Preface

Bats are found all over the world and provide significant ecosystem services [1]. Their elusive lifestyle and unusual appearance have always stimulated peoples' imagination, perhaps more so than any other animal [2]. This book highlights how these airborne mammals have been associated with death, witchcraft, vampires, malevolent spirits, and evil in some cultures, while they have been linked to luck and good fortune and used as spiritual totems in other places.

Emerging infectious diseases (EIDs) are a growing problem for humans, wildlife, and domestic animals, despite substantial progress in disease control. It is estimated that 75% of EIDs are zoonotic, that is, they are transmitted from animals to humans. Bats are known to host the rabies virus as well as SARS, MERS, and COVID coronavirus types [3].

Due to the rabies virus in bat populations, the disease is an ever-present threat to public health that can lead to a particularly unpleasant death [4, 5]. In 1985, a bat researcher in Finland died of rabies encephalitis caused by European bat lyssavirus type 2 (EBLV-2). After that, well over 1150 bats of seven species were examined for lyssaviruses in Finland during a 28-year period. EBLV-2 may circulate in Finland even though the seroprevalence is low [6]. The health risk in Finland to the public, which has no direct contact with bats through work or leisure activities, is considered negligible [6].

Since the first case of bat rabies in Germany in 1954, 1040 cases of rabid bats have been reported in Europe [6]. This number is much higher than that in North America where millions of dollars are used "to educate" the public about the dangers of bat-borne rabies in humans [7]. This has simply exacerbated the already unreasonable fears that many people have of bats. In the period 1950−2007, only 56 cases of bat-borne rabies transmission to humans occurred in the United States and Canada, which translates to 3.9 cases per billion person-years [8], which indeed is negligible as in Finland [6].

The situation of rabies in Latin America is complex. Rabies in dogs has decreased dramatically, but bats are increasingly recognized as natural reservoirs of other rabies variants. One fifth of Latin American and Caribbean bat species have been confirmed as rabies positive. Brazil, Peru, Mexico, and Colombia are the countries with the most cases of rabies in humans in the region. In Latin America mortality rates are estimated at 0.01–0.60 per 100,000 individuals [9].

During the past decade, bats have clearly been identified as an important source of new viruses that can affect humans [10]. Bat-transmitted viruses that have caused emerging infectious diseases in humans fall into different families: paramyxoviruses including Hendra and Nipah viruses [11, 12]; Ebola and Marburg hemorrhagic fever filoviruses [13, 14]; and sudden acute respiratory syndrome-like coronaviruses [15]. This list is probably far from complete. Recently, it has been reported that avian and

human influenza virus-compatible sialic acid receptors are found in little brown bats *Myotis lucifungus* widely distributed in North America, which could potentially facilitate the emergence of new zoonotic strains [16].

Epidemiologists talk about 'spillover,' which is when a virus makes the leap from one host species to another. The most dangerous spillovers to people are those from other animals to humans, creating 'zoonotic' diseases [17]. The original host of SARS-COV-2 is believed to be an as-yet-undetermined species of bat; in humans, this zoonotic disease is COVID-19 [18]. There is now broad agreement among scientists that COVID-19 probably originated in a wildlife market in Wuhan, China. The theory is that coronavirus from a bat infected wild-caught or farmed wild animals. With subsequent mutation and recombination, that virus became capable of infecting humans. A similar event was responsible for the outbreak of severe acute respiratory syndrome (SARS) in 2003 [10].

It has been shown that culling and disturbance of bat colonies have been unsuccessful in eliminating the risk of zoonotic spillover and even increased the number of infected animals in other bat-virus systems [19]. Therefore, conservationists have repeatedly emphasized the need for balanced discourse when informing the public about zoonotic risks related to bats. Even well-framed messages risk reinforcing negative associations between bats and infectious diseases, easily leading to disproportionate consequences. Thus, conservationists and health authorities are confronted with the challenge of informing people about the potential health risks associated with bats, without eroding already limited support for their conservation [19].

Additional factors that further increase the risk of disease transmission between bats and people include illegal hunting of bats for consumption and the use of bats in traditional medicine [3]. Bats have been used in medicine in various parts of the world since ancient times [20]. The oldest occurrence of bats in medicine is from 1500 BC in the medical papyri of ancient Egypt. In modern times, clinical trials are investigating the substance (desmoteplase), which is present in the saliva of the common vampire bat *Desmodus rotundus*, for its potential to help patients with acute ischemic stroke. This exploitation of animals in traditional medicine has no consideration for sustainability of populations of animals in the wild. Thus, overharvesting of medical species contributes to species loss [20].

Bat populations continue to decline worldwide because of myriad human activities. To enhance bat conservation, human behaviour needs to change. Deforestation could be a major contributing factor to new viral emergences due to more frequent contact of livestock and humans with bats possibly containing infectious viruses [10]. Monitoring bat-borne diseases and, more importantly, the environmental conditions bringing bats, viruses, and humans into contact, is crucial and should lead to the development of scenarios of risk management.

Educational campaigns should be intensified and targeted to groups that are most at risk of capturing bat-borne zoonotic diseases. Awareness programs are urgently needed in schools to improve the general knowledge of and attitudes toward bats, and to inspire the next generation of bat conservationists [1].

This book suggests that education is a suitable tool to minimize prejudice against bats and a key step to creating a harmonious coexistence between humans and bats. Chapters address such topics as bats in folklore and culture, bat dispersal patterns, bats in ecosystem management, pesticide exposure risks, roost-tier preference, diversity and conservation, and ecology of white-nose syndrome.

My warmest thanks to Author Service Manager Nera Butigan at IntechOpen for her professional and helpful cooperation in all aspects of the publication process.

> **Heimo Mikkola** Eastern Finland University, Kuopio, Finland
