Smallpox

Smallpox (variola) is a severe contagious Orthopoxvirus disease with high mortality. Crops of generalized rash progressing macule→papule→vesicle→pustule with severe viremia; pustules crust leaving pitted scars for life. Variola minor (alastrim) is milder. Eradicated 1980 but bioterrorism concern.

Common Symptoms

Macule; intense pruritus; pustule; nasal congestion; fatigue; pitted scar; crusting; toxemia

Causes and Pathogenesis

Orthopoxvirus, brick-shaped 200×300 nm, dry/cold-resistant (months to 1.5 years in crusts/dust/clothes). Highly contagious; respiratory droplet/direct contact. Pathogenesis: URT adsorption → local nodes → primary viremia → mononuclear phagocyte replication → secondary viremia → widespread skin/mucosa/viscera. After 2-3 day prodrome, rash appears; virus preferentially in cooler skin. Dermal capillary dilation → macule; epidermal proliferation → papule; cell degeneration/necrosis → multiloculated umbilicated vesicle; inflammatory cells → pustule; drying → crust. Secondary bacterial infection by scratching worsens; mucosal lesions ulcerate rapidly and are highly contagious; corneal involvement blinds.

Treatment

Drug therapy, symptomatic, supportive therapy

Preventive Measures

Strict isolation; disinfection; supportive care; smallpox vaccination is the most effective prevention. (1) Isolate/suspected cases; disinfect/incinerate low-value items; report to CDC. (2) Contact tracing; 16-day quarantine; immediate vaccination; vaccinia-immune IG for contraindicated contacts. (3) Traffic quarantine/checkpoints.

Department to Visit

It is recommended to visit the Infectious Diseases department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.