Bats, Emerging Diseases, and the Human Interface

The tragic death of a Dutch patient due to Duvenhage virus infection acquired after bat exposure in Kenya during 2007 emphasizes the potential dangers associated with ecotourism, underscores the role of Chiroptera as reservoirs of emerging infectious diseases, and highlights modern attempts to prevent and treat these zoonotic diseases. The patient in this incident, a physician from The Netherlands, was a visitor to a game park in eastern Kenya, and had not been previously vaccinated against rabies. Often, many travelers abroad may not be well versed in local environmental conditions. Well before expected departure, travel medicine consultants should discuss both generic and country-specific risks with their clients. For maximum benefit, several biologics require administration a month in advance of departure, such as rabies pre-exposure immunization. Besides primary vaccination suggestions, and health insurance considerations for emergency care abroad or medical evacuation as needed, basic education is necessary concerning realistic public health concerns, especially in developing countries. Selective positive social behaviors should be promoted, especially as related to personal interactions with animals, both domestic and wild. Greater appreciation of animals from a distance is ideal, rather than any personal provocations. If animal bites or scratches do occur, immediate thorough washing of wounds with soap and clean water is valuable, followed by careful biomedical evaluation. While the latter was attempted in this particular Kenyan incident, the global implications of bat rabies were not appreciated. Unlike the epidemiological situation in Europe and the developed world, rabid dogs remain responsible for the vast majority of human rabies cases in other parts of the world. For this reason, less attention is paid to infections acquired from other mammals, such as wildlife. With the exception of Antarctica, bat rabies occurs on all continents. The existence of lyssaviruses associated with infected Chiroptera in Africa has been documented for several decades [1]. Although surveillance is often limited or lacking, multiple studies to date suggest that bat rabies is much more widespread throughout Africa, and other continents, than is commonly communicated. In contrast to bites from mammalian carnivores, such as dogs, resulting injuries after even superficial direct contact with bats may appear rather trivial by comparison, as illustrated in this patient, with only superficial wounds noticed on her nose. In another typical example from Texas in 2006, a teenager died from rabies 1 month after a report of a bat that had awakened him, after landing upon his face [2]. Clearly, based upon both experimental and epidemiological criteria, any probable likelihood for bona fide transdermal or mucosal exposures to a bat is a reasonable consideration for rabies prophylaxis, regardless of geographical locality. Confusion in the use of specific viral taxonomy related to the presence or absence of ‘‘rabies virus’’ per se, versus other ‘‘lyssaviruses’’, or bio-political considerations over so-called ‘‘rabies-free’’ areas, are largely irrelevant to the health provider and traveler alike, and pale in the face of obvious public health concerns when ignored or misunderstood, in the wake of volant reservoirs. To simplify: rabies is an acute progressive encephalitis; the clear majority of cases occur after animal bite; lyssaviruses are the neurotropic etiological agents that cause rabies; rabies virus is only one of at least 11 types of lyssavirus; rabies is a preventable infectious disease; any suggestions of ‘‘rabies-like diseases’’ are obvious misnomers that only obfuscate health communications.