Itsuro Yamane

A survey of Theileria sergenti infection, daily weight gain and conception proportions in 85 herds of grazing heifers in Japan

A survey of Theileria sergenti infections, daily weight gain and conception proportion was conducted in 85 herds of grazing heifers in Japan. Basic information and epidemiological data from participating herds were obtained by mailed questionnaires, which were completed by field veterinarians. The average cumulative incidence and proportion of treated animals in the participating herds were 25.7 and 21.1%, respectively. The average daily weight gain and conception proportion were 0.51 kg per day and 56.9%, respectively. The basic information and epidemiological data had a large range and standard deviation, which reflect the wide diversity of the grazing herds in Japan. Herds with heavy tick infestation had significantly higher cumulative incidence and proportion of treated animals, therefore, this factor can be a good estimator to predict the occurrence and loss by theileriosis of the herds. The present questionnaire survey was useful for obtaining information about herds in different regions, and this survey method can be applied to the research of other animal diseases in Japan.

A stochastic-modeling evaluation of the foot-and-mouth-disease survey conducted after the outbreak in Miyazaki, Japan in 2000

When foot-and-mouth-disease (FMD) was identified in Miyazaki prefecture in March 2000, Japan conducted an intensive serological and clinical survey in the areas surrounding the index herd. As a result of the survey during the 21 days of the movement-restriction period, two infected herds were detected and destroyed; there were no other cases in the months that followed. To evaluate the survey used for screening the disease-control area and surveillance area, we estimated the herd-level sensitivity of the survey (HSe) through a spreadsheet model using Monte-Carlo methods. The Reed-Frost model was incorporated to simulate the spread of FMD within an infected herd. In the simulations, 4, 8 and 12 effective-contact scenarios during the 5-day period were examined. The estimated HSes of serological tests (HSeE) were 71.0, 75.3 and 76.3% under the 4, 8 and 12 contact scenarios, respectively. The sensitivity analysis showed that increasing the number of contacts beyond 12 did not improve HSeE, but increasing the number of sampled animals and delaying the dates of sampling did raise HSeEs. Small herd size in the outbreak area (>80% of herds have <20 animals) seems to have helped in maintaining HSeE relatively high, although the serological inspection was carried out before sero-positive animals had a chance to increase in infected herds. The estimated herd-level specificity of serological tests (HSpE) was 98.6%. This HSpE predicted 224 false-positive herds (5th percentile estimate was 200 and 95th percentile was 249), which proved close to the 232 false-positive herds actually observed. The combined-test herd-level sensitivity (serological and clinical inspections combined; CTHSe), averaged 85.5, 87.6 and 88.1% for the 4, 8 and 12 contact scenarios, respectively. Using these CTHSes, the calculated probability that no infected herd was overlooked by the survey was > or =62.5% under the most-conservative, four-contact scenario. The probability that no more than one infected herd was overlooked was > or =89.7%.

Cross-Sectional Survey of Ixodid Tick Species on Grazing Cattle in Japan

Ixodid tick species were collected from cattle in 60 grazing fields throughout Japan. Haemaphysalis longicornis was mainly recovered in the western and southern regions, while Ixodes species were collected mainly in the central to northern regions. Other tick species such as Amblyomma testudinarium, Boophilus microplus, H. flava and H. kitaokai were identified from a few fields in the central and southern regions. Haemaphysalis longicornis were recovered in the fields with higher temperatures and annual rainfall, whereas I. ovatus and I. persulcatus were collected in fields with lower temperatures and annual rainfall. Some of these tick species are capable of transmitting pathogens harmful to cattle and humans, so proper control strategies are required.

