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Use of epidemiologic risk modeling to evaluate control of foot-and-mouth disease in southern Thailand
2008
Wongsathapornchai, K. | Salmān, Muḥammad | Edwards, J.R. | Morley, P.S. | Keefe, T.J. | Van Campen, H. | Weber, S. | Premashthira, S.
Objective--To assess the impacts of the introduction of foot-and-mouth disease (FMD) and various FMD control programs in southern Thailand. Animals--A native population of 562,910 cattle and 33,088 buffalo as well as 89,294 animals legally transported into southern Thailand. Procedures--A quantitative risk assessment was used to ascertain the probability of FMD introduction, and an intrinsic dynamic model was used to assess impacts. Value for the transmission rate (β) was estimated. Five scenarios created to assess the impacts of nonstructural protein (NSP) testing, mass vaccination, and culling were examined. Impacts were assessed through an examination of the estimated annual cumulative incidence (ACI) of FMD. The ACIs of various scenarios were compared by use of the Tukey Studentized range technique. Results--β was estimated at 0.115. Approximately 35,000 cases of FMD would be expected from the baseline situation. A 30% reduction of ACI was detected with the introduction of NSP antibody testing. Prophylactic vaccination resulted in an 85% reduction of ACI. Concurrent use of NSP antibody testing and vaccination reduced the ACI by 96%, and the addition of an eradication policy resulted in a slightly greater decrease in the ACI (98%). Conclusions and Clinical Relevance--The study used epidemiologic models to investigate FMD control interventions. Results suggested that vaccination has more impact than the use of NSP testing. Use of the NSP test reduced ACI during peak seasons, whereas vaccination diminished the underlying incidence. The best mitigation plan was an integrated and strategic use of multiple control techniques.
Show more [+] Less [-]Infection patterns of porcine reproductive and respiratory syndrome virus by serological analysis on a farm level
2008
Park, C.K. (National Veterinary Research and Quarantine Service, Anyang, Republic of Korea), E-mail: parkck@nvrqs.go.kr | Yoon, H.C. (National Veterinary Research and Quarantine Service, Anyang, Republic of Korea) | Lee, C.H. (Kyungpook National University, Daegu, Republic of Korea) | Jung, B.Y. (National Veterinary Research and Quarantine Service, Anyang, Republic of Korea) | Lee, K.K. (National Veterinary Research and Quarantine Service, Anyang, Republic of Korea) | Kim, H.S. (Chungnam National University, Daejeon, Republic of Korea)
Porcine reproductive and respiratory syndrome (PRRS) is the most economically important viral infectious disease in pig populations worldwide. This study was conducted to better understand the epidemic and dynamics of PRRS virus (PRRSV) on each farm and to evaluate the risk of PRRSV infection in Korea. Interviews with pig farmers were carried out to obtain PRRS vaccination programmes in 60 pig farms throughout Korea. Blood samples were also collected from the 59 pig farms to investigate outbreak patterns of each farm. Vaccination against PRRS was performed in 16.7% farms for breeding pigs and 8.3% of farm for nursery pigs. According to the seroepidemiological analysis, 56 (94.9%) out of 59 farms were considered to be affected by PRRSV infection. The results revealed that 68.9% of sows tested were seroconverted and interestingly, gilt herds had the highest seropositive rate (73%), suggesting that gilts may play a key role in PRRSV transmission in sow herds. Among the PRRS-affected piglet herds, 33 (55.9%), 14 (23.7%) and 6 (10.2%) farms were initially infected with PRRSV during the weaning, suckling and nursery period, respectively. It seems likely, therefore, that PRRSV infection predominantly occurs around the weaning period in piglet herds. Based on antibody seroprevalence levels in both sow and piglet groups, we were able to classify patterns of PRRSV infection per farm unit into 4 categories; category 1 (stable sow groups and non-infected piglet groups), category 2 (unstable sow groups and non-infected piglet groups), category 3 (stable sow groups and infected piglet groups), and category 4 (unstable sow groups and infected piglet groups). Our data suggested that 43 (72.9%) farms were analysed to belong to category 4, which is considered to be at high-risk for PRRS outbreak. Taken together, our information from this study will provide insight into the establishment of an effective control strategy for PRRS on the field.
