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Field application of anthelmintic baits against Echinococcus multilocularis in red foxes (Vulpes vulpes) was conducted on Nemuro Peninsula at the eastern edge of Hokkaido, Japan. The total study area was 412 km(2), of which 135 km(2) were used for bait distribution. Commercial baits containing 50mg praziquantel were distributed by car along roads outside towns and villages in a density of 15/km(2). Additional baits were distributed around fox breeding dens. Baiting was done from November 1999 to January 2006 at an average frequency of 4.3 distribution rounds per years (in total 27 rounds). Prevalence in foxes collected in the baiting and non-baiting areas were determined by necropsy. Base prevalence (before baiting) was 49.4% (CI95%: 43.7-55.0) in the baiting area and 70.5% (CI95%: 60.2-79.2) in the non-baiting area. During the first and second half of the baiting period, the prevalence in the baited area changed to 26.2% (CI95%: 14.4-42.3) and later to 15.8% (CI95%: 7.9-28.4), but remained at a high level in the neighboring non-baited area with 60.4% (CI95%: 45.3-73.9) and 65.0% (CI95%: 40.9-83.7). Our data show, that significant prevalence reduction (but not elimination) of E. multilocularis in foxes can be achieved by this method under epidemiological conditions, which are fundamentally different from those in Europe where most previous studies have been done., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The authors describe the current control strategies targeting definitive hosts of the most important zoonotic parasite in Japan, Echinococcus multilocularis. A dramatic increase in the prevalence of echinococcosis in foxes in Hokkaido (the second largest of Japan's islands), the invasion of wild foxes into urban areas, infection among pet and stray dogs, and the possibility of spreading the disease to the main island of Japan (Honshu)--all these pose significant threats to public health. Previous research findings and current strategies such as control measures against infections in wild foxes, suggest that it will be possible to eliminate echinococcosis in the future. The enforcement of a national reporting system for veterinarians, international collaboration, and the establishment of a Forum on Environment and Animals (FEA) give further reason to believe that success is possible. This is the first report of a multifaceted control strategy against echinococcosis in definitive hosts that includes collaborative efforts with local residents. This model might provide new ideas for Veterinary Services worldwide in their efforts to control other related zoonotic diseases.

Echinococcus multilocularis is distributed all over Hokkaido, the northern island of Japan. The prevalence in foxes has been around 40% in the last decade. Three trials of anthelmintic bait distribution have been conducted in Hokkaido to reduce the prevalence in foxes. In those trials, bait distribution was done along roads in the study area using cars and/or around fox breeding dens by hand. Changes in the prevalence in foxes were evaluated either by necropsy of captured foxes or by coproantigen and egg detection of faeces collected in field. All of the trials showed bait distribution was effective for the reduction of the prevalence in foxes; however, it was also suggested that a frequent and continuous baiting program is necessary for effective and stable control of the prevalence in foxes. As observed in some cities in Europe, urban foxes infected with the parasite were also recognized in Sapporo. A survey of pet dogs showed that 0.4% of surveyed dogs were determined infected. In addition, a dog which was transported from Hokkaido to the main island of Japan was found excreting E. multilocularis eggs. The results raised the public recognition of canine infections, which in turn lead to the modification of a Japanese law for infectious diseases and to the enforcement of a national reporting system of dogs infected with E. multilocularis by veterinarians.

The history of cystic hydatidosis (CH) in Japan is reviewed on the basis of case reports and other references during the period from 1881 to 2003. A total of 76 cases were identified as CH patients in Japan of which 47 were reported prior to 1945 and 29 thereafter. The occurrence was divided into 2 stages before and after the Slaughterhouse Act that was brought into force in 1906. The presence of endemic foci of CH was suggested before the Act was introduced in Japan, especially in southwestern prefectures, and the development of cattle breeding and unsanitary small slaughterhouses in the areas were thought to be cause. Japan emphasized cattle as a dietary protein source and also for various military accouterments such as shoes and rucksacks for soldiers. China was a transit port to Japan from Europe and also a big endemic area of CH. Japan had sent a huge number of soldiers and citizens to China in the Japanese-Sino and Japanese-Russian War and a number of cattle, pet dogs and people have also came to Japan from China. After enforcement of the Slaughterhouse Act in 1906, the number of CH cases decreased dramatically, and only 2 cases were reported for the 30 years between 1920 and 1950 in Japan. The situation regarding CH in Japan thus suggested the existence of endemic foci in southwestern prefectures, although direct evidence was lacking because no one had found E. granulosus in dogs of the area. Almost all of the patients recently presenting with CH appear to have been infected in overseas endemic countries. The available information strongly suggest that sanitary control of slaughterhouses is essential for preventing CH in endemic areas. Diagnostic laboratory examinations and appropriate medical intervention are clearly important. An animal quarantine system against echinococcal infestation of pet dogs should also be established urgently in Japan, because hundreds of pet dogs are being imported annually from endemic countries in Europe and Asia.

