Learning from Bats to Escape from Potent or Severe Viral Infections

The COVID-19 pandemic that started in December 2019 in Wuhan city, China has created chaos all over the world with over 185 million infection cases and 4 million deaths world-wide. The pathogen behind COVID-19 has been identified as severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) that is more close to the previous SARS-CoV responsible for SARS epidemic 2002–2003. Although, SARS-CoV-2 also differs from SARS-CoV in many aspects as indicated by genetic studies. For example, SARS-CoV does not have a furin binding domain or site, whereas its presence in SARS-CoV-2 spike (S) protein increases its potential for infectivity. The horseshoe bats (Rhinolphus species) from China are considered as primary animal reservoirs for SARS-CoV and SARS-CoV-2. However, along with CoVs, bats also harbor many other viral pathogens (Ebola, Nipah, and Hendra viruses) without having serious infections. The bat physiology plays a crucial role in harboring these viruses along with adaptations to longevity and slow aging process. The immune system plays a crucial role in the clearance or establishment of the infection. Present chapter discusses different immunological aspects (innate immune response comprising the virus recognizing pattern recognition receptors (PRRs), type 1 interferon production, pro- and anti-inflammatory immune response, and adaptive immune response) that help bats to control viral infection without getting a severe infection as compared to other mammals, including humans.