EVOLUTION OF VIRUSES VIRUS CLASSIFICATION VIRAL COMPONENTS & STRUCTURES REPLICATION OF VIRUSES HOST RESPONSE TO VIRAL INFECTIONS HUMAN IMMUNODEFICIENCY VIRUS HERPES VIRUS HERPES SIMPLEX VIRUS EPSTEIN BARR VIRUS HUMAN CYTOMEGALO VIRUS EVIDENCE HUMAN PAPILLOMA VIRUS SARS COV-2 DIAGNOSTIC METHODS TREATMENT

1. VIRUSES IN
PERIODONTICS
DR. BEENA VIJAYAN PARVATHY
2nd YEAR

2. CONTENTS
EVOLUTION OF VIRUSES
VIRUS CLASSIFICATION
VIRAL COMPONENTS & STRUCTURES
REPLICATION OF VIRUSES
HOST RESPONSE TO VIRAL INFECTIONS
HUMAN IMMUNODEFICIENCY VIRUS
HERPES VIRUS
HERPES SIMPLEX VIRUS
EPSTEIN BARR VIRUS
HUMAN CYTOMEGALO VIRUS
EVIDENCE
HUMAN PAPILLOMA VIRUS
SARS COV-2
DIAGNOSTIC METHODS
TREATMENT

3. VIRUS

4. EVOLUTION OF VIRUSES

5. VIRUS CLASSIFICATION
CLASSIFICATION ON THE BASIS OF NUCLEIC ACID

6. Most of the animal viruses are roughly spherical with some exceptions.
Rabies virus: Bullet shaped
Ebola virus: Filamentous shaped
Poxvirus: Brick shaped
Adenovirus: Space vehicle shaped
CLASSIFICATION ON THE BASIS OF SHAPE

7. CLASSIFICATION ON THE BASIS OF STRUCTURE
Cubical virus: They are also known as icosahedral symmetry virus
Eg. Reo virus, Picorna virus.
Spiral virus: They are also known as helical symmetry virus
Eg. Paramyxovirus, orthomyxovirus.
Radial symmetry virus: eg. Bacteriophage.
Complex virus: eg. Pox virus.

8. CLASSIFICATION ON THE BASIS OF THE TYPE OF HOST
They are:
Animal viruses
Plant viruses
Bacteriophage
Animal Viruses
The viruses which infect and live inside the animal cell including man are called animal
viruses.
Eg; influenza virus, rabies virus, mumps virus, poliovirus etc. Their genetic material is RNA or
DNA.
Plant Viruses
The viruses that infect plants are called plant viruses. Their genetic material is RNA which
remains enclosed in the protein coat. Some plant viruses are tobacco mosaic virus, potato virus,
beet yellow virus and turnip yellow virus etc.

9. Bacteriophages
Viruses which infect bacterial cells are known as bacteriophage or bacteria eaters. They contain
DNA as genetic material. There are many varieties of bacteriophages. Usually, each kind of
bacteriophage will attack only one species or only one strain of bacteria.
CLASSIFICATION OF VIRUS ON THE BASIS OF MODE OF TRANSMISSION
Virus transmitted through respiratory route:
Eg, Swine flu, Rhino virus
Virus transmitted through faeco-oral route:
Eg. Hepatitis A virus, Polio virus, Rota virus
Virus transmitted through sexual contacts:
Eg. Retro virus
Virus transmitted through blood transfusion:
Eg. Hepatitis B virus, HIV
Zoonotic virus:
Virus transmitted through biting of infected animals;
Eg. Rabies virus, Alpha virus, Flavi virus

10. CLASSIFICATION OF VIRUS ON THE BASIS OF REPLICATION PROPERTIES AND
SITE OF REPLICATION
Replication and assembly in cytoplasm of host:
All RNA virus replicate and assemble in cytoplasm of host cell except Influenza virus
Replication in nucleus and assembly in cytoplasm of host:
Influenza virus, Pox virus
Replication and assembly in nucleus of host:
All DNA viruses replicate and assemble in nucleus of host cell except Pox virus.
Virus replication through ds DNA intermediate:
All DNA virus, Retro virus and some tumor causing RNA virus replicates through ds DNA as
intermediates.
Virus replication through ss RNA intermediate:
All RNA virus except Reo virus and tumor causing RNA viruses.

11. VIRAL COMPONENTS & STRUCTURES

12. REPLICATION OF VIRUSES

14. HOST RESPONSE TO VIRAL INFECTIONS
Viruses gain entry into the host through different routes which include:
a) Inoculation via the skin and mucosa  needle stick injury, or accidental abrasions
b) Inhalation through respiratory tract aerosol or drops
c) Ingestion via the gastrointestinal tract  oro –fecal route
d) Genitourinary tract sexual activity
Viruses will interact with the host cell in two main ways:
•Permissive infection: the synthesis of viral components, their assembly and release can lead to
consequent death of the host cell.
•Non permissive infection : infection can result in cell transformation often with the
integration of viral DNA into the host genome.