Following a brief introduction of recent advances in molecular and immunological technology for detection of persons and animals infected with Echinococcus multilocularis and an overview of the current situation of alveolar echinococcosis (AE) in Japan, perspectives on control options are discussed with reference to different epidemiological situations. AE is considered the most serious parasitic zoonosis in temperate and arctic regions of the northern hemisphere. The number of human cases differs drastically among regions. While high numbers of patients are apparently associated with high E. multilocularis prevalence in domestic dogs, e.g. in parts of Alaska and western China, the number of cases is moderate or low in areas where the parasite is mainly transmitted by wild canid species (e.g. in central Europe or temperate North America). However, the severity of the disease, the absence of curative treatment for most cases, the high cost of long-term chemotherapy and the anxiety caused for the population in highly endemic areas call for the development of preventive strategies even in regions where human AE is rare. Furthermore, in view of (1) drastically increasing numbers and infection rates of foxes involved in transmission of E. multilocularis, and (2) increasingly close contact between humans and foxes e.g. in Europe and Japan, there is considerable concern that AE incidences may in future increase in these regions. Control options depend on a variety of factors including the species of canid principally responsible for transmission and the socio-economic situation in the region. Where domestic dogs (stray or owned) are the principal hosts for E. multilocularis, control options can include those applicable to E. granulosus, i.e. reduction of the number of stray dogs, registration and regular preventive chemotherapy of owned dogs, and information campaigns for the population promoting low-risk behaviour for man and dogs. Where E. multilocularis is mainly transmitted by wild canids, the situation is far more difficult with preventive strategies still being in trial stage. Integrated control measures could include prevention information campaigns, restricting access of pet animals (dogs and cats) to rodents, chemotherapy of foxes on local or regional scales, and strategies to minimize contacts between people and foxes.

The effect of bait-delivered anthelmintic to reduce the prevalence of Echinococcus multilocularis in wild red foxes was evaluated in Koshimizu, in the eastern part of Hokkaido, Japan. The study area (200 km2) was divided into baited and non-baited sections. The anthelmintic baits were distributed around fox den sites in the baited section every month for 13 months. After 1 year of the anthelmintic bait distribution, the prevalence of E. multilocularis in foxes, evaluated either by the parasite egg examination (from 27.1 to 5.6%) or coproantigen ELISA (from 59.6 to 29.7%), decreased in the baited section contrasting to that in the non-baited section (parasite egg: from 18.8 to 24.2%; ELISA: from 41.9 to 45.8%). The prevalence of E. multilocularis in grey red-backed vole Clethrionomys rufocanus, caught around fox dens, born after bait distribution also decreased and was significantly lower than that in non-baited section. However, within the study periods, the coproantigen-positive rate in fox faeces sporadically increased, while egg-positive rate constantly decreased. Since coproantigen ELISA can detect pre-patent infection, this observation indicates that reinfection pressure in the baited section was still high even after the 13 months of anthelmintic bait distribution. Therefore, the bait distribution longer than our study period is required for the efficient control of E. multilocularis in wild red fox population.

