Evaluating the contact rate between companion dogs during dog walking and the practices towards potential cases of rabies among dog owners in Japan.

This study aimed to examine the habits of dog walking in Japan using an internet survey of insured dog owners. About 96.4% of the respondents (n = 1,151) reported that they would take their dogs for a walk and they most frequently walk their dogs once or twice a day (75.9%) for 30 min to 1 hr (83.1%). The probability of a companion dog having contact with other dogs during dog walking was estimated to be 0.83 (95% confidence interval [CI]: 0.81-0.85), and the associated daily contact rate was estimated using log-normal distribution with a mean of 2.73 (95% CI: 2.42-3.11) and a standard deviation (SD) of 6.39 (95% CI: 5.18-7.84). Multiple linear regression revealed that the contact rate is mainly influenced by the social behaviour of the owner and to a lesser degree by his/her demographic characteristics including the area of residence, the breed size of dog and the age of the owner. In addition, ten Likert items measured on a 5-point scale were designed to assess the practices towards potential cases of rabies among dog owners. The respondents (n = 972) achieved a mean score of 2.99 (out of a full score of 4) with a SD of 0.90 in responding to situations related to dog bite incidents and injury from stray cat scratches during dog walking. They achieved a higher score in responding to situations related to sighting a stray or wild animal during dog walking and situations related to non-specific clinical signs of rabies and bite injuries from stray dogs or wild animals during dog walking with a mean of 3.70 (SD = 0.58) and 3.84 (SD = 0.34), respectively. The level of best practice was also proved to be significantly associated with the demographic characteristics of the dog owner.

A Comparative Review of Prevention of Rabies Incursion between Japan and Other Rabies-Free Countries or Regions.

Although rabies still kills many people, the global eradication of human rabies is considered to be feasible. Progress towards eradication may differ among regions with differing socio-economic statuses; therefore, states that successfully eradicate this disease must be vigilant for rabies re-emergence. Here, we discuss challenges that remain concerning current rabies prevention measures and risk assessment results concerning possible rabies introduction and spread in rabies-free Japan. We summarize the preventative measures undertaken by representative rabies-free countries and regions. Our risk assessment results show that the risk of rabies reintroduction under current circumstances is very low, and that subsequent spread of the disease would be minimal because of quite low value of basic reproduction number. Similar assessments conducted in other rabies-free areas also showed limited risks of introduction. The majority of rabies-free countries maintain their rabies-free status through strict import quarantine of carnivorous animals, efficient surveillance of animal rabies including wildlife, quick emergency responses, and raising public awareness of the disease. To maintain the current rabies-free status in Japan, we strongly recommend maintaining the current quarantine system and reinforcing stakeholder compliance for those involved in international movement of dogs. Moreover, sustainable surveillance systems targeting wildlife are indispensable.

Benefit-cost analysis of the policy of mandatory annual rabies vaccination of domestic dogs in rabies-free Japan.

Japan is one of the few rabies-free countries/territories which implement the policy of mandatory vaccination of domestic dogs. In order to assess the economic efficiency of such policy in reducing the economic burden of a future canine rabies outbreak in Japan, a benefit-cost analysis (BCA) was performed using probabilistic decision tree modelling. Input data derived from simulation results of published mathematical model, field investigation conducted by the authors at prefectural governments, literature review, international or Japanese database and empirical data of rabies outbreaks in other countries/territories. The current study revealed that the annual costs of implementing the current vaccination policy would be US$160,472,075 (90% prediction interval [PI]: $149,268,935-171,669,974). The economic burden of a potential single canine rabies outbreak in Japan were estimated to be US$1,682,707 (90% PI: $1,180,289-2,249,283) under the current vaccination policy, while it would be US$5,019,093 (90% PI: $3,986,882-6,133,687) under hypothetical abolition of vaccination policy, which is 3-fold higher. Under a damage-avoided approach, the annual benefits of implementing the current vaccination policy in expected value were estimated to be US$85.75 (90% PI: $55.73-116.89). The benefit-cost ratio (BCR) was estimated to be 5.35 X 10(-7) (90% PI: 3.46 X 10(-7)-7.37 X 10(-7)), indicating that the implementation of the current policy is very economically inefficient for the purpose of reducing the economic burden of a potential canine rabies outbreak. In worse-case scenario analysis, the BCR would become above 1 (indicating economic efficiency) if the risk of rabies introduction increased to 0.04 corresponding to a level of risk where rabies would enter Japan in 26 years while the economic burden of a rabies outbreak under the abolition of vaccination policy increased to $7.53 billion. Best-case analysis further revealed that under relatively extreme circumstances the economic efficiency of the current policy could be improved by decreasing the vaccination price charged to dog owners, relaxing the frequency of vaccination to every two to three years and implementing the policy on a smaller scale, e.g. only in targeted prefectures instead of the whole Japan.

Estimating the life expectancy of companion dogs in Japan using pet cemetery data.

