Hot answers tagged virology
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It is possible for viruses to live in mutualistic relationships with their hosts, these associations are often overlooked due to the devastating effect that many viruses can have.
To give an example in humans, when HIV-1-infected patients are also infected with hepatitis G virus, progression to AIDS is slowed significantly (Heringlake et al., 1998; Tillmann ...
17
The sub-type is named for the broad classes of the hemagglutinin (HA) or neuraminidase (NA) surface proteins sticking through the viral envelope. There are 16 HA sub-types (designated H1 - H16) and 9 NA sub-types (designated N1 - N9). All of the possible combinations of these influenza A subtypes infect birds, but only those containing the H1, H2, H3, H5, H7 ...
15
This is because rabies is a viral infection of nervous tissue that propagates through peripheral nerves into the brain and causes brain tissue inflammation (encephalitis).
As long as the virus is in the brain there is no way to get rid of it. The main trade-off here is that everything that would kill the virus will be as (or even more) aggressive against ...
15
Subtype is denoted using the HxNy notation for the variant of hemagglutinin and neuraminidase.
Strain names are specified as: [virus type]/[location of origin]/[sequential number of isolation]/[year of isolation] ([subtype]), such as "A/Alabama/AF2070/2010(H1N1)"
Virus type would be A, B, or C for the various forms of influenza (influenza A being the most ...
9
Adding to the other answers posted:
Hemagglutinin (HA or H) - Helps the virus enter the cell by binding to sialic acid receptors on cell membrane. It then unfolds in a lysosome and fuses the viral and lysosome membranes.
Neuraminidase (NA or N) - Helps the virus exit the cell by cleaving the terminal sialic acid residues at the progeny virus release.
9
Firstly, it's important to recognize that "plant viruses" do not exist. There are only "viruses that affect particular plant cells", or "viruses that affect a particular cell type". You'll see why in a moment.
One of the structural components of many virus is its protein coat. Different types of biological molecules protrude from the surface of this ...
8
It's mainly caused by swelling of large veins and by an increase in vascular permeability that leads to an accumulation of fluids in the nasal mucosa. These effects are mediated, at least in part, by bradykinin and histamine, and can be counteracted by epinephrine. These mediators are part of the immune response to the viral particles.
You can read more ...
7
This article has some good information. It's certainly more than I want to know about warts.
Isolated warts may remain unaltered for
months or years, or a large number of new lesions
may develop rapidly in a short period of time. The
development of warts is not predictable.
Approximately 65% of warts disappear spontaneously
within two years. ...
7
The organelle form in the same way they would if they were coded for by the host's genetic code, except in this case the virus uses its own genome to specify the type of organelle.
The article you link to indicates this. The "systems" in the quote are in part the organelle that it needs
A study of the giant virus’s DNA shows it to have over a ...
7
The two letters represent the type of hemagglutinin (H) and neuraminidase (N) present on the viral surface. Those are the major surface proteins of the influenza virus and therefore crucial for the immune response.
From Immunology and Evolution of Infectious Disease
HA and NA reactivities with antibodies define the subtypes of
influenza A (Cox and ...
7
They appear sick because they are sick, but with other, opportunistic infections. The "immune deficiency" part of AIDS means that the immune system is not functioning normally and, thus, is unable to protect them. Typical illnesses that are more found more frequently in AIDS patients are pneumocystis pneumonia and Kaposi's sarcoma.
7
I found a book chapter for you here
Quick summary:
3 hypotheses to Origin of viruses
From pre-cellular world (virus first hypothesis)
From reductive evolution of parasites (reduction hypothesis)
From fragments of cellular genetic material (escape hypothesis)
Drawbacks:
virus require cells (to infect) so how can they come first
virus do not look like ...
6
It may actually be curable, as shown by success stories involving the Milwaukee protocol in which the brain is effectively shut down to allow for the immune system to eradicate the virus. In most cases, however, it is fatal once symptomatic. Note that the Milwaukee protocol boasts an imporessive (sarcastic) survival rate of under 15%
5
Alright, having read the citation linked, and doing a little poking of my own, here's my approach at an answer:
Some human herpes virus infections may compete with HIV infection. Essentially, some strains (not the ones you normally think of) infect CD4 cells - the same cells targeted by HIV. These strains down regulate transcription in CD4 cells, which in ...
5
As mentioned in this question , Adeno-associated virus is often used for gene therapy. This is due largely to its predictability when injecting genes (1), however it is also used as it is not implicated in any human pathology. As it is a replication deficient/helper dependent virus, natural infection is much less likely.
