They did so by tracing contacts, educating the public regarding disease signs and symptoms and serving in research teams in related case control studies. Nursing researchers have also benefited HIV testing and prevention in Malawi via identifying the benefits of working with religious leaders to promote HIV testing and prevention behaviors.
Additionally, nurses have developed family planning services in Kenya by providing childbearing families with the opportunity to space pregnancies to support the health of pregnant women. Advanced practice nurses are uniquely qualified to conduct research and assist government leaders and public health officials in creating an informed response to viral outbreaks. The input and insight of experienced nurses will help prevent the spread of infectious diseases and ensure a healthier future.
Our innovative way of thinking makes us adaptable, but our focus on education makes us formidable. Skip to main content. Types of Viruses and How They Work Over many centuries and even millennia, infectious diseases such as smallpox and measles have claimed millions of lives.
The Cost of Deadly Virus Infections Viruses gain their infamy through a combination of large infection rates and death, even when their power has been relatively subdued. The Three Categories of Viruses There are three different virus types that are made distinct by their shape. How a Virus Spreads The first thing a virion does is enter a cell and becomes a virus. Treating Viruses Antiviral drugs can treat viruses by inhibiting viral development and slowing down disease progression.
The Role of Advanced Practice Nurses Worldwide Around the world, nurses contribute to the prevention, management and containment of viral outbreaks by caring for infected patients and educating the public on prevention strategies.
The Invaluable Contribution of Nurses Across a variety of roles and specializations, nursing professionals fight viruses in numerous ways. Viruses are found in different shapes and sizes. In this article, we will learn what viruses are and about the typical structural components of a virus and its types according to morphology in structures.
Viruses can be defined as ultramicroscopic, obligate intracellular parasites that can stay alive only in host cells. Viruses are called particles because they are non-cellular organisms, they depend on host cell components to carry various functions. Viruses cannot reproduce outside the host body nor can they produce energy.
They remain as a non-living thing outside the host cell. They use DNA of host cells to replicate. When the infected tobacco plants were passed through filters the filtrate could induce mosaic disease in healthy plants.
Tobacco mosaic virus was the first to be found. Later with further growth in technologies aided a lot to study viruses. The study of viruses is called virology. Learn Exam Concepts on Embibe. Viruses are observed in a wide range of shapes and sizes, but these shapes are constant in a particular viral family. In some cases, the capsid is surrounded by an envelope which is usually a bilayer of glycoprotein and lipoproteins.
Some species of the virus also contain enzymes. The central part of the virus that contains nucleic acid is called Genome. Functions of Viral Genome : a. Viral genome has codes with genetic information for the synthesis of various proteins.
The main motive of the virus is to replicate its genetic material to produce more of its kind. The capsid, also known as the shell or coat of viruses, is the outer protein coat of the virus. This protein coat is made of up small subunits called capsomeres which in return is made up of protomere.
The number of capsomeres differs in different species of viruses. The genome and capsid of a virus are collectively called virus nucleo-capsid. Functions of Capsid : Capsid has three important functions: a. It protects the viral genome from getting digested by enzymes.
Both polyhedral upper and spherical lower forms more Viruses were first found to have symmetry by x-ray diffraction studies and subsequently by electron microscopy with negative-staining techniques.
In most icosahedral viruses, the protomers, i. The arrangement of capsomeres into an icosahedral shell compare Fig. This requires the identification of the nearest pair of vertex capsomeres called penton: those through which the fivefold symmetry axes pass and the distribution of capsomeres between them.
Adenovirus after negative stain electron microscopy. A The capsid reveals the typical isometric shell made up from 20 equilateral triangular faces. The net axes are formed by lines of the closest-packed neighboring capsomeres. In adenoviruses, the h and k axes also coincide with the edges of the triangular faces. This symmetry and number of capsomeres is typical of all members of the adenovirus family.
Except in helical nucleocapsids, little is known about the packaging or organization of the viral genome within the core. Small virions are simple nucleocapsids containing 1 to 2 protein species. The larger viruses contain in a core the nucleic acid genome complexed with basic protein s and protected by a single- or double layered capsid consisting of more than one species of protein or by an envelope Fig.
Two-dimensional diagram of HIV-1 correlating immuno- electron microscopic findings with the recent nomenclature for the structural components in a 2-letter code and with the molecular weights of the virus structural glyco- proteins. SU stands for more Because of the error rate of the enzymes involved in RNA replication, these viruses usually show much higher mutation rates than do the DNA viruses. Mutation rates of 10 -4 lead to the continuous generation of virus variants which show great adaptability to new hosts.
