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Smallpox
Variola virus causes the acute, contagious disease smallpox. It was effectively eradicated through global vaccination efforts led by the WHO between 1966-1979. Smallpox is characterized by an initial fever and flu-like symptoms followed by a distinctive pustular rash. It spreads through respiratory droplets or direct contact with infected individuals or contaminated objects. Vaccination provided effective immunity and was a major factor in eliminating smallpox worldwide by 1980, making it the only human infectious disease to be fully eradicated.
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Smallpox
- 2. PRESENTED BY: OM VERMA ASSISTANTPROFESSOR RELIANCE INSTITUTE OF NURSING DHAMTARI
- 4. An acute contagiousviral disease, with fever and pustules that usually leave permanent scars. It was effectively eradicated through vaccination by 1979.
- 7. # Caused byVariola virus # Double stranded DNA virus # Genus: Orthopoxvirus # Variola major or minor # Stable outside host(retains infectivity) The Organism
- 8. Variola major – Classicsmallpox – Predominant form in Asian epidemics – Highest mortality (~30%) Variola minor – Causes milderdisease – Discovered in 20thcentury – Started in S.Africa – Was most predominant form in N.America Microbiology
- 9. • All agesand genders affected • Incubation period • From infection to onset of prodrome • Range 7-17 days • Mortality • 30% overall in unvaccinated population • Infants, elderly greatest risk (>40%) • Dependent on virus strain • Dependent on disease variant Microbiology continues
- 11. No animal reservoirand no human carriers. First certain evidence comes from the mummified remains of Ramses(1157 B.C.). First Case of Smallpox
- 12. ETIOLOGY Smallpox is causedby infection with the variola virus. The virus can be transmitted: Directly from person to person. Direct transmission of the virus requires fairly prolonged face-to-face contact. The virus can be transmitted through the air by droplets that escape when an infected person coughs, sneezes or talks. Indirectly from an infected person. In rare instances, airborne virus can spread farther, possibly through the ventilation system in a building, infecting people in other rooms or on other floors.
- 13. Via contaminated items. Smallpoxcan also spread through contact with contaminated clothing and bedding, although the risk of infection from these sources is less common. As a terrorist weapon, potentially. A deliberate release of smallpox is a remote threat. However, because any release of the virus could spread the disease quickly, government officials have taken numerous precautions to protect against this possibility, such as stockpiling smallpox vaccine.
- 14. Pathophysiology Virus lands onrespiratory/oral mucosa Macrophages carry to regionalnodes Invades reticuloendothelial organs White Blood Cells infected Systemic inflammatory response
- 15. Stages of Smallpox Threestages of disease: • 1. Incubation • Asymptomatic • 2. Prodromal • Nonspecific febrile illness, flu-like • 3. Eruptive • Characteristic rash
- 23. Rash Stages ofDevelopment
- 25. • The firstsymptoms of smallpox usually appear 12 to 14 days after you're infected. • During the incubation period of seven to 17 days, you look and feel healthy and can't infect others. Symptoms & Signs
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- 28. • Initially viaaerosol • Then person-to-person • Hospital outbreaks fromcoughing patients • Highly infectious Airborne route Infectious Materials: Saliva Vesicularfluid Scabs Urine Conjunctival fluid Possiblyblood Transmission
- 29. • Physical examinationand blood tests. Fever and the distinctive, progressive skin rash will indicate smallpox. • Smallpox and monkeypox virions may be indistinguishable. Diagnosis
- 31. • The smallpoxvaccine is the only known way to prevent smallpox in an exposed person. The smallpox vaccine helps the body develop immunity to smallpox. Prevention
- 32. Variolation • Inoculation withinfectious smallpox • Scabs or pustular material • 3% mortality • Immunized were infectious - outbreaks • Provided full immunity • Originated in Eastern countries in ancient times • Started in U.S. by Rev. Cotton Mather 1721 Treatment
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- 34. Vaccine Administration Jet gun •Rapid • High maintenance Bifurcated needle • High efficacy, sterilizable, rapid (1500/day) • Uses less vaccine • Mainstay for the WHO eradication campaign
- 35. Smallpox (Vaccinia) Vaccine Dryvax® •Lyophilized vaccinia containing calf lymph. • Trace amounts of antibiotics: • Polymyxin B. • Streptomycin. • Chlortetracycline. • Neomycin. Smallpox Vaccine
- 36. Complications of Vaccination Treatmentsfor Complications: 1. Vaccinia Immune Globulin(VIG) 2. Cidofovir Eczema vaccinatum Progressive vaccinia Generalized vaccinia Post-vaccinial encephalitis
- 37. • Exposure toa case patient after fever onset • Contact with secretions or • Face-to-face contact or • In nosocomial setting with a case • Includes all hospital patients and staff Carefully identify true contacts:- Management of Case Contacts
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- 40. • Oct 26,1977, last case of smallpox. • May 8, 1980, official declaration by WHO - Smallpox Eradicated! The End of Smallpox Last case of Variola minor, Somalia 1977 Last case of Variola major, Bangladesh 1975
- 41. Slowspread Effective, relatively safe vaccine No animal/insect vectors Infectious only with symptoms Priorinfection giveslifelong immunity International cooperation Factors That Allowed Smallpox Eradication
- 42.