Perspective on control options forEchinococcus multiloculariswith particular reference to Japan

Abstract

Following a brief introduction of recent advances in molecular and immunological technology for detection of persons and animals infected withEchinococcus multilocularisand 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 highE. multilocularisprevalence 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 ofE. 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 forE. multilocularis, control options can include those applicable toE. 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. WhereE. multilocularisis 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.

Historical Aspects of Echinococcosis

“…However, the prevalence rebounded to precontrol levels after termination of baiting (Romig, 2011). A significant reduction of the E. multilocularis prevalence in wild foxes by baiting with praziquantel was also documented in Hokkaido, Japan (Ito et al, 2003;Takahashi et al, 2013). On the other hand, it has been shown that fox baiting in small (w1 km 2 ), highly endemic urban areas can contribute to the reduction of environmental contamination with E. multilocularis eggs (Hegglin et al, 2003).…”

Global Distribution of Alveolar and Cystic Echinococcosis

“…Since then there is no additional information from this province. Ito et al (2003)]. These animal infections document a high environmental contamination with E. multilocularis eggs in the Hokkaido endemic area.…”

“…However, the infection has since been eliminated successfully from the island. A probable independent introduction of Asian haplotypes of E. multilocularis happened in eastern Hokkaido, where AE cases in humans have been diagnosed continuously since 1965 (reviewed in Schantz et al, 1995;Ito et al, 2003). Based on longitudinal studies, during the 1980s the parasite dispersed geographically and, during the 1990s, it became increasingly prevalent in the fox population.…”

Serological diagnosis of echinococcosis: the diagnostic potential of native antigens

“…In Kyrgyzstan, the incidence of CE has increased from 5.4 in 1991 to 18 in 2000 [8]. Several regions endemic for CE as well as AE have been recognised in north-western, central and north-eastern China, and AE has also spread to the Japanese island of Hokkaido in the last decades [9,10].…”