Bats, viruses, emerging diseases and humans

This paper reviews the unique characteristics of bats, their important roles in providing ecosystem services, their viruses in relation to emerging diseases. Bats, as flying mammals, are the second largest order following rodents, with a wide variety (over 1400 identified species among 230 genera of 21 families in the world) due to their flying power and echolocation. Despite their importance as natural host reservoirs and providing ecosystem services, till relatively recently, bats have been among the least studied mammals. So far, over 200 viruses from 27 families isolated or identified amonf bats, some related fatal disease, including EBOLA, SARS, MERS, MARBURG and current COVID-19. It is hypothesized, perhaps, the flight evolution has exerted strong selective pressure on bats immune systems’ and their viruses, through the fluctuations in metabolic rate and body temperature. Higher body temperatures in bats raises immune responses leading to fast replication of viruses; so while in humans and other mammals’ body, with low or moderate immune responses, the same viruses could bring about fatal epidemics. However, bats are not to be blamed mediating the fatal diseases, rather mostly human misbehavior makes it possible to facilitate the spread of these diseases in different ways, such as destroying natural habitats, hunting, and handling them as pets, along with the planet population growth. At the last, disease like covid-19, could persist and may affect humans to adjust their behavior, supposedly, these adjustments easier than producing very expensive vaccines to cure viral disease! The current coronavirus pandemic is perhaps the first clear indisputable sign that environmental damages could kill humans reckless, too.