A virus is a small infectious agent that can replicate only inside the living cells of an organism. Virology is the study of viruses.

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Why isn't a virus “alive”?

The recent news about a new supermassive virus being discovered got me thinking. What biological differences between viruses and cellular organisms have made viruses be deemed non-living?
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Is it known how the first viruses formed?

The oldest known virus is known to have infected prehistoric insects 300 million years ago. A virus is basically a parasitic strand if DNA or RNA encapsulated in a protein coat. It enters cells by ...
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1answer
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What do viruses do during incubation period?

For example, there is an incubation period of around 1 to 3 days for common cold, and that of AIDS can range over to decades. What do viruses do actually do during the incubation period? What ...
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2answers
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Why don't we develop immunity against common cold?

We all suffer from common cold, and that, frequently. Why have we not developed immunity against it till now? By immunity I mean immunity as a species.
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How long does the Ebola virus remain infectious on contaminated items or surfaces?

I'm sure there will be variation depending on what the contaminated item or surface is made of - linens, I could imagine, would remain dangerous for longer than a door-knob. But if the items are not ...
11
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4answers
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Is there a period after you have had a cold when you cannot get a cold again?

I always assumed colds ran on a 'no tagbacks' principle: once it's out of your system, it takes a while before you can get a cold again. Is there any truth to this, or can rhinoviruses hit you at any ...
9
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5answers
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Is there an 'anti-virus'?

A virus spreads around and usually attaches itself to the host, multiplies & causes diseases. But is there something like an anti-virus? A single celled entity that does the opposite: spreads ...
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How are viruses weakened to be suitable for vaccination?

I understand there are two kinds of active vaccination Injecting complete viruses that are weakened to not cause the disease being vaccinated against Injecting only antigen particles of viruses that ...
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How does the ebola virus attack?

How does the ebola virus attack and how do some people get away with it? Normally any virus would attack a cell with some kind of receptors and some kind of lock and key mechanism entering the cell ...
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1answer
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Why are people unable to develop lasting immunity against Norovirus?

Infection with many viruses will result in decades-long if not lifetime immunity, for example chicken pox. Because of the large number of viruses responsible for the common cold, lifelong immunity to ...
8
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1answer
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What is the difference between influenza A and B viruses that causes their distinct seasonal patterns?

I recently learned from an answer at health.SE* that influenza B tends to occur later in the season compared to influenza A. According to the graph in that answer, during this year’s flu season the ...
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1answer
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What about a bat's immune system protects them from Ebola?

Current evidence indicates that fruit bats are a reservoir host for Ebola. Has any research established what is different about their cell biology or immune system that reduces virulence for them? ...
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1answer
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How the conjunctivitis virus spread just by seeing a person's eye who is infected

Conjunctivitis or 'pink eye'. I have a few questions on conjunctivitis. When I was suffering from conjunctivitis, my doctor advised me to wear sunglasses so that no one else gets infected. I ...
6
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1answer
389 views

Ebola: cleaning of protective suit

As far as I know, in developed countries protection suits used by people who treat patients with Ebola are disposed of after a shift. From a rather ambitious costume last year, I still have a hazmat ...
6
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1answer
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Healing rate of cut while suffering from a cold

I recently cut my finger fairly deeply with a box cutter and had to have it stitched. During the healing process I contracted a strong cold/mild flu (a sore throat and runny nose with a high fever, ...
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4answers
548 views

What is the advantage of restriction enzymes cutting only at specific sites?

Bacteriophages have sequences which often do not have specific sites for restriction enzymes of bacteria to cut at and so can attack the bacteria. Wouldn't it be better if bacteria had something ...
5
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1answer
106 views

Why don't warts caused by HPV spread to the whole body?

My son had a plantar wart on his foot, which (as I understand it) is caused by a virus which only infects skin cells. Once in the skin cell the virus replicates, but when attacked by the immune system ...
5
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1answer
42 views

What are the positive effects of wrongful antibiotic use on a viral infection?

