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West Nile Virus
West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever.
It belongs to the Flaviviridae family of viruses, which also includes the Zika virus, dengue virus, and yellow fever virus.
In humans, the West Nile virus can cause a fatal neurological disease.
In horses, the virus can cause serious illness and death.
The West Nile virus's natural hosts are birds.
Infected mosquito bites are the most common source of human infection.
Mosquitoes become infected after feeding on infected birds, which then carry the virus around in their blood for a few days.
Contact with other infected animals, their blood, or other tissues can also spread the virus.
Usually, people who are infected with WNV do not experience any symptoms, even if they are mild.
Fever, headache, body aches, skin rash, and swollen lymph glands are among the symptoms.
- Virus
The viruses are non-cellular organisms that are characterised by having an inert crystalline structure outside the living cell.
In 1898, Friedrich Loeffler and Paul Frosch found evidence that the cause of foot-and-mouth disease in livestock was an infectious particle smaller than any bacteria. This was the first clue to the nature of viruses, genetic entities that lie somewhere in the grey area between living and non-living states.
The name virus that means venom or poisonous fluid was given by Dmitri Ivanowsky (1892) recognised certain microbes as causal organism of the mosaic disease of tobacco.
Important Features of Viruses:
Viruses are the smallest of all the microbes.
Virus are unique because they are only alive and able to multiply inside the cells of other living things. The cell they multiply in is called the host cell.
A virus is made up of a core of genetic material, either DNA or RNA. No virus contains both RNA and DNA.
A virus is a nucleoprotein (In simple terms Virus is surrounded by a protective coat called a capsid which is made up of protein) and the genetic material is infectious.
In general, viruses that infect plants have single stranded RNA and viruses that infect animals have either single or double stranded RNA or double stranded DNA.
Bacterial viruses or bacteriophages (viruses that infect the bacteria) are usually double stranded DNA viruses.
Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.
Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity.
Viroid:
They are smaller than viruses.
Viroid are the smallest infectious pathogens known.
It was found to be a free RNA; it lacked the protein coat that is found in viruses, hence the name viroid.
Prions:
Prions are similar in size to viruses consisting of abnormally folded Proteins.
Prions do not have nucleic acid
They are transmitting agents of certain infectious neurological diseases Bovine spongiform encephalopathy (BSE) commonly called mad cow disease in cattle and its analogous variant Cr–Jacob disease (CJD) in humans are caused by Prions.