We now know that viruses are found as parastics in all types of
organisms. They can reproduce only within cells. Many diseases
of humans are known to be caused by viruses; some diseases of
agriculturally important animals and plants are also known to be
caused by viruses. Viruses infect fungi, bacteria and protists
as well. Advances in molecular biology techniques in the 1980s
and 1990s have led to the discovery of new human viruses.
Hepatitis C and Pestivirus which causes severe pediatric
diarrhea were discovered in the 1989. Public health officers are
concerned about health risks posed by thses new viruses and they
are also concerned that the ease of world travel and changing
enviroment will spread viruses to new areas. The 1993 outbreak
of a Hantavirus infection in the southwestern U.S.A illustrates
the potential for new infections to emerge at any time.
Hantavirus diseases is an acute, often fatal, respiratory
diseases.Although the virus had previously been isolated from
rodents, the disease had not been