Prevalence of rabies

The prevalence of rabies, a deadly viral disease affecting mammals, varies significantly across regions worldwide, posing a persistent public health problem. Rabies is caused by lyssaviruses, including the rabies virus, the Australian bat lyssavirus, the European bat 1 lyssavirus and the European bat 2 lyssavirus. At a global level dog bites and scratches cause 99% of the human rabies cases, but in some countries, including the United States, most cases of human rabies are acquired from bats. Almost all cases of human rabies are transmitted by animal bites or scratches, or other contact of animal saliva with the eyes, mouth, or open wounds. Although human-to-human transmission is theoretically possible, given that the rabies virus is present in the saliva, sperm and vaginal secretions of infected people and therefore could be transmitted through bites or sexual intercourse, no such case of transmission has ever been documented. There have been, however, rare cases of transmission of rabies through organ transplants. No case of rabies transmission from consuming the meat or milk of rabid animals has ever been documented, although the World Health Organization strongly discourages eating products from rabid animals. Almost all human deaths caused by rabies occur in Asia and Africa. It is estimated that 60% of rabies human deaths occur in Africa. Outside of Africa, rabies is especially prevalent in India (which accounts for 36% of global rabies deaths) and in parts of Southeast Asia. Rabies is rare in Europe, although sporadic cases do occur in Eastern Europe, particularly in red foxes. In the Americas, bats are the primary vectors of the disease. There are an estimated 59,000 human deaths annually from rabies worldwide. However, this data is not substantiated by the World Health Organization (WHO) reports registering numbers of death attributed by rabies, worldwide. Reported numbers often add up to less than 1,000 yearly. Dog licensing, euthanasia of stray dogs, muzzling, and other measures contributed to the elimination of rabies from the United Kingdom in the early 20th century. More recently, large-scale vaccination of cats, dogs and ferrets has been successful in combating rabies in many developed countries, such as Turkey, where pre-exposure vaccinations have been used to combat the prevalence of rabies. Rabies is a zoonotic disease, caused by the rabies virus. The rabies virus, a member of the Lyssavirus genus of the Rhabdoviridae family, survives in a diverse variety of animal species, including bats, monkeys, raccoons, foxes, skunks, wolves, coyotes, dogs, mongooses, weasels, cats, cattle, domestic farm animals, groundhogs, bears, and wild carnivores. However dogs are the principal host in Asia, parts of the Americas and large parts of Africa. Oral vaccines can be safely administered to wild animals through bait, a method first used in Switzerland in the 1970s, and that has successfully reduced rabies in rural areas of Canada, the United States, parts of Europe and elsewhere. For example in Montreal baits are successfully ingested by raccoons in the Mount Royal park area.

Dog-mediated rabies

Dog-mediated rabies is defined as "any case caused by rabies virus maintained in the dog population (Canis lupus familiaris) independently of other animal reservoir species, as determined by epidemiological studies". Most Western countries have eliminated dog-mediated rabies but it remains prevalent in developing countries. Dog-mediated rabies represents a threat to human health, particularly in Asia and Africa, especially in areas where there are numerous stray dogs. In India rabies is primarily transmitted to humans from dogs (97% of human rabies cases), followed by cats (2%), jackals, mongooses and others (1%). In places where human consumption of dog meat is common, such as Vietnam, butchers who slaughter dogs are at risk of contracting rabies. In Western countries illegal smuggling of dogs from other countries, or travelling with unvaccinated dogs abroad to countries where rabies is prevalent, can reintroduce rabies in the rabies-free Western countries. For instance in Spain in 2013 a rabid dog, which had been infected in Morocco, was discovered in Toledo.

Bats

Bats in most parts of the world carry lyssaviruses. In the Americas, bats carry the classical rabies virus (RABV), with vampire bats being the principal vector of human transmission of rabies in Latin America. In the United States, the silver haired bat and the tricolored bat are responsible for about 60% of human rabies infections in cases where the virus variant was identified. The most common lyssaviruses carried by bats in Europe are European bat 1 lyssavirus and European bat 2 lyssavirus, although Bokeloh bat lyssavirus (BBLV), West Caucasian bat lyssavirus (WCBV), Lleida bat lyssavirus (LLEBV) and Kotalahti bat lyssavirus have also been discovered.

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