I categorically accept that bacteria differ from viruses; so antibiotics DON'T help in viral infections. I also read this and this; so no need to explain this. I've read about the negative effects (eg ...
5
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2answers
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Viruses: Adaptation to a new host through repeated host jumps

A friend told me, during a 3 minute discussion, that viruses that are endemic in host $A$ and make repeated jumps to host $B$ but can't be transmitted between individuals of species $B$, may slowly ...
4
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4answers
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Theoretically, what technique would one use to modify a virus so that it only affected a subset of the population?

I'm writing a novel and i would like to know some of the equipment and techniques involved with modifying a virus. Is it feasible for a virus to be engineered to only affect certain people? It ...
4
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1answer
156 views

How do wild animals get rabies?

I can see the chain of spreading disease: Humans usually get rabies from domestic animals, those usually get it from wild animals, wild animals in their turn get from the other wild animals and here ...
4
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1answer
403 views

What do you call a virus when it's cured?

When a cure has been found for a virus, can it be called such anymore? Virus implies it's something you've contracted that you just have to live with until (hopefully) your body can overwhelm and ...
4
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1answer
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Is viral protein expression important for peptide vaccine?

I would like to know if proteins expressed in higher quantities, such as DNA polymerase, would be better vaccine candidates for a T-cell based vaccine. Thanks, Bernardo
4
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1answer
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Why is the ebola virus so intense now?

So i'm looking into the ebola crisis and it seems the death toll is really getting crazy. I understand that it's a cytomegalovirus and that it basically overwhelms the immune system due to it's size ...
3
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2answers
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Changing the definition of life?

Viruses at this period of time do not fit the current definition of life. Much of the reasoning behind this is that we currently believe that all life must be made up of cells. Also, many ...
3
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2answers
51 views

What virus transforms full grown plants?

I read an article by a gardener describing how a virus had transmitted a negative trait to his plants. It rather shocked me, because I hadn't realized that a virus could transform an adult plant. I ...
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3answers
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Restriction endonucleases are found in?

Quoting from : Scientific American July 1975 The Manipulation of genes by Stanley Cohen : Restriction endonucleases (and modification methylases) are widespread in microorganisms; genes for ...
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2answers
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How is RNA of retrovirus converted into cDNA?

The retrovirus (oncovirus) contains RNA. It also has a molecule called reverse transcriptase. This molecule transcribes RNA into cDNA. This cDNA is the DNA copy of viral RNA genome RNA has Uracil ...
3
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1answer
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At which temperature is the Tick-Borne Encephalitis Virus destroyed?

At which temperature is the Tick-Borne Encephalitis Virus destroyed? If there is no data specifically for TBEV, is there any data for typical temperatures at which other Flaviviruses / Flaviviridae / ...
3
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2answers
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Why does rabies cause hydrophobia?

What feature of rabies pathophysiology causes hydrophobia? Why is hydrophobia unique to this one particular type of viral infection?
3
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1answer
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How does a virus take control over the host cell?

When the virus integrates its DNA with the hosts and enters the lytic pathway, do the viral proteins that produced destroy the cells DNA? Do they deactivate it? Also does the cell function in the same ...
3
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2answers
385 views

Why does methylation not occur in viral DNA?

Why does methylation not occur in viral DNA? Can viral DNA undergo the process of methylation? If not then why does this process does not occur in viruses?
3
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2answers
110 views

Are viruses self-propelled?

So obviously, viruses are nonliving. But when my teacher was teaching viruses in the video (we're doing "flip" learning this semester), the way he described it, it seemed like the viruses responded to ...
3
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1answer
35 views

What is the Baculovirus and how does it help in research?

I was reading up about Biotechnology and the use of insects, and came across an interesting article about Insect Cell culture Techniques that specifically talked about the usage of the Baculovirus. If ...
3
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1answer
15 views

Can virus resistance be acquired through generational exposure?

