Rabies is a deadly viral disease that can infect all warm-blooded animals, including humans. It attacks the central nervous system and, without proper treatment, almost always results in death. Rabies poses a serious public health risk in many parts of the world. However, some countries, like Japan, have been able to effectively control and eliminate rabies within their borders.
What is Rabies?
Rabies is caused by a virus belonging to the genus Lyssavirus. It is primarily spread through infected saliva biting or scratching. Once the rabies virus enters the body, it travels along the neural pathways to the brain.
Early symptoms of rabies include fever, headache, weakness, discomfort, loss of appetite, nausea, and anxiety. As the disease progresses, neurological symptoms appear including anxiety, confusion, agitation, hallucinations, excessive salivation, difficulty swallowing, and a fear of water. Death usually occurs within a few days after neurological symptoms first appear.
Rabies causes tens of thousands of deaths worldwide per year, with over 95% of cases occurring in Africa and Asia. Dogs are the main transmission vector for the rabies virus, contributing up to 99% of transmissions to humans. Bats, foxes, raccoons, skunks and mongoose can also carry and transmit the disease.
Rabies has the highest mortality rate of any infectious disease. However, it is also entirely preventable through prompt post-exposure prophylaxis (PEP). PEP involves thoroughly cleaning the wound as well as administering a dose of rabies vaccine and antibodies. Pre-exposure vaccination is also recommended for people at high risk of exposure.
History of Rabies in Japan
Rabies has been present in Japan for centuries. Historical records show major outbreaks occurring from the 17th to 19th centuries. During the Meiji era (1868-1912), the government recognized rabies as a serious problem and began recording cases and deaths.
In the early 20th century, rabies was widespread in Japan with several thousand cases reported every year. The Sino-Japanese War and World War II hindered rabies control efforts. Large epidemics occurred after both wars.
After World War II, Japan began implemented measures to control rabies. In 1950, the Rabies Prevention Law established a registration system for dogs. Stray dog population control programs were initiated. Dog vaccination regulations were enacted in 1952.
These efforts led to a dramatic decline in rabies cases over the next few decades. Whereas thousands of cases were reported annually in the early 1900s, only a few hundred cases occurred each year by the 1960s. Human deaths dropped from over 300 per year to zero.
Key Historical Dates
- 1732 – Earliest recorded rabies outbreak in Japan
- 1868-1912 – Over 100,000 recorded human deaths during Meiji era
- 1950 – Rabies Prevention Law enacted
- 1954 – Over 5,400 animal cases reported, representing peak of rabies in Japan
- 1957 – Last recorded human rabies death in Japan
- 1970 – Only 13 animal cases reported
Rabies Elimination Efforts
Japan was able to successfully eliminate rabies through concerted efforts in key areas:
Dog Vaccination
Mass vaccination of domestic dogs was a critical factor in controlling rabies. In 1954, Japan passed the Rabies Prevention Law mandating registration and vaccination of dogs. This law was amended in 1975 to require mandatory annual vaccination of dogs with inactivated vaccine. High vaccination coverage created herd immunity that stopped transmission cycles amongst dogs.
Animal Control
Stray and free-roaming dogs are a major reservoir and vector for rabies transmission. Japan implemented animal control measures including registration, stray removal and facilities for housing seized animals. Dog reproduction was limited through enforced spaying and neutering. These steps reduced stray populations and limited rabies spread.
Quarantines and Import Regulations
Strict quarantines and import regulations prevented reintroduction of rabies from outside. Dogs and cats entering Japan must have proof of vaccination and undergo quarantines for up to 180 days. Japan also banned importation of certain high-risk animals like raccoons, foxes, skunks, and bats.
Surveillance
Extensive surveillance was conducted to monitor rabies prevalence. Passive surveillance involved mandatory reporting of animal cases by veterinarians and pet owners. Active surveillance entailed laboratory testing of samples from dead animals with suspected rabies.
Human Rabies Deaths
Human rabies deaths became increasingly rare in Japan after the 1950s due to dog vaccination and control programs. The number of fatalities dropped sharply within a few years:
- 1940s – 300-500 rabies deaths per year
- 1950s – Approximately 150 deaths per year
- 1960s – About 25 deaths per year
- 1970s – 10 deaths or fewer per year
The last human death from rabies in Japan occurred in 1970. Since then, no indigenous human rabies case has been reported despite continued extensive surveillance. Only a few imported cases have occurred in travelers returning from endemic countries.
