AC

Bloodborne, Oral, and Respiratory Pathogens – Key Vocabulary

Herpesviridae Family & Oral/Respiratory Relevance

  • General framework
    • 8 known human herpes viruses (HHV) ≈ herpes simplex viruses (HSV) 1\text{–}8.
    • All are enveloped DNA viruses; establish lifelong latency, reactivate with immunosuppression/stress.
    • Course focus: clinically important members encountered in dental/medical settings (HSV-3 to HSV-4 in detail today; brief mention of HSV-5\text{–}8).

Varicella-Zoster Virus (HSV-3)

  • Dual disease spectrum
    • Primary infection → Chickenpox (Varicella).
    • Reactivation (usually decades later) → Shingles (Herpes Zoster).
  • Contagiousness & immunity
    • Chickenpox is “extremely contagious.” Once infected, durable immunity against varicella forms → second episodes of chickenpox are rare.
    • Re-exposure in an individual with prior chickenpox typically produces shingles rather than a second varicella case.
    • Shingles lesions also shed infectious virus → still contagious, particularly to varicella-naïve contacts.
  • Vaccination
    • Routine childhood varicella immunization now available in the U.S.; adult zoster vaccine recommended to curb shingles in older populations.
  • Anecdotal illustration (instructor’s story)
    • Parent-encouraged exposure approach ("chickenpox parties") used pre-vaccine era.
    • Instructor never contracted chickenpox despite repeated exposures; later serologically tested → not immune; chose vaccination.
    • Sister’s adult-onset chickenpox (age 35) described as severe: widespread vesicles, including oral mucosa and scalp – underscores higher morbidity of adult disease.

Epstein–Barr Virus (EBV) (HSV-4) – Mononucleosis

  • Alias: “Mono,” “The Kissing Disease.”
  • Transmission
    • Salivary exchange: sharing drinks, utensils, kissing, dental aerosols, etc.
  • Clinical spectrum
    • Mild/nonspecific in young children; more florid in adolescents/young adults.
    • Classic triad: pharyngitis, lymphadenopathy, fever.
    • Oral manifestations
    • Severe sore throat; tonsillar exudates – may mimic bacterial strep throat.
    • Petechiae on soft palate: small pinpoint \text{red} macules/“polka-dots.” Helpful diagnostic clue.
    • Whitish oral plaques/lesions possible.
  • Significance to dentistry
    • Highly contagious; strict instrument/handpiece sterilization and avoidance of sharing items are mandatory.
    • Awareness that a patient with “strep-like” complaints might actually harbor EBV.

Streptococcal Respiratory Infections

Streptococcus pyogenes

  • Gram-positive, spherical (coccus) bacterium; Group A β-hemolytic streptococcus.
  • Diseases
    • Streptococcal Pharyngitis (Strep Throat)
    • Thick white/purulent exudate on tonsils & oropharynx.
    • Severe odynophagia, fever.
    • Scarlet Fever = Strep throat + diffuse, sandpaper-like skin rash.
  • Dental‐office implications
    • Both illnesses “extremely contagious.”
    • Patient with active signs (exudative throat, fever) should be deferred – risk to staff & other patients.

Streptococcus pneumoniae

  • α-hemolytic, encapsulated Gram-positive diplococcus; normal flora in many noses/throats.
  • Pathogenic potential
    • Pneumonia: bacterial form treatable with antibiotics; viral pneumonias do not respond to antibacterials.
    • Otitis media (middle-ear infection): leading microbial cause in children.
    • Bacterial meningitis: serious CNS infection.
  • Carriage facts
    • Asymptomatic carriage common in preschoolers & adults → silent reservoir.
    • Emphasizes importance of standard precautions; children may spread pneumococcus without symptoms.

Tuberculosis (TB)

  • Etiologic agent: Mycobacterium tuberculosis (acid-fast bacillus).
  • Pathophysiology
    • Primarily a lung infection; can disseminate.
    • Requires prolonged close exposure for transmission – airborne droplet nuclei.
  • Healthcare perspective
    • Incidence relatively low in U.S.; higher in resource-limited regions (“third world”).
    • Mandatory annual screening for dental/medical personnel: PPD (two-step) or IGRA blood test.
    • Emergence of multidrug-resistant TB (MDR-TB) & extensively drug-resistant TB (XDR-TB) noted; rising global concern, though routine U.S. dental risk remains minimal.

Other Human Herpesviruses (Brief Overview)

  • HSV-5 = Cytomegalovirus (CMV)
    • Usually asymptomatic; problematic in immunocompromised & congenital infections.
  • HSV-6 & HSV-7
    • Cause exanthem subitum/roseola infantum; details not emphasized in course.
  • HSV-8 = Kaposi’s Sarcoma-associated Herpesvirus (KSHV)
    • Linked to Kaposi’s sarcoma in AIDS and transplant recipients.
  • Course takeaway: These types exist but are less central to routine dental infection-control decisions.

Clinical & Infection-Control Implications for Dental Professionals

  • Always evaluate oral mucosa & oropharynx for infectious signs (white plaques, petechiae, purulence, vesicles).
  • Defer elective treatment for patients with active contagious conditions (strep throat, mono, shingles, chickenpox).
  • Maintain up-to-date immunizations (varicella, influenza, hepatitis B, etc.).
  • Annual TB testing is mandatory; understand low but non-zero occupational risk.
  • Recognize that antimicrobial resistance (MDR-TB, drug-resistant Streptococcus strains) is an evolving threat; follow evidence-based guidelines for referral and prophylaxis.
  • Standard precautions (PPE, hand hygiene, sterilization) remain cornerstone defense against salivary & respiratory pathogens.