What Is Viral Infection?
Viruses are tiny particles smaller than bacteria. After invading an animal or plant, viruses use the organism's cells to reproduce themselves. The plant or animal cell may die as the viral DNA or RNA takes over control of the cell's functions. New copies of the virus are released, which go on to infect other cells to begin the process again.
Every type of human cell is susceptible to a virus of one kind or another. Most viruses are more likely to invade certain types of cells. The nature of the infection depends on the type of virus, the system affected and the host response. Some viruses cause mild symptoms that disappear in a few days, such as the common cold viruses. Others such as influenza (flu) or coronavirus, which causes SARS, may bring on severe or even life-threatening respiratory symptoms.
Viruses cause most respiratory infections, including the common cold. Adults on average suffer from about three or four colds a year. Viruses are also responsible for infections of the nervous system, skin, liver and digestive system. Viruses that attack white blood cells include Epstein Barr virus (infectious mononucleosis), which infects the B lymphocyte and human immunodeficiency virus (HIV), the virus that causes AIDS, which targets the helper T cells that coordinate the immune system.
What Causes Viral Infections
More than 80 different types of HPV have been identified, and they have tropism (affinity) for different types of body tissue. Most types of HPV have an affinity for the skin and produce common warts (verruca vulgaris), flat warts (verruca plana), and plantar or foot warts (verruca plantaris). Several other types of HPV have an affinity for mucous membranes and some of these cause ano-genital warts (condyloma acuminata).
HPV is passed from person to person by direct or indirect contact, and from one body location to another on the same person. The virus more easily enters the body through an area of skin that is moist, peeling, or cracked. Some types (e.g., condyloma acuminta) are transmitted sexually. The degree of contact, location of the lesions, the amount of virus present (newer warts tend to contain more viral particles than older warts), and the state of a person's immunity are among the factors that determine HPV infection.
What is the Treatment of Viral Infections
Use of antivirals
Viral illnesses are not treated with antibiotics. Instead, therapy is intended to treat symptoms while the body's own immune defenses work at eradicating the virus. However, there are instances when antiviral agents are used:
1- Acquired immune deficiency syndrome (AIDS). Antiretroviral therapy is given to suppress the replication of human immunodeficiency virus (HIV), even if there are no symptoms. The goal of treatment is to lower the concentration of virus (viral load) as much as possible in addition to treating any of the secondary, opportunistic infections.
2- Influenza. Antiviral therapy is given to high-risk individuals during a flu outbreak. People 65 or older or those with chronic medical conditions are at risk for developing complications of the flu, such as a bacterial pneumonia, and may be given antiviral medication over a two-week period from the start of the outbreak as a preventative measure. If started within 48 hours of symptom onset, antivirals can shorten the duration and degree of severity of influenza. Four antivirals are currently approved for this indication. However, the CDC recommended that amantadine and rimantidine not be used either for the prevention or treatment during the 2006-2007 flu season. The influenza viruses circulating in the population became highly resistant to the two antivirals. Until viruses are susceptible again, these antivirals should not be used.
Treating symptoms
General symptoms (fever, chills, muscle aches):
1- Anti-fever medication may be used according to the dosage schedules. However, do not use an anti-fever medication for a child younger than 3 months without first talking to your doctor. Infants ages 12 weeks or less who develop a rectal temperature of 100.4 degrees F or higher usually need to go to the emergency room for an immediate medical evaluation. Aspirin should not be used in children and teenagers because of the dangers of Reye's syndrome.
Colds and flu:
1- Humidify the room to keep nasal secretions moist.
2- Use salt-water nose drops in infants to help keep nasal mucus thin. These nose drops are available in the pharmacy. This is especially recommended before feeding an infant so that the infant can breathe through the nose during a feeding.
3- If the mucus is thick, drink more fluids. A syringe can be used to remove nasal mucus from an infant.
To treat cough
A number of cough suppressants containing DM (dextromethorphan) are available. Dosages may vary. These medicines may not be used for everyone. It is not advisable to use over the counter cough or cold remedies for children 6 or under unless upon the advice of the child's treating physician.