Virus:- A virus is a small infection agent that reproduce inside the cell of a living host. Virus can infect animals and plants to Bacteria, archaic. Virus was first discovered by Iwanowaski in the year 1812. Virus are made of RNA or DNA. It consists Nucleic Acids.
all living things are made of one or more cells,"see the modern cell theory" viruses are not cells. Viruses aren’t technically classified as living things since they lack many characteristics of life, but there is debate in calling them nonliving as well. Medications like antibiotics attack bacteria like which are living cells. Anti-fungal drugs can be used on fungi like athlete’s foot which are made of living cells. Viruses are not bacteria or fungi. virus is not a cell. all, viruses are much, much smaller than cells. You need an electron microscope in order to see a virus. Viruses come in many shapes. One of them is the bacteriophage! It sounds very fancy, but it is a type of virus that tends to attack bacteria. One thing is common for all viruses , that they have some type of genetic material. This genetic material can be in the form of DNA or RNA. Viruses usually have some kind protein coat, also known as a capsid. The capsid can protect that DNA or RNA genetic material. Viruses can also can have other structures. Some viruses package special enzymes with them. Some viruses have an outer envelope. These additions can be useful to the virus in virus replication. One thing that makes virus replication, or reproduction, unique is that they can’t replicate without a host.It is their reproducing that tends to be a problem for its host: whether the host is you --- in the case of a common cold---, an insect, plant, or this bacterium. Viruses tend to be very specific for the host that they are going to go infect, but anything that is alive can be a host, because cells have the machinery viruses need in order to replicate.

We're going to focus on kinds of viral replication cycles. The first one is the lytic cycle. Inside the lytic cycle, the virus, remember very selective, attaches to a number cellular. It often binds to a receptor that this cell has which gives it access to dock there. The virus can then inject either its DNA or RNA, relying on what form of genetic material it has, into the cell. A few types of viruses are clearly taken inside the cell themselves. Now you would think the cell could notice viral DNA or RNA or an entire virus that has been taken in, however in many instances it does not. It takes the genetic material from the virus and it starts following the instructions, which in this example may be very bad, due to the fact the instructions inform it to makes copies of the virus. The cell makes use of its very own sources to begin building. It starts offevolved making such a lot of copies of the virus that it could cause the cellular membrane of the host to rupture, explode, lyse! So what takes place is now these new viral copies get out of the cellular, and they go and infect different cells. That is called the lytic cycle. By using the manner, the lysing of the cell membrane is a very bad element for the cell. The cell cannot survive without its cell membrane.The other cycle is known as the lysogenic cycle. Viruses that go through this cycle have a tendency to do the equal factor at the beginning. They inject their genetic material, but this time, the genetic material remains hidden within the host’s genetic material. What occurs is that when the host makes new cells, it replicates its own genetic material and the viral genetic material. Then the ones daughter cells make new cells, and they also reflect their personal genetic material and the viral genetic material. And so forth. That is the lysogenic cycle. That may not look like a problem, however it honestly turns into one, if it gets brought about to go into the lytic cycle from that factor, because then all of these cells that had the viral genetic material can begin assembling viruses.As far as what triggers it to go into the lytic cycle, it can vary. It could be a chemical trigger for example or a lack of food for the host.
'Viral Diseases in Human' is cundition of the body or its part in which functions are disturbed or deranged .

Human Diseases Caused By Virus
Diseases Virus Affected Part Symptom
Measles(Rubella disease) Rubella Virus Whole Body Loss of appetite, reddish eruption on the body.
Chicken Pox Vericella Virus Whiole Body High fever, reddish eruption on the body.
Small Pox Variola Virus Whole body Light fever,eruption of bile on the body.
Polio or Poliomyelitis Polio Virus Throat, back bone and nerve. Fever, backbone and intestine wall cells are destroyed. It leads to paralysis.
Influnza(flu)Spread from person to person) Influenza Virus(Family Orthomyxoviridae) Whole body Inflammation of upper respiratory tract nose,throat and eyes.
Rabies(hydrophobia) RNA virus called rabies virus Nervous System Encephalitis,fear of water,high fever,headache,spasm of throat and chest leading to death.
A(epidemic Jaundice) A virus Liver Loss of appetite, nausea,whitish stool and jaundice.
Dengu fever(transmitted by female Aedes aegypti mosquito) RNA containing dengue virus Whole body,particularly head, eyes and joints High fever, backache, headache,retro-orbital painbehiond eye ball.
AIDS(Acquired immune Deficiency Syndrome) Human immouno deficiency virus(HIV) White blood cells Weak immune system.
Herpes Herpes virus Skin Swelling of skin.
Ebola virus disease Ebola virus(filovirus) Whole body Fatal hemorrhagic fever, liver and kidney disfuction, vomiting,headache.
Swine influenza(flu) H1 N1 flu virus Whole body(mucles) Headache, tiredness, sore throat, vomiting, breathing problems.
SARS(severe acute respiratory syndrome) SARS-CoV Respiratory system Difficulty in breathing
Zika Zika virus Brain cells and immune system Mild fever,conjuctivitis,mucle and joint pain
Corona Corona virus(nCOVID-19) severely impact the lungs Fever and symptoms of lower respiratory illness. Such as coughing or difficulty breathing .mild nausea, vomiting or mild diarrhea are possible to set in

Important Note:-

Ebola Virus:- Ebola is caused by Ebola virus(filovirus).According to World Health Organisation (WHO) 19th August,2015 Situation Report,there were three confirmed case of Ebola reported in the week up to 16th August all of which were reported from Guinea.For the first time since the beginning of the outbreak in sierra Leone, a full epidemiological week has passed with no confirmed cases reported. A total of 72 cases remain under monitoring in sierra Leone.

Corona Virus:- Corona(COVID-19) case first noticed in Wuhan China in November-December 2019.Coronaviruses are a group of viruses covered in little protein spikes that look like a crown— or "corona" in Latin. There are hundreds of known coronaviruses. Seven of them infect humans, and can cause disease. The coronavirus SARS-CoV causes SARS, MERS-CoV causes MERS, and SARS-CoV-2 causes the disease COVID-19. Of the seven human coronaviruses, four cause colds, mild, highly contagious infections of the nose and throat. Two infect the lungs, and cause much more severe illnesses. The seventh, which causes COVID-19, has features of each: it spreads easily, but can severely impact the lungs. When an infected person coughs, droplets containing the virus spray out. The virus can infect a new person when the droplets enter their nose or mouth. Coronaviruses transmit best in enclosed spaces, where people are close together.Coronaviruses are a large family of enveloped, RNA viruses. There are 4 groups of coronaviruses: alpha and beta, originated from bats and rodents; and gamma and delta, originated from avian species. Coronaviruses are responsible for a wide range of diseases in many animals, including livestock and pets. In humans, they were thought to cause mild, self-limiting respiratory infections until 2002, when a beta-coronavirus crossed species barriers from bats to a mammalian host, before jumping to humans, causing the Severe Acute Respiratory Syndrome, SARS, epidemic. More recently, another beta-coronavirus is responsible for the serious Middle East Respiratory Syndrome, MERS, started in 2012. The novel coronavirus responsible for the Coronavirus Disease 2019 pandemic, COVID-19, is also a beta-coronavirus. The genome of the virus is fully sequenced and appears to be most similar to a strain in bats, suggesting that it also originated from bats. The virus is also very similar to the SARS-coronavirus and is therefore named SARS-coronavirus 2, SARS-CoV 2. At the moment, it’s not yet clear if the virus jumped directly from bats to humans, or if there is a mammalian intermediate host.