University at Albany Prevention Research Center

SMALLPOX

Infectious Agent

A DNA virus Variola Virus (Family: Poxviridae; Subfamily: Chordopoxviridae; Genus: Orthopoxvirus).
More Information On Infectious Agent at CIDRAP
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Clinical Symptoms

Incubation Period - 10 to 13 days
Prodromal Period - lasts for 2 to 4 days and is characterized by fever, chills, headcahe, nausea, vomiting, diarrhea, abdominal pain, backache.
Rash - Emanthems on oral and pharyngeal mucosa followed by skin lesions first on the face and then on the trunk, upper extremity and then the lower extremities. Lesions are initially maculopapular (days 1-2), then vesicular (days 3-5), pustular (days 7-14) followed by gradual scabbing by the end of 2nd or 3rd week. The skin lesions are usually painful, are either discrete or confluent or semi-confluent and cause pitted scarring as they heal.
Complications - severe fluid-electrolyte imbalance, respiratory failure, viral bronchitis and pneumonitis, corneal ulceration, encephalopathy, orchitis and osteomyelitis.
More Information On Clinical Symptoms at CIDRAP & CDC
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Epidemiology

Reservoir - Before global eradication, the only reservoir was humans; currently none. Stocks of Variola virus have been retained in two WHO approved collaborating centers, the Centers for Disease Control & Prevention (CDC) in Atlanta, USA and the Russian State Center for Research on Virology & Biotechnology in Koltsovo, Novosobirsk region, Russian Federation.
Modes of Transmission -
- Predominantly transmitted person-to-person via inhalation of droplet nuclei (most commonly face-to-face contact)
- Airborne transmission (less common)
- Fomite transmission has also been reported
Communicability - Low infectious dose (10 to 150 organisms). A patient is highly infectious during the first week after rash onset and remains infectious until all lesions have scabbed over and the scabs have fallen off.
More Information On Epidemiology at CIDRAP & CDC

Smallpox as a Bioterrorism Agent

Smallpox can be a highly dangerous and effective bioterrorist agent owing to the following factors:
- Susceptibility of the majority of the population
- High morbidity and mortality rate
- Unavailability of vaccine for general use
- Great deal of havoc and panic
More Information on Smallpox as a Bioterrorism Agent at CIDRAP & CDC

Prevention & Control

Isolation Precautions: Airborne and Contact Precautions in addition to Standard Precautions
Vaccination of Health Care Workers
Disinfection/Sterilization of Reusable Medical Equipment
Cleaning and Disinfection of Environmental Sources
Laundry and Waste
Decontamination
More Information on Prevention & Control at CIDRAP , NYSDOH & CDC

Click here for Information on

Naturally Occurring Smallpox at CIDRAP
Laboratory Diagnosis at CIDRAP , NYSDOH & CDC
Treatment & Vaccination Information at CIDRAP , NYSDOH & CDC

Additional Sources of Information

- Visit the Centers for Disease Control & Prevention (CDC) Smallpox Home Page
- Visit Infectious Disease Society of America (IDSA) for Smallpox Information


Category A Anthrax Botulism Plague Smallpox Tularemia Viral Hemorrhagic Fevers Category B Brucellosis Glanders Melioidosis Psittacosis Q Fever Typhus Fever Viral Encephalitis Toxins Food Safety Water Safety Category C Nipah Hanta Virus Other Important Zoonotic Diseases Transmissible Spongiform Encephalopathy Rift Valley Fever Virus Handra Virus West Nile Fever	SMALLPOX Infectious Agent A DNA virus Variola Virus (Family: Poxviridae; Subfamily: Chordopoxviridae; Genus: Orthopoxvirus). More Information On Infectious Agent at CIDRAP Images at CIDRAP , NYSDOH & CDC Clinical Symptoms Incubation Period - 10 to 13 days Prodromal Period - lasts for 2 to 4 days and is characterized by fever, chills, headcahe, nausea, vomiting, diarrhea, abdominal pain, backache. Rash - Emanthems on oral and pharyngeal mucosa followed by skin lesions first on the face and then on the trunk, upper extremity and then the lower extremities. Lesions are initially maculopapular (days 1-2), then vesicular (days 3-5), pustular (days 7-14) followed by gradual scabbing by the end of 2nd or 3rd week. The skin lesions are usually painful, are either discrete or confluent or semi-confluent and cause pitted scarring as they heal. Complications - severe fluid-electrolyte imbalance, respiratory failure, viral bronchitis and pneumonitis, corneal ulceration, encephalopathy, orchitis and osteomyelitis. More Information On Clinical Symptoms at CIDRAP & CDC Images at CIDRAP , NYSDOH & CDC Epidemiology Reservoir - Before global eradication, the only reservoir was humans; currently none. Stocks of Variola virus have been retained in two WHO approved collaborating centers, the Centers for Disease Control & Prevention (CDC) in Atlanta, USA and the Russian State Center for Research on Virology & Biotechnology in Koltsovo, Novosobirsk region, Russian Federation. Modes of Transmission - - Predominantly transmitted person-to-person via inhalation of droplet nuclei (most commonly face-to-face contact) - Airborne transmission (less common) - Fomite transmission has also been reported Communicability - Low infectious dose (10 to 150 organisms). A patient is highly infectious during the first week after rash onset and remains infectious until all lesions have scabbed over and the scabs have fallen off. More Information On Epidemiology at CIDRAP & CDC Smallpox as a Bioterrorism Agent Smallpox can be a highly dangerous and effective bioterrorist agent owing to the following factors: - Susceptibility of the majority of the population - High morbidity and mortality rate - Unavailability of vaccine for general use - Great deal of havoc and panic More Information on Smallpox as a Bioterrorism Agent at CIDRAP & CDC Prevention & Control Isolation Precautions: Airborne and Contact Precautions in addition to Standard Precautions Vaccination of Health Care Workers Disinfection/Sterilization of Reusable Medical Equipment Cleaning and Disinfection of Environmental Sources Laundry and Waste Decontamination More Information on Prevention & Control at CIDRAP , NYSDOH & CDC Click here for Information on Naturally Occurring Smallpox at CIDRAP Laboratory Diagnosis at CIDRAP , NYSDOH & CDC Treatment & Vaccination Information at CIDRAP , NYSDOH & CDC Additional Sources of Information - Visit the Centers for Disease Control & Prevention (CDC) Smallpox Home Page - Visit Infectious Disease Society of America (IDSA) for Smallpox Information
Created by the School of Public Health University at Albany Updated July 2004