Show more [+] Less [-]Эпизоотологическая ситуация по ротавирусной инфекции крупного рогатого скота в Республике Беларусь
2008
Maksimovich, V.V., Vitebsk State Academy of Veterinary Medicine (Belarus) | Yaromchik, Ya.P. | Krasochko, P.A. | Lomako, Yu.V. | Borisovets, D.S., National Academy of Sciences. Scientific and Practical Center of Animal Breding (Belarus). The S.N. Vyshelesskij Inst. of Experimental Veterinary Medicine
There was studied the epizootic conditions on cattle rotavirus infections by the analysis of veterinary reporting of diagnostic organizations of Belarus and results of own research. Results of the data analysis about spreading of cattle rotavirus infection from 2002 for 2006 are presented. The material analysis has allowed to conclude, that annually in Belarus on rotavirus infections is registered on the average about 30 unsuccessful points. The obtained data testify that lethality for the reason of rotavirus infections makes calves from 15,9 to 32,9%. Decrease, in comparison with previous years, quantities fallen for the reason of rotavirus infections of calves testifies to purposefully spent specific preventive maintenance of the given infection, however lethality at rotavirus to an infection remains practically at one level. In the tabular form results of virology research of regional veterinary laboratory on cattle rotavirus infection on corresponding areas of Belarus are presented. From the data resulted in the table it is visible, that rotavirus allocation percent in various regions of the republic made from 9,8 to 56,7% at calves sick with enteritis. | Эпизоотическую обстановку по ротавирусной инфекции крупного рогатого скота устанавливали путем анализа ветотчетности диагностических учреждений Республики Беларусь и результатов собственных исследований. Представлены результаты анализа данных о распространении ротавирусной инфекции крупного рогатого скота за период с 2002 по 2006 годы. Анализ материала позволил заключить, что ежегодно в Республике Беларусь по ротавирусной инфекции регистрируется в среднем около 30 неблагополучных пунктов. Полученные данные свидетельствуют о том, что летальность телят по причине ротавирусной инфекции составляет от 15,9 до 32,9%. Снижение, в сравнении с предыдущими годами, количества павших по причине ротавирусной инфекции телят свидетельствует о целенаправленно проводимой специфической профилактике данной инфекции, однако летальность при ротавирусной инфекции остается практически на одном уровне. В табличной форме представлены результаты вирусологических исследований областных ветлабораторий на ротавирусную инфекцию крупного рогатого скота по соответствующим областям Республики Беларусь. Из приведенных в таблице данных видно, что процент выделения ротавируса в различных областях республики составлял от 9,8 до 56,7% у обследованных больных энтеритами телят.
Show more [+] Less [-]Эпизоотическая ситуация по пастереллезу пушных зверей в звероводческих хозяйствах Республики Беларусь
2008
Birman, B.Ya. | Andrusevich, A.S., The National Academy of Sciences, Minsk (Belarus). The S.N.Vyshelesskij Inst. of Experimental Veterinary Medicine
Among bacterial infections of fur animals in beast breeding farm in Belarus pasteurellosis takes a leading place - 42,06%. Pasteurellosis of fur animals is characterized by the expressed seasonal prevalence. The greatest percent of Pasteurella allocation is registered during the autumn and spring periods. The maximum allocation is noted in October and March accordingly 18,55% and 13,21%. Infection rate with pasteurellosis depends on age of fur animals. The most susceptible is the young growth at the age from 2 till 5 months. Pasteurellosis of fur animals is most often clinically shown by symptoms of defeat of respiratory organs and has subacute and chronic current. Pathoanatomical changes at fur animals at pasteurellosis have expressed tropism to respiratory system with formation of characteristic changes without dependence from a disease current; at acute process the picture of hemorrhagic diathesis is added, at a chronic current are observed necrotic changes in a number of tissues. | Среди бактериальных инфекций пушных зверей в звероводческих хозяйствах Республики Беларусь пастереллез занимает ведущее место - 42,06%. Пастереллез пушных зверей характеризуется выраженной сезонностью. Наибольший процент выделения пастерелл регистрируется в осенний и весенний периоды. Максимальное выделение отмечено в октябре и марте соответственно 18,55% и 13,21%. Уровень заболеваемости пастереллезом зависит от возраста пушных зверей. Наиболее восприимчивым является молодняк в возрасте от 2 до 5 месяцев. У пушных зверей пастереллез наиболее часто клинически проявляется симптомами поражения органов дыхания и имеет подострое и хроническое течение. Патологоанатомические изменения у пушных зверей при пастереллезе имеют выраженный тропизм к дыхательной системе с формированием характерных изменений вне зависимости от течения заболевания; при остром процессе добавляется картина гемораггического диатеза, при хроническом течении наблюдаются некротические изменения в ряде тканей.
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