Purpose: This article focuses on understanding epidemiological features of alveolar echinococcosis and discussing its prevention and control, especially from a viewpoint of the ecosystem and risk management., Method: Publications on alveolar echinococcosis throughout the world were systematically reviewed with special reference to ecology, epidemiology and countermeasures., Results: Alveolar echinococcosis, caused by accidental infection with larva of the parasite Echinococcus multilocularis is fatal to humans unless diagnosed at an early stage. No effective control measures have been identified so far because it is difficult to fully understand the ecology of the parasite and its intermediate and definitive hosts. It is also not easy to determine the precise infection route to humans mainly because of the long latent period. In Hokkaido, infection rates among red foxes have recently risen even in low endemic districts. Not only stray and domestic dogs but also some pigs in Hokkaido have been found to be infected. While the number of reported human cases is still small, around 10 cases per year, local residents seem to be threatened with the risk of infection., Discussion and Conclusions: We predict that the incidence of alveolar echinococcosis among humans in Japan will increase in the near future if no effective preventive measures are conducted. In addition, Echinococcus multilocularis infection has the potential to affect the economy of Hokkaido because of its impact on the agricultural and tourist industries. Well-designed epidemiological surveys are therefore urgently required, in the context of ecosystem and risk management prior to large outbreaks. International collaboration is also desired.

The first patient with echinococcosis who had lived in Rebun island was discovered in 1937 at Otaru and 134 patients had been identified as Rebun cases till 1989. In the meantime, the eradication of echinococcosis succeeded with extermination of dogs and foxes from the island. On the other hand, the first patient of Kon-sen cases was found in 1965 and 208 patients have been treated so far. The patients had been restricted within the Kon-sen region until 1979, but thereafter the patients have been found sporadically all over Hokkaido. This distributional tendency of the patients coincides with the explosion of the infection with Echinococcus multilocularis in foxes in Hokkaido after 1980. Prevention measure against echinococcosis has been carried out by the Committee for the Disorder of Hokkaido, by which we have been successful. We succeed in the early diagnosis and treatment of the patients, but still have no decisive methods to eradicate E. multilocularis in Hokkaido. This is one of the important problems of zoonosis to solve for the next century of Hokkaido.

To determine the risk factors for echinococcus infection, we conducted a case-control study in the Nemuro region of Hokkaido Prefecture. The cases included both clinically diagnosed patients with echinococcosis and registered persons who were seropositive. The control group was matched by residence, age (+/- 5 years) and sex. The data on the 99 cases and 430 controls were collected by mailed questionnaire. Because of the long latency of echinococcosis, we investigated the potential risk factors over two different periods-from 11-20 years before the time of registration, and from 10 years before the registration to the time of registration. For the 11-20 years before registration period, using well water as drinking water and cattle raising significantly increased the risk of echinococcosis. In the period 10 years before registration to the time of registration, hog raising also increased the risk. In contrast, drinking tap water decreased the risk. These results suggest the importance of a screening program, especially targeting people engaged in dairy farming and hog raising, as well as the need for extension of tap water services and health education on refuse disposal.

A population-based comparative study was performed on public awareness and knowledge about the risk of Echinococcosis and the life habits of the people living in 2 towns in eastern Hokkaido, Bekkai and akan. Bekkai has had an anti-echinococcosis policy and Akan has only limited experiences with such countermeasures. The results of the survey were as follows: 1) Compared with the inhabitants in the town of Akan, the residents in Bekkai had significantly higher correct response rates for many questions concerning parasitological knowledge and the risks of echinococcosis, and knew about subjects such as the pathogen, latency period, susceptible organs, the prognosis, the possibility of transmission of echinococcosis from human to human and methods for the sterilization of eggs from infected animals. 2) The rate of correct answers to such questions were approximately 70 to 90% in both towns. However the percentage of correct answers to questions about carrier animals and the question of human susceptibility were relatively low, ie., 45% and 20%, respectively, even in Bekkai. 3) The residents of Akan knew more about carrier animals of echinococcosis than the inhabitants of Bekkai. In Akan woman and persons in their 20's and 30's had lower rates of correct answers. Further health education should be aimed toward such people. 4) Foxes appeared near private homes more frequently in Akan than in Bekkai. More inhabitants of Akan used spring water as drinking water than in Bekkai, while more inhabitants used tap water as drinking water in Bekkai. Only a few inhabitants paid attention to how to prepare vegetables for cooking. This information suggests that echinococcosis may spread in Akan in the near future. 5) Our results suggest that better organized health education programs, the extension of tap water services in Akan, and the establishment of proper methods for disposal of garbage and the afterbirth of cattle are necessary to reduce the presence of foxes in inhabited areas.