Information About Viral Diseases

By: james sameul

Viral gastroenteritis is an intestinal infection caused by several different viruses. Highly contagious, viral gastroenteritis is the second most common illness in the United States. It causes millions of cases of diarrhea each year.Anyone can get viral gastroenteritis and most people recover without any complications. However, viral gastroenteritis can be serious when people cannot drink enough fluids to replace what is lost through vomiting and diarrhea-especially infants, young children, the elderly, and people with weak immune systems.

Viruses are a very common type of infectious disease. Many of the most common human diseases are viral. There are literally hundreds of types of viral conditions. Viruses are the smallest life-form existing, since they are not even a single cell. It is almost like they are not alive at all. They are small strands of DNA-like cell material. A virus consists mostly of RNA and cannot survive without host cells.

Viruses lie around our environment all of the time just waiting for a host cell to come along. They can enter us through the nose, mouth or breaks in the skin (see How the Immune System Works for details). Once inside, they find a host cell to infect. For example, cold and flu viruses will attack cells that line the respiratory or digestive tracts. The human immunodeficiency virus (HIV), which causes AIDS, attacks the T-cells of the immune system.

Fowl pox can be transmitted by direct or indirect contact. The virus is highly resistant in dried scabs and under certain conditions may survive for months on contaminated premises. The disease may be transmitted by a number of species of mosquitoes. Mosquitoes can harbor infective virus for a month or more after feeding on affected birds. After the infection is introduced, it spreads within the flock by mosquitoes as well as direct and indirect contact. Recovered birds do not remain carriers.

Most wheat cultivars are resistant to this aphid-borne virus disease. Some spring wheat cultivars and winter wheat selections are quite susceptible, as shown by stunting and leaf yellowing. Barley yellow dwarf virus overwinters in wild grasses. Grain aphids transmit this virus once infested in a persistent manner. At the end of the growing season in mid- to late-August, most Alberta wheat plants will test positive for this virus though no symptoms may be visible.

Influenza virus strains that cause worldwide outbreaks (pandemics) are classic examples of emerging viruses that are maintained in other animal hosts before transmission to humans. Influenza viruses are isolated from a variety of animals, including humans, pigs, horses, wild and domestic birds, and even sea mammals. The most devastating viral infection in this century was not caused by HIV, but by Spanish influenza, which killed more than 20 million people worldwide. Genetic studies suggest that the Spanish influenza virus originally was derived from birds.

Furthermore, the causative viruses for the 1957 and 1968 influenza pandemics were hybrids between human and avian influenza viruses. Because humans did not have immunity to avian influenza viruses.

Under natural conditions, the virus seems limited to the macaques, with both the rhesus and cynomolgus considered primary natural hosts; however, other macaque species are also incriminated from results of serologic testing. As high as 25 per cent of macaques, both imported and domestically bred, have antibodies to herpes B virus. A short incubation period of 4 to 10 days is required from initial exposure.

Top Searches on
Medical Conditions
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 
 • 

» More on Medical Conditions
 



Share this article :
Click to see more related articles