The human immune system does ...
5
Further to LanceLafontaine's answer I'd just like to mention that, although as he mentioned viruses interact with DNA replication in different ways, DNA replication in itself is the same process in both plant and animal cells. For example, a human cheek cell and a potato root cell replicate their DNA in the same way (as both are eukaryotic cells - cells ...
5
I don't know if this is a comprehensive enough answer, but viruses are taxonomically broken down into order (-virales), family (-viridae), subfamily (-virinae), genus (-virus) and species. This system was developed by the ICTV and is concurrently used with the Baltimore System.
A lot of species contain variations called virus strains. There are two types, ...
5
It is common knowledge that when you're cold you could get a cold.
This may be a nice illustration why we need to be wary of “common knowledge”.
What is the mechanism linking temperature and viral infection?
This isn’t clear. There are a few proposed mechanisms but a likely explanation is: “there is no mechanism” – and the assumed correlation ...
5
The species of wasp you're referring to is Glyptapanteles. I'm not sure which virus it is.
http://www.newscientist.com/article/dn14053-zombie-caterpillars-controlled-by-voodoo-wasps.html?feedId=online-news_rss20
Is it possible? Of course, you have an example! Though, there is a small caveat. Some of the offspring sacrifice themselves to induce the ...
4
Since early March we know, that there is the first patient which has been cured by HAART. According to the paper it has been proven that the infant was infected with HIV. This was done by detecting the virus even after the first 48 hours, this rules out that the virus transmitted by the mother without infection.
The infant was first treated when it was 30 ...
4
Well, for him the virus is already likely at minimum levels within his body. If he's recovered (pass the fever phase) then his immune system has already dealt with the majority of the viral bodies in his system, since the peak of the immune response comes after the peak of the viral infection density (ignore B):
How much of the virus was left in his ...
3
In the publication by Leibbrandt et al.[1], it could be shown that the iota-carrageenan directly binds to viruses and thereby prevents the attachment to cells. This is a critical step in the viral life-cycle and therefore replication is reduced. Iota carrageenan rather acts unspecifically and besides influenza also other viruses such as human Rhinoviruses ...
3
Through two different pathways, one relying on a non-specific (innate) response, and another through a reactive oxygen species, the level of NF-kB(**) is amplified, as such a response would have happened as a result of the presence of the virus anyway.
In thousands of experiments, carrageenans have been used to
induce inflammation, since inflammation is ...
3
The processes that control the germline of metazoans (multicellular animals) are highly regulated compared to single cell bacteria and eukaryotes as well as plants.
At this point there are no clear stories of gene transfer into a complex animal, though there are some for plants:
"animals and fungi seem to be largely unaffected, with a few exceptions, ...
3
Conner's response contained just the type of source material I was looking for. Thanks Conner -- let us all +1 him. Allow me to summarize the specifics of the article in relation to my question:
Transmission
PVs are transmitted through direct or indirect contact with an
individual who has the lesion. Dysfunctions in the epithelial barrier
by ...
3
While it's difficult to prove a negative, I know of no cases where a patient has been treated with HAART to the extent that their viral load never rises again. Keep in mind that, if nothing else, such a study would be extremely hard to do, as proving you've "cured" someone would require extremely long term followup.
HAART is however quite good at ...
3
The nature of infectious agents is that they transmit between organisms. This means that they have reservoirs outside a single host, and hence of course reinfection with the exact strain is possible if this strain leaves the body and at a later stage is carried back to it. This could typically happen for example with the common influenza, spreading from one ...
2
Every atom produces a magnetic field, so the formally correct answer would be "yes" (assuming that viruses belong to the tree of life, which is disputed -- otherwise, one would not use the prefix 'bio').
However, biomagnetism as a science (and not pseudoscience) is concerned with more measurable effects. The biomagnetism of a virus will be negligible ...
2
The hydrophobia symptom is most likely a bi-product of the effects the virus has on the brain and not an evolutionarily derived strategy to create an appropriate environment to reproduce in. Just the same as other symptoms the infection causes, like fever for example, is a reaction the body has to the presence of the virus and not something the virus is ...
1
HIV has nine genes. According to the paper cited below, three of these genes (vpu, vpr and nef) are not required for replication in cultured cells.
Gibbs JS et al. (1994) Construction and in vitro properties of HIV-1 mutants with deletions in "nonessential" genes. AIDS Res Hum Retroviruses 10: 343 - 50
Abstract
Auxiliary genes that are not ...
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