Abstract
Viruses that emerge pose challenges for treatment options as their
uniqueness would not know completely. In spite of large diversity,
viruses share common characteristics for infection. There are at least
12 different respiratory borne viruses that belong to different virus
taxonomic families. Many of these viruses multiply and cause damage to
the upper and lower respiratory tracts. The description about these
viruses in comparison to each other with reference to their
epidemiology, molecular characteristics, disease manifestations,
diagnosis and treatment is lacking. Such information helps to diagnose,
differentiate and for formulating the control measures at faster pace.
The leading cause of acute illness worldwide are the acute respiratory
infections (ARIs) and are being responsible for nearly 4 million deaths
every year which are mostly in young children and infants. Among the
above ARIs, influenza, respiratory syncytial virus (RSV), parainfluenza
virus type 3 (PIV-3), Streptococcus pneumoniae, Haemophilus influenzae
and corona viruses are the main infectious agents. WHO recognized
respiratory syncytial virus, parainfluenza viruses, coronavirus,
rhinovirus, and human metapneumovirus [non-influenza RNA respiratory
viruses (NIRVs)], as considerable global health burden. Lower
respiratory tract infections are the fourth most common cause of death
globally, after the non-infectious chronic conditions. This review aimed
at presenting the characteristics of different viruses causing the
respiratory infections highlighting the uniqueness of Covid-19. We
expect that this review would help in understanding the similarities and
differences among the closely related viruses causing respiratory
infections and hence to formulate the specific preventive or control
measures.