An epidemic is when an infectious disease spreads within a community or area during a specific time period. Learn about the biggest outbreaks to spread across the United States, and where we are now. People had symptoms of high fever, chills, severe back pain, and rashes.
Species Variola virus Smallpox was caused by infection with variola virus, which belongs to the genus Orthopoxvirusthe family Poxviridae and subfamily chordopoxvirinae. Evolution The date of the appearance of smallpox is not settled. It most likely evolved from a terrestrial African rodent virus between 68, and 16, years ago.
One clade was the variola major strains the more clinically severe form of smallpox which spread from Asia between and 1, years ago.
A second clade included both alastrim minor a phenotypically mild smallpox described from the American continents and isolates from West Africa which diverged from an ancestral strain between 1, and 6, years before present.
This clade further diverged into two subclades at least years ago. If the mutation rate is assumed to be similar to that of the herpesvirusesthe divergence date between variola from Taterapox has been estimated to be 50, years ago. Better estimates of mutation rates in these viruses are needed.
Diversification of strains only occurred in the 18th and 19th centuries. Four orthopoxviruses cause infection in humans: Variola virus infects only humans in nature, although primates and other animals have been infected in a laboratory setting.
Vaccinia, cowpox, and monkeypox viruses can infect both humans and other animals in nature. Poxviruses are unique among DNA viruses in that they replicate in the cytoplasm of the cell rather than in the nucleus.
In order to replicate, poxviruses produce a variety of specialized proteins not produced by other DNA virusesthe most important of which is a viral-associated DNA-dependent RNA polymerase. Both enveloped and unenveloped virions are infectious.
The viral envelope is made of modified Golgi membranes containing viral-specific polypeptides, including hemagglutinin. It was transmitted from one person to another primarily through prolonged face-to-face contact with an infected person, usually within a distance of 1.
Rarely, smallpox was spread by virus carried in the air in enclosed settings such as buildings, buses, and trains. The virus can be transmitted throughout the course of the illness, but this happened most frequently during the first week of the rash, when most of the skin lesions were intact.
The overall rate of infection was also affected by the short duration of the infectious stage. In temperate areas, the number of smallpox infections was highest during the winter and spring. In tropical areas, seasonal variation was less evident and the disease was present throughout the year.
Vaccination immunity declined over time and was probably lost within thirty years. Microscopicallypoxviruses produce characteristic cytoplasmic inclusions, the most important of which are known as Guarnieri bodiesand are the sites of viral replication.
Guarnieri bodies are readily identified in skin biopsies stained with hematoxylin and eosin, and appear as pink blobs. They are found in virtually all poxvirus infections but the absence of Guarnieri bodies could not be used to rule out smallpox.
All orthopoxviruses exhibit identical brick-shaped virions by electron microscopy. Definitive laboratory identification of variola virus involved growing the virus on chorioallantoic membrane part of a chicken embryo and examining the resulting pock lesions under defined temperature conditions.
Serologic tests and enzyme linked immunosorbent assays ELISAwhich measured variola virus-specific immunoglobulin and antigen were also developed to assist in the diagnosis of infection. Chickenpox and smallpox could be distinguished by several methods.
Unlike smallpox, chickenpox does not usually affect the palms and soles. Additionally, chickenpox pustules are of varying size due to variations in the timing of pustule eruption: A variety of laboratory methods were available for detecting chickenpox in evaluation of suspected smallpox cases.
In contrast to the rash in smallpox, the rash in chickenpox occurred mostly on the torso, spreading less to the limbs. An Italian female smallpox patient whose skin displayed the characteristics of late-stage confluent maculopapular scarring, Share on Pinterest. Smallpox came to North America in the s.
People had symptoms of high fever, chills, severe back pain, and rashes. Starting from the Northeast, smallpox wiped out entire.
Smallpox is a dire, highly contagious, and often lethal disease that is caused by the variola virus that can be spread by air or by direct contact through people or clothing that has been contaminated by . Apr 19, · Essay About Vaccines; Essay About Vaccines.
Hpv Vaccine. as some say it is highly dangerous, while most medical professionals strongly advise it. Although it may be the greatest chance of not catching influenza, it can come with serious complications and side effects that can damage or even kill a person.
The question of whether. The smallpox vaccine does not contain smallpox virus and cannot spread or cause smallpox. However, the vaccine does contain another virus called vaccinia which is live in the vaccine.
Because the virus is alive, it can spread to other parts of the body or to other people from the vaccine site. Smallpox is a disease caused by a poxvirus that is transmitted from person to person that causes high fever, characteristic rash, and may kill about one-third of those monstermanfilm.comox (also called variola) is the only disease that has been completely wiped out throughout the world.
Smallpox Questions and Answers: The Disease and the Vaccine How dangerous is the smallpox threat? What is the smallpox vaccine, and is it still required? The smallpox vaccine is the only way to prevent smallpox. The vaccine is made from a virus called vaccinia, which is another pox-type virus related to smallpox.