15. UNDERLYING MECHANISMS OF POLYMICROBIAL DISEASE PATHOGENESIS
1. Predisposing factors in the host
2. Alterations in mucosa induced by microbial infection favor the colonization of other
microorganisms
3. Synergistic triggering of proinflammatory cytokines by microorganisms
4. Sharing of determinants among organisms
5. Suppression of the immune response by one organism allowing colonization by others

16. a) Antibody Mediated Antiviral Immunity

17. b) Cell Mediated Antiviral Immunity

18. HUMAN IMMUNODEFICIENCY VIRUS

19. ETIOPATHOGENESIS

21. PROPOSED MODEL OF HIV REACTIVATION DURING CO-INFECTION

22. LINEAR GINGIVAL ERYTHEMA

23. NECROTISING ULCERATIVE GINGIVITIS, PERIODONTITIS, STOMATITIS

25. HERPES VIRUS
CLASSIFICATION

26. REPLICATION

27. ETIOPATHOGENESIS

28. HERPES SIMPLEX VIRUS

30. HERPETIC GINGIVOSTOMATITIS

31. VARICELLA ZOSTER

32. HERPES ZOSTER

33. EPSTEIN BARR VIRUS

35. ORAL HAIRY LEUKOPLAKIA

36. HUMAN CYTOMEGALO VIRUS

37. ETIOPATHOGENESIS

38. EVIDENCES

43. HUMAN PAPILLOMA VIRUS
•HPV belongs to Papilloma viridae family and is a double stranded, non enveloped DNA virus.
• HPV exhibit tropism for epithelial tissue thereby it can affect both skin and mucosa.
•Studies confirm that HPV types 6, 11 and 16 DNA are detected in gingival samples from
patients with periodontal disease explaining the development of gingival papillomas and
condylomas in the oral cavity.

44. REPLICATION

45. SARS COV-2
•The major receptor for SARS-CoV-2 is angiotensin-converting enzyme 2 (ACE2), which binds
to the receptor-binding domain (RBD) of the spike protein.
•ACE2 receptors  respiratory tract and the CVS, CNS, and GIT systems.
•Following the cell entrance and replication, the SARS-CoV-2 leads to pyroptosis, an
inflammatory programmed cell death.
•In conjunction with the pathogen-associated molecular patterns (PAMPs) and damage-associated
molecular patterns (DAMPs), pyroptosis normally stimulates the limited and controlled release of
inflammatory cytokines.
• The excessive immune responses in some patients, however, leads to the cytokine storm and a
tissue-wide damage, followed by septic shock and multiorgan (heart, liver, and kidney) damage.
• The disorder finally leading to death is the respiratory failure primarily and also symptoms of
sepsis

46. •Severity and complications of COVID-19 are highly associated with dysregulated
hyperinflammation in response to viral infection.
•The cytokine storm following the periodontal inflammation releasing into the blood circulation
leads to systemic hyperinflammatory responses bound to be amplified by the production of more
acute phase proteins (e.g., IL-6 and C-reactive protein) in the liver.
•This in turn will strengthen the severe inflammation in lungs and other organs.
•Periodontitis has been associated with several systemic diseases such as diabetes, atherosclerosis
, chronic obstructive pulmonary disease (COPD), and cerebrovascular disease.
• Cytokine storm syndrome has been assumed to be the plausible link between COVID-19 and
periodontal diseases.

49. DIAGNOSTIC METHODS

52. TREATMENT

54. REFERENCES
VIRUSES IN PERIODONTAL DISEASE: A REVIEW Sajini Raj .C, R. Madhumala,
R.Saranyan, D. Jayachandran, N. Sayeeganesh, K. Priya
Periodontology 2000, Focal infection of periodontal origin, Jørgen Slots
Periodontology 2000, Herpesvirus-bacteria synergistic interaction in periodontitis Casey Chen,
Pinghui Feng, Jørgen Slots
Role of Viruses in Periodontal Diseases Mithlesh Bhagat, Roopali Tapashetti, Ghousia
Fatima, Neha Bhutani
Periodontology 2000, Human viruses in periodontitis, JØRGEN SLOTS
Is There a Link between COVID-19 and Periodontal Disease? A Narrative Review
Andreas Grigoriadis, Ismo T. Räisänen, Pirjo Pärnänen, Taina Tervahartiala, Timo Sorsa

55. Thank you