Types Of Influenza
A, B, C, and D are the four main types of influenza viruses. Influenza A and B viruses infecting humans are responsible for the seasonal outbreak of diseases known as flu season. The influenza epidemic typically occurs at the onset of winter and affects the majority of the population. Different influenza virus subtypes are classified based on surface proteins such as neuraminidase (N) and hemagglutinin (H). There are approximately eleven distinct NA subtypes and eighteen distinct HA subtypes that cause influenza infection. The following is a description of the four most prevalent varieties of influenza viruses:
The influenza A pathogen
Influenza virus A is the leading cause of influenza pandemics worldwide, and a pandemic occurs when old and novel influenza virus strains co-circulate. The efficiency with which influenza virus A can propagate results in the outbreak of a pandemic. The presence or absence of protein on the surface of influenza virus A subtypes the virus into additional subtypes. Recent investigations indicate that there are nearly 198 distinct subtype influenza virus A combinations. A(H3N2) and A(H1N1) are the most prevalent and highly contagious subtypes of influenza, respectively. The classification of influenza virus A now includes clades and sub-clades. The clades and sub-clades illustrate the proportion of viruses in the community and aid in preventing influenza outbreaks.
Influenza virus subtype B
Influenza virus B is also responsible for the most prevalent flu transmission in the community. There are no additional classifications of influenza virus B into subtypes, but the virus is divided into two lineages. The antigenic and genetic properties of influenza virus B change significantly less rapidly than those of influenza virus B. The two influenza virus B lineages are B/Victoria and B/Yamagata. Recent influenza surveillance data demonstrates that the geographical distribution of influenza B virus varies. Both lineages are expanding their global distribution.
Influenza virus subtype C
Generally, influenza virus C causes mild symptoms and is not liable for epidemics. The frequency of influenza virus C is extremely low and has no public health significance.
Influenza virus subtype D
The influenza virus D typically affects cattle, and there is no evidence that it causes illness or infects humans, according to studies.
