Geographical Analysis of Risk Factors of Bovine Spongiform Encephalopathy

Nonaka, Takashi; Yamamoto, Takehisa; Hashimoto, S; Nishiguchi, Akiko; Yamane, Ichirō; Kobayashi, Sota; Tsutsui, Toshiyuki

doi:10.2743/jve.9.15

Cited by 3 publications

(3 citation statements)

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“…In public health epidemiology, spatial scan statistics have been applied for detecting disease clusters to enable investigation of risk factors or planning of intervention trials [2,7,9]. On the other hand, few spatial analyses are reported in animal diseases in Japan [13], and there are no reports concerning the clustering of animal diseases based on individual farm location. In order to investigate the risk factors in areas with a high incidence of AI, we investigated the geographical cluster of AI-case farms based on the individual farm location and their disease status using a spatial statistic, and analyzed the characteristics of the chicken farms located in the area.…”

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confidence: 99%

Spatial Analysis of Low Pathogenic H5N2 Avian Influenza Outbreaks in Japan in 2005

Nishiguchi

Kobayashi

Ouchi³

et al. 2009

The Journal of Veterinary Medical Science

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ABSTRACT. We conducted a spatial analysis of low pathogenic H5N2 avian influenza (AI) outbreaks, that affected 41 chicken farms in Japan in 2005. A statistically significant (p=0.001) cluster of AI-positive farms was identified in the central part of Ibaraki Prefecture. Inside the AI cluster, the density was high for both chicken farms and chicken population, the proportion of layer finisher type farms was high and the farm size was large. We considered it important to take precautions for AI outbreaks in densely chicken-populated areas and to implement appropriate movement control around the affected farms to prevent transmission among farms located within small distances in the case of AI outbreaks. Spatial scan statistics are applicable in veterinary epidemiology to detection of high risk areas for animal diseases.KEY WORDS: avian influenza, cluster, spatial scan statistic.J. Vet. Med. Sci. 71 (7): [979][980][981][982] 2009 On the 26th of June 2005, a H5N2 subtype of avian influenza (AI) virus was recovered from a layer chicken flock in Ibaraki Prefecture, Japan, that showed a slight decrease in egg production. Nine more virus-positive farms and 32 seropositive farms (by haemagglutination inhibition tests) were detected over the course of 26 weeks. Since the virus strain was low in pathogenicity, with an intravenous pathogenicity index [14] of 0.0, and did not induce any particular clinical signs in the chickens of most flocks [15,16], the disease spread silently and the timing of virus introduction was unclear. This strain was considered to be newly introduced into Japan, taking into account its genetic characteristics and the results of national AI monitoring implemented periodically prior to the outbreaks [9]. Of 41 affected farms, 40 were located in Ibaraki Prefecture, approximately 60 km north of Tokyo. In this prefecture, almost all the poultry raised were chickens; 70% of these were laying hens, and 30% were broilers.When animal disease outbreaks occur, effective steps to explore the risk factors include investigation of the clustering of the affected farms and identification of their location and size. Nevertheless, it is generally difficult to recognize clusters visually when the locations of the cases and noncases (not affected by AI) are irregularly scattered. On the other hand, the Geographic Information System offers an opportunity to explore the associations between potential risk factors and disease incidence in combination with spatial analyses, and complements traditional visual approaches. Among the spatial analyses, spatial scan statistics enable researchers to locate statistically significant geographical clusters (the locations of the clusters and their size) [10]. In public health epidemiology, spatial scan statistics have been applied for detecting disease clusters to enable investigation of risk factors or planning of intervention trials [2,7,9]. On the other hand, few spatial analyses are reported in animal diseases in Japan [13], and there are no reports concerning the clustering ...

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confidence: 99%

Spatial Analysis of Low Pathogenic H5N2 Avian Influenza Outbreaks in Japan in 2005

Nishiguchi

Kobayashi

Ouchi³

et al. 2009

The Journal of Veterinary Medical Science

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“…Although none of the farms with BSE cases had a record of using MBM for cattle, their feed might have been crosscontaminated with MBM for feed for non-ruminant species (31). Nonaka et al conducted a geographical analysis using a geographical information system to examine the possible spatial relationship between the suspected feed and BSE cases in Hokkaido, with no significant relationship found (18).…”

Section: Higher Prevalence In 1996 and 2000 Birth Cohortsmentioning

confidence: 99%

Epidemiological features of the bovine spongiform encephalopathy epidemic in Japan

Sugiura¹,

Onodera²,

Bradley³

2009

Rev. Sci. Tech. OIE

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, the first case of bovine spongiform encephalopathy (BSE) in Japan was confirmed in a five-year-old dairy cow born in Hokkaido and raised in Chiba prefecture. Subsequently, BSE surveillance was enhanced. As a result, 35 additional cases were detected by the end of March 2009, with two to ten cases being detected each year up to the end of 2007. The epidemic appeared to peak in 2006. Cases are detected mostly in dairy cattle; in cattle born in 1996 and 2000; and in cattle born in Hokkaido. Two were atypical cases of BSE and the remainder classical cases. This paper describes and discusses the demographic structure of dairy and beef cattle, surveillance programmes in place and the epidemiological features of the BSE epidemic in Japan.

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“…Through all the surveillance systems, 20 heads of cattle were confirmed to be positive for BSE until June 20, 2005 6 . More than half of these were reported from Hokkaido, a northern island in which dairy production is the main industry ( 1).…”

Section: Cases Of Bsementioning

confidence: 99%

Epidemics of Emerging Animal Diseases and Food‐Borne Infection Problems Over the Last 5 Years in Japan

Yamane

2006

Annals of the New York Academy of Sciences

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There have been several emerging animal diseases and food-borne infection problems occurring in Japan over the last 5 years. We describe brief pictures of these epidemics and our control activities. As acute contagious and/or emerging animal diseases, the foot and mouth disease (FMD) outbreak caused by the Pan-Asian topotype of the type O virus occurred in March 2000 after 92 years of FMD-free status. In 2004, four cases of the highly pathogenic avian influenza (HPAI), which was the first outbreak after 79 years, and caused by the H5N1 subtype, were identified. As part of the responses against these outbreaks, all the animals in the affected farms were destroyed, and movement control areas were established around the infected premises, and a nation-wide intensive survey for FMD and HPAI was performed. As for food-borne or feed-borne infections, the first bovine spongiform encephalopathy (BSE) was identified in September 2001 and 19 more cases have been reported until June 2005. A large outbreak of food-borne infection caused by low-fat milk contaminated with enterotoxin A produced by Staphylococcus aureus, involving more than 13,000 patients, occurred in 2000. In 2003, people who consumed uncooked liver and meat from wild boar and deer developed clinical signs of hepatitis caused by the hepatitis E virus. Pork is also suspected as natural source of virus transmission. Early detection of the first cases and rapid action in preventing and controlling the spread of infections are very important combined with proper risk communication about correct information of the diseases.

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Geographical Analysis of Risk Factors of Bovine Spongiform Encephalopathy

Cited by 3 publications

References 9 publications

Spatial Analysis of Low Pathogenic H5N2 Avian Influenza Outbreaks in Japan in 2005

Spatial Analysis of Low Pathogenic H5N2 Avian Influenza Outbreaks in Japan in 2005

Epidemiological features of the bovine spongiform encephalopathy epidemic in Japan

Epidemics of Emerging Animal Diseases and Food‐Borne Infection Problems Over the Last 5 Years in Japan

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