Adenovirus Infections

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Adenovirus Infections

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Adenovirus Infections

  1. 1. ADENOVIRUSES Basics Dr.T.V.Rao MD Dr.T.V.Rao MD 1
  2. 2. Human Adenoviruses Adenoviruses were first isolated in 1935 from human adenoid tissues. Since then, at least 52 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. Dr.T.V.Rao MD 2
  3. 3. Basis of Adenovirus typing 52 human serotypes, 7 distinct species A-G  based on hemagglutination properties, DNA homology and oncogenic potential in rodents Different serotypes may cause infection or distinct diseases in different age groups or patient populations Neutralizing antibodies are serotype-specific Cellular immune response cross-reactive across various serotypes
  4. 4. What are Adenoviruses Adenoviruses are a group of medium sized, nonenvelopedd, double stranded DNA viruses that share a common complement fixing antigen They infect humans and animals Dr.T.V.Rao MD 4
  5. 5. Chaterstics of Adenovirus Adenoviruses are medium-sized (90–100 nm, nonenveloped (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. Dr.T.V.Rao MD 5
  6. 6. Adenovirus Genome The adenovirus genome is linear, non- segmented double stranded (ds) DNA which is around 30–38 Kbp. This allows the virus to theoretically carry 30 to 40 genes. Although this is significantly larger than other viruses in its Baltimore group it is still a very simple virus and is heavily reliant on the host cell for survival and replication. An interesting feature of this viral genome is that it has a terminal 55 kDa protein associated with each of the 5 ends of the linear dsDNA, these are used as primers in viral replication and ensure that the ends of the virus linear genome are adequately replicated Dr.T.V.Rao MD 6
  7. 7. Morphology of Adenovirus Adenovirus are 70-75 nm in size The capsid contains 252 capsomers arranged as icosahedrons with 20 triangular facets and 12 vertices 240 are called as hexons 12 are called as pentons Dr.T.V.Rao MD 7
  8. 8. Appear as space vehicle Dr.T.V.Rao MD 8
  9. 9. Adenoviruses are prevalent all over the world Over 50 serotypes are isolated Most of the recent isolates are from AIDS patients Infections are common in children and world wide prevalence. Dr.T.V.Rao MD 9
  10. 10. Morphological configuration Each penton unit consists of penton base anchored in the capsid and projection or fibre consists of a rode like portion with a knob attached at the distal end The virus appears like a space vehicle. Dr.T.V.Rao MD 10
  11. 11. Classification Contain two genera Mast adenovirus. Infects the mammals Aviaadenovirus Infects birds They infect only the homologues species with the exception of oncogenic human adenovirus Type 12, 18,and 31 cause sarcoma when injected into new born hamsters. Dr.T.V.Rao MD 11
  12. 12. Diseases caused by AdenovirusesGroup Affected Syndromes SerotypesNeonates Fatal disseminated infection 3, 7, 21, 30Infants Coryza, pharyngitis 1, 2, 5 (C)Children Upper respiratory disease 1, 2, 4-6 Pharyngoconjunctival fever 3, 7 (B) Hemorrhagic cystitis 7, 11, 21 (B) Diarrhea 2, 3, 5, 40, 41 (F) Intussussception 1, 2, 4, 5 Meningoencephalitis 2, 6, 7, 12Young adults Acute respiratory disease and PNA 3, 4, 7Adults Epidemic keratoconjunctivitis 8, 19, 37 (D)Immunocompromised PNA with dissemination 5, 31, 34patients Liver infection 1, 2, 5 (C) Urinary Tract Infection 35, 39 Intestinal Infection 42-51 (D) CNS disease including encephalitis 7, 12, 32
  13. 13. 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. Dr.T.V.Rao MD 13
  14. 14. Pathogenesis Adenovirus cause infections in Respiratory tract Eye, Urinary bladder, and Intestines More than one type of virus may cause clinically different diseases Dr.T.V.Rao MD 14
  15. 15. CLINICAL SYNDROMESA. Respiratory diseases:B. Eye infections:C. Gastrointestinal diseaseD. Other diseases:E. Adenoviral infections of the immune compromised host Dr.T.V.Rao MD 15
  16. 16. Clinical Features 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. Dr.T.V.Rao MD 16
  17. 17. 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 childrens summer camps (swimming pool conjunctivitis). Dr.T.V.Rao MD 17
  18. 18. 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. Dr.T.V.Rao MD 18
  19. 19. Adenovirus infections are important in Military MedicineAdenoviruses are responsible for 3-5% ofacute respiratory infections in children and2% of respiratory illnesses in civilian adults.They are more apt to cause infection amongmilitary recruits and other young people wholive in institutional environments. Outbreaksamong children are frequently reported atboarding schools and summer camps. Dr.T.V.Rao MD 19
