What are the viruses of the cold?
The viruses of the cold: The cold is one of the most common illnesses of humans. In the United States alone, there are more than one billion colds each year. Typically a cold produces sneezing, scratchy throat, and a runny nose for one or two weeks. The causes of the common cold are viruses. More than 200 different viruses can cause a cold.
Rhinoviruses account for anywhere from 35% to over half of all colds, particularly in younger and older people. This has likely been the case for millennia. Indeed, the name Rhinovirus is from the Greek word RHIN, meaning, “nose”. There are over one hundred different types of Rhinovirus, based on the different proteins that are on the surface of the virus particle. Rhinovirus belongs to the virus family Picornaviridae.
The genetic material of the virus is ribonucleic acid (RNA) and the genome is of a very small size. Rhinovirus is spread from one person to another by “hand to hand” contact, that is, by physical contact or from one person sneezing close by another person. The virus needs to inside the human body to be able to replicate. The internal temperature of the body, which is normally between 97–99°F (36.1–37.2° C) is perfect for Rhinovirus.
If the temperature varies only a few degrees either way of the window, the virus will not replicate. Rhinovirus has been successful in causing colds for such a long time because of the large number of antigenic types of the virus that exist. Producing a vaccine against the virus would require the inclusion of hundreds of antibodies to the hundreds of different possible antigens. This is not practical to achieve.
Furthermore, not all the Rhinovirus antigens that are important in generating a cold are exposed at the surface. So, even if a corresponding antibody were present, neutralization of the antigen via the binding of the antibody with the antigen would not occur. Another factor against vaccine development is the difficulty in being able to grow Rhinovirus in the laboratory. Another virus that causes colds are members of the Coronavirus family.
The name of the virus derives from the distinctive flexible shape and appearance of the virus particle. Surface projections give the virus a crown-like, or corona, appearance. There are more than 30 known strains of Coronavirus. Of these, three or four from the genus Coronavirus can infect humans. Cattle, pigs, rodents, cats, dogs, and birds are also hosts. Members of the genus Norovirus can also cause gastroenteritis.
Coronavirus has been known since 1937 when it was isolated from chickens. It was suspected of being a cause of colds, but this could not be proven until the 1960s when techniques to grow the virus in laboratory cultures were devised. Like Rhinovirus, Coronavirus also contains RNA. However, in contrast to the same amount of genetic material carried in Rhinoviruses, the genome of the Coronavirus is the largest of all the RNA-containing viruses.
Other viruses account for 10–15% of colds in adults. These adenoviruses, coxsackieviruses, echoviruses, orthomyxoviruses (including the influenza A and B viruses), paramyxoviruses, respiratory syncytial virus, and enteroviruses can also cause other, more severe illnesses. Aside from vaccines, various “home remedies” to the common cold exist.
Larger than normal doses of Vitamin C have been claimed to lessen the symptoms or prevent the common cold. The evidence for this claim is still not definitive. Another remedy, mythologized as an example of a mother’s care for her children, is chicken soup. Studies have demonstrated that chicken soup may indeed shorten the length of a cold and relieve some of the symptoms.
The active ingredient(s), if any, that are responsible are not known, however. For now, the best treatment for a cold is to attempt to relieve the symptoms via such home remedies and over the counter medications. Nasal decongestants decrease the secretions from the nose and help relieve congestion. Antihistamines act to depress the histamine allergic response of the immune system.
This has been claimed to help relieve cold symptoms. Analgesics relieve some of the pain and fever associated with a cold. Some so-called alternative medications may have some benefit. For example, lozenges composed of zinc can sometimes reduce the duration of the common cold, perhaps due to the need for zinc by the immune system. Echinacea is known to stimulate white blood cell activity.
Rhinoviruses account for anywhere from 35% to over half of all colds, particularly in younger and older people. This has likely been the case for millennia. Indeed, the name Rhinovirus is from the Greek word RHIN, meaning, “nose”. There are over one hundred different types of Rhinovirus, based on the different proteins that are on the surface of the virus particle. Rhinovirus belongs to the virus family Picornaviridae.
The genetic material of the virus is ribonucleic acid (RNA) and the genome is of a very small size. Rhinovirus is spread from one person to another by “hand to hand” contact, that is, by physical contact or from one person sneezing close by another person. The virus needs to inside the human body to be able to replicate. The internal temperature of the body, which is normally between 97–99°F (36.1–37.2° C) is perfect for Rhinovirus.
If the temperature varies only a few degrees either way of the window, the virus will not replicate. Rhinovirus has been successful in causing colds for such a long time because of the large number of antigenic types of the virus that exist. Producing a vaccine against the virus would require the inclusion of hundreds of antibodies to the hundreds of different possible antigens. This is not practical to achieve.
Furthermore, not all the Rhinovirus antigens that are important in generating a cold are exposed at the surface. So, even if a corresponding antibody were present, neutralization of the antigen via the binding of the antibody with the antigen would not occur. Another factor against vaccine development is the difficulty in being able to grow Rhinovirus in the laboratory. Another virus that causes colds are members of the Coronavirus family.
The name of the virus derives from the distinctive flexible shape and appearance of the virus particle. Surface projections give the virus a crown-like, or corona, appearance. There are more than 30 known strains of Coronavirus. Of these, three or four from the genus Coronavirus can infect humans. Cattle, pigs, rodents, cats, dogs, and birds are also hosts. Members of the genus Norovirus can also cause gastroenteritis.
Coronavirus has been known since 1937 when it was isolated from chickens. It was suspected of being a cause of colds, but this could not be proven until the 1960s when techniques to grow the virus in laboratory cultures were devised. Like Rhinovirus, Coronavirus also contains RNA. However, in contrast to the same amount of genetic material carried in Rhinoviruses, the genome of the Coronavirus is the largest of all the RNA-containing viruses.
Other viruses account for 10–15% of colds in adults. These adenoviruses, coxsackieviruses, echoviruses, orthomyxoviruses (including the influenza A and B viruses), paramyxoviruses, respiratory syncytial virus, and enteroviruses can also cause other, more severe illnesses. Aside from vaccines, various “home remedies” to the common cold exist.
Larger than normal doses of Vitamin C have been claimed to lessen the symptoms or prevent the common cold. The evidence for this claim is still not definitive. Another remedy, mythologized as an example of a mother’s care for her children, is chicken soup. Studies have demonstrated that chicken soup may indeed shorten the length of a cold and relieve some of the symptoms.
The active ingredient(s), if any, that are responsible are not known, however. For now, the best treatment for a cold is to attempt to relieve the symptoms via such home remedies and over the counter medications. Nasal decongestants decrease the secretions from the nose and help relieve congestion. Antihistamines act to depress the histamine allergic response of the immune system.
This has been claimed to help relieve cold symptoms. Analgesics relieve some of the pain and fever associated with a cold. Some so-called alternative medications may have some benefit. For example, lozenges composed of zinc can sometimes reduce the duration of the common cold, perhaps due to the need for zinc by the immune system. Echinacea is known to stimulate white blood cell activity.
No comments: