A brief outline of respiratory viral disease outbreaks: 1889-till date on the public health perspectives

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently causing the respiratory illness termed as the coronavirus disease 2019 or the COVID-19 pandemic. Indeed, the significant increase in deaths in the current days due to influenza around the world started in 1889 is a continued public health threat because of its intermittent style of pandemic outbreaks. An array of research on the influenza viruses has been conducted especially pointing on (1) the development of the anti-viral drugs and the design of probable vaccines on trial basis, (2) the biochemical and genetic aspects underlying the viral pathogenicity, (3) the viral epidemiology, and on (4) the protective immunity against the influenza viruses. Current review briefly discussed the epidemic/ pandemic history of influenza and correlated with the current epidemiology, the possible preventive measures that may be taken by the public health professionals as well as to increase the protective awareness among the general people. The viral reassortments during the initiation of pandemics have also been focused based on the previous literatures.

Keywords: COVID-19; History; Influenza viruses; Pandemic; Public health.

Fig. 1

Simple illustration of viral reassortment between the influenza viruses. After the 1918–1920 Spanish influenza outbreak the 1918 A/H1N1 subtype (thought to be generated from manifold reassortments between avian-, swine-, and human borne viruses) was likely to circulate continuously and thereby triggering the subsequent epidemics [20]. In 1957 the A/H1N1 subtype was depicted to be reassorted with an avian A/H2N2 virus, which circulated until 1968, and reassorted again with the avian H3Nx virus [37]. In 1977 the A1/H1N1 virus was reestablished among the humans (contained the M gene segment of 1918 origin, encoding the matrix protein, M1 and M2, grossly required for the viral pathogenecity) and was co-circulated with H3N2 viruses till 2009 [20, 36, 38, 39] when it was thought to be swapped by another A/H1N1 subtype, H1N1pdm2009 [38] as a result of the numerous reassortments between avian-, swine-, and human influenza viruses yy[, –38]. This is to be noted that such viral reaasortments have not been shown between the SARS or SARS-CoV2 in this illustration. PB2 Polymerase basic protein 2, involved in transcription initiation and cap stealing mechanism; PA polymerase acidic protein, involved in viral RNA transcription and replication; NP nuceloprotein, involved in the encapsulation of the viral genome for RNA transcription, replication and packaging; M matrix protein, involved in the formation of the viral envelope; NS non-structural protein, involved in the inhibition of host immune responses; PB1: Polymerase basic protein 1, a determinant of the influenza virus virulence; HA hemagglutinin, a homotrimeric glycoprotein found on the surface of influenza viruses which is integral to its infectivity, and is involved in the viral attachment and acts as a membrane fusion protein.; NA neuraminidase, involved in cleaving sialic acid groups from glycoproteins and are required for influenza virus replication; i.e., it is essential for release of progeny virus particles from the surface of an infected cell