If I have a squash plant that has a mosaic virus of some kind, and I breed its descendants (via seed) for generations, each with exposure to the same virus, will future generations be likely to ...
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2answers
200 views

What happen's to a virus's capsid after it injects its genetic material into the host cell?

After a virus (one of the varieties which infects the cell via injection and not endocytosis) injects its genetic material into the host cell, what happens to its protein coat? I would guess that it ...
2
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1answer
94 views

It is possible for person with AIDS be negative for HIV antibodies?

I'm just curious as there was a bit controversy around this topic. It is possible for person with AIDS be negative for HIV antibodies? As of 1989, the CDC reported that 5% of all U.S. AIDS patients ...
2
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2answers
42 views

Do Noroviruses include many families?

Wikipedia says Caliciviridae Family. My notes say that Norovirus includes the following Noroviruses Norwalk-like viruses Caliciviruses Astroviruses and some small gastroenteroviruses which is a ...
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3answers
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How do a viruses or bacteria survive outside the body long enough to spread?

Say I cough on my table, then someone else touches it and picks up something I've got... how is it that these things can live outside the body, how long can they manage it, and how long is generally ...
2
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1answer
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How do I interpret this graph regarding introduced genes and virus-infected cells?

This graph appeared in a practice test for the MCAT. I am trying to interpret it, but it confuses me a bit. On the x-axis we have some introduced genes, and on the y-axis we have % of cells ...
2
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1answer
114 views

Do lysogenic viruses only infect bacteria?

In the video sent by my teacher on viruses, the example he used for lysogenic viruses was a bacteriophage infecting a bacteria. When he was describing how the genetic material was incorporated into ...
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2answers
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How did viruses learn to utilize the workings of a cell?

This is my first post here, so excuse me for its simplicity. Viruses can infiltrate a cell, overtake it and multiply. It has projecting fibers whose ends are shaped as kind of a "key" to a mobile ...
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2answers
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Why restriction enzymes cut (usually) at palindromic sequences?

Restriction enzymes usually cut only at palindromic sequences. Is there any specific reason for that ? Is there any advantage for bacteria if it cuts up virus at this type of sequences ?
2
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1answer
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Retrovirus Production

I have been having difficulties with low transduction efficiencies of my retrovirus production. I expand my plasmid of interest (on MiG-GFP plasmid) in DH5α E Coli for ~24 hours, purify with Qiagen ...
2
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1answer
37 views

Which virus capsids consist of only one type of capsid protein?

The Tobacco Mosaic Virus (TMV) capsid consists of many copies of one protein (http://www.rcsb.org/pdb/101/motm.do?momID=109). Which other viral capsids consist of only one kind of coat protein? Does ...
2
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1answer
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How does the MMR vaccine affect lymph nodes in preventing measles?

I am trying to understand this statement about the Measles part of the MMR (Mumps, Measles and Rubella) vaccine Measles prevention: MMR (AB protect during primary and secondary viremia) Measles ...
2
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1answer
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Size of DNA in phage

I have read that DNA(after recombination) is packaged in bacteriophages lambda only if it's between 40000 and 53000 bp long. This constraint can be used to ensure packaging of recombinant DNA. I ...
2
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1answer
301 views

Is it impossible for a retrovirus to be lysogenic?

Is it impossible for retroviruses to be lysogenic? In the lysogenic cycle, the viral genetic material is incorporated into the host cell's DNA. Because retroviruses have RNA, it would be impossible ...
2
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1answer
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Lytic Viruses — Cell lysis?

So in the video my instructor sent on viruses, he said that for lytic viruses, new viruses manufactured by the host cell could get out of the cell in one of two ways. The new viruses would leave by ...
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1answer
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Mutation rate in viruses

Mutation rate is a phenotypic trait that evolves. The process of evolution of such kind of traits are often referred to as evolvability. I am wondering about the evolution of the mutation rates in ...