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

An equine infectious anemia (EIA) transmission model was developed by constructing a network structure of horse movement patterns in a non-racehorse population. This model was then used to evaluate the effectiveness and efficiency of several EIA surveillance strategies. Because EIA had not been detected in Japan since 1993, it was appropriate to review the current surveillance strategy, which aims to eradicate EIA by intensive testing, and to consider alternative strategies suitable for the current EIA status in Japan.The non-racehorse population was divided into four sectors based on horse usage: the equestrian sector, private owner sector, exhibition sector, and fattening sector. To evaluate the risk of disease spread within and between sectors accompanied by horse movements, a stochastic individual-based network model was developed based on a previous survey of horse movement patterns. Surveillance parameters such as targeting sectors and frequency of testing were added into the model to compare surveillance strategies.The disease spread heterogeneously among sectors. Infection occurred mainly in the equestrian sector; the infection was less disseminated in other sectors. Therefore, we considered that the equestrian sector posed a higher risk of disease dissemination within and between sectors through horse movements. However, surveillance strategies targeting only the equestrian sector were not effective enough 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 is recommended to achieve effectiveness equivalent to that of the current surveillance. In terms of surveillance efficacy, by increasing the testing interval (once yearly to once every 3 years), this testing scheme could reduce the number of tested horses to 44% of the current surveillance, while maintaining almost equivalent effectiveness. Intensive strategies targeting high-risk populations are considered to enhance effectiveness and efficiency of surveillance. The approach in this study may be helpful in the decision-making process that is involved in setting up strategies for risk-based surveillance.     

Gastrointestinal uptake of nasunin, acylated anthocyanin in eggplant

We previously showed that nasunin, acylated anthocyanins in eggplant peel, comprises two isomers, cis-nasunin and trans-nasunin. In this study, gastrointestinal absorption of cis- and trans-nasunins was studied in rats. Orally administered nasunins were quickly absorbed in their original acylated forms and maximally appeared in blood plasma after 15 min. When the maximum plasma concentration and area under the plasma concentration curve were normalized by orally administered dose (micromoles per kilogram), there was no significant difference in the uptake efficiency between two isomers and both exhibited a plasma level almost identical to that of delphinidin 3-O-beta-D-glucopyranoside. However, metabolites such as 4'-O-methyl analogues and extended glucuronides which were observed for delphinidin 3-O-beta-D-glucopyranoside and cyanidin 3-O-beta-D-glucopyranoside metabolisms were not detected in urine or blood plasma. Moreover, deacylated and glycolytic products of nasunins such as delphinidin 3-O-beta-D-glucopyranoside or delphinidin (aglycone) were also not detected in blood plasma even after oral administration for 8 h. These results indicated that nasunins were absorbed in their original acylated forms and exhibit a bioavailability almost identical to that of nonacylated anthocyanins.     

Caffeoylsophorose in a red vinegar produced through fermentation with purple sweetpotato

Recently, a new red vinegar has been developed via fermentation with the storage root of purple-fleshed sweetpotato, Ipomoea batatas L. cv. Ayamurasaki. The red vinegar had a higher antioxidative activity than white or black vinegars. The red vinegar contained some new components possibly derived from the original purple sweetpotato. A major component was isolated using preparative HPLC, and the chemical structure was determined to be 6-O-(E)-caffeoyl-(2-O-beta-d-glucopyranosyl)-alpha-d-glucopyranose (caffeoylsophorose) by MS and NMR. Because the caffeoylsophorose showed a high antioxidative activity, it plays an important functional role in red vinegar as do anthocyanins and other components. Examination of the mechanism of formation is now in progress.     

Potential impact of species and livestock density on the epidemic size and effectiveness of control measures for foot-and-mouth disease in Japan

The characteristics of a livestock area, including farm density and animal species, influence the spread of foot-and-mouth disease (FMD). In this study, the impact of livestock area on FMD epidemics was examined using an FMD transmission model. For this simulation, three major livestock areas were selected: the 2010 FMD epidemic area in Japan as the baseline area (BS), a cattle and pig mixed production area (CP) and a cattle production area (C). Simulation results demonstrated that under the 24-hr culling policy, only 12% of epidemics among 1,000 simulations were abated within 100 days in the CP area, whereas 90% of the epidemics ceased in the BS area. In the C area, all epidemics were successfully contained within 100 days. Evaluation of additional control measures in the CP area showed that the 0.5-km pre-emptive culling, even when only targeting pig farms, raised the potential for successful containment to 94%. A 10-km vaccination on day 7 or 14 after initial detection was also effective in halting the epidemics (80%), but accompanied a large number of culled or vaccinated farms. The combined strategy of 10-km vaccination and 0.5-km pre-emptive culling targeting pig farms succeeded in containing all epidemics within 100 days. The present study suggests the importance of preparedness for the 24-hr culling policy and additional control measures when an FMD outbreak occurs in a densely populated area. Considering the characteristics of the livestock area is important in planning FMD control strategies.     