The life expectancy provides valuable information about population health. The life expectancies were evaluated in 12,039 dogs which were buried or cremated during January 2012 to March 2015. The data of dogs were collected at the eight animal cemeteries in Tokyo. The overall life expectancy of dogs was 13.7 (95% confidence interval (CI): 13.7-13.8) years. The probability of death was high in the first year of life, lowest in the fourth year, and increased exponentially after four years of age like Gompertz curve in semilog graph. The life expectancy of companion dogs in Tokyo has increased 1.67 fold from 8.6 years to 13.7 years over the past three decades. Canine crossbreed life expectancy (15.1 years, 95% CI 14.9-15.3) was significantly greater than pure breed life expectancy (13.6 years, 95%CI 13.5-13.7, P-value <0.001). The life expectancy for male and for female dogs were 13.6 (95% CI: 13.5-13.7) and 13.5 (95% CI: 13.4-13.6) years, respectively, with no significant difference (P=0.097). In terms of the median age of death and life expectancy for major breeds, Shiba had the highest median age of death (15.7 years), life expectancy (15.5 years) and French Bulldog had the lowest median age of death (10.2 years), life expectancy (10.2 years). When considering life expectancy alone, these results suggest that the health of companion dogs in Japan has significantly improved over the past 30 years.

Evaluation of the efficacy of the Japanese rabies RC-HL strain vaccine in domestic dogs using past and present data: Prediction based on logistic regression and meta-analysis.

Japan is one of the few rabies-free countries or territories (under the OIE standard) which still implement the policy of mandatory vaccination of domestic dogs. Under the Rabies Prevention Law enacted since 1950, pet owners in Japan are obliged to vaccinate their dogs every year. However, the national vaccination rate is estimated to average 42% over the past decade. Given this low owner compliance, there is debate over whether or not the mandatory vaccination policy should be maintained and if it were to be maintained, whether the yearly booster requirement is necessary or not. Data on 144 companion dogs vaccinated with the Japanese rabies RC-HL strain vaccine were analysed using multiple logistic regression. An extensive literature review was conducted and five previous vaccination studies were selected for meta-analysis. Results of logistic regression indicate that the proportion of dogs having a satisfactory antibody level lasting for 12 months (P_protected12) with only one vaccination was 74.7% (95% prediction interval (PI): 51.4%-90.5%). By contrast, P_protected12 for dogs vaccinated 2-4 times and 5 times or more was estimated as 96.6% (95%PI: 83.1%-99.3%) and 98.7% (95%PI: 96.9%-99.6%), respectively. Moreover, P_protected for 36 months would drop to 33.4% (95%PI: 11.4%-71.6%) for dogs vaccinated only once, while it would be 83.0% (95% PI: 39.4%-97.1%) and 93.0% (95%PI: 59.7%-99.2%) for dogs vaccinated 2-4 times and 5 times or more, respectively. The pooled P_protected for at least 12 months from meta-analysis was estimated as 83.8% (95%CI: 66.1%-97.5%) for dogs vaccinated only once, while it was estimated as 94.7% (95%CI: 87.7%-99.1%) for dogs vaccinated at least twice. Therefore, the yearly booster requirement of the current mandatory vaccination policy in Japan is reasonable in terms of its frequency. However, there is potential for future policy amendment to one that requires less frequent boosters, i.e. a booster is required within one year after primary vaccination and then every two to three years.

Quantitative risk assessment of the introduction of rabies into Japan through the illegal landing of dogs from Russian fishing boats in the ports of Hokkaido, Japan.

Japan has been free from rabies since 1958 and various preventive measures are in place protecting the country from the introduction of the disease. Historical reviews indicate that the illegal landing of dogs from Russian fishing boats in the ports of Hokkaido occurred frequently especially in the early 2000s and this could potentially be a source of introduction of rabies into Japan. The method of scenario tree modelling was used and the following entry and exposure pathway was considered the most likely route of rabies entry: a rabies-infected dog arriving on a Russian fishing boat lands in a port of Hokkaido in Japan, it becomes infectious, contacts and infects a susceptible domestic animal (companion dog, stray dog or wildlife). Input parameter values were based on surveys of Russian fishermen, expert opinion and scientific data from the literature. At present (2006-2015), the probability of the introduction of rabies as a result of one Russian fishing boat arriving at a port of Hokkaido is 8.33×10(-10) (90% Prediction Interval (PI): 7.15×10(-11)-5.34×10(-9)), while this probability would have been 7.70×10(-9) (90% PI: 6.40×10(-10)-4.81×10(-8)) in the past (1998-2005). Under the current situation (average annual number of boat arrivals is 1106), rabies would enter Japan every 1,084,849 (90% PI: 169,215-20,188,348) years, while the disease would have been introduced every 18,309 (90% PI: 2929-220,048) years in the past (average annual number of boat arrivals is 7092). The risk of rabies introduction has decreased 59 fold due to both the effective control of the issue of illegal landing of dogs and the decline in the number of Russian boat arrivals. Control efforts include education of Russian fishermen, establishment of warning signs, daily patrols and regular port surveillance of potential dog landing activity. Furthermore, scenario analysis revealed that the policy of mandatory domestic dog vaccination does not contribute effectively to Japan's rabies prevention system under rabies-free situation. Although the current risk of rabies introduction is minimal, control measures against the illegal landing of dogs must be maintained. Further risk management measures, such as the removal of wildlife from the port area and regular monitoring of the rabies situation in Russia (particularly the easternmost regions), can be established to strengthen the current rabies prevention system in Hokkaido.