Summary about Disease
Smallpox was a highly contagious and often fatal infectious disease caused by the variola virus. It was characterized by a distinctive skin rash with fluid-filled blisters (pustules) all over the body. Through successful global vaccination efforts, smallpox was eradicated worldwide, with the last naturally occurring case in 1977. The World Health Organization (WHO) officially declared smallpox eradicated in 1980. While eradicated, concerns remain about potential re-emergence from stored virus samples.
Symptoms
Fever
Malaise (general feeling of discomfort, illness, or unease)
Headache
Severe back pain
Sometimes, abdominal pain and vomiting
Characteristic rash: appearing as small, red spots on the face, hands, and forearms, which spread to the trunk. These spots turn into papules (raised bumps), then vesicles (small blisters filled with clear fluid), and finally pustules (blisters filled with thick, opaque fluid). The pustules scab over and eventually form scars (pockmarks).
Causes
Smallpox was caused by the variola virus, a member of the orthopoxvirus family. The virus spread through:
Direct contact with infected individuals (e.g., face-to-face contact).
Contact with contaminated objects such as bedding or clothing.
Droplets spread through the air (less common, but could occur with prolonged close contact).
Medicine Used
Vaccinia Immune Globulin (VIG): Could reduce the severity of the disease if given early.
Tecovirimat (Tpoxx): An antiviral medication approved for the treatment of smallpox.
Brincidofovir (Tembexa): Another antiviral medication approved for the treatment of smallpox.
Supportive care: Prior to specific antivirals, treatment focused on managing symptoms, preventing secondary bacterial infections, and maintaining hydration.
Is Communicable
Yes, smallpox was highly communicable. It spread primarily through person-to-person contact. Individuals were most contagious from the onset of the rash until all scabs had separated.
Precautions
Vaccination: The smallpox vaccine was highly effective in preventing the disease. Ring vaccination (vaccinating close contacts of infected individuals) was a key strategy in eradication.
Isolation: Infected individuals needed to be strictly isolated to prevent further spread.
Contact tracing: Identifying and monitoring individuals who had been in contact with infected persons was crucial.
Proper disposal of contaminated materials: Careful handling and disinfection of contaminated items were essential.
How long does an outbreak last?
Historically, an outbreak could last for weeks or months, depending on the effectiveness of control measures like vaccination and isolation. The duration of an individual's illness was typically several weeks, from the onset of symptoms to the shedding of all scabs.
How is it diagnosed?
Diagnosis would involve:
Clinical evaluation: Examination of the characteristic rash and symptoms.
Laboratory testing:
PCR (polymerase chain reaction) to detect the variola virus DNA in samples from skin lesions or other bodily fluids.
Virus isolation in cell culture (performed in specialized laboratories).
Electron microscopy to visualize the virus particles.
Serological tests to detect antibodies against the variola virus (less useful for early diagnosis).
Timeline of Symptoms
Incubation period (7-19 days, typically 12-14 days): Asymptomatic.
Initial symptoms (2-4 days): Sudden onset of fever, malaise, headache, severe back pain, and sometimes abdominal pain and vomiting.
Early rash (approximately 4 days after initial symptoms): Small red spots appear on the tongue and in the mouth. These develop into sores that break open and spread the virus. A rash starts on the face and spreads to the arms and legs, then to the hands and feet.
Rash development (next 1-2 weeks): The rash progresses from macules (flat spots) to papules (raised bumps) to vesicles (small blisters filled with clear fluid) to pustules (blisters filled with thick, opaque fluid).
Pustules scab over (5-7 days): The pustules begin to scab over.
Scabs fall off (weeks): The scabs eventually fall off, leaving pitted scars (pockmarks). A person is contagious until all scabs have separated.
Important Considerations
Eradication: Smallpox is officially eradicated, making naturally occurring cases extremely unlikely.
Laboratory storage: Samples of the variola virus are stored in highly secure laboratories (CDC in the US and Vector Institute in Russia) for research purposes.
Bioterrorism threat: There is concern that the virus could be used as a biological weapon.
Vaccine availability: The smallpox vaccine is no longer routinely administered to the general public but is stockpiled for use in the event of an outbreak or bioterrorism event.
Cross-protection: The smallpox vaccine also provides some protection against other orthopoxviruses, such as monkeypox.