National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2011

27. Network simulation modeling of equine infectious anemia in the non-racehorse population in Japan


 Considering the recent infrequent occurrence of equine infectious anemia (EIA) in Japan, an EIA transmission model was developed to review the current EIA surveillance strategy, and then effectiveness and efficiency of several surveillance strategies were evaluated. A network structure of horse movement patterns was constructed in the model by dividing the non-racehorse population into four sectors based on horse usage (the equestrian sector, private owner sector, exhibition sector, and fattening sector). Using this model, we evaluated the risk of disease spread within and between sectors by horse movement. Surveillance strategies were then compared by adding surveillance parameters such as the targeting of sectors and frequency of testing. Model outputs showed that most infection occurred in the equestrian sector, which was considered to pose a higher risk of disease dissemination among sectors through horse movement. However, surveillance strategies targeting only the equestrian sector were ineffective for early detection of the disease. Alternatively, targeting horses that moved permanently and those in the private owner sector in addition to the equestrian sector showed effectiveness equivalent to that of the current surveillance system. In terms of efficacy, prolongation of the testing interval reduced the number of tested horses to 44% of that of the current surveillance, with almost equivalent effectiveness. Targeting high-risk populations enhanced the effectiveness and efficiency of surveillance. This study may be helpful in considering alternative surveillance strategies for EIA in Japan.
(Viral Disease and Epidemiology Research Division)


Hayama Y. et al (2012) Prev. Vet. Med. 103(1):38-48