Cardiopulmonary bypass influences the plasma levels of calcitonin gene-related peptides in dogs: effects of hemofiltration and hemodilution

Calcitonin gene-related peptides (CGRP), which are potent vasodilators, are elevated during cardiopulmonary bypass (CPB) in humans. We evaluated the plasma levels of CGRP in dogs during CPB with hemofiltration with and without hemodilution. Female beagles were divided into control (n=5) and hemodilution (n=5) groups. The CPB with hemofiltration was performed with or without hemodilution. For the measurement of CGRP, blood samples were collected pre-CPB, during CPB, and post-CPB. The concentrations of CGRP in the hemofiltration solution were measured. Although the CPB elevated the plasma CGRP levels in both groups, its elevation was significant in the hemodilution group when compared to the pre-CPB levels. CGRP levels returned to normal post-CPB. Significant differences were found between the two groups in the CGRP amount in hemofiltration. The results show that hemofiltration should be used during CPB to decrease the plasma levels of CGRP.     

The role of neighboring infected cattle in bovine leukemia virus transmission risk

A cohort study was conducted to evaluate the risk of bovine leukemia virus (BLV) transmission to uninfected cattle by adjacent infected cattle in 6 dairy farms. Animals were initially tested in 2010–2011 using a commercial ELISA kit. Uninfected cattle were repeatedly tested every 4 to 6 months until fall of 2012. The Cox proportional hazard model with frailty showed that uninfected cattle neighboring to infected cattle (n=53) had a significant higher risk of seroconversion than those without any infected neighbors (n=81) (hazard ratio: 12.4, P=0.001), implying that neighboring infected cattle were a significant risk factor for BLV transmission. This finding provides scientific support for animal health authorities and farmers to segregate infected cattle on farms to prevent spread of BLV.     

Sheep genetic diversity in Bhutan using microsatellite markers

Genotype data from eight microsatellite markers were used to assess genetic diversity and relationships among five indigenous Bhutanese sheep populations, Sakten, Jakar, Sarpang, Sipsu and Tsirang. Estimates of mean observed and expected heterozygosities, mean number of alleles per locus/population were obtained. The highest observed heterozygosities were found in Jakar (0.657) and Sakten (0.647), while the lowest one was found in Tsirang (0.539). Genetic distances, pairwise proportion of different alleles, UPGMA tree, and principal component analysis indicate close relationship among Tsirang, Sipsu and Sarpang populations, while Jakar and Sakten populations are located in one cluster. These two clusters are separated geographically, and show distinct phenotypic as well as molecular characters. We therefore recommend that the Bhutanese native sheep populations be classified into at least two distinct breeds, Jakar‐Sakten sheep and Sipsu sheep. Since Jakar and Sakten sheep have different morphological phenotypes, further analyses will be required to understand the genetic differences between these two sheep populations.     

Occurrence of bacterial black shoot disease of European pear in Yamagata Prefecture

Black lesions on shoots of European pear trees observed in an orchard in Yamagata Prefecture in May 2007 were suspected to be caused by a bacterial pathogen. The surface of the colonies isolated on a high sucrose medium did not have the crater morphology that is characteristic of E. amylovora bvs. 1–3, and a specific DNA fragment was amplified from the isolates in the PCR using the EprpoD primer set. The partial sequences of the 16S rRNA gene placed the isolates in the genus Erwinia. The isolates differed serologically from E. amylovora biovars and E. pyrifoliae in an Ouchterlony double-diffusion test although their bacterial properties suggested that they are closely related to E. amylovora biovars and E. pyrifoliae. In a DNA–DNA hybridization test, the relatedness between the isolates and E. amylovora biovars or E. pyrifoliae did not exceed 70% level, indicating that they are independent species. Thus, the isolates belongs to the genus Erwnia but are not E. amylovra or E. pyrifoliae. After succulent pear shoots were injected with bacterial suspensions (10⁹, 10⁸, 10⁷ and 10⁶ cfu/ml) of the isolates, lesions formed with 10⁹ and 10⁸ cfu/ml, but the disease incidence with 10⁸ cfu/ml was much lower than with E. amylovora and E. pyrifoliae. Virulence of the present isolates is thus thought to be very weak. On the basis of these results, we consider that this is a new shoot disease of European pear. In the 2007 season, all affected trees were pulled out after harvest. No symptoms have been observed in field surveys since the fruitlet season in 2007.     

Electroretinography using contact lens electrode with built-in light source in dogs

Electroretinography (ERG) is an effective method for the diagnosis of retinal disease. In the dog, dependable ERG recording is difficult without the use of an expensive device like a Ganzfeld full-field stimulator. The International Society for Clinical Electrophysiology of Vision has defined the standard flash stimulus condition (SF) and evaluation of the retina using the b/a ratio in humans. In dogs, evaluation using the b/a ratio has not been reported, whereas the intensity of SF has been defined. In this study, we performed a convenient ERG recording method using a contact lens electrode with a built-in light source (LED-electrode), and confirmed SF as reported previously. ERG recordings were performed on 15 healthy beagle dogs under sedation. We performed bilateral ERG at 12 different intensities after 30 min dark adaptation. After 10 min light adaptation, we recorded single flash cone and flicker cone response using the SF determined in this study. In this study, SF of 3.0 cd/m(2)/sec (6,000 cd/m(2), 0.5 msec) resulted in b/a=2. The intensity for rod response that recorded only the b-wave was 0.0096 cd/m(2)/sec (80 cd/m(2), 0.12 msec). We could achieve ERG for each response easily and smoothly under sedation, and without general anesthesia. Using an LED-electrode, we could perform more quantitative and reproducible ERG examinations than with traditional methods. We propose that the b/a ratio is the most useful parameter in ERG reporting for evaluating retinal function.