Variola

DNA viruses Poxviruses Variola Vaccinia Large particles 200 x 250nm complex symmetry Variola is the smallpox virus. It produces a systemic infection with a characteristic vesicular rash affecting the face, arms and legs, and has a high mortality rate. Vaccinia has been derived from the cowpox virus and is used to immunize against smallpox... 

Methisazone (Fig. 5.2IB) inhibits DNA viruses (particularly vaccinia and variola) but not RNA viruses, and has been used in the prophylaxis of smallpox. It is now little used, especially as, according to the World Health Organization, smallpox has now been eradicated. 

Human immunodeficiency virus Influenza Kala-azar Malaria Mycobacteria Mycoplasma Paramyxoviruses Rocky Mountain spotted fever Rubella Typhoid Varicella Variola... 

Slow-acting, contagious Variola major (smallpox) Flu-like symptoms 12 to 14 days... 

Viral agents, such as the alpha virus that causes Venezuelan equine encephalitis (VEE) or variola major (the causative agent for smallpox). 

CDC Case Definition An illness with acute onset of fever >101°F followed by a rash characterized by firm, deep seated vesicles or pustules in the same stage of development without other apparent cause. Clinically consistent cases are those presentations of smallpox that do not meet this classical clinical case definition (1) hemorrhagic type, (2) flat type, and (3) variola sine eruptione. Laboratory criteria for diagnosis is (1) polymerase chain reaction (PCR) identification of variola DNA in a clinical specimen, or (2) isolation of smallpox (variola) virus from a clinical specimen (Level D laboratory only confirmed by variola PCR). 

Guides for Emergency Response Biological Agent or Weapon Smallpox (Variola)... 

Vaccinia An infection, primarily local and limited to the site of inoculation, induced in man by inoculation with the vaccinia (coxpox) virus in order to confer resistance to smallpox (variola). On about the third day after vaccination, papules form at the site of inoculation which become transformed into umbilicated vesicles and later pustules they then dry up, and the scab falls off on about the twenty-first day, leaving a pitted scar in some cases there are more or less marked constitutional disturbances. 

Is the smallpox virus, variola, that causes smallpox still around ... 

The vaccine against smallpox is made with a virus related to smallpox virus called vaccinia virus. It is not made with smallpox virus called variola. The vaccine is a highly effective immunizing agent against smallpox infection. It was successfully used to eradicate smallpox from the human population. 

Although smallpox disease has been eradicated, two countries still keep smallpox virus (variola) stocks. Two laboratories hold stocks of smallpox virus (variola). These are the WHO Collaborating Centres in Atlanta, USA and Koltsovo, Russian Federation. 

Yes. Vaccinia vaccine is recommended for laboratory workers who directly handle cultures, animals contaminated or infected with, nonhighly attenuated vaccinia virus, recombinant vaccinia viruses derived from nonhighly attenuated vaccinia strains, or other orthopoxviruses that infect humans. These would include monkeypox, cowpox, vaccinia, and variola. Other health-care workers, such as physicians and nurses whose contact with nonhighly attenuated vaccinia viruses is limited to contaminated materials such as medical dressings but who adhere to appropriate infection control measures, are at lower risk for accidental infection than laboratory workers. However, because a theoretical risk for infection exists, vaccination can be offered to this group. Vaccination is not recommended for people who do not directly handle nonhighly attenuated virus cultures or materials or who do not work with animals contaminated or infected with these viruses. 

In addition to the stock of smallpox vaccine in the US, an additional 50-100 million doses are estimated to exist worldwide. Many countries still hold smallpox vaccine (vaccinia) stocks. WHO recommends that countries that still have stocks of smallpox vaccine (vaccinia) maintain these stocks. This recommendation has been made for two reasons. Firstly, small amounts of vaccine are still needed to vaccinate laboratory personnel handling vaccinia virus and other members of this virus family. Some of these viruses are found in nature and cause illness among animals, and some are used in research to make new, safer vaccines against a variety of infectious diseases. Secondly, smallpox vaccine, vaccinia, will also be needed in case of a deliberate or accidental release of smallpox virus, variola. 

Variola virus causes smallpox. The incubation period is about 12 days with a range of 7 to 17 days following exposure. Initial symptoms include high fever, fatigue, and head and back aches. A characteristic rash, most prominent on the face, arms, and legs, follows in 2-3 days. The rash starts with flat red lesions that evolve at the same rate. Lesions become pus-filled and begin to crust early in the second week. Scabs develop and then separate and fall off after about 3-4 weeks. Most patients with smallpox recover, but death occurs in up to 30% of cases. 

Although personnel who have been vaccinated recently and who have a demonstrated immune response should be fully protected against infection with smallpox virus, they should continue to observe standard contact precautions including using protective clothing and shoe covers when in contact with smallpox patients or contaminated materials to prevent inadvertent spread of variola virus to susceptible persons and potential self-contact with other infectious agents. 

Smallpox (variola). The acute clinical symptoms of smallpox resemble other acute viral illnesses, such as influenza, beginning with a 2-4 day nonspecific prodrome of fever and myalgias before rash onset. Several clinical features can help clinicians differentiate varicella (chickenpox) from smallpox. The rash of varicella is most prominent on the trunk and develops in successive groups of lesions over several days, resulting in lesions in various stages of development and resolution. In comparison, the vesicular/pustular rash of smallpox is typically most prominent on the face and extremities, and lesions develop at the same time. 

When a laboratory is unable to identify an organism in a clinical specimen, it should be sent to a laboratory where the agent can be characterized, such as the state public health laboratory or, in some large metropolitan areas, the local health department laboratory. Any clinical specimens suspected to contain variola (smallpox) should be reported to local and state health authorities and then transported to CDC. All variola diagnostics should be conducted at CDC laboratories. Clinical laboratories should report any clusters or findings that could indicate intentional release of a biologic agent to their state and local health departments. 

This section addresses the viral forms of biological agents that would most likely be considered by terrorists. They include variola major (smallpox), Venezuelan equine encephalitis (encephalitis), Crimean Congo hemorrhagic fever, and Rift Valley hemorrhagic fever. 

Variola major Eruption of skin or rash (begins with... 

The dehnition of vaccination, in the strict use of the term, stems from the work of Edward Jenner with cowpox and smallpox. Jenner invented the Latin name Variolae vaccinea for cowpox. From this, the term vaccination arose. 

Jenner attempted to publish the results of his experiment in Transactions of Royal Society but the paper was rejected. He then repeated the experiment with 13 volunteers and published the results in his treatise, An inquiry into the causes and effects of the variolae vaccinae, a disease discovered in some parts of the western counties of England, particularly Gloucestershire, and known by the name of the Cow Pox , published in 1798. Following its publication, vaccination quickly spread through Europe and America, earning Jenner worldwide fame. 

Farnsworth NR, Akerele O, Bingel AS, Soejarto DD, Guo Z. (1985) Can variola-like viruses be derived from monkeypox virus An investigation based on DNA mapping. Bull WHO 63 695-981. 

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