Impact of a porcine epidemic diarrhea outbreak on swine productivity in Japan: a retrospective cohort study

The objective was to investigate porcine epidemic diarrhea (PED) outbreak that occurred in 2014 in Japan and its effects on herd-level productivity using a data recording system (PigINFO). The study herds were selected from farrow-to-finish herds (n=99) that entered in the PigINFO system between July 2013 and March 2015. From 1 April to 30 June 2014 (PED epidemic), any herds with clinical signs of PED and feces positive for porcine epidemic diarrhea virus (PEDV) on polymerase chain reaction analysis and/or immunohistochemical staining were defined as PED-positive (n=38). They were further classified into those with long PED periods (L-PED-positive; n=28) and those with short PED periods (S-PED-positive; n=10). Herds with no clinical signs of PED were classified as PED-negative (n=61). Herd-level production data, including preweaning mortality (%; PRWM), postweaning mortality (%; POWM), pigs weaned per litter (PWL), pigs born alive per litter, litters per mated female per year and pigs marketed per sow (MP), were calculated every 3 months during study period. During the PED epidemic, L-PED-positive herds had significantly higher PRWM and POWM than PED-negative herds, and L-PED-positive and S-PED-positive herds had significantly lower PWL. During October–December 2014, L-PED-positive herds had significantly fewer MP than PED-negative herds. The PED outbreak increased mortality and consequently reduced the numbers of marketed pigs. The rapid control of an outbreak is important for reducing the financial losses arising from PED infections.

Aujeszky's disease and the effects of infection on Japanese swine herd productivity: a cross-sectional study

Pseudorabies virus (PRV) is endemic in some regions of Japan. We investigated the effects of PRV infection status on herd productivity. Serum samples were obtained from 48 swine herds in Japan. Within each herd, three serum samples were obtained from growing pigs at four different ages, as well as from sows in low and high parity groups. Sera were tested for antibodies against wild-type PRV via competitive ELISA. Herds were classified into PRV positive and negative groups based on serological results. Herds infected with PRV exhibited postweaning mortalities (6.84%) that were significantly (P=0.0018) higher than those in unaffected herds (4.73%). Because of the reduced productivity in PRV positive herds, the current PRV eradication program must be strengthened.

An Evaluation of the Economical Losses Due to PRRS Outbreaks in Large-scale Swine Farms

豚繁殖・呼吸器障害症候群（以下PRRS）は，雌豚の繁殖障害と子豚の呼吸器症状を伴う疾病である。PRRSは全国の養豚場で大きな問題となっているが，その経済的な損失について調べた報告は少ない。そこで，関東地域の養豚場3戸を対象に，PRRSの発生に伴う経済的な損失について検討を行った。

Effects of the Environmental Improvements and Probiotic Supplement on Productivities of Weaned Pigs

茨城県内の離乳後死亡率の高い農家(母豚 140頭,一貫 経営)を試験対象とした。2010年 10月中に生まれた子豚(n =140)を離乳時の体重に応じて 4群(重,中,軽,極軽) に分け,下記の 4つの処置群(n=35×4群)をランダム に割り振った。 A 豚舎全体を清掃・消毒し(清掃群),飼料に生菌剤 Lactobacillus casei I-5(1%)を添加 B 豚舎全体を清掃・消毒し(清掃群),通常の飼料を 投与 C 従来通りの豚舎で(従来群),飼料に生菌剤(1%) を添加 D 従来通りの豚舎で(従来群),通常の飼料を投与 対象豚の健康状態を観察し,体重を 1週毎に離乳後 9週 齢まで測定した。また唾液を離乳直後,離乳舎移動後 1週 間,同 4週間および肥育舎移動(離乳舎移動後 6-7週間後) 直後に個体ごとに採取し,唾液中のストレス指標(コルチ ゾール)を測定した。清掃群,従来群の畜舎内のメタン, アンモニア,二酸化炭素,一酸化二窒素,エアロゾル,空 中浮遊一般細菌を継続的に測定した。以上の結果を清掃群・ 従来群,生菌剤投与群・非投与群,性別(去勢雄・雌), 離乳時体重などの要因に分けて解析した。

Evaluation of the Environmental Factors, Stress Markers and Economical Losses in a Swine Farm with High Mortality Rate

茨城県内の1養豚農家においては，呼吸器病や下痢による高い死亡率による損耗が大きな問題となっていた。当農家では，木造開放式の比較的環境の良い離乳期育成舎（以下育成舎A）と，糞尿処理能力が十分でないコンクリート製の離乳期育成舎（以下育成舎B）を有していた。今回当該農家の育成豚の追跡調査を行い，異なる育成舎の空気環境やそこで飼養される育成豚にかかるストレスや生産性について調査を行い，得られた結果より死亡事故による経済的損失の算出を試みた。