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.