What causes the variola virus?

By | January 8, 2022

Smallpox is caused by infection with the variola virus. The disease is spread through person to person contact, most often from inhalation of droplet nuclei expelled through the back of the throat (oropharynx) of an infected person.

What type of virus is variola?

The variola virus is a large, brick-shaped, double-stranded DNA virus that serologically cross-reacts with other members of the poxvirus family, including ectromelia, cowpox, monkeypox, vaccinia, and camelpox. Unlike other DNA viruses, the variola virus multiplies in the cytoplasm of parasitized host cells.

Where is variola virus found?

There are now only two locations that officially store and handle variola virus under WHO supervision: the Centers for Disease Control and Prevention in Atlanta, Georgia, and the State Research Center of Virology and Biotechnology (VECTOR Institute) in Koltsovo, Russia.

What animal carries smallpox?

Smallpox can be spread by humans only. Scientists have no evidence that smallpox can be spread by insects or animals.

What animal does measles come from?

The common ancestor of measles virus is thought to have been a virus circulating in cattle which, according to Louise Cosby, emeritus, honorary professor at the Wellcome Wolfson Institute for Experimental Medicine, probably jumped into humans when cattle were domesticated thousands of years ago.

Is smallpox a retrovirus?

Smallpox was an infectious disease caused by one of two virus variants, Variola major and Variola minor. The agent of variola virus (VARV) belongs to the genus Orthopoxvirus. …

Causes Variola major, Variola minor (spread between people)
Diagnostic method Based on symptoms and confirmed by PCR

What causes Measle?

Measles is caused by morbillivirus, which is mostly seen in the winter and spring. It’s spread from one child to another through direct contact with discharge from the nose and throat. Sometimes, it is spread through airborne droplets (from a cough or sneeze) from an infected child.

What type of virus is small pox?

Before smallpox was eradicated, it was a serious infectious disease caused by the variola virus. It was contagiousmeaning, it spread from one person to another. People who had smallpox had a fever and a distinctive, progressive skin rash.

Can smallpox come back?

Smallpox was eradicated (eliminated from the world) in 1980. Since then, there haven’t been any recorded cases of smallpox. Because smallpox no longer occurs naturally, scientists are only concerned that it could reemerge through bioterrorism.

Where did chicken pox come from?

Chickenpox has been traced back to Europe in the 17th century. It was originally thought to be a milder form of smallpox by an English doctor by the name of Richard Morton.

Is smallpox vaccine still given?

The smallpox vaccine is no longer available to the public. In 1972, routine smallpox vaccination in the United States ended. In 1980, the World Health Organization (WHO) declared smallpox was eliminated. Because of this, the public doesn’t need protection from the disease.

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.

Is smallpox a respiratory?

The smallpox virus spreads directly from person to person and is acquired by breathing air contaminated with droplets of moisture breathed or coughed out by an infected person. Contact with clothing or bed linens used by an infected person can also spread the disease.

Is polio A virus?

Polio, or poliomyelitis, is a disabling and life-threatening disease caused by the poliovirus. The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis (can’t move parts of the body).

Is chickenpox a virus or bacteria?

Chickenpox is a highly contagious disease caused by the varicella-zoster virus (VZV). It can cause an itchy, blister-like rash.

Is measles a virus or bacteria?

Measles is a highly contagious virus that lives in the nose and throat mucus of an infected person. It can spread to others through coughing and sneezing. If other people breathe the contaminated air or touch the infected surface, then touch their eyes, noses, or mouths, they can become infected.

Did measles come from cows?

Like many human diseases, measles originated in animals. A spill-over of a cattle-infecting virus, the common ancestor to both measles virus and its closest relative rinderpest virus is understood as likely to have given rise to the disease.

What is Variola major?

The name is derived from the Latin word for spotted and refers to the raised bumps that appear on the face and body of an infected person. Two clinical forms of smallpox have been described. Variola major is the severe form of smallpox, with a more extensive rash and higher fever.

What is flu?

Flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent flu is by getting a flu vaccine each year.

Is diphtheria a virus?

Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make a toxin (poison). It is the toxin that can cause people to get very sick. Diphtheria bacteria spread from person to person, usually through respiratory droplets, like from coughing or sneezing.

What are the 3 types of measles?

3-day measles, German measles, and soft measles were what we medical types would call rubella. These three diseases all have morbilliform (or measles-like) rashes defined as macular, erythematous lesions 2- to 10-mm in diameter but often confluent.

What are 3 symptoms of measles?

Measles symptoms appear 7 to 14 days after contact with the virus and typically include high fever, cough, runny nose, and watery eyes. Measles rash appears 3 to 5 days after the first symptoms.

Who is at risk for measles?

People and groups at risk of measles complications Children younger than 5 years of age. Adults older than 20 years of age. Pregnant women. People with compromised immune systems, such as from leukemia or HIV infection.

What does variola minor mean?

Alastrim, also known as variola minor, was the milder strain of Variola virus that caused smallpox. The last known case of variola minor was in Somalia in 1977. Smallpox was formally declared eradicated on May 8, 1980.

What is the difference between variola major and variola minor?

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.

Is smallpox droplet or airborne?

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.

Does smallpox still exist in India?

India has eradicated smallpox. After an assiduous search of the country for any case of the disease for two full years, the World Health Organizations’s International Smallpox Assessment Commission declared in New Delhi on April 23 that India is free from the age-old scourge. India has eradicated smallpox.

Are smallpox and chickenpox the same thing?

Chickenpox is the most important disease likely to be confused with smallpox. It is caused by a different virus. In smallpox, fever is present for 2 to 4 days before the rash begins, while with chickenpox, fever and rash develop at the same time.

Is chicken pox still around?

Chickenpox is still around. Smallpox is pretty much extinct. Until recently, chickenpox was a very common illness, especially in kids. It made about 4 million people sick every year and sent more than 10,000 to the hospital.