microbio 2125 unit 6 part 3 - smallpox

Etiological Agent:

Orthopoxvirus (Variola virus)

Distinguishing Characteristics of Etiological Agent:

• Member of the Poxviridae family

• Largest and most complex of animal viruses

• dsDNA genome, replicates in cytoplasmic "factory areas"

• Shows specificity for epidermal cells and subcutaneous connective tissues

• Produces eruptive skin pustules (pox) that leave permanent scars

Virulence Factor(s):

• Variola major strain: causes severe disease with toxemia, shock, and intravascular coagulation

• Ability to evade immune response and replicate rapidly in host tissues

Predisposing Factors:

• No prior immunity or vaccination

• Close contact with infected individuals or contaminated materials

Transmission:

• Inhalation of respiratory droplets

• Direct skin contact with infected lesions or contaminated surfaces

Syndrome (Signs + Symptoms):

• initial symptoms: Fever, malaise, prostration (severe exhaustion)

• Rash progression:

  • Macular (flat spots)

  • Papular (raised lesions)

  • Vesicular (fluid-filled)

  • Pustular (filled with pus)

Affected Body Region/System:

• Primarily affects the skin

• Can involve systemic complications in severe cases (e.g., shock, coagulation disorders)

Treatment:

Supportive care for symptoms

Prevention:

• Vaccination with vaccinia virus (related virus, not Variola)

• First disease eliminated by vaccination

• Routine U.S. vaccination ended in 1972, but reintroduced in 2002 for military and healthcare personnel

Other Notes:

• Two forms:

  • Variola major: severe and highly virulent

  • Variola minor: less virulent

• Virus is highly contagious

• No longer naturally occurring due to global vaccination efforts