  20. 20. Adenovirus - Pharyngitis Major cause of infections associated with nonbacterial pharyngitis and tonsillitis Causes febrile common cold Types 1 – 7 are common types Dr.T.V.Rao MD 20
  21. 21. Adenovirus Common cause of Respiratory infections Dr.T.V.Rao MD 21
  22. 22. Pneumonia - Adenovirus  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 Dr.T.V.Rao MD 22
  23. 23. ARD – Acute respiratory disease with Adenovirus Occurs usually in military recruits Serotypes 4,7,and 21 are agents commonly associated. Dr.T.V.Rao MD 23
  24. 24. Pharyngocongunctival fever Occurs in civilian population manifest with syndrome of febrile Pharyngitis and conjunctivitis Serotypes 3, 7, and 14 are associated. Dr.T.V.Rao MD 24
  25. 25. B. Eye infections: Mild conjunctivitis:  can occur as a part of respiratory pharyngeal syndromes.  Complete recovery with no lasting sequellae is the common outcome.  Can occur sporadically or in outbreaks. 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. Dr.T.V.Rao MD 25
  26. 26. Epidemic keratoconjunctivitis  Occurs with serious epidemic  Caused by serotypes 8, and less frequently with 19, and 37. Dr.T.V.Rao MD 26
  27. 27. A severe Adenoviral Infection Dr.T.V.Rao MD 27
  28. 28. C. Gastrointestinal disease:1. No disease association 1. Many Adenoviruses replicate in intestinal cells and are present in the stools without being associated with GIT disease.2. Infantile gastroenteritis 1. Two serotypes (40, 41) have been etiologically associated with infantile gastroenteritis. Dr.T.V.Rao MD 28
  29. 29. D. Other diseases: Acute hemorrhagic cystitis:  types 11, 21 may cause acute hemorrhagic cystitis in children especially boys. Dr.T.V.Rao MD 29
  30. 30. Other manifestations Acute follicular conjunctivitis, types 3,4 and 11 are responsible Adenoviral and chlamydial conjunctivitis are clinically similar Diarrhoea – not conclusively established Acute hemorrhagic cystitis in children and types 11 and 21 are responsible Mesenteric adenitis and intussusceptions in children. Dr.T.V.Rao MD 30
  31. 31. E. Adenoviral infections of the immune compromised host The most common clinical manifestations are:  pneumonia,  hepatitis  gastroenteritis. Dr.T.V.Rao MD 31
  32. 32. Adenovirus in immunocompromised Patients with compromised immune systems are especially susceptible to severe complications of adenovirus infection. Acute respiratory disease (ARD), first recognized among military recruits during World War II, can be caused by adenovirus infections during conditions of crowding and stress. Dr.T.V.Rao MD 32
  33. 33. Immunity in Children Most children have been infected by at least one adenovirus by the time they reach school age. Most adults have acquired immunity to multiple adenovirus types due to infections they had as children. Dr.T.V.Rao MD 33
  34. 34. Diagnosis of Adenoviral Infections Diagnosis: Antigen detection, polymerase chain reaction assay, virus isolation, and serology can be used to identify adenovirus infections. Adenovirus typing is usually accomplished by haemagglutination-inhibition and/or neutralization with type-specific antiserum. Since adenovirus can be excreted for prolonged periods, the presence Dr.T.V.Rao MD 34
  35. 35. Laboratory DiagnosisDirect detection:IsolationSerology Dr.T.V.Rao MD 35
  36. 36. Laboratory DiagnosisDirect 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. Dr.T.V.Rao MD 36
  37. 37. Laboratory DiagnosisIsolation 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 Dr.T.V.Rao MD 37
  38. 38. Laboratory DiagnosisSerology Haemagglutination inhibition Neutralization tests can be used to detect specific antibodies following Adenovirus infection. Dr.T.V.Rao MD 38
  39. 39. Adenovirus TreatmentAntivirals against AdV: Potential targets:  AdV DNA polymerase  AdV cysteine protease  receptors for binding host cells Antivirals in use:  Ribavirin  Cidofovir  Ganciclovir  (Vidarabine)
  40. 40. Prevention and control Careful hand washing is the easiest way to prevent infection. Disinfection of Environmental surfaces with hypochlorites. 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. Dr.T.V.Rao MD 40
  41. 41. Prevention of Adenoviral Infections 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. Dr.T.V.Rao MD 41
  42. 42. Adenovirus asVectors On trails Vaccine production  HIV  Malaria  Ebola  Hepatitis C  TB
  43. 43. Hand Washing still can reduce Adenoviral Infections Dr.T.V.Rao MD 43
  44. 44.  Programme created by Dr.T.V.Rao MD for Medical and Paramedical students in the developing world  Email  doctortvrao@gmail.com Dr.T.V.Rao MD 44

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