When Was Rabies Eliminated in Japan?
The number of reported animal rabies cases also rapidly declined due to vigorous vaccination and control efforts:
- 1950s – Approximately 5,000 cases per year
- 1960s – About 500 cases per year
- 1970s – 100 cases or fewer per year
The last case of animal rabies was reported in a cow in Okinawa in 1957. Japan celebrated becoming rabies-free in 1956. However, sporadic animal and human cases continued over the next decade, particularly in Okinawa where rabies control lagged.
Finally, in 1970, Japan reported no indigenous animal or human cases for an entire year. Based on this achievement, Japan was declared rabies-free by the World Health Organization in 1994.
Recent Rabies Situations in Japan
Over the past 50 years, Japan has successfully maintained its rabies-free status through sustained vigilance:
- No indigenous animal rabies cases since 1957
- No indigenous human rabies deaths since 1970
- Mandatory annual vaccination requirements for dogs
- Ongoing animal surveillance and testing (>10,000 samples tested per year)
- Restrictions on importing dogs, cats and wildlife
However, several imported cases and outbreaks have occurred:
- 1975 – Illegally imported infected puppies caused outbreak in Saitama and Chiba prefectures with 80 animal cases
- 2006 – Imported dog from Philippines tested positive after quarantine
- 2018 – Rabid bat imported in cargo container from Philippines bit veterinarian
These incidents prompted tightening of animal import restrictions. But they demonstrate the constant threat of reintroduction from endemic countries. Maintaining rabies-free status requires continued vigilance through surveillance, vaccination, public awareness and control measures.
Is Japan Currently Rabies-Free?
Based on World Health Organization criteria, Japan is classified as a rabies-free country. The main evidence supporting its rabies-free status includes:
- No indigenously-acquired animal or human cases for over 50 years
- Mandatory vaccination of dogs with >70% coverage rates
- Ongoing surveillance showing no circulation of rabies virus
- Tight import and border controls for animals
WHO guidelines define a rabies-free country as one that has not reported indigenously-acquired animal or human cases for at least 2 years. Japan far exceeds this requirement, having reported no indigenous transmission in animals or humans for several decades now.
Key Facts about Rabies in Japan:
- No animal rabies cases since 1957
- No human rabies deaths since 1970
- Over 70% of dogs vaccinated against rabies
- Thousands of animal samples tested annually for rabies
- Strict quarantines for imported animals
Based on this data, Japan clearly meets the criteria for being designated as a rabies-free country. However, ongoing surveillance and control measures are critical to prevent virus reintroduction from other regions where rabies remains endemic.
Could Rabies Reemerge in Japan?
Although Japan is currently rabies-free, the threat of rabies reemergence always exists. Possible scenarios that could lead to rabies re-establishing include:
- Imported infected animal slipping through quarantine
- Rabid wild animal like a bat stowing away in international cargo
- Traveler importing exposed pet without following protocol
- Bioterrorist deliberately releasing rabies virus
If introduced into the domestic animal population, rabies could spread rapidly again in the absence of herd immunity through vaccination. Other countries like the UK and Sweden have experienced rabies reintroductions after being declared rabies-free.
To prevent reemergence, Japan sustains ongoing measures:
- Mandatory vaccination of dogs against rabies
- Active surveillance by testing dead animals
- Public education and awareness campaigns
- Restrictions on high-risk animal imports
- Collaboration with global rabies prevention and control programs
Vigilance through surveillance, vaccination, import controls and public cooperation is required to ensure rabies remains absent from Japan.
Conclusion
In summary, Japan has not reported any indigenously-acquired animal or human rabies cases since the 1950s and 1970s respectively. Based on WHO criteria, Japan is officially recognized as a rabies-free country due to its decades-long absence of indigenous transmission. Ongoing animal vaccination, surveillance, public education, and import restrictions have maintained its rabies-free status. However, the threat of imported cases or bioterrorism remains. Sustained vigilant control measures are critical to prevent rabies from ever regaining a foothold in Japan.