Il ruolo del cavallo nel fenomeno dello spillover ed il suo impatto sulla salute animale e dell'uomo

Abstract

New emerging diseases are often about a consequence of the spillover event. Spillover or cross- species transmissions, interspecies transmissions or host jumps, are the transmissions of a pathogen between hosts belonging different species. For this event to occur, a break in the balance between the protagonists of this phenomenon (the reservoir, the host and the pathogen), is necessary. This, occasionally, may also involve horses, endangering the health of other animal species but also of humans. Horses are among the most important animals in human history, and therefore, in relation to this, the detection of infectious diseases that affect both humans and horses is crucial, especially in cases of highly transmissible diseases. There are many examples in history that are related to the spillover of different diseases from horses. Among them, there are two of particular importance: the cross-species transmission of the equine influenza virus to dogs, and the spillover of the Hendra virus to humans. The influenza virus affects many different species, including equines. In fact, the equine influenza virus is one of the most frequent and important diseases concerning the equine industry all over the world. In January 2004, one of the two strains of the virus, the H3N8, was firstly isolated in racing greyhounds, becoming, from that moment on, one of the main strains of the canine influenza. The Hendra virus, instead, is an emerging virus jumping from flying foxes to horses and from horses to humans. This virus is confined to Australia only, but it is characterized by a high mortality range, becoming not only a major concern for the Australian National public health ministry, but also for the other health authorities around the world. The Hendra virus is significant because it demonstrates the epidemic potential of an emerging virus.