The viral RNA may be single-stranded ss or double-stranded ds , and the genome may occupy a single RNA segment or be distributed on two or more separate segments segmented genomes. In addition, the RNA strand of a single-stranded genome may be either a sense strand plus strand , which can function as messenger RNA mRNA , or an antisense strand minus strand , which is complementary to the sense strand and cannot function as mRNA protein translation see Ch.
Sense viral RNA alone can replicate if injected into cells, since it can function as mRNA and initiate translation of virus-encoded proteins. Antisense RNA, on the other hand, has no translational function and cannot per se produce viral components. Schemes of 21 virus families infecting humans showing a number of distinctive criteria: presence of an envelope or double- capsid and internal nucleic acid genome. DsRNA viruses, e. Each segment consists of a complementary sense and antisense strand that is hydrogen bonded into a linear ds molecule.
The replication of these viruses is complex; only the sense RNA strands are released from the infecting virion to initiate replication. The retrovirus genome comprises two identical, plus-sense ssRNA molecules, each monomer 7—11 kb in size, that are noncovalently linked over a short terminal region.
Retroviruses contain 2 envelope proteins encoded by the env-gene, 4—6 nonglycosylated core proteins and 3 non-structural functional proteins reverse transcriptase, integrase, protease: RT, IN, PR specified by the gag-gene Fig.
This DNA, mediated by the viral integrase, becomes covalently bonded into the DNA of the host cell to make possible the subsequent transcription of the sense strands that eventually give rise to retrovirus progeny.
After assembly and budding, retroviruses show structural and functional maturation. In immature virions the structural proteins of the core are present as a large precursor protein shell.
After proteolytic processing by the viral protease the proteins of the mature virion are rearranged and form the dense isometric or cone-shaped core typical of the mature virion, and the particle becomes infectious. Most DNA viruses Fig. The papovaviruses, comprising the polyoma- and papillomaviruses, however, have circular DNA genomes, about 5. Three or 2 structural proteins make up the papovavirus capsid: in addition, nonstructural proteins are encoded that are functional in virus transcription, DNA replication and cell transformation.
Single-stranded linear DNA, 4—6 kb in size, is found with the members of the Parvovirus family that comprises the parvo-, the erythro- and the dependoviruses. The virion contains 2—4 structural protein species which are differently derived from the same gene product see Ch. The adeno-associated virus AAV, a dependovirus is incapable of producing progeny virions except in the presence of helper viruses adenovirus or herpesvirus.
It is therefore said to be replication defective. Circular single-stranded DNA of only 1. The isometric capsid measures 17 nm and is composed of 2 protein species only. On the basis of shared properties viruses are grouped at different hierarchical levels of order, family, subfamily, genus and species.
More than 30, different virus isolates are known today and grouped in more than 3, species, in genera and 71 families. Viral morphology provides the basis for grouping viruses into families. A virus family may consist of members that replicate only in vertebrates, only in invertebrates, only in plants, or only in bacteria.
Certain families contain viruses that replicate in more than one of these hosts. Who was Andy? Who knows. Storm Worm was a Trojan horse that infected computers, sometimes turning them into zombies or bots to continue the spread of the virus and to send a huge amount of spam mail. By July , Storm Worm was picked up in more than million emails. Sasser spread through infected computers by scanning random IP addresses and instructing them to download the virus.
Netsky was the more familiar email-based worm. Netsky was actually the more viral virus, and caused a huge amount of problems in A German student, Jaschan was arrested when multiple tip-offs were reported to the police. Because he was under 18 when he wrote the virus, Jaschan spent his prison sentence on probation. MyDoom was spreading rapidly at the time and Jaschan, a newbie coder, wanted to see what would happen if his bug could spread faster than MyDoom.
Things quickly escalated from there. Sasser was so effective it actually ground one third of the post offices in Taiwan to a halt, shut down branches of a Finnish bank, and forced rail and transatlantic flights to be cancelled. Quite a lot, as it so happens. So in the early to mid-noughties, Anna Kournikova was one of the most searched terms on the internet. People were just very into tennis. The mayor of the town came forward and said the city should be proud to have produced such a talented young man and offered him a job as a techie once he was finished his education.
While most of the malware on this list strictly hit computers, Slammer was created with broader ambitions. Slammer is the kind of virus that makes it into films, as only a few minutes after infecting its first victim, it was doubling itself every few seconds.
Slammer, quite aptly, caused a huge panic as it had effectively managed to crash the internet in 15 quick minutes.
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