: • most commonly seen in infants and young children, • symptoms include cough, stuffy nose, fever and sore throat. • Pharyngo conjunctival 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).

11. A. Respiratory diseases: • 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 • Pneumonia: a complication of acute respiratory disease in both children and adults.

12. B. Eye infections: • Mild conjunctivitis: • can occur as a part of respiratory pharyngeal syndromes. • Complete recovery with no lasting sequelae is the common outcome. • Epidemic keratoconjunctivitis: • a highly contagious and a more serious disease occurring mainly in adults. • Corneal involvement may be followed by various degrees of visual disability.

13. C. Gastrointestinal disease: • Infantile gastroenteritis • Two serotypes (40, 41) have been etiologically associated with infantile gastroenteritis. NOTE • The enteric Adenoviruses are very difficult to cultivate. • Lab diagnosis depend on direct detection

14. D. Other diseases: • Acute haemorrhagic cystitis: • types 11, 21 may cause acute haemorrhagic cystitis in children especially boys.

15. Laboratory Diagnosis • Direct detection: • Isolation • Serology

16. Laboratory Diagnosis Direct detection: • Virus particle byEM: fecal extracts • Detection of adenoviral antigens byELISA. • Detection of adenoviral NA by Polymerase chain reaction:tissue samples or body fluids.

17. Laboratory Diagnosis Isolation • Isolation from throat, or conjunctival swabs or and urine. • Isolation is much more difficult from the stool or rectal swabs

18. Laboratory Diagnosis Serology • Haemagglutination inhibition • Neutralization tests can be used to detect specific antibodies.