A sample can also be examined under a microscope or sent to a laboratory for the virus to be grown cultured and analyzed. The smallpox vaccine Smallpox Vaccine In the United States, routine vaccination with the smallpox vaccine was stopped in because smallpox had been eliminated in the United States.
Instead, the vaccine contains live vaccinia virus, which is related to the viruses that cause monkeypox Monkeypox Monkeypox is caused by the monkeypox virus, which is related to the smallpox virus and causes a similar, but usually milder illness. See also Overview of Viral Infections. Where monkeypox There are 2 smallpox vaccines licensed in the United States:.
ACAM is a live vaccinia virus that reproduces in the person who receives it. Vaccination with vaccinia virus causes a mild infection and protects people against smallpox. It is approved for prevention of both smallpox and monkeypox. ACAM vaccine is given with a special type of needle dipped in reconstituted vaccine. The needle is rapidly jabbed 15 times in an area about 5 mm in diameter and with sufficient force to draw a trace of blood.
If vaccination is successful, a blister develops at the vaccination site within about 7 days. The vaccine site is covered with a dressing to prevent spread of the vaccine virus to other body sites or to close contacts.
Fever, muscle aches, and a general ill feeling are common the week after vaccination. Vaccination with ACAM can be helpful up to 7 days after exposure to smallpox, but it is more effective the sooner it is given. ACAM is a live virus, and so it dangerous for some people, especially those with a weakened immune system such as those who have AIDS or who take drugs that suppress the immune system Overview of the Immune System The immune system is designed to defend the body against foreign or dangerous invaders.
Such invaders include Microorganisms commonly called germs, such as bacteria, viruses, and fungi Parasites Rarely, even some healthy people have adverse reactions to this smallpox vaccination.
Adverse reactions are less common among previously vaccinated people than among those who have never received the vaccine:. About 1 in every 10, previously unvaccinated healthy people have serious complications, and 1 in every million die. If people have a very severe reaction to the vaccine, doctors may try giving antiviral drugs such as tecovirimat , cidofovir , or brincidofovir.
It is approved for people 18 years of age and older and may have a particular role in vaccinating people for whom ACAM may be dangerous, such as those with a weak immune system or atopic dermatitis Atopic Dermatitis Eczema Atopic dermatitis commonly referred to as eczema is chronic, itchy inflammation of the upper layers of the skin that often develops in people who have hay fever or asthma and in people who Vaccination for smallpox is recommended only for people at high risk of exposure, mainly certain military personnel and laboratory technicians and health care workers who give or handle the vaccine and related materials.
People with symptoms suggesting smallpox need to be isolated to prevent spread of the infection. Contacts of these people need not be isolated because they cannot spread the infection unless they become sick and develop a rash. However, contacts are watched closely and isolated at the first sign of infection. That's why it's not recommended that everyone be vaccinated at this time.
The potential risks of the vaccine outweigh the benefits, in the absence of an actual smallpox outbreak. A second vaccine, a modified vaccinia Ankara vaccine Jynneos , has been found to be safe, and it can be used in people who aren't able to take ACAM, who have weakened immune systems or who have skin disorders.
Immunity or partial immunity after a smallpox vaccine may last up to 10 years, and 20 years with revaccination. If an outbreak ever occurred, people who were vaccinated as children would still likely receive a new vaccination after direct exposure to someone with the virus. Mayo Clinic does not endorse companies or products.
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Overview Smallpox is a contagious, disfiguring and often deadly disease that has affected humans for thousands of years. Smallpox Open pop-up dialog box Close. Smallpox These are smallpox lesions on the skin of the trunk.
Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references Friedman HM, et al. Some people worry that terrorists could release the virus and spread smallpox to many people. The first symptoms of smallpox include a high fever, fatigue, a headache, and a backache. After 2 to 3 days of illness, a flat, red rash appears. It usually starts on the face and upper arms, and then it spreads all over your body. Over the next 2 to 3 weeks, the flat, red spots become firm and dome-shaped and fill with pus.
Then they scab over. Scabs fall off 3 to 4 weeks after the rash first appears, and they leave pitted scars. The incubation period for smallpox is about 12 days.
But symptoms can develop as soon as 7 days or as long as 19 days after exposure. You may mistake a severe chickenpox rash for a smallpox rash at first. But different viruses cause these illnesses and there are many differences between chickenpox and smallpox rashes. Smallpox is contagious. It can be passed from one person to another through coughing, sneezing, or breathing, or by contact with the scabs or the fluid from blisters.
It can even spread from an infected person's personal items and bedding. Smallpox is easiest to spread during the first week of the rash. As scabs form, the person is less contagious. But a person can spread the virus from the time the rash first appears until all scabs have fallen off.
If a terrorist were to release a small amount of the virus into the air, it is possible that it could spread among a large number of people. The virus may be able to survive and infect people for up to a day. People who get this disease must stay away from others to help prevent it from spreading. If there has been a smallpox outbreak and you think you might have been exposed, call your doctor or local health department. Do not go directly to a health facility, because you could pass the disease to other people.
If a doctor suspected a case of smallpox, blood and skin tests would be needed to confirm the diagnosis. A confirmed case of smallpox would be considered a worldwide health emergency. In the U.
Inhaling only Variola viruses can result in smallpox. Smallpox can also be spread through direct contact with the scabs or pus from the skin lesions caused by Variola. It can also be acquired by contact with infected body fluids or contaminated objects such as bedding or clothing but this route of transmission is less common. Rarely, smallpox has been spread by virus carried in the air in enclosed settings such as buildings, buses, and trains.
Humans are the only natural hosts of Variola; insects and animals can not transmit smallpox. 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. By day three of the infection the virus gets into the bloodstream. This is called the primary or first viremia virus in the blood.
The Variola virus then invades more macrophages and the cells that cover the inside surfaces of the blood vessels endothelial cells in the liver, spleen, lymph nodes and bone marrow. During this time, which can last from days, the person will appear to be healthy with no signs of the Variola virus infection. The viruses reproduce to such an extent that another viremia will occur. During this second viremia the person will suddenly develop a high fever, severe headache, pharyngitis, nausea and backache.
The fever will be quite high; o F and they will be too ill to carry on with normal activities. The viruses will also get into the skin at this time. This phase of the disease is called the prodrome. Meanwhile, the viruses in the skin will cause a skin rash to develop. In ordinary Variola major the rash starts out as irregularly shaped red spots macules.
The first spots are usually seen on the face and neck and will then develop on the hands, wrists, forearms, feet, ankles, and lower leg. These spots will also develop on the chest and abdomen but are much less numerous than those seen on the head, neck and limbs.
These macules will all appear within 24 hours. The red spots will all at the same time develop into red bumps papules after about three days. By the fourth day, the all the papules will fill with a thick, opaque fluid and have a depression in the center. These skin lesions are now called pustules. Their fever will rise again at this time and remain high until scabs form. In time all the pustules will break open and a crust will form over the skin lesions followed by a scab. On day 14 of the rash the skin lesions will scab over.
All the skin lesions will go from macule, to papule, to pustule, to crust, to scab at the same time and it will take about 17 days for this to occur. People with smallpox are infectious to others until all the scabs have fallen off. When t he scabs fall off they leave marks on the skin that eventually become pitted scars. The skin rash takes about three weeks to complete macule to last scab falling off. People with the hemorrhagic form of Variola major do not develop the same rash as in ordinary Variola major.
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