Introduction
     Over 50,000 people and over 100,000 animals reportedly die of rabies every year. In Japan, this disease has been culled out since 1956 thanks to the strong implementation of measures against rabies, such as vaccination of dogs, quarantine and control of wild dogs under the "Rabies Prevention Law" enacted in 1950. Nevertheless one cannot deny the possibility of introduction of rabies into Japan in view of the recent increase in the international movements of people and animals.
     Should an outbreak of rabies be suspected now in Japan where this disease has not been observed for many years, the society would probably overreact due to a decreased awareness of risks and a lack of correct knowledge about this disease. Therefore measures against this disease in Japan should be first of all aimed at disseminating correct information on rabies and educating the general public as well as workers in administrative organizations, doctors and veterinarians.
Status of rabies
     Rabies is observed not only in dogs but also in all mammals as well as in humans. The mortality in both humans and animals contracting this ailment is 100%. According to a report by the World Health Organization (WHO), over 90% of humans dying of rabies are found in Asia. Apart from that region, 500 to 5,000 people in Africa, 200~400 people in Latin America, 4~8 people in North America and 10~20 people in Europe are dying of rabies every year. The species of rabid animals differs with the countries and regions. The animals causing rabies outbreaks are mainly dogs (especially stray dogs) in Asian countries, dogs, jackals and mongooses in Africa, dogs and bats (mainly vampire bats) in Latin America, raccoons, skunks, coyotes and bats in North America, and mainly foxes in Europe.
     When traveling abroad, one should know well the situation regarding rabies in the country of destination and refrain from being in contact with stray domesticated animals and wild animals.
Route of transmission of rabies and symptoms
     In general, in case of rabies, the virus excreted in the saliva penetrates the nerve tissues from the bite wound and the surface of the mucous membrane through the bite and it causes infection. Besides the incubation period is long and lasts 1~2 months on average or even sometimes up to 7 years, and it is impossible to detect the virus before the onset of the disease. Therefore wild animals from regions where rabies is endemic should not be imported, bred or moved to other destinations,even though they may be healthy.
     When contracting rabies, the subject becomes extremely sensitive to external stimulation and shows a state of agitation. Animals will bite anything that moves in front of them (furious form). After onset, generalized paralysis occurs, and in the final stage, the subject falls into coma and passes away. On the other hand, 15~20% of the animals display a constant state of paralysis (paralytic form). Hydrophobia is observed in humans. It is a condition in which the subject cannot drink water due to the pain caused by spasms of the pharynx, the larynx and the whole body when drinking.
Prevention of rabies
     Rabies is an infectious disease with a 100% mortality. Humans and dogs will die relentlessly after contracting the disease. However its onset can be prevented through appropriate immunization.
In case rabies infection is suspected in humans, it is possible to prevent onset through an appropriate and rapid series of "Rabies Postexposure Prophylaxis (the combination of anti-rabies vaccine and rabies immune globulin)". The WHO recommends cleaning of the wound after the bite and post-exposure vaccination with successive injections (5 doses given on day 0, 3, 7, 14 and 30 and depending on the case, a 6th dose on day 90). These injections are given during the long incubation period of rabies.
Every year over 10 million people are immunized after exposure, and the majority is in Asia. On the other hand, tens of thousands of people are vaccinated annually even in Western countries where human rabies has receded. Researchers, veterinarians, etc. who have frequent occasions to be in contact with the rabies virus, as well as those traveling to endemic regions should be immunized beforehand against this disease.
In Japan, dog rabies has been brought under control thanks to the obligation to vaccinate dogs against this disease, the mop-up of wild dogs contributing to its propagation and the quarantine of imported animals.
Nonetheless dog rabies continues to prevail in Asian neighboring countries. Vaccination of dogs every year (April~June) constitutes one of the important measures for the prophylaxis of rabies.
Recent topics
     Over the last few years, the risk of imported infectious diseases has become a reality, as shown by the unexpected outbreaks of foot-and-mouth disease and BSE in this country, the movements of SARS-infected travelers, the importation of prairie dogs suspected of being infected with Tularemia (a bacterial zoonosis caused by Francisella tularensis), etc. Various infectious diseases may well penetrate into Japan in the coming years due to scenarios unthought-of so far or unpredictable routes of transmission.
     Recently Japan has imposed a ban on the import of prairie dogs on October 18th, 2002, since it has been pointed out that these animals imported as pets were the reservoir of pest in the US, their country of origin. Then the import of weasels, badgers and civets became prohibited on July 14, 2003, due to the risk of involvement with SARS infection. In November of that year, a ban was imposed on the import of bats, animals responsible for outbreaks of Nipah virus and Lyssa virus. The status of outbreaks of rabies in the Asian countries surrounding Japan, the illegal debarkation of dogs from foreign ships calling from countries where rabies is prevalent and the abandonment of these animals, and the press coverage on the decrease in the immunization rate for dogs in Japan constitute issues for defining measures against rabies in this country.
     The prevention of penetration of rabies into Japan due to the import of wild animals was reinforced by the "Rabies Prevention Law" partly amended together with the enactment of the New Law on Infectious Diseases in 2000. The amended Rabies Prevention Law stipulates that not only dogs, which have traditionally been subject to the law, but also cats, raccoons, foxes and skunks that could transmit rabies must be quarantined under the law. It is important, on the one hand, to improve the environment so as not to import rabid animals and, on the other hand, to be able to initiate rapidly and appropriately a response without panicking in case of accidental outbreak of rabies. In 2001, the Tuberculosis & Infectious Disease Control Division, Health Service Bureau, Ministry of Health, Labour & Welfare, distributed to the related organizations in the municipalities a booklet titled "Guidelines for a Response to Rabies - 2001".
Conclusion
     Rabies is an infectious disease common to humans and animals and it is still prevalent all over the world (animal-origin infectious disease, zoonosis).
     At the present stage, it is impossible to diagnose rabies before its onset in humans and animals. Nonetheless it is possible to prevent its onset through post-exposure vaccination of subjects suspected of having been infected by this disease, or to eliminate occasions of infection in humans by vaccinating animals having a high risk of transmission (dogs). Consequently in case of "animal-origin infectious diseases", it is important to proactively take measures concerning the animals transmitting the infection to humans combined with action concerning people, and not infection control measures focused on humans as this is done in case of "human infectious diseases".
     In the event rabies is suspected in Japan, unless the correct information is relayed by the press, there will be a panic concerning the vaccination of domesticated dogs, unnecessary disposal of pets, and an overflow of requests for immunization from people. This will develop into a major societal problem. Officials of the government and the municipalities, veterinarians and doctors should exchange correct information on rabies and on prevention control and raise their awareness, while providing also information to the public on a timely basis. Besides it is needless to say that it is important to set up a crisis management system allowing a quick and adequate response in case of an outbreak of rabies and to continue to implement appropriate prevention measures in normal times.

[Recommended internet sites]
- Homepage of the Zoonosis Association
[http://www.hdkkk.net/]

- Do you know animal-origin infectious diseases?
[http://www.forth.go.jp/mhlw/animal/index.html]

WHO's homepage
[http://oms2.b3e.jussieu.fr/rabnet/]

US CDC's homepage
[http://www.cdc.gov/ncidod/dvrd/ rabies/]