What are the 6 stages of smallpox?
Signs and Symptoms
- Incubation Period. This stage can last anywhere from 7 to 19 days (although the average length is 10 to 14 days).
- Initial Symptoms. This stage lasts anywhere from 2 to 4 days.
- Early Rash.
- Pustular Rash and Scabs.
- Scabs Fall Off.
- No Scabs.
What are the characteristics of variola virus?
Smallpox is an infectious disease caused by the variola virus. It is characterized by fever, a general feeling of ill health (malaise), headaches and back pain. These initial symptoms are followed by a rash and small, raised bumps or lesions (pocks) within two or three days.
What is the structure of variola virus?
The variola virus is a large brick-shaped particle that measure about 300 by 250 by 200 nm. The virion contains an envelope, a surface membrane, a concave core and two lateral bodies. The envelope of the virus is made of modified Golgi membranes that contain viral-specific polypeptides, including hemagglutinin.
What does smallpox physically look like?
The rash looks like red bumps that gradually fill with a milky fluid. The fluid-filled bumps are all in the same stage at the same time, compared to chickenpox, where the skin blisters are in different stages of appearance with a mix of blisters, bumps, and crusted lesions at a given time.
How many stages does smallpox have?
A case of smallpox passes through six stages. Incubation of the disease averages 12 to 14 days. During this stage, the newly infected person may feel fine or have very mild symptoms that mimic the early stages of a cold or flu and is not contagious.
During which phase is smallpox most contagious?
*Smallpox may be contagious during the prodrome phase, but is most infectious during the first 7 to 10 days following rash onset.
What is the shape of the smallpox virus?
Brick-shaped virion approximately 200 nm in diameter, 250 to 300 nm long, and 250 nm high (International Committee on Taxonomy of Viruses); about the size of a bacterial spore. Enveloped.
What is the difference between variola and smallpox?
Smallpox is caused by 1 of 2 closely related strains: variola major and variola minor. The 2 viruses are indistinguishable except by polymerase chain reaction (PCR) testing. Variola minor infection (known as Alastrim) causes fewer systemic symptoms, a less extensive rash, less scarring, and fewer fatalities.
What is the shape of poliovirus?
The poliovirus capsid contains 60 copies each of the four viral polypeptides VP1, VP2, VP3, and VP4. The arrangement of proteins in the capsid creates icosahedral symmetry. The virion surface is covered with star-shaped mesas at its fivefold axes surrounded by deep canyons and three-bladed propellers.
Why does smallpox cause pustules?
Smallpox virus tended to attack skin cells, causing the characteristic pimples, or macules, associated with the disease. A rash developed on the skin 24 to 48 hours after lesions on the mucous membranes appeared.
What happens physically to a person who gets smallpox?
Smallpox can cause a severe rash over the whole body that can leave scars. Other symptoms include high fever and severe headache or body aches. Death occurs in about 30 percent of infected people. Some survivors may suffer blindness.
What are the stages of chickenpox?
The three stages of chickenpox usually refer to the way the rash looks. Stage one is a red and bumpy rash. Stage two is the fluid-filled blistered rash. Stage three is when the blisters break and scab over.
Is smallpox airborne or droplet?
Smallpox is spread through prolonged face-to-face contact via droplets expelled from the patient’s nose and mouth, usually by coughing. Smallpox may also be transmitted through contact with materials from smallpox pustules or scabs.
Is smallpox helical?
Virion: The virion is about 200-350 nm by 115-260 nm, thus it is considered to be a very large virus and can be seen under a light microscope. In addition, the capsid morphology is neither icosahedral nor helical.
Is variola virus enveloped?
The virion is a brick-shaped structure with a diameter of about 200 nm. Its lipoprotein outer membrane (envelope) encloses a single linear, double-stranded DNA.
How does variola virus replicate?
Upon invasion of a host cell, the smallpox virus replicates in the host cytoplasm, rather than the host nucleus, using many of the host’s own enzymes to replicate.. Replication begins once the virion has reached the cytoplasm of the host cell..
How did the variola virus start?
Early Victims. Smallpox is thought to have originated in India or Egypt at least 3,000 years ago. The earliest evidence for the disease comes from the Egyptian Pharaoh Ramses V, who died in 1157 B.C. His mummified remains show telltale pockmarks on his skin.
Does poliovirus have an envelope?
Poliovirus, the causative agent of paralytic poliomyelitis, is a small non-enveloped virus, with a single strand RNA genome encased in an icosahedral protein capsid.
Does the polio virus have a membrane?
Lacking a membrane, nonenveloped viruses must provide some other mechanism that allows the viral genome or the nucleocapsid to enter their hosts. In many ways, poliovirus is an excellent model system for studying the cell entry mechanism of simple nonenveloped viruses.
Which parts of the body develop the most pustules in smallpox?
Lesions usually appear first on the oropharynx, followed by the face and extremities, and then spread to the trunk, palms, and soles in a centrifugal pattern of distribution. Lesions develop uniformly throughout the disease and progress from macules to papules to vesicles over the course of 4 to 5 days.
How does the variola virus work?
Once the Variola virus is inhaled it lands on and infects the cells that cover the mouth, throat and respiratory tract. All viruses must infect a cell to reproduce. Macrophages infected by the Variola virus then take the virus to the lymph nodes in the head and neck.
Where do smallpox lesions develop first?
What is the difference between chickenpox and smallpox?
Doctors can tell chickenpox and smallpox apart. While they may look similar to the untrained eye, smallpox rashes are different: Chickenpox sores show up at different times in different areas. They’re mostly on the stomach, chest, and back, and rarely on the palms or the soles of your feet.
What are tiny red dots on skin?
Petechiae are tiny spots of bleeding under the skin. They can be caused by a simple injury, straining or more serious conditions. If you have pinpoint-sized red dots under your skin that spread quickly, or petechiae plus other symptoms, seek medical attention.