Picornaviridae History, Family Group, Classification, Features

Picornaviridae is a family of small viruses with single-stranded RNA genomes, causing illnesses from mild fevers to severe diseases affecting the heart, liver, and nervous system in humans and animals.

Picornaviridae Overview

• "Picornavirus" comes from "picorna-" an acronym for several viruses
• It also comes from "pico-," a tiny unit of measurement, combined with "RNA" to describe these tiny RNA viruses.
• Scientists are testing solid drugs to fight these viruses at different life cycle stages.

• RNA-protein interactions are essential for how these viruses grow and spread.
• Some new drugs have shown promise in treating infections caused by these viruses, which could help prevent diseases like the common cold.

The History of the Picornaviridae Family

Classification of Picornaviridae Family

Characterstic Features  of Picornaviridae

• Picornaviruses are tiny and shaped like a soccer ball, about 28-30 nanometers wide.
• They don't have a covering layer (envelope), so they're called nonenveloped.
• The outer layer of the virus, called the capsid, comprises 60 protein subunits.
• Inside the capsid is the virus's genetic material, RNA.
• The capsid has spots where antibodies can attach, which is essential for fighting the virus.
• The capsid proteins VP1 and VP4 are essential for antibody binding.
• The virus's RNA has about 7,500 building blocks called nucleotides.
• A particular protein called VPg is attached to both ends of the RNA, helping protect it.
• Picornaviruses don't have any essential fats, so they're not affected by ether.
• Some picornaviruses carry a sphingosine-like molecule and myristic acid attached to specific proteins.
• Viral proteins are not glycosylated.

Diseases Caused by Picornaviridae Family

• Respiratory Tract Infections: They often lead to infections in the respiratory system, such as the common cold.
• Gastrointestinal Disturbances: Picornaviruses are associated with stomach and digestive issues.
• Conjunctivitis: They can cause inflammation of the eyes, commonly known as pink eye.
• Mucous Membrane Disintegration: Infections by these viruses can result in the breakdown of mucous membranes in various parts of the body.
• Lesions in Mucous Membranes and Skin : They may lead to sores or lesions on mucous membranes and the skin.
• Intrauterine Infections: Pregnant women infected with picornaviruses can pass the virus to their unborn babies, causing infections.
• Pancreatitis: Some cases of pancreatitis, such as inflammation of the pancreas, are associated with picornavirus infections.
• Orchitis: Inflammation of one or both testicles can occur due to picornavirus infections

Picornaviridae Family  Polioviruses

• Before vaccines, most cases of paralysis were caused by type 1 poliovirus.
• Polioviruses mainly infect humans and can cause paralysis.
• They can infect other primates and mammals, but humans are their primary hosts.
• Attenuated oral polio vaccine (OPV) strains are less harmful and distinguishable from wild-type strains.
• Circulating vaccine-derived polioviruses (cVDPVs) can become similar to wild-type polioviruses due to mutations.
• cVDPVs have distinct RNA sequences and can acquire traits of wild-type polioviruses.

Picornaviridae Family- Rhinovirus

• Rhinovirus is found worldwide and causes infections throughout the year.
• Infections increase in September when children return to school and occur in the spring.
• It spreads through small-particle aerosols, large-particle aerosols, or direct contact.
• The virus must be deposited on the nasal mucosa or conjunctiva for infection.
• Infections primarily affect the respiratory tract epithelium.
• It can be transmitted through hand contact, making sneezing and coughing less efficient.

Picornaviridae Family- Hepatitis A Virus(HAV)