**Introduction**

I hope that this work might increase the interest in this field of research and that the readers will find it useful for their investigations, management, and clinical usage. Also, I would like to thank our contributors, colleagues, family, and friends who gave us a lot of encourage‐

**Prof. Dr. Shailendra K. Saxena**

Center for Advanced Research

Lucknow, India

King George's Medical University (KGMU)

FRSC (UK), FRSB (UK), FAcadTM (Austria), FBRS, FAEB, FIVS, MNYAS (USA), MASM (USA), MASV (USA)

ment and support during the work on this book

VIII Preface

**Chapter 1**

**Provisional chapter**

**Introductory Chapter: Human Influenza A Virus**

**Virus Infection - Global Prevalence, Prevention,** 

**Introductory Chapter: Human Influenza A** 

**and Challenges**

**1. Introduction**

Shailendra K. Saxena, Amrita Haikerwal, Swatantra Kumar and Madan L.B. Bhatt

Shailendra K. Saxena, Amrita Haikerwal, Swatantra Kumar and Madan L.B. Bhatt

**Therapeutics, and Challenges**

http://dx.doi.org/10.5772/intechopen.77350

Additional information is available at the end of the chapter

cause of mortality associated with influenza virus.

Additional information is available at the end of the chapter

**Infection - Global Prevalence, Prevention, Therapeutics,**

Influenza virus is a perpetual economic burden that causes a significant morbidity and mortality rate in humans. Globally, the reported cases of seasonal influenza viruses (SIVs) rise up to 3–5 million during epidemics with an estimated death toll of 290,000–650,000 per year [1]. The Global Influenza Surveillance and Response System (GISRS), a surveillance system of the World Health Organization (WHO), analyses the incidences of avian and zoonotic influenza virus to accurately estimate the severity of the disease. As of March 5–18, 2018, GISRS-WHO has reported 46.8% cases of influenza A virus (where 64% were influenza A(H1N1)pdm09 cases and 36% were infected with H3N2) and 53.2% of influenza B virus (where 91% were B-Yamagata strain and 9% were B-Victoria) [2]. The co-morbidity condition (such as diabetes, heart or liver disease) or the immuno-compromised condition of patients is the predominant

Influenza virus belongs to the *Orthomyxoviridae* family and is categorized as influenza A virus (IAV), influenza B virus (IBV), and influenza C virus (ICV). The genome of influenza virus is segmented with 8 negative-sense single-stranded viral RNA (vRNA) strands which code for 11 proteins in cases of IAV and IAB, whereas IAC has seven vRNA segments that code for nine proteins. These segments are named after their main proteins such as segment 1-PB2 (polymerase basic 2), segment 2-PB1 (polymerase basic 1), segment 3-PA (polymerase acid), segment 4-HA (hemagglutinin), segment 5-NP (nucleoprotein), segment 6-NA (neuraminidase), segment 7-M (matrix), and segment 8-NS (non-structural) [3]. Influenza vRNA has heterotrimeric RNA-dependent RNA polymerase (RdRp) at the 5′ and 3′ end of the segment

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

DOI: 10.5772/intechopen.77350

#### **Introductory Chapter: Human Influenza A Virus Infection - Global Prevalence, Prevention, Therapeutics, and Challenges Introductory Chapter: Human Influenza A Virus Infection - Global Prevalence, Prevention, Therapeutics, and Challenges**

DOI: 10.5772/intechopen.77350

Shailendra K. Saxena, Amrita Haikerwal, Swatantra Kumar and Madan L.B. Bhatt Shailendra K. Saxena, Amrita Haikerwal, Swatantra Kumar and Madan L.B. Bhatt

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.77350
