Do all viral diseases are contagious???
Viruses are non living outside the body. They contain genetic material (DNA or RNA) but cannot grow independently. Instead, they need a host organism for its survival as they use host genetic instructions.
Contagious is defined as the ability of a virus to be transmitted from one person to another. Contagious diseases can be spread in several ways such as through direct physical contact (by touching or kissing an infected person), through airways sneezing or coughing of an infected person.
Viral infections have an incubation period which means time between exposure of virus to the emergence of symptoms.
Viruses can be transmitted by touch (contagious), saliva, or even the air. Some viruses can be transmitted by sexual contact. Insects such as mosquitoes can act as vectors that transmits virus from one person to another. Food and water that are contaminated can also be the sources of virus.
Some disease-causing viruses are influenza, common cold, human immunodeficiency virus (HIV) etc. These may affect reproductive, gastrointestinal systems